SUMMER TRAINING REPORT

ON

Networking In Organization

BY

VISHEKHA CHATURVEDI

2007- 2008

IN PARTIAL FULFILLMENT OF

MASTER OF BUSINESS ADMINISTRATION DEGREE

Of

Chhattisgarh Swami Vivekanand Technical University

Bhilai (C.G.)
Session 2010-12

------------------------------------------------------------------------------------------------------------
DISHA INSTITUTE OF MANAGEMENT AND TECHNOLOGY
(Disha Education Society)
Satya Vihar, Vidhansabha-Chandrakhuri Marg, Mandir Hasaud,
Raipur (C.G.) 492007
Certificate frm the company
 CERTIFICATE

This is to certify that Miss VISHEKHA CHATURVEDI Of

DIMAT, MBA Semester II has successfully completed the
summer training in partial fulfillment of requirement for the
award of MBA Degree prescribed by the Chhattisgarh
Swami Vivekananda Technical University, Bhilai.

This report is the record of authentic work carried out by the

student during the academic year 2007-08.

Prof. Anup Kumar Ghosh Dr. S.N .Singh

Internal Guide Director
 DECLARATION
I, Vishekha Chaturvedi hereby declare that this report is the
record of authentic work carried out by me during the
academic year 2007-2008 in Software Technology Parks of
India (STPI), Nehru Nagar, Bhilai, Chhattisgarh.

Vishekha Chaturvedi
DIMAT
MBA II A
 ACKNOWLEDGEMENT

First of all I would like to place on record my gratitude to all concerned

respectable people in SOFTWARE TECHNOLOGY PARKS OF INDIA (STPI),
BHILAI for giving me this opportunity of internship which has been a pure
learning experience and which have enlightened my knowledge and skills about
networking setup for Organizations.

I would also like to express my gratitude towards the Disha Institute Of

Management and Technology for giving me the opportunity to undergo Summer
internship at STPI, Bhilai.

I am especially thankful to my internal guide Prof Anup Kumar Ghosh ,faculty of

management ,DIMAT and external guide Mr.Umesh Choubey, member of STPI,
for guidance and cooperation during this internship and in fact without their
navigational assistance life would have been very difficult as far as structuring
the projects are concerned. I would be always grateful to them for their help and
support.

Vishekha Chaturvedi
DIMAT
MBA II A
 Table Of Contents
S.No Particulars Pg No.
ABSTRACT
LIST OF ABBREVIATIONS USED
LIST OF TABLES
LIST OF FIGURES
1 CHAPTER 1: INTRODUCTION
1.1 ABOUT STPI
1.2 Future Plans of STPI
1.3 Soft NET: (Data Communication Network)
1.4 STPI SCHEME
1.5 Soft POINT: (International Leased Line)
1.6 Soft Link: (Shared Internet Connection)
1.7 Infrastructure
1.8 Objectives
2 CHAPTER 2 SCOPE OF WORK & METHODOLOGY
2.1 Scope of Work
2.1.1 Basic Networking Concepts
2.1.2 Connection
2.1.3 Need of an Organization
2.2 Methodology
3 CHAPTER 3: OVERVIEW OF THE PROJECT
3.1 Networking in Organization
3.2 Office Network Design Strategies
3.3 Networking Concepts
3.3.1 What is Computer Networking?
3.3.2 Networking Basics
4 CHAPTER 4: OBSERVATIONS AND FINDINGS
4.1 Need Of Networking in Organization
4.2 Network Design
5 CHAPTER 5: RECOMMENDATIONS
6 CHAPTER 6 CONCLUSION AND FUTURE SCOPE OF WORK
7 APPENDICES
8 BIBLIOGRAPHY
 LIST OF ABBREVIATIONS USED
1. STPI-Software Tech Parks of India
2. IT-Information Technology
3. VPN-Virtual Private Network
4. VSAT-Very Small Aperture Terminal
5. UTM-Unified Threat Management
6. ATM-Asynchronous Transfer Mode
7. ISP-Internet Service Provider
8. ISDN-Integrated Service Digital Network
9. DNS-Domain Name Server
10. DHCP-Dynamic Host Configuration Protocol
11. LAN-Local Area Network
12. WAN-Wide Area Network
13. MAN-Metropolitan Area Network
14. WWW-World Wide Web
15. FTP-File Transfer Protocol
16. OSI-Open Systems Interconnection
17. MAU-Media Attachment Unit
18. NIC-Network Interface Card
19. URL-Uniform Resource Locator
20. P2P-Peer to Peer
21. TCP/IP-Transmission Control Protocol/Internet Protocol
22. IANA-Internet Assigned Numbers Authority
23. ICANN-Internet Corporation for Assigned Names and Numbers
24. MAC-Media Access Control
25. NFS-Network File System
26. CIFS- Common Internet File System
27. QOS-Quality Of Service
28. NAT-Network Address Translation
29. NAS-Network Attached Storage/Server
30. CAT5-Category 5
31. CBR-Constant Bit Rate
32. ABR-Available Bit Rate
33. VBR-Variable Bit Rate
34. UBR-Unspecified Bit Rate
35. VOIP-Voice Over Internet Protocol
36. OFC-Optical Fibre cable
37. RFT-Receiver Frequency Transmitter
38. SSPA-Soli state Power Amplifier
39. EMR-Edge Media Router
40. LNB-Low Noise Block
41. LNA-Low Noise Amplifier
42. UDP-User Datagram Protocol
43. SNMP-Simple Network Management Protocol
44. SMTP-Simple Mail Transfer Protocol
45. RADIUS- Remote Authentication Dial In User Service
46. POP3-Post Office Protocol 3
47. RIP-Routing Information Protocol
48. BGP-Border Gateway Protocol
49. OSPF-Open Shortest Path First
50. HTTP-Hyper Text Transfer Protocol

List Of Figures Used

Figure 1: STPIs Antenna
Figure 2: STPI providing technical support
Figure 3: showing earth connected by a cable
Figure 4: Basic LAN Topology
Figure 5: WAN Network
Figure 6: Leased line to an organization
Figure 7: OSI layer functions
Figure 8:
Figure 9:
Figure 10:
Figure 11:
Figure 12:
Figure 13:
Figure 14:
Figure 15:
Figure 16:
Figure 17:
Figure 18:
Figure 19:
Figure 20:
Figure 21:
Figure 22:
Figure 23:
Figure 24:
Figure 25:
Figure 26:
Figure 27:
Figure 28:
Figure 29:
Figure 30:
Figure 31:
Figure 32:
Figure 33:
Figure 34:
Figure 35:
Figure 36:
Figure 37:
Figure 38:
Figure 39:
Figure 40:
Figure 1:
Figure1:
Figure1:
Figure1:
Figure1:
Figure1:
Figure1:
Figure1:
Figure1:
Figure1:
 Figure1:
Figure1:
Figure1:

Abstract
Information and communication are two of the most important strategic
issues for the success of every enterprise. While today nearly every organization
uses a substantial number of computers and communication tools, but they are
still isolated. While managers today are able to use the newest applications,
many departments still do not communicate and much needed information
cannot be readily accessed. In any organization, whether it is large or small, it
needs to communicate with each other so that it may be able to function well and
be able to reach the goal of the organization itself.
To overcome these obstacles an effective usage of information technology is
required, and computer networks are necessary. Only with the help of computer
networks a borderless communication and information environment can be built.

The immediate objective of this research project is to understand the basics of

networking, need of computer networks for any big or small organization. So that
an advanced network setup can be developed .This would satisfy the basic
needs of communication and information sharing.

This study was an exploratory research to gain a deeper understanding of

networking needs of any organization. For this purpose many literature were
reviewed. Many advanced networking equipments were studied, tried to
understand as how networks are established with best possible devices available
in market.

This summer a computer network setup is designed to cope up the difficulty of

effective usage of information technology which would satisfy the need of cost
reduction by sharing hardware and software resources, high reliability by having
multiple sources of supply, cost reduction by downsizing to microcomputer-based
networks instead of using mainframes, greater flexibility because of possibility to
connect devices from various vendors.

The research showed that networks with Ethernet cables predominated in

businesses, schools, and homes for several decades. Recently, however,
wireless networking alternatives have emerged as the premier technology for
building new computer networks. And thus, there is a great scope for wireless
technology in future.

Keeping costs in check is an important consideration when developing business

networks. To balance this with the necessity to actually implement a network
which will meet the current and foreseeable needs is the role of the network
designer.
Because of the importance of this technology, decisions of purchase, structure,
and operation of computer networks cannot be left to technical staff.
Management as well has a critical need for understanding the technology of
computer networks.
Businesses use their computer networks to organize their assets, inventory,
finances, communications, customer records, and operations. The network, and
the systems attached to it are important, and like any business, keeping costs
under control is crucial.
Business class networks are a step up in complexity over residential networks.
The requirements of any business network are more or less as follows: Reliable,
Maintainable, Performance, Feature Complete, Affordable.
As IT is growing there is increased number of attacks on corporate information
systems a hacking / cracking, viruses, worms - mostly an outcome of blended
threats and insider threats. Data security and unauthorized employee access
have become major business concerns for enterprises today. This is because
malicious intent and the resultant loss of confidential data can lead to huge
financial losses as well as corresponding legal liabilities. To solve this problem
systems like SAP and ERP are maintained in the organization. Also special
devices like Unified Threat Management which is a combination of applications
like Antivirus, Anti spam & Intrusion Detection Systems is used.

Chapter 1: Introduction

1.1 About STPI

Software Technology Parks of India is a chain of Government of India owned
Technology facilitator institutions. The entire India is divided into zones where a
regional STPI takes control of the units, companies and export oriented IT
institutions, providing them with High-speed data carrying circuits on lease, apart
from other Info-Tech backbone services such as server co-location, VPN.
Solutions , gateway, services, etc.

Software Technology Parks of India has been set up by the Ministry of

Information Technology, Government of India, in 1991, with the objective of
encouraging, promoting and boosting software exports from India. Its services
cover network design, system integration, installation, operations and
 maintenance of application networks and facilities in varied areas ranging from
VSATs to ATM based networks.

STPIs objective is to provide effective data communication facilities to software

exporters and the society has established its own gateways at its nodal centers
located in different parts of the country. These gateways are integrated with the
line of sight point to multipoint digital
equipment.
STPIs soft Link is the TCP/IP based
shared internet service that uses its
own International gateways for the
upstream connectivity. The TCP/IP
service is called Shared Internet as
the upstream bandwidth is shared
among the users.

1.2 Future Plans of

STPI
I. Setting Up New STPs:

So far the larger cities have the benefit of better infrastructure and have a major
role in software exports from the country. Off late, a large number of units in the IT
enables services sector have been set up in India. Smaller cities, which have the
advantage of lower costs, can play a major role in this sector. Most ISPs are not
setting up communication infrastructure at secondary locations because of
commercial considerations. STPI has plans to set up additional STP centres with
centre/state Government support at secondary locations, which will contribute to
the export of IT services.

II. Fiber Landing Station By STPI:

The availability of bandwidth through Satellite is not very high. DOT has recently
announced the landing policy of submarine cable. It is felt that few submarine fibre
cable are likely to land in Chennai, Mumbai, Cochin and Vizag. STPI is already
providing the data communication through its satellite earth stations. Due to the
growth of IT software export segment, the software companies also need
bandwidth through fibre. Some of the companies, that are doing mission critical
applications like call centre operation, security services, etc require fiber to avoid

Fig 1:STPIs Antenna

 transition delay inherent in satellite link. STPI is planning to setup a landing station,
in order to meet these requirements.

III. Export Promotion:

At present, the major share of software exports market is in Europe and US. The
smaller companies are unable to garner market share due to lack of market
knowledge and ability to leverage their abilities in spite of inherent skills in product
development and management. Such a situation, if continued, could confine them
to very low growth rates for future. Accordingly, STPI plans to increase its focus as
business promotion through increased participation in Exhibitions, Trade Fairs and
Delegations etc for the SME sector.

1.3 Soft NET: (Data Communication Network)

One of the objective of Software Technology Parks Of India is to provide effective

data communication facility to the esteemed software exporters and the IT
enabled services specially true in emerging areas like software maintenance,
application re-engineering, remote computing and executing off shore projects,
etc which involve interactive applications recognizing the importance HSDC
facilities providing global connectivity at all over India. In persuasion of this
objective the STPI established its own gateways at its nodal centres located in
different parts of the country. STPI names the Data Communication Network
owned by it as soft NET.

Bhilai : STPI centre has been providing the High Speed Data communication
facilities to the IT industry through the international gateway with scalable
configuration is setup in Bhilai. The location of the earth station is such that it is
in the line of sight from most of the locations in Bhilai as from various other
locations with a radius of 30 kms from the station. These gateways are
integrated with the line of sight point-to-multipoint equipment for connecting the
user premises located outside the complex by means of microwave links.

The customers premises in India will be connected to their client located abroad
by gateway which will be located at Bhilai through a radio link using either point
or point to multi point radio link. This will facilitate any company operating in India
or abroad connected to Internet, and to access soft NET.

1.4 STPI SCHEME

The Software Technology Park (STP) scheme is a 100% export oriented scheme
for the development and export of computer software using data communication
links or in the form of physical media including the export of professional services.
The major attraction of this scheme is single point contact service to the STP units.

HIGHLIGHTS
o Approvals are given under single window clearance scheme.
o An STP project may be set up anywhere in India.
o Director STP is empowered to approve projects with an investment of Rs.100 million ($
2.5 million).
o 100% foreign equity is permitted and is approved under the automatic route delegated
powers to the Director STPI.
o Simplified minimum exports performance norms i.e. US $0.25 million or 3 times CIF
value of imported goods whichever is higher and positive Net Foreign Exchange Earning
against Export Earnings.
o Use of the Computer System for commercial training purpose is permissible subject to
the condition that no computer terminals are installed outside the STP premises.
o The sales in the Domestic Tariff Area (DTA) shall be permissible up to 50 % of the export
value terms.
o STP units are exempted from payment of corporate income tax up to 2010.
o The capital goods purchased from the Domestic Tariff Area (DTA) are entitled for the
benefits like levy of excise Duty and Reimbursement of Central Sales Tax (CST).
o Domestic project will not attract any local levies.
o Repartition of foreign currency for payment can be freely done.

1.5 Soft POINT: (International Leased Line)

Soft POINT (International Digital Private Leased Lines) offers POINT-TO POINT
International Leased HIGH SPEED DATA Communication links of 64 KBPS up to
2 MBPS. The customer premises in India will be connected to their client located
abroad by gateway which will be located at Dehradun through a radio link using
either the point to point to multi point radio (TDMA) link. SoftPOINT services act
as the lifeline for business applications in global enterprise networking and
building virtual organization.

Features:
64 Kbps to 45 Mbps or higher.
One stop shop arrangements with many carriers for ordering or Billing.
Resilient International routes and partners.
Customers Interface: V.35, X.21, G.703.
End to End management up to the customers using strong Network monitoring.
 The services will be available round the clock and charges will be fixed
irrespective of the time and volume of data transferred by the user.

1.6 Soft Link: (Shared Internet Connection)

SOFT LINK is the TCP/IP based shared internet connection which uses its own
International Gateway for the upstream connectivity. At present STPI backbone is
connected through many service providers like Teleglobe, AT&T, Thaicom etc. to
provide load balancing and fully redundant services.

The TCP/IP service is called shared internet as the upstream bandwidth is

shared among the users. The user connected on the service has access to the
complete internet services available worldwide such as:
E-Mail
FTP-File Transfer Protocol
Remote Login
WWW(World Wide Web )
Usenet
Database access

Availing access and setting up the connection to SOFT LINK

How to access the SOFT LINK?
SOFT LINK will be managed through a wide area network plan and you will get
connected to the network. You will get a port on the Ethernet Hub which will be
located in the LAN. The LAN will be further connected to the International Gateway
and managed from network Dehradun Control Centre which will be located at
STPI- Dehradun. The LAN setup will be directly connected to the International
Gateway through a UTP backbone, whereas the LANs in different locations will be
connected to the International Gateway via a microwave link.

You can locate your unit anywhere outside in the city. STPI- Dehradun will provide
point-point or point-multipoint radio link up to the ROUTER at your premises.
a) Leased Internet Access on Radio Local Loops:
Microwave radio connection of the desired bandwidth is set up from
customers premises to the International Gateways of STPI. These links
are installed and maintained by STPI itself and the customer has to pay
just one time installation charge. The data rate options for the Leased
Internet Service on Radio are n x.
b) Leased Internet Access on Dot Local Loop:
 A wired n x 64k is hired form DOT for the customers. The customer will
need to hire a lease line, of the required data rate, from Dot and will pay
for the installation and annual lease access for the local loop. STPI will
provide port access on its router and will charge for the same.
c) Leased Internet Access Using ISDN Lines:
Those who wished to use their ISDN lines for Internet access can use this
facility. Customer will have to pay for an additional ISDN line at STPI as
the line has to be used in dedicated made. Service is presently available
for ISDN BRI and leased connection is for 64kbps or 128 kbps.

Dial-up Internet Access

In dial-up access, a
connection is established
between the access and
the STPI network on
dialing the specific
number(s) by the
authorized subscribers.
A dial up access is
offered with the
following options:
Dial-up Internet Access Using ISDN lines:
This is for those who wish to use a digital access for Internet and for limited access
period. This service is run in shared mode.
Dial-up Internet Access PSTN lines:
This is the dial-up internet access on PSTN lines and is available in limited
locations only.
1.7 INFRASTRUCTURE
INCUBATION
Business and Technology incubation catalyzes the process of starting and growing
companies. It provides entrepreneurs with the expertise, networks & tools they need to
make their ventures successful. As an incubator we will nurture young firms, helping
them to survive & grow during the startup period when they are most vulnerable. We
would provide to entrepreneurial firms a shared office services, access to equipment ,
flexible lease and expandable space; all under one roof.
As an incubator, we plan to provide our services in the following areas:
1. Full service Office Facilities
2. Web hosting services
3. Business plan development

Fig 2: STPI providing technical

support
Strength of STPI to act as an Incubator:-
Technical Support:
STPI has got in house expertise, most of the latest
technologies details & machinery, most of the latest
technological details & machinery which would support
technical development. Software Policy and
Legal Advice:
STPI has been giving consultancy in Data Com,
Software Export, facilities/ provisions, and setting up of
STPI units and related services.
Quality Certification:
As STPI is an ISO9002 company, so undoubtedly
quality will be maintained at all levels.
Maintenance and Repairs:
Our highly technical staff and 24 hr. helpdesk shows
commitment to provide efficient services by which the
entrepreneur will be benefited. Infrastructure Support
(Back Bone) : STPI has got strong backup of all related facilities which are required
for an upcoming organization in Software export such as LAN, ISP, Power back-
ups etc.

1.8 OBJECTIVES

The purpose behind the research was to understand the basics

of computer networking.

The research was carried out to understand networking in

organization.

To know the basic networking need of an organization.

The research was also conducted to learn designing a network

setup.
Chapter 2: Scope of Work And Methodology

2.1 Scope of Work

The assessment covered the following aspects:

2.1.1 Basic Networking Concepts: Before starting the main topic

of Computer Networking In Organization, the basic concepts of
networking was studied and their working was understood.

2.1.2 Connection: Learned how devices are connected and network is

setup.

2.1.3 Need of an Organization: Basic computer networking needs

of organization were studied.

2.2 Methodology
2.2.1 Research Type: This is an exploratory research.
This genre of research simply allows the marketer to gain a greater
understanding of something that he/she doesnt know enough
about. For example, just because we know that 3G phones exist, it
doesnt necessarily mean that we understand how they work.
Similarly we all are a part of computer networks but we do not know
the working.
Exploratory research can help in this instance. Differing mainly in
design from descriptive research, exploratory research is used
principally to gain a deeper understanding of something. The
design is far more flexible and dynamic than that of descriptive
research.
2.2.2 Sources of Data: There are two sources of data used any
research. The first one is Primary source: and the second is
Secondary source.

The primary source consists of questionnaires, personal

interviews and observations.
The secondary source consists of internet, magazines, and
journals.
.
2.2.3 Sampling Design: Convenience sampling was adopted.
Organizations which were convenient to approach were included.

2.2.4 Data Collection tools/instruments: Personal Interview.

Internet and Study material.

2.2.5 Methods of data collection: For Primary data, Personal

interviews were conducted with the system administrator in 5 different
organizations.
And Secondary data was collected through internet and books.
 Chapter 3: Overview of the Project

3.1 Networking In Organization

.
Information and communication are two of the most important strategic issues
for the success of every enterprise. While today nearly every organization uses a
substantial number of computers and communication tools (telephones, fax,
personal handheld devices), but they are still isolated. While managers today are
able to use the newest applications, many departments still do not communicate
and much needed information cannot be readily accessed.

To overcome these obstacles an effective usage of information technology is

required, thus, computer networks are necessary. They are a new kind (one might
call it paradigm) of organization of computer systems produced by the need to
merge computers and communications. At the same time they are the means to
converge the two areas; the unnecessary distinction between tools to process and
store information and tools to collect and transport information can disappear.

Computer networks can manage to put down the barriers between information held
on several (not only computer) systems. Only with the help of computer networks a
borderless communication (Borderless Networks deliver the new workspace
experience, connecting anyone, anywhere, using any device, to any resource
securely, reliably, seamlessly) and information environment can be built.

Computer networks allow the user to access remote programs and remote
databases either of the same organization or from other enterprises or public
sources. Computer networks provide communication possibilities faster than other
facilities. Because of these optimal information and communication possibilities,
computer networks may increase the organizational learning rate, which many
authors declare as the only fundamental advantage in competition.

Besides this major reason why any organization should not fail to have a computer
network, there are other reasons as well:
cost reduction by sharing hard- and software resources
high reliability by having multiple sources of supply
cost reduction by downsizing to microcomputer-based networks instead of
using mainframes
greater flexibility because of possibility to connect devices from various
vendors
Because of the importance of this technology, decisions of purchase, structure,
and operation of computer networks cannot be left to technical staff. Management
as well has a critical need for understanding the technology of computer networks.
Businesses use their computer networks to organize their assets, inventory,
finances, communications, customer records, and operations. The network, and
the systems attached to it are important, and like any business, keeping costs
under control is crucial.
Business class networks are a step up in complexity over residential networks. The
requirements of any business network are more or less as follows:
Reliable
Maintainable
Performance
Feature Complete
Affordable

Since all the requirements in some way impact the bottom line of the business, it is
worth taking some time on how these requirements impact the design and what
they mean.
1. A Reliable Network
A simple rule of thumb for reliability is, the more reliable, the more expensive. Also,
there is no such thing as a 100% reliable design.
What's left is a trade-off between reliability and costs.
From an office perspective, hardware decisions should look at characteristics like
warranty, peer review, environmental durability and mean time to failure. Complex
features such as redundancy and remote administration is also important and very
much needed.
If there is a power outage then system must be able to recover itself.

2. A Maintainable Network
Since 100% reliability is impossible, eventually maintenance will be necessary.
Either a technician will be called in to handle maintenance when it is required, or
office staff will handle the situation. Situations that resolve without the necessity
for a technician are less expensive; therefore network designs where the majority
of the network faults can be handled by the people onsite are preferable.
Although maintainability is difficult to quantify, there are some characteristics of
maintainable networks to take into consideration:
Minimized failure points
Failure Indicators
Network Maps
Clean Wiring
Consider the following circumstance with a maintainable network. A single
computer on a wired network is unable to connect since the cable from the patch
panel to the Ethernet switch has come loose.
From glancing at a network map and looking at the connectivity lights at a
centralized switch it becomes apparent that the physical connection between the
switch and the computer has been broken. Reconnecting the loose patch cable will
fix the problem, and was easy to spot.
The same situation with an unmaintainable network might involve tracking down
the series of connections tying the computer to the network and identifying which
one has become loose. This could take hours in the worst case and require
disconnecting other machines in the process of trying to find the right one.
Designing for maintainability is important if avoiding disruption during service calls
is important.
Designing for maintainability is critical to the long term costs of having a network.

3. Network Performance
Most offices favor functionality over performance when it comes to their computer
networks. However that doesn't mean that the topic should be ignored when
considering the design for the network.
The highest level of performance and reliability is available through the use of
wired network technologies. This will remain the case for the foreseeable future,
however wireless technology has experienced a marked boost in performance and
reliability with the advent of the 802.11n amendment to the wifi standard.
Small offices which are interested in maximizing the performance of their network
should look to use gigabit wired network technologies, routed through a single
gigabit Ethernet switch. Additional performance can be achieved by switching the
MTU (Maximum Transmission Size) of data on the network to 9k bytes up from the
old standard of 1500 bytes. This is achieved by reducing the effective overhead of
transmitting data on the network. Check for jumbo frame compatibility on any
connected wired hardware before deploying this strategy.

4. A Feature Complete Network

Unless office networks are well designed, they can be difficult to upgrade. For
instance, a business network which has most of its routing configuration stored in
the router with no way to export the configuration to a different machine will be
harder to take down and replace than a device which can export its configuration.
Sometimes a new feature is required after the network has already been built, only
to discover that the current system cannot handle the new feature. One example
may be DHCP static allocation, which is a feature that is not uniformly available
across commodity routers. Another example is VPN support; a feature highly in
demand for those on the road or with a home office trying to tie into work.
Designing a network that can accommodate future necessities can be challenging,
especially when dealing with commodity hardware, however there are variety of
router appliances which can make these challenges much less cumbersome.
Examples of these appliances are pfSense, m0n0wall, freenas, smoothwall and
others.
Determining whether router appliances are necessary is a useful exercise since it
helps specify the networks feature requirements.

5. An Affordable Network
The cost to build, maintain, and extend a computer network is the true deciding
factor for most if not all business. Commodity components may be affordable from
an upfront perspective, undesirable from a reliability perspective and completely
pointless from a maintenance, or feature perspective.

The costs that comprise working on a new network design are as follows:
Design
Installation
Maintenance
Designing a network takes into account the logical and physical topology, the
performance requirements, hardware, cable requirements (outdoor, indoor).
Installation examines how long, and what will be necessary to implement the
design. The maintenance cost deals with what will be involved in ensuring the
network continues to function over time.
Upfront design costs can seem fairly intimidating; however it is important to
consider the long term benefit of having a well designed office network. Downtime
is minimized, maintenance is straightforward when necessary, the network
generally performs well.
3.2 Office Network Design Strategies
Keeping costs in check is an important consideration when developing business
networks. Small businesses by their nature do not have large amounts of
resources to devote to business infrastructure. To balance this with the necessity to
actually implement a network which will meet the current and foreseeable needs is
the role of the network designer.

Hardware
Some hardware components are straightforward to replace such as switches,
patch cables and to a lesser extent, routers. This contrasts to in-wall cabling,
keystone jacks, cable tracks and any other fixed device or installation.
It is a good practice to use high-quality components for any hard to reach parts that
will need to remain functional and compatible. Using Cat6 over Cat5e cable for in-
wall cable drops is a good example of this; another example is using shielded
keystones rather than the unshielded alternatives. Even though a business may
not initially require high-speed components, it is a useful strategy to future-proof
the implementation by using materials capable handling future technologies.

Services
Keep services centralized as much as possible. Relying on user desktops to
provide services to the network will eventually result in business downtime during
reboots or other maintenance. Setting up a small business server which runs file-
sharing, backups, CRM, financial and other business applications makes
managing a network simpler.
Network related services such as local DNS, DHCP and routing can generally be
provided by a single machine such as a commodity router

Topology
Small network planning does not require much effort on the logical topology,
beyond some basic analysis of which services need to be available and how they
will be controlled. On the other hand, a well executed physical topology plan is very
useful since it gives a clear map of how the network works.
Plan on creating a port map which shows where each component is connected and
how the connections map out to locations on the network.

At the end of the day, the challenge of designing an organizations network is

finding that balance point between reliability, maintainability and cost. The limiting
factor, as always, is the projects budget.
3.3 Networking Concepts
3.3.1 What is Computer Networking?

Computer Networking is basically the process of connecting two or more

computers or devices, using hardware and software, so that data can be
transferred and shared between them.
There are different types of networking, for instance there are LANs (local area
networks) and WANs (wide area networks). The difference between these two
lies in their spans. LANs are restricted to small areas, typically homes, whereas
WANs are widely spread and can reach across cities, countries or even
continents.
Networks may also be different in their design and layout. There are client/server
networks and peer-to-peer networks. Client/server networks tend to be
centralized with most functions being supported by the central/main system.
Peer-to-peer networks consist of computers which all support the same functions
and can interact with each other.
This being understood, client/server networks work well within businesses
whereas peer-to-peer is better suited to home use.

Layouts can be the different ways in which a network is arranged to share data.
Bus, ring, star, mesh is all different layouts. It all depends on how information is
to travel through the network, if the data is expected to go through all the
systems then bus network is suitable but if data is to be sent to single units
separately then star networks or mesh networks might be better suited.

Networks are all about communication, as such there is a communication

standard which is implemented by protocols, which are like rules for the
operation of the network. There may be many protocols used by a network at one
time, for instance, TCP/IP, the most common protocol found on the Internet and
in home networks.

Networks can be wired or wireless. Most protocols for wired networks are also
supported by wireless networks. Wired networks have been around for a long
time as compared to wireless ones. But with advancements in technology
wireless networks are fast becoming more reliable and common.
III.3.2 Networking basics
1) Internet:
The Internet is a global system of interconnected
computer that use the standard Internet Protocol
Suite (TCP/IP) to serve billions of users worldwide. It
is a network of networks that consists of millions of
private, public, academic, business, and government
networks, of local to global scope, that are linked by
a broad array of electronic, wireless and optical
networking technologies. The Internet can also be
defined as a worldwide interconnection of computers
and computer networks that facilitate the sharing or
exchange of information among users. The Internet
carries a vast range of information resources and
services, such as the inter-
Fig 3: showing earth
linked hypertext documents of the World Wide connected by a cable
Web (WWW) and the infrastructure to
support electronic mail.

General information about the Internet:

The Internet is explored, aka surfed, using a computer browser.
Finding information on the Internet is achieved by using a search engine.
Users browse web pages by following hyperlinks.
Besides browsing web pages, the Internet is also a popular method of
communicating with others through online web forums, chat rooms, e-
mails, and instant messages. In addition to communicating, users also use
the Internet to share files, pictures, songs, and video over the Internet.
2) Intranet:
A basic definition of Intranet an Intranet can be viewed as a small Internet which
resides on company or private LANs or local area networks. Intranets can be
designed and built to suit the needs of all companies or home users, big or small,
basic or complex, as in many large corporations which are used to encompass
everything from Human Resources information, to Payroll, to service desks to
projects.

What's the difference between intranet and internet?

The Internet is quite literally open to everyone with an internet connection,
an Intranet usually resides on a LAN or local area network, and as such is
totally separate from the Internet.
Intranets operate in a secure area and their content can only be seen by
people within the this LAN or secure area.The purpose of an Intranet is to
store any information which can be shared amongst.
Security on the internet is primarily on the web server itself, as opposed to
security on Intranets which can be both web server security or integrated
into domain security.
Corporate networks generally force you to use proxy servers to connect to
the Internet, but not to the Intranet.
Generally an Intranet will be faster than the Intranet, due to local servers
and less users.

Similarities between Intranet and Internet:

Both the Intranet and Internet operate on the same technologies, primarily
HTML (Hyper Text Markup Language) and TCP/IP (Transmission Control
Protocol / Internet Protocol).Both are there to collectively share
information.
3) LAN:
A local area network (LAN) supplies networking capability to a group of
computers in close proximity to each other such as in an office building, a school,
or a home. A LAN is useful for sharing resources like files, printers, games or
other applications. A LAN in turn often connects to other LANs, and to the
Internet or other WAN.
Most local area networks are built with relatively inexpensive hardware such
as Ethernet cables, network adapters, and hubs. Wireless LAN and other more
advanced LAN hardware options also exist.
Specialized operating system software may
be used to configure a local area network.
For example, most flavors of Microsoft
Windows provide a software package
called Internet Connection Sharing
Fig 4: Basic LAN Topology (ICS) that supports controlled access to LAN
resources.
The term LAN party refers to a multiplayer
gaming event where participants bring their
own computers and build a temporary LAN.
Also Known As: local area network
Examples:
The most common type of local area network is an Ethernet LAN. The smallest
home LAN can have exactly two computers; a large LAN can accommodate
many thousands of computers. Many LANs are divided into logical groups called
subnets. An Internet Protocol (IP) "Class A" LAN can in theory accommodate
more than 16 million devices organized into subnets.

4) WAN:
WAN stands for Wide Area Network. As
its name suggests, it is a computer
network that covers a far wider area
than a LAN (Local Area Network). WANs
cover cities, countries, continents and
the whole world. A WAN is formed by
linking LANs together. For example,
several major LANs in a city can connect
together forming a WAN.
When networks connect to form a bigger
network (a bigger WAN), the resulting
Fig 5: WAN Network
network is called an internetwork, which
is generically abbreviated to an internet.
Now when all WANs in the world connect forming a global internet, we
 call it The Internet, which everyone knows! Thats why the Internet is always
written with a capital I. It is the biggest WAN we have.

5) Broadband:
Broadband is a term referred to some technologies that offers high speed
internet connectivity depending on framework and environment. In general
terms broadband referred to communication technology that can employ
different channels of data or data streams by using any medium (air or
Physical). Broadband is a term for wide band. It defines the speed of data
transfer rate.
Often this question arises in the minds of common folks that what is
broadband? The literal meaning of broadband is a wide band capturing the
signals and delivering it as an independent bandwidth channels. As term broad
tells that it is related to something bigger something vast still it limits are
undefined. Roughly for about 7-10 years, you are seeing advertisements
regarding the publicity of broadband. They are boasting about so many things
like, speed, phone calls accessibility, cheaper, download acceleration etc.
Broadband basically works through its bandwidth. As you increase the width of
the band, so you get the speedy access to the internet. Broadband it-self usually
refer to services that offer high bandwidth over the medium of fiber optic, DSL,
cellular services or broadcasting services.

Broadband Features: Prominent features of broadband make it unique

from the other ISPs providers. So the term broadband is introduced which means
high speed data transfer rate. The basic feature of broadband is to offer
amazingly fast speed of internet connectivity with the ease of downloading large
amount of data. Where there dial-up fails to work broadband comes to help you
by fulfilling your demand. What is special feature about broadband? Basically
broadband is the way of communication through internet, phone or satellite.
Broadband is originally a broadcast system using frequencies at wide range to
send a message whether short or long at high speed, used by fastest internet
connection. Some of the broadband features are described here.

Broadband Connectivity: As the whole world become a global village, one

reason of it being so is the broadband connectivity. Signals are sent through
fiber optic glass cable in the shape of light. This light source has the ability to
carry a huge amount of information (data) in a very short time period. It supports
multiple signals after distributing the whole into multiple independent bandwidth
channels.
Broadband Availability: Another very unique feature of this broadband
connection is that it remains connected 24/7 hrs and still does not disrupt the
telephone line. You can access the broadband through cable operators or direct
through satellite. It depends on the type of broadband you are using. The
important characteristic is that it only uses the ISP number of phone line without
interrupting its own exercise.

Broadband Desired Bandwidth: We can increase and decrease

the broadband bandwidth according to our need. For this you need to ask
to your internet service provider. There are different packages on different
rates you go for the one which suits you the most.

Benefits of Broadband: No doubt internet is facilitating since many years yet

broadband is like seasoning it with freed condiment. Thats why if you really
want to enjoy the internet facility in its true sense then go for broadband.
Using positively, it will help to prosper your business by leaps and bound. If
you are doing research work, it will surely be a quality output. You can design
your website at best with graphics oriented and animated; broadband will
facilitate to upload it and surely broadband user

6) Leased Line:
A leased line connects two locations for private voice and/or data
telecommunication service. Not a dedicated cable, a leased line is actually a
reserved circuit between two points. Leased lines can span short or long
distances. They maintain a single open circuit at all times, as opposed to
traditional telephone services that reuse the same lines for many different
conversations through a process called "switching."
Leased lines most commonly are rented by businesses to connect
branch offices, because these lines guarantee bandwidth for network traffic.
Leased lines are dedicated circuits provided by Basic Service Providers
(BSPs), which provide permanent connectivity to the Internet. Leased lines
provide the last mile access from the user premises to the ISP. They provide
permanent connection as compared to the temporary connectivity through
dialup access. The quality of the connection is far superior to what is normally
available through dialup, thanks to digital signaling, less noise, fewer
exchanges etc.
Since the access is "always on", it is possible to associate a pool of
permanent IP addresses with a particular leased line. Normally, the ISP would
provide 16/32 IP addresses for each 64 Kbps chunk of bandwidth. Using
these IP addresses it becomes possible to deploy a variety of services such
as mail, FTP, WWW, DNS, and proxy, to name the most common
requirements of organizations. In other words, leased lines enable hosting of
services of all types, and provide a platform for enterprise intranets and
extranets, apart from what we may term as "entry level" services such as
messaging, which still account for over 70 percent of all Internet access.

Applications of leased lines

Point-to-point:
For Data only
one of the widely
used applications
of leased lines is
having a secure
dedicated data
circuit between two locations via a private line, used
to transmit data at a constant speed equal to the
bandwidth of the circuit.

Fig 6: Leased line to an organization.

Point-to-point: For Voice and Data

This kind of application allows transmission of voice and data over the same
connection. Here also two separate locations are joined together. This type of
configuration is commonly provided on a higher bandwidth circuit. The bandwidth
of the circuit is divided into individual voice channels and data channels.

Multiplexing: Multiplexing basically connects multiple remote sites to a single

Centralized location. Typically a connection originating at the host location is
connected into a multiplexer at a service provider's end. At the multiplexer, the
host circuit is split into smaller individual circuits, and those are then delivered to
the remote sites.

Advantages: It provides permanent, reliable, high-speed connectivity as

compared to the temporary connectivity of dial up access. The quality of the
connection is far superior to what is normally available through dialup, because
of the digital signaling, less noise, fewer exchanges etc.

7) What is OSI Model?

Open Systems Interconnection ( OSI ) is a standard reference model for
communication between two end users in a network. The OSI Model is a model
that illustrates how data communications should take place. The model is used in
developing products and understanding networks. It segregates the process into
seven groups, called layers. Into these layers are integrated the protocol
standards developed by the ISO and other standards organization, including the
Institute of Electrical and Electronic Engineers (IEEE), American National
Standards Institute (ANSI), and the International Telecommunications Union
(ITU), formerly known as the CCITT (Comite Consultatif Internationale de
Telegraphique et Telephone). The OSI Model tells us what protocols and
standards should be used at each layer. It is modular, each layer of the OSI
Model functions with the one above and below it.

OSI Model Layers:

LAYER 7 The APPLICATION Layer:
The top layer of the OSI
model provides a set of
interfaces for sending and
receiving applications to gain
access to and use network Fig: Function of different layers
services, such as: networked
file transfer, message
handling and database query
processing.
The application layer Fig 7: Layer Functions
is responsible for providing
services to the user.

LAYER 6 The PRESENTATION Layer:

Manages data-format information for networked communications
(the networks translator).
For outgoing messages, it converts data into a generic format for
network transmission; for incoming messages, it converts data from
the generic network format to a format that the receiving application
can understand.
This layer is also responsible for certain protocol conversions, data
encryption or decryption, or data compression/decompression.
The presentation layer is responsible for translation, compression,
and encryption.

LAYER 5 The SESSION Layer:

Enables two networked resources to hold ongoing
communications (called a session) across a network .
Applications on either end of the session are able to exhange
data for the duration of the session.
This layer is responsible for initiating, maintaining and
terminating Sessions.
 Responsible for security and access control to session
information (via session participant identification).
Responsible for synchronization services, and for checkpoint
services.
The session layer is responsible for dialog control and
synchronization.

LAYER 4 The TRANSPORT Layer:

Manages the transmission of data across a network.
Manages the flow of data between parties by segmenting long
data streams into smaller data chunks (based on allowed
packet size for a given transmission medium).
Reassembles chunks into their original sequence at the
receiving end.
Provides acknowledgements of successful transmissions and
requests resends for packets which arrive with errors.
The transport layer is responsible for the delivery of a message
from one process to another.

LAYER 3 The NETWORK Layer:

Handles addressing messages for delivery, as well as
translating logical network addresses and names into their
physical counterparts.
Responsible for deciding how to route transmissions between
computers.
This layer also handles the decisions needed to get data from
one point to the next point along a network path.
This layer also handles packet switching and network
congestion control.
The network layer is responsible for the delivery of individual
packets from the source host to the destination host.

LAYER 2 The DATA LINK Layer:
Handles special data frames (packets) between the Network
layer and the Physical layer.
At the receiving end, this layer packages raw data from the
physical layer into data frames for delivery to the Network layer.
At the sending end this layer handles conversion of data into
raw formats that can be handled by the Physical Layer.
 The data link layer is responsible for moving frames from one
hop (node) to the next.

LAYER 1 The PHYSICAL Layer:

Converts bits into electronic signals for outgoing messages
Converts electronic signals into bits for incoming messages
This layer manages the interface between the computer and
the network medium (coax, twisted pair, etc.)
This layer tells the driver software for the MAU (media
attachment unit, ex. network interface cards (NICs, modems,
etc.)) what needs to be sent across the medium
The bottom layer of the OSI model is responsible for
movements of individual bits from one hop (node) to the next.

Fig: 8 layers of OSI model

8) Client-Server Model:
A client/server system: consists of a client and a server that are linked through a
network.
Client: requests the server for a given service through a special software
Server: provides the requested service to the client under a set of conditions.
Examples:- Internet, intranet, and extranet Another example of a popular C/S
system is financial software that allows bank clients that can access their
accounts from their home or office.
Interactions between Client and Server
A number of rules guide the interactions between a client and a server
When a server receives a request from a client, it checks to see if the
client is authorized
A server can serve multiple clients at the same time and, conversely, a
client may request services from multiple servers
Client processes are independent of server processes.
This independence maximizes the computing power of both client and
server.
It allows clients to be added to or deleted from the network without
effecting either the server or other clients
System administrator can make changes without effecting clients on the
network.

Characteristics of Client-Server Architecture:

Application components are distributed between the server and client
software.
In addition to part of the application software, the server also stores the
data, and all data accesses are through the server.
The presentation is handled strictly by the client software.
The PC clients assume the bulk of the responsibility for the application
logic.
The server assumes the bulk of the responsibility for data integrity checks,
query capabilities, data extraction and most of the data intensive tasks,
including sending the appropriate data to the appropriate clients.
SQL is a standard used on the clients to request appropriate subsets of
data from the server.
Data returned from the server to the clients is manipulated the client
software for reporting, business analysis and what if analysis.

Advantages of Client Server Application :

Centralization: Access, resource and data security are controlled through

the server.
Scalability: Any element can be upgraded when needed.
Flexibility: New technology can be easily integrated into the system.
Interoperability: All components (Clients, Network, and Servers) work
together.
Ease of application development.
 Lower total costs than Mainframe legacy systems
User friendly: Familiar point and click interface
Data Are Readily Accessible to Decision Makers
a) Accessibility to reliable, up-to-date information when needed
b) Timely information can often translate into tangible benefits, such as
increased profits or reduced operating costs; and intangible benefits,
such as greater customer satisfaction.
c) Server can be accessed remotely and across multiple platforms.
Reduced Operating Costs: In the long run, the cost of information
processing may be cheaper for client/server systems than for mainframe
systems, thereby lowering overall operating costs.
Reduced System Development and Maintenance Time
a) In general C/S systems tend to be easier to develop than mainframe
system.
b) With proper planning and the necessary expertise, developers can create
client/server systems more quickly and efficiently than mainframe
applications.
c) C/S system maintenance time is reduced as compared with systems that
must be shut down to make upgrades or perform maintenance
d) Changes or additions to an existing S/S system without much disruption
because server applications are independent of client applications
Increased Organizational Responsiveness: Designing a client/server
system often compels managers and employees to search for more
efficient, more effective business practices.

Disadvantages of Client Server Application:

Resistance to Change
a) The transition from a mainframe environment to a client/server
environment is fraught with obstacles. It is clear that the knowledge,
experience, and expertise guiding these mainframe and client/server
technologies are quite different.
b) The challenge is how to encourage professionals to move from mainframe
to client/server environment (they should be flexible & open-minded).
High Training Costs
a) Users need extensive training to successfully use and manage
client/server environments. Because these systems often change the
dynamics of the business environment, training must be comprehensive
and include both the business and the technology side.
 b) Workers need training in using the technology to improve the way
business operates.
c) This training usually expensive and long term.
Extensive Planning Required
a) Businesses tend to grow fast and in unexpected places, so a business
must plan carefully and develop a strategic plan for a client/server system.
Without a plan, the system becomes an ad hoc collection of systems that
dont integrate information and streamline business processes.
b) Company plan should identify the role of client/server system to achieve
the company goals. The plan identifies hardware issues. (ex. Nature &
type of network) operating system, system security, user training and
access method.
Inadequate Standards
a) Like any other new and evolving technology, client/server systems lack
standardization in terms of system management, maintenance, and
security, resulting in some reinventing of the wheel.
b) Developers become burdened with a host of issues that other environment
would be a standard part of the hardware & software packages.
Susceptible to Security Violations: The security concerns associated with
client/server systems are greater than those associated with other
information systems because client/server systems are prone to security
violations. The same features that make the client/server flexible, modular,
open, and responsive also make it risky and vulnerable.

9) Peer to peer
It is an approach to computer networking where all computers share equivalent
responsibility for processing data. Peer-to-peer networking (also known simply
as peer networking) differs from client-server networking, where certain devices
have responsibility for providing or "serving" data and other devices consume or
otherwise act as "clients" of those servers.

Characteristics of a Peer Network:

Peer to peer networking is common on small local area networks (LANs),

particularly home networks. Both wired and wireless home networks can be
configured as peer to peer environments.
Computers in a peer to peer network run the same networking protocols and
software. Peer networks are also often situated physically near to each other,
typically in homes, small businesses or schools. Some peer networks, however,
utilize the Internet and are geographically dispersed worldwide.
Home networks that utilize broadband routers are hybrid peer to peer and client-
server environments. The router provides centralized Internet connection
sharing, but file, printer and other resource sharing is managed directly between
the local computers involved.

Peer to Peer and P2P Networks: Internet-based peer to peer networks

emerged in the 1990s due to the development of P2P file sharing
networks like Napster. Technically, many P2P networks (including the
original Napster) are not pure peer networks but rather hybrid designs as
they utilize central servers for some functions such as search.

Peer to Peer and Ad Hoc Wi-Fi Networks: Wi-Fi wireless networks support so-
called ad hoc connections between devices. Ad hoc Wi-Fi networks are
pure peer to peer compared to those utilizing wireless routers as an
intermediate device.

Benefits of a Peer to Peer Network

You can configure computers in peer to peer workgroups to allow sharing of files,
printers and other resources across all of the devices. Peer networks allow data
to be shared easily in both directions, whether for downloads to your computer or
uploads from your computer.

On the Internet, peer to peer networks handle a very high volume of file sharing
traffic by distributing the load across many computers. Because they do not rely
exclusively on central servers, P2P networks both scale better and are more
resilient than client-server networks in case of failures or traffic bottlenecks.

10) Servers:
A server is primarily a program that runs on a machine, providing a particular and
specific service to other machines connected to the machine on which it is found.
Nowadays, server functionality has become so rich, complex and varied in nature
that there are whole very powerful computers dedicated to being exclusively
servers. This has led many non-technical people to denote servers as being
machines that run services.
Generally speaking, a server is a machine with a specific set of programs that
offer different types of service, which other machines (then called clients) request
to do certain tasks. For example, a file server is a machine which keeps files, and
allows clients to upload and download them from it. A web server is a machine
that hosts web sites and allows Internet users (clients) to access these web sites.
The page you are reading now comes from the about.com web server. A mail
server is a machine which, along with the storage and management of email
messages, provides service to email users who can read, retrieve, and manage
these emails messages.
How Web Servers Work?
The Basic Process
Let's say that you are sitting at your computer, surfing the Web, and you get a
call from a friend who says, "I just read a great article! Type in this URL and
check it out. It's at http://www.abcdef.com/web-server.htm." So you type that URL
into your browser and press return. And magically, no matter where in the world
that URL lives, the page pops up on your screen.
At the most basic level possible, the following diagram shows the steps that
brought that page to your screen:

Fig 9: Working of Web Server

Your browser formed a connection to a Web server, requested a page and

received it.
Behind the Scenes
If you want to get into a bit more detail on the process of getting a Web page
onto your computer screen, here are the basic steps that occurred behind the
scenes:
The browser broke the URL into three parts:
1. The protocol ("http")
2. The server name ("www.abcdef.com")
3. The file name ("web-server.htm")
The browser communicated with a name server to translate the server
name "www.abcdef.com" into an IP Address, which it uses to connect to
the server machine.
The browser then formed a connection to the server at that IP address
on port 80. (We'll discuss ports later in this article.)
Following the HTTP protocol, the browser sent a GET request to the
server, asking for the file "http://www.abcdef.com/web-server.htm." (Note
that cookies may be sent from browser to server with the GET request --
see How Internet Cookies Work for details.)
The server then sent the HTML text for the Web page to the browser.
(Cookies may also be sent from server to browser in the header for the
page.)
 The browser read the HTML tags and formatted the page onto your
screen.
If you've never explored this process before, that's a lot of new vocabulary. To
understand this whole process in detail, you need to learn about IP addresses,
ports, protocols... The following sections will lead you through a complete
explanation
DNS
If you've ever used the Internet, it's a good bet that you've used the Domain
Name System, or DNS, even without realizing it. DNS is a protocol within the set
of standards for how computers exchange data on the Internet and on many
private networks, known as the TCP/IP protocol suite. Its basic job is to turn a
user-friendly domain name like "abcdef.com" into an Internet Protocol (IP)
address like 70.42.251.42 that computers use to identify each other on the
network. It's like your computer's GPS for the Internet.
Computers and other network devices on the Internet use an IP address to route
your request to the site you're trying to reach. This is similar to dialing a phone
number to connect to the person you're trying to call. Thanks to DNS, though,
you don't have to keep your own address book of IP addresses. Instead, you just
connect through a domain name server, also called a DNS server or name
server, which manages a massive database that maps domain names to IP
addresses.
Whether you're accessing a Web site or sending e-mail, your computer uses a
DNS server to look up the domain name you're trying to access. The proper term
for this process is DNS name resolution, and you would say that the DNS
server resolves the domain name to the IP address. For example, when you
enter "http://www.abcdef.com" in your browser, part of the network connection
includes resolving the domain name "abcdef.com" into an IP address, like
70.42.251.42, for Abcdef' Web servers.
You can always bypass a DNS lookup by entering 70.42.251.42 directly in your
browser (give it a try). However, you're probably more likely to remember
"abcdef.com" when you want to return later. In addition, a Web site's IP address
can change over time, and some sites associate multiple IP addresses with a
single domain name.
Without DNS servers, the Internet would shut down very quickly. But how does
your computer know what DNS server to use? Typically, when you connect to
your home network, Internet service provider (ISP) or WiFi network, the modem
or router that assigns your computer's network address also sends some
important network configuration information to your computer or mobile device.
That configuration includes one or more DNS servers that the device should use
when translating DNS names to IP address.
So far, you've read about some important DNS basics. The rest of this article
dives deeper into domain name servers and name resolution. It even includes an
introduction to managing your own DNS server. Let's start by looking at how IP
addresses are structured and how that's important to the name resolution
process.

DNS Servers and IP Addresses

Primary job of a domain name server, or DNS server, is to resolve (translate) a
domain name into an IP address. That sounds like a simple task, and it would be,
except for the following points:
There are billions of IP addresses currently in use, and most machines
have a human-readable name as well.
DNS servers (cumulatively) are processing billions of requests across
the Internet at any given time.
Millions of people are adding and changing domain names and IP
addresses each day.
With so much to handle, DNS servers rely on network efficiency and Internet
protocols. Part of the IP's effectiveness is that each machine on a network has a
unique IP address in both the IPV4 and IPV6 standards managed by the Internet
Assigned Numbers Authority (IANA). Here are some ways to recognize an IP
address:
An IP address in the IPV4 standard has four numbers separated by
three decimals, as in: 70.74.251.42
An IP address in the IPV6 standard has eight hexadecimal numbers
(base-16) separated by colons, as in
2001:0cb8:85a3:0000:0000:8a2e:0370:7334. Because IPV6 is still a very
new standard, we'll concentrate on the more common IPV4 for this article.
Each number in an IPV4 number is called an "octet" because it's a base-
10 equivalent of an 8-digit base-2 (binary) number used in routing network
traffic. For example, the octet written as 42 stands for 00101010. Each
digit in the binary number is the placeholder for a certain power of two
from 20 to 27, reading from right to left. That means that in 00101010, you
have one each of 21, 23 and 25. So, to get the base-10 equivalent, just add
21 + 23 + 25 = 2 + 8 + 32 = 42. For more about how IP addresses are
constructed, see our article "What is an IP address?"
There are only 256 possibilities for the value of each octect: the
numbers 0 through 255.
Certain addresses and ranges are designated by the IANA as reserved
IP addresses, which means they have a specific job in IP. For example,
 the IP address 127.0.0.1 is reserved to identify the computer you're
currently using. So, talking to 127.0.0.1 is just talking to yourself!
Where does your computer's IP address come from? If we're talking about your
desktop or laptop computer, it probably comes from a Dynamic Host
Configuration Protocol (DHCP) server on your network. The job of a DHCP
server is to make sure your computer has the IP address and other network
configuration it needs whenever you're online. Because this is "dynamic," the IP
address for your computer will probably change from time to time, such as when
you shut down your computer for a few days. As the user, you'll probably never
notice all this taking place. See the sidebar on this page for hints on where to find
the IP address assigned to your computer or mobile device.
Web servers and other computers that need a consistent point of contact
use static IP addresses. This means that the same IP address is always
assigned to that system's network interface when it's online. To make sure that
interface always gets the same IP address, IP associates the address with the
Media Access Control (MAC) address for that network interface. Every network

interface, both wired and wireless, has a unique MAC address embedded in it by
the manufacturer.
For more information on IP addresses, see the IANA, operated by the Internet
Corporation for Assigned Names and Numbers (ICANN). Now, though, let's look
at the other side of the DNS equation: domain names.

Domain Names

What's in a name? For your domain, the name could make a difference in
whether people remember or want to visit your Web site.
If we had to remember the IP addresses of all our favorite Web sites, we'd
probably go nuts! Human beings are just not that good at remembering strings of
numbers. We are good at remembering words, however, and that is where
domain names come in. You probably have hundreds of domain names stored in
your head, such as:
abcdef.com -- our favorite domain name
google.com -- one of the most used domain names in the world
 mit.edu -- a popular EDU name
bbc.co.uk -- a three-part domain name using the country code UK
You'll recognize domain names as having strings of characters separated by dots
(periods). The last word in a domain name represents a top-level domain.
These top-level domains are controlled by the IANA in what's called the Root
Zone Database, which we'll examine more closely later. The following are some
common top-level domains:
COM -- commercial Web sites, though open to everyone
NET -- network Web sites, though open to everyone
ORG -- non-profit organization Web sites, though open to everyone
EDU -- restricted to schools and educational organizations
MIL -- restricted to the U.S. military
GOV -- restricted to the U.S. government
US, UK, RU and other two-letter country codes -- each is assigned to a
domain name authority in the respective country
In a domain name, each word and dot combination you add before a top-level
domain indicates a level in the domain structure. Each level refers to a server or
a group of servers that manage that domain level. For example, "abcdef" in our
domain name is a second-level domain off the COM top-level domain. An
organization may have a hierarchy of sub-domains further organizing its Internet
presence, like "bbc.co.uk" which is the BBC's domain under CO, an additional
level created by the domain name authority responsible for the UK country code.
The left-most word in the domain name, such as www or mail, is a host name. It
specifies the name of a specific machine (with a specific IP address) in a domain,
typically dedicated to a specific purpose. A given domain can potentially contain
millions of host names as long as they're all unique to that domain.
Because all of the names in a given domain need to be unique, there has to be
some way to control the list and makes sure no duplicates arise. That's where
registrars come in. A registrar is an authority that can assign domain names
directly under one or more top-level domains and register them with InterNIC, a
service of ICANN, which enforces uniqueness of domain names across the
Internet. Each domain registration becomes part of a central domain registration
database known as the whois database. Network Solutions, Inc. (NSI) was one
of the first registrars, and today companies like GoDaddy.com offer domain
registration in addition to many other Web site and domain management
services. [source: InterNIC]
Later, when we look at how to create a domain name, we'll see that part of
registering a domain requires identifying one or more name servers (DNS
servers) that have the authority to resolve the host names and sub-domains in
that domain. Typically, you would do this through a hosting service, which has its
 own DNS servers. Next, we'll look at how these DNS servers manage your
domain, and how DNS servers across the Internet work together to ensure traffic
is routed properly between IP addresses.

11) Network Attached Storage (NAS)

Several new methods of utilizing computer networks for data storage have
emerged in recent years. One popular approach, Network Attached Storage
(NAS), allows homes and businesses to store and retrieve large amounts of data
more affordable than ever before.

Background: Historically, floppy drives have been widely used to share data
files, but today the storage needs of the average person far exceed the capacity
of floppies. Businesses now maintain an increasingly large number of electronic
documents and presentation sets including video clips. Home computer users,
with the advent of MP3 music files and JPEG images scanned from photographs,
likewise require greater and more convenient storage.
Central file servers use basic client/server networking technologies to solve these
data storage problems. In its simplest form, a file server consists of PC or
workstation hardware running a network operating system (NOS) that supports
controlled file sharing (such as Novell NetWare, UNIX or Microsoft
Windows). Hard drives installed in the server provide gigabytes of space per
disk, and tape drives attached to these servers can extend this capacity even
further.
File servers boast a long track record of success, but many homes, workgroups
and small businesses cannot justify dedicating a fully general-purpose computer
to relatively simple data storage tasks. Enter NAS.

What Is NAS?
NAS challenges the traditional file server approach by creating systems designed
specifically for data storage. Instead of starting with a general-purpose
computer and configuring or removing features from that base, NAS
designs begin with the bare-bones components necessary to support file
transfers and add features "from the bottom up."
Like traditional file servers, NAS follows a client/server design. A single hardware
device, often called the NAS box or NAS head, acts as the interface between the
NAS and network clients. These NAS devices require no monitor, keyboard or
mouse. They generally run an embedded operating system rather than a full-
featured NOS. One or more disk (and possibly tape) drives can be attached to
many NAS systems to increase total capacity. Clients always connect to the NAS
head, however, rather than to the individual storage devices.
Clients generally access a NAS over an Ethernet connection. The NAS appears
on the network as a single "node" that is the IP address of the head device.
A NAS can store any data that appears in the form of files, such as email boxes,
Web content, remote system backups, and so on. Overall, the uses of a NAS
parallel those of traditional file servers.
NAS systems strive for reliable operation and easy administration. They often
include built-in features such as disk space quotas, secure authentication, or the
automatic sending of email alerts should an error be detected.

NAS Protocols
Communication with a NAS head occurs over TCP/IP. More specifically, clients
utilize any of several higher-level protocols (application or layer seven protocols
in the OSI model) built on top of TCP/IP.
The two application protocols most commonly associated with NAS are Sun
Network File System (NFS) and Common Internet File System (CIFS). Both NFS
and CIFS operate in client/server fashion. Both predate the modern NAS by
many years; original work on these protocols took place in the 1980s.
NFS was developed originally for sharing files between UNIX systems across
a LAN. Support for NFS soon expanded to include non-UNIX systems; however,
most NFS clients today are computers running some flavor of the UNIX operating
system.
The CIFS was formerly known as Server Message Block (SMB). SMB was
developed by IBM and Microsoft to support file sharing in DOS. As the protocol
became widely used in Windows, the name changed to CIFS. This same protocol
appears today in UNIX systems as part of the Samba package.
Many NAS systems also support Hypertext Transfer Protocol (HTTP). Clients can
often download files in their Web browser from a NAS that supports HTTP. NAS
systems also commonly employ HTTP as an access protocol for Web-based
administrative user interfaces.
12) Layer 1 Switches/HUB:
In the OSI model, at Physical Layer ,Hub is classified as a layer 1 device. Or in
other words we should say it as a Layer 1 switch..
Hub is a physical device used to connect two or more devices to form a single
network. it includes a series of ports which accepts cable. A hub facilitates direct
communication of computers.
Hub is no intelligent. It does not looks after the sender and receivers address.
Whenever any data is sent from one port, hub copies it to all the ports including
the senders port as well. Computer/device for whom the message is intended
for, receives it, and the others deny.
There are basically three types of hubs:
Passive hubs do not amplify the electrical signals of incoming packets
before broadcasting them out to the network
Active hubs provide with this amplification with the help of a repeater. An
active hub takes a larger role in Ethernet communications with the help of
technology called store & forward.
An intelligent hub however, adds extra features to an active hub that is
crucial to the success of businesses. It includes remote management
capabilities via SNMP. it provides with the ability to manage the network
from one central location. With the help of an intelligent hub, one can
easily identify, diagnose problems and even come up with remedial
solutions

Hubs, sometimes even called repeaters, just replicate every packets they
receive to all network ports connected. Every packet is treated as though it
were sent to the Broadcast Address.
Advantages:
When the data is needed to be sent to all the computers then hubs are
very useful.
Costs very less
Less complicated, and easy to understand the working.
Disadvantage:
Because they repeat all traffic they receive on all attached ports each
connected NIC will have a more difficult time getting its traffic onto the
network. Whenever one NIC sends a message, all others must wait for
it to pass before they get their own message onto the network.
13) Switch:
A network switch is a small hardware
device that joins multiple computers
together within one local area network
(LAN). Technically, network switches
operate at layer two (Data Link Layer) of
the OSI model.
Network switches appear nearly
identical to network hubs, but a switch
generally contains more intelligence (and a Fig 10: A switch connecting server to
slightly higher price tag) than a hub. Unlike terminals and printer.
hubs, network switches are capable of
inspecting data packets as they are received, determining the source and
destination device of each packet, and forwarding them appropriately. By
delivering messages only to the connected device intended, a network switch
conserves network bandwidth and offers generally better performance than a
hub.
Different models of network switches support differing numbers of
connected devices. Most consumer-grade network switches provide either four or
eight connections for Ethernet devices. With some ISPs and other
networking environments where there is a need for much analysis of network
performance and security, switches may be connected between WAN routers as
places for analytic modules. Some switches provide inbuilt firewall, network
intrusion detection and performance analysis modules that can plug into switch
ports.

Functions of a Switch:
A switch is a device that is used at the Access or OSI Layer 2; a switch
can be used to connect multiple hosts (PCs) to the network.
Unlike a hub, a switch forwards a message to a specific host. When any
host on the network or a switch sends a message to another host on the
same network or same switch, the switch receives and decodes the
frames to read the physical MAC (Media access Control) address portion
of the message.
Forwards Frames with MAC address:
When a message is sent between hosts on a network or the same switch, the
switch checks its MAC address table for the destination address. A switch MAC
address table contains a list of all active ports, host or PCs MAC addresses that
are attached to it. If the destination MAC address is not found in the table, the
switch will not have the necessary information to forward the message. When the
switch cannot determine where the destination host is located, it will flood or
forward the message out to all attached hosts. Each host compares the
destination MAC address in the message to its own MAC address, but only the
host with the correct destination address processes the message and responds
to it.
How Switches Learn MAC addresses:

A switch builds its MAC address table by examining the source MAC address of
each frame that is sent between hosts. When a new host sends a message or
responds to a flooded message, the switch immediately learns its MAC address
and the port to which it is connected. The table is dynamically updated each time
a new source MAC address is read by the switch. In this way, a switch quickly
learns the MAC addresses of all attached hosts.

Collision Prevention:
A switch prevents collisions by providing a circuit between the source and
destination ports. This circuit provides a dedicated channel over which the hosts
connected to the various ports on the switch can communicate. Each port is
allocated with a separate bandwidth; these separate circuits allow many
conversations to take place at the same time, without collisions occurring.

Types of switches:

A.
i. Managed Switch:
These switches have one or more methods to modify the operation of the
switch. Common management methods include: a command-line interface (CLI)
accessed via serial console, telnet or Secure Shell, an embedded Simple
Network Management Protocol (SNMP) agent allowing management from a
remote console or management station, or a web interface for management from
a web browser.
 As the number of devices increases, the ability to ensure that the time-
sensitive packets are prioritized becomes increasingly difficult as more
concurrent streams of data hit the network. Another issue that may need to be
dealt with is which devices have access to what portion of the network. An
example of this might be where the accounting department needs to be walled off
from the rest of the network for security purposes or where the production floor
should be blocked from having Internet access. In both those cases a managed
switch can fulfill that need. In addition, managed switches provide the ability to
monitor each device on the network as well as limit the amount of bandwidth any
device can use.

ii. Unmanaged switch:

Unmanaged switches are ideal for the small to medium office and for data
applications where no switch management is necessary. They are truly plug and
play and have no configuration interface or options.
In scenarios where the network traffic is light, all that is required is a way for
the data to pass from one device to another. In this case there is no need for
prioritizing the packets as all the traffic will flow unimpeded. An unmanaged
switch will fill this need without issues. It is important to note that a switch is not a
hub. Unmanaged switch allows devices to talk to each other.

Difference between unmanaged and managed switches:

Managed switches provide all the features of an unmanaged switch and
provide ability to configure, manage, and monitor your LAN. And this gives
you greater control over how data travels over the network and who has
access to it.
Also, managed switches use protocols such as the Simple Network
Management Protocol, or what we call SNMP, for monitoring the devices
on the network. SNMP is a protocol that facilitates the exchange of
management information between network devices. SNMP queries can
determine the health of the network or the status of a particular device.
By displaying this data in an easily understood format, IT managers
located at a central site can monitor the performance of the network and
quickly detect and repair network problems without having to physically
interact with the switch.
SNMP allows to remotely monitoring our network devices, and one
doesnt have to go to the site to make changes or troubleshoot the switch.
Managed switches are more expensive than unmanaged
switches, then why should one pay more for a managed switch?

There are many additional features we get with a managed switch, such as
quality of service, virtual LANs, redundancy, and port mirroring.

These features help provide control over the traffic traveling over the switch.
Quality of service allows you to prioritize network traffic by assigning a
higher priority to critical traffic. This helps ensure consistent network
performance and can support delay-sensitive data such as real-time voice.
For instance, if voice packets are traveling over a network, then it should
be made sure they have the highest priority so that these voice packets
dont get dropped or delayed and mangle the phone conversation.
VLANs allow a switch to logically group devices together to isolate traffic
between these groups even when the traffic is passing over the same
physical switch. This segmentation and isolation of network traffic help
reduce unnecessary traffic. For instance, traffic between your finance and
marketing groups can be segmented, so that mission-critical finance
information can flow without delay to the finance users and get bogged
down by marketing traffic. This allows better network performance and in
many cases provides an additional level of security.
Another important feature of a managed switch is redundancy.
Redundancy provides the ability to safeguard a network in case a
connection or cable fails by providing an alternate data path for traffic.
Managed switches incorporate what is called Spanning Tree Protocol
standard, or STP, to provide path redundancy in the network. Using the
spanning-tree algorithm, STP provides redundant paths while preventing
loops that are created by multiple active paths between switches.
STP allows for one active path at a time between two network devices,
preventing loops and establishing the redundant links as a backup to keep
integrated systems available and preventing expensive downtime, which
network admins can appreciate.
And, finally, there is port mirroring. In conjunction with a network
analyzer, this feature is useful to diagnose problems. It copies the switch
network traffic and forwards it to a single port on the same switch for
analysis by a network analyzer. You can use the analyzer on a monitor
port to troubleshoot network problems by examining traffic on other ports
or segments. The benefit of this is you can troubleshoot problems without
taking the network out of service.
Why consider using a managed switch?

Each business needs to evaluate the needs of their network. When their
network
requirements have evolved to the point where they would like to have some input
and control over the behavior of traffic on their LAN, then it is a good time to
consider a managed switch. Also, if one is planning to deploy advanced services
such as wireless LANs or IP telephony in the near future, managed switches can
lay the foundation for these technologies.

B.
i. Fixed configuration switches:
These types of switches are fixed in their configuration. What that means is
that you cannot add features or options to the switch beyond those that originally
came with the switch. The particular model you purchase determines the features
and options available. For example, if you purchase a 24-port gigabit fixed
switch, you cannot add additional ports when you need them. There are typically
different configuration choices that vary in how many and what types of ports are
included.
ii. Modular switches:
These types of switches offer more flexibility in their configuration. Modular
switches typically come with different sized chassis that allow for the installation
of different numbers of modular line cards the line cards actually contain the
ports. The line card fits into the switch chassis like expansion cards fit into a PC.
The larger the chassis, the more modules it can support.

iii. Stackable Switches:

Stackable switches can be interconnected using a special back cable that
provides high-bandwidth between the switches. Cisco introduced Stack Wise
technology in one of its switch product lines. Stack Wise allows you to
interconnect up to nine switches using fully redundant back plane connections..
Stackable switches use a special port for interconnections and do not use line
ports for inter-switch connections. The speeds are also typically faster than using
line ports for connection switches
Difference Between a Hub & a Switch
Hubs and switches are two of the more common networking devices that people
see today. While both devices will repeat data that is received, the switch will only
send the information out to specific devices while the hub may send it out to
many devices.
a) The Network Hub Definition: A hub is often referred to as a multiport
repeater. That is because whatever data comes into the hub gets repeated
out on all ports.
For example, if you have two computers connected to a hub and the user
on one computer goes to a website that data will go through the hub.
When the hub gets the data it cleans up the signal to remove any noise
and then sends the data out on all ports. The user that went to the web
page will get the information that he requested but the computer that did
not request the information will get the data also. The computer that did
not request the information will just ignore it.
b) Networks and IP Addresses: Every device connected to a network is
assigned a number called an IP Address. Whenever this device makes a
request over a network, including the internet, the IP Address is sent as
part of the information request. When the computer that receives the
request sends back the requested data, the IP Address is part of the data.
That is how it knows which computer to send the information to.
c) The Network Switch: A switch works on the same concept. When it
receives that data back, it looks at the IP Address; the switch has a table
of which IP Address is connected to which port. The switch checks the IP
Address against this table and sends the information to the computer that
requested it and no other computer will get the information.

o The most practical difference between hubs and switches is that hubs
can greatly slow down a busy network since they are sending the data to
all computers that are connected to it. Switches on the other hand can
speed up networks by only sending data to the computer that requested
it.
14) Bridge:
A network bridge connects multiple network segments at the data link
layer (Layer 2) of the OSI model. A bridge device filters data traffic at a network
boundary. Bridges reduce the amount of traffic on a LAN by dividing it into two
segments. A LAN segment is a single section of network media that connects
computers.
Bridging is a forwarding technique used in packet-switched computer networks.
Unlike routing, bridging makes no assumptions about where in a network a
particular address is located. Instead, it depends on flooding and examination of
source addresses in received packet headers to locate unknown devices. Once a
device has been located, its location is recorded in a table where the MAC
address is stored so as to facilitate the need for further broadcasting.
A bridge uses a forwarding database to send frames across network segments.
The forwarding database is initially empty and entries in the database are built
as the bridge receives frames. If an address entry is not found in the forwarding
database, the frame is flooded to all other ports of the bridge, forwarding the
frame to all segments except the source address. By means of these broadcast
frames, the destination network will respond and forwarding database entry will
be created. Both source and destination addresses are used in this algorithm.
Source addresses are recorded in entries in the table, while destination
addresses are looked up in the table and matched to the proper segment to send
the frame to.
Filtering database
To translate between two segments, a bridge reads a frame's destination MAC
address and decides to either forward or filter. If the bridge determines that the
destination node is on another segment on the network, it forwards (retransmits)
the packet to that segment. If the destination address belongs to the same
segment as the source address, the bridge filters (discards) the frame The bridge
uses its filtering database to determine whether a packet should be forwarded or
filtered.
Network Bridge Characteristic
Bridges have the following characteristic:
Bridges Connect two media segments that use the same protocol
Bridges examine the source address to determine the media segment
of network devices
Bridges operate at the data link layer of the OSI model
Bridges maintain a table of devices address and their corresponding
segments
Each segment connected by a bridge can have the same network address
 Messages within a media segment are prevented from crossing over to
another segment

The Advantages of Network Bridge

Switches (which use the Network Bridge concept) in today industry replace the
legacy Hubs devices to increase the performance of the LAN.
Bridges prevent wasted bandwidth by eliminating unnecessary traffic
between segments
Bridges increase the maximum network length
Bridges forward packets for multiple upper-layer protocols
Bridges can link segments with dissimilar transmission media and media
access methods

The Limitation Architecture of the Network Bridge

Besides the advantages, Network Bridges have the architecture limitation.
Bridges cannot link multiple architecture because different frame types are
used
Bridges cannot translate upper-layer protocols
Bridges cannot forward packets to different networks based on the
network address. Networking routers are used for internetworking
communications.
Bridges do not filter broadcast packets

15) Routers:
Routers are physical devices that
join multiple wired or wireless Fig 11: Router Connects LAN to Internet
networks together.
A hardware device designed to
take incoming packets, analyzing
the packets and then directing
them to the appropriate locations,
moving the packets to
another network, converting the
packets to be moved across
a different network interface,
dropping the packets, or
performing any other number of other actions. Most routers use Network
Address Translation (NAT) to determine the smartest path of a data packet to
its destination. Routers are located at gateways, the places where two or more
networks connect, and are the critical device that keeps data flowing between
networks and keeps the networks connected to the Internet.
When data is sent between locations on one network or from one network to a
second network the data is always seen and directed to the correct location by
the router. The router accomplishes this by using headers and forwarding tables
to determine the best path for forwarding the data packets, and they also
use protocols to communicate with each other and configure the best route
between any two hosts. A network router will typically utilize one or more routing
protocols, such as RIP, OSPF, or BGP. Routers also accept routes which are
configured manually by a network administrator. Those routes are called static
routes. The router will use this information to create a routing table.The network
router will then use its routing table to make intelligent decisions about which
packets to copy to which of its interfaces.
This process is known as routing.
The routers determine where to send information from one computer to another.
Routers are specialized computers that send your messages and those of every
other Internet user speeding to their destinations along thousands of pathways. A
router has two separate, but related, jobs:
It ensures that information doesn't go where it's not needed. This is
crucial for keeping large volumes of data from clogging the connections.
It makes sure that information does make it to the intended destination.

Advantages of a Router:
In addition to packet forwarding, a router provides other services as well. To meet
the demands on today's networks, routers are also used :
To ensure steady, reliance availability of network connectivity. Routers use
alternative parts in the case the primary part fails to the delivery of
packets.
To provide integrated services of data, video, and voice over wired and
wireless networks.
For security, router helps in mitigating the impact of worms, viruses, and
other attacks on the network by permitting or denying the forwarding of
packets.
Configuring of various devices.

How to Use a Router to Connect Two Computers to the Internet

1. Ensure that both computers have a LAN (or an Ethernet) card allowing the
sharing of files and peripherals. Though all new computers and laptops
are equipped with such cards, you may need to buy and attach LAN cards
for older models.
2. Connect the cable from your Internet Service Provider (ISP) to the Internet
port of your router. Note that if you have an ADSL connection, your input
cable would be a telephone line that needs to be inserted into the ADSL
 3. port of the router. For all other connections, you would have a thicker
cable known as CAT5 (or CAT6).
4. Take two Ethernet cables and plug them into the Ethernet ports of the
router. Note that you will require a router with at least two Ethernet ports to
share Internet on two computers. Plug the other end of each of the cables
into the Ethernet port of the computers. If you have a router with a single
Ethernet port, buy a switch or hub and connect the router with it (using the
Ethernet cable). In turn, the switch (or hub) that includes at least two
Ethernet ports will have to be connected to the computers.
5. Switch on the router and the computers.
6. Configure the router by referring to its user manual. The configuration
process defers depending on the type and brand of the router. Once
configured, you should be able to access Internet on both computers

` Fig 12: Router Connecting Two LANs:

16) Wireless network:

Over the past decade, WiFi / wireless networking has significantly grown
in popularity. It is so widely used that it can be found in many homes, airports,
cities, and schools world-wide. The popularity of WiFi is due to its low-cost and
how easy it is to setup the network. This allows average consumers to setup
networks anywhere that they have a internet connection. Also, the fact that it is
almost impossible to buy a laptop that doesnt have a wireless card built into the
screen will ensure that WiFis popularity continues to grow..
Wireless network refers to any type of computer network that is not
connected by cables of any kind. It is a method by which telecommunications
networks and enterprise (business), installations avoid the costly process of
introducing cables into a building, or as a connection between various equipment
locations. Wireless telecommunications networks are generally implemented and
administered using a transmission system called radio waves. This
implementation takes place at the physical level (layer) of the network structure.
How Does a Wireless Network Work?
Wireless networks use radio frequency waves that are transmitted in the
2.4 GHz to 5 GHz spectrum that are very similar to television or cell phone signal
transmissions. When your computer is connected to a wireless network, its
wireless adapter will encode information into a radio signal and then transmit it
using the wireless antenna that is normally built into the screen of new laptops.
Wireless signals can also be received via an external antenna plugged into
theUSB slot of a computer. The WiFi router for the network then receives this
information, decodes it, and sends to the Internet through a wired, high-speed
connection.

How Do You Connect to a Wireless Network?

In order to connect to a wireless network or WiFi hotspot, the computer
must have a wireless adapter. Most new computers will have this built into the
computer, but you still need to check. If the PC does not have a built-in one,
a PCI or USB adapter can be purchased from most electronics stores. Once the
wireless adapter is installed (or the PC has one already), it will be able to
automatically detect available wireless networks in range of the computer. On a
Windows computer, you can double click the Network icon in the Windows
System Tray followed by selecting the Show Available Networks menu option.
The WiFi networks that are in range of the computer will then be displayed, and
the user can then click the network that they want to join. However, if a network is
labeled as being secure, a passphrase or
password established by the network
administrator will be needed to start the
connection.
17) Wireless routers:
A wireless router is a device that performs
the functions of arouter but also includes
the functions of a wireless access point and Fig 13: D-Link Wireless Router
a network switch. They are commonly used to allow
access to the Internet or a computer network without the need for a cabled
connection. It can function in a wired LAN (local area network), a wireless only
LAN (WLAN), or a mixed wired/wireless network. Most current wireless routers
have the following characteristics:
LAN ports which function in the same manner as the ports of a network
switch
 A WAN port to connect to a wide area network, typically one with Internet
access. External destinations are accessed using this port. If it is not used,
many functions of the router will be bypassed.
Wireless antennae These allow connections from other wireless devices
(NICs (network interface cards), wireless repeaters, wireless access
points, and wireless bridges, for example), usually using the Wi-
Fi standard.

18) Wireless Modem:

A wireless modem is a network device which connects to a wireless
network. Modems are frequently associated with telephone systems, but wireless
modems are used with computers to connect to the Internet. Connecting a
wireless modem to the computer will directly connect to your wireless ISP
(Internet Service Provider).
Wireless modems operate at speeds comparable to dialup modems, not
anywhere near the speed of broadband Internet connections.

19) NAT-Network Address Translation:

NAT allows an Internet Protocol (IP) network to maintain public IP
addresses separately from private IP addresses. NAT is a popular technology for
Internet connection sharing. In it's most common configuration, NAT maps all of
the private IP addresses on a home network to the single IP address supplied by
an Internet Service Provider (ISP). This allows computers on the home LAN to
share a single Internet connection. Additionally, it enhances home network
security by limiting the access of external computers into the home IP network
space.
NAT functionality is usually found on routers and other gateway devices at the
network boundary.

20) Thin client:

Thin client is a general term used for the devices that rely on a server to proceed
its operations. It offers a display device, keyboard and mouse and basic
processing power for interacting with the web server. No storage devices are
involved in it and have very thin features and roles; therefore it is termed as thin
clients.
No local storage is involved in case of a thin client therefore needs very less
resources for processing. Users can even make use of their old personal
computers that were left unused since decades, or a dedicated thin client device
or even a cheap personal computer with an installation of thin client Operating
ystem. Your expenditure can be significantly reduced as very limited processing
power is required in turn offering an increased hardware life.
Moreover, the recurring expenditure over administration, hardware/software
maintenance, technical support, and hardware as well as data security can be
greatly reduced in comparison to the old methods.

Advantages:
1. Make changes once and in one place
Software installation, updating and removal is kept easier because its in
one place. Keeping an eye on disk space, memory and processor usages
is a lot easier on one machine than keeping an eye on 50 or more.
Backing up is also a lot quicker and all important recovery is faster.
Changes can be made quickly and rolled out across a wide distributed
user base with no intervention from end users.
2. Take advantage of the unused load on your server
Many servers and client PCs are often highly under-loaded. Virtual
computing technology is taking huge advantage of this and thin clients can
too. Take advantage of that unused load and save money from
unnecessary equipment and make the most of the money you have spent.
Savings can always be put back into the network by securing and
enhancing the infrastructure making it even more reliable.
3. Make support and management easier
See at a glance what user processes are running. There are tools out
there that will do this across a traditional distributed network of
workstations but it is much easier to see whats installed on just one
machine making it easier to protect against software that shouldnt be
installed. There are also a lot less machines to keep up to date which
means that patch management is improved making the job quicker (lets
you go home earlier which is always a plus point). Configuring a thin client
terminal is often a simple and painless process just point the device to
your chosen server and off you go. Thin clients can often be locked down
too keeping them safe from experimental fingers.
4. Bring down the costs
Bring down the cost of the equipment, the cost of repairs and the cost of
support and other ongoing costs. New users can be quickly and easily
added even if they are remotely based. PCs tend to need regular
upgrades, especially driven by user desire. Thin clients can be installed
and left often for many years which lets you maximise your return on your
investment. Solving a problem for one user can often have a knock on
effect of solving the problem for many users even when they didnt know
 they had a problem thus reducing the load on the helpdesk. The number
of desk visits to deal with hardware problems can also be reduced.
5. Security
There isnt much that can be changed on a thin client and they arent as
appetising to thieves as desktop PCs. Network bandwidth is reduced
often to a more manageable (and budgetable) level. Also, important data
can be kept away from the main network and kept in the computer room
only screen and keyboard data needs to be sent over the cable. Keeps
data where it should be in a central location instead of it being dispersed
around the network on different computers. Remote works can also
benefit from rapid deployment of remote thin clients and the IT team can
be safe in the knowledge that very little can happen to the home based
workers.

Disadvantages:
1. The Server
One of the main disadvantages of a thin client computer is the server
itself. Since thin clients do not process anything or store any data on their
own, they require a connection to a server to handle these tasks for them.
Unlike a standard desktop computer, or thick client, should the server go
down or suffer from hardware failure, all connected thin clients are
affected, and they will not work. Desktops, on the other hand, can still
work in a local computing capacity without network resources should
connected servers fail.
2. Network Bandwidth Issues
Since thin clients require a connection to a server, they are also
dependent on the networking infrastructure. Should the network suffer
from bottlenecks, lags or outages, the thin clients work at a minimal
capacity, if they can function at all. As with issues associated with the
server going down, if thin clients lose their connection to the server due to
a network outage, they will not work.
3. Lack of Multimedia Support
Media-rich applications like audio and video require a great deal of
network resources as well as computing power to play. With thin clients,
computing power is shared among all the clients connected to the
computer. Bandwidth used to deliver packets between the server and thin
client is also shared between all connections. Due to these resources
being at a premium in a thin-client setting, resource-rich multimedia
applications do not run effectively on these machines.
21) ATM- Asynchronous Transfer Mode:
Short for Asynchronous Transfer Mode, a network technology based on
transferring data in cells or packets of a fixed size. The cell used with ATM is
relatively small compared to units used with older technologies. The small,
constant cell size allows ATM equipment to transmit video, audio, and computer
data over the same network, and assure that no single type of data hogs the line.
Some people think that ATM holds the answer to the Internet bandwidth problem,
but others are skeptical. ATM creates a fixed channel, or route, between two
points whenever data transfer begins. This differs from TCP/IP, in which
messages are divided into packets and each packet can take a different route
from source to destination. This difference makes it easier to track and bill data
usage across an ATM network, but it makes it less adaptable to sudden surges in
network traffic.
When purchasing ATM service, you generally have a choice of four different
types of service:
constant bit rate (CBR): specifies a fixed bit rate so that data is sent
in a steady stream. This is analogous to a leased line.
variable bit rate (VBR): provides a specified throughput capacity but
data is not sent evenly. This is a popular choice for voice and
videoconferencing data.
available bit rate (ABR): provides a guaranteed minimum capacity
but allows data to be bursted at higher capacities when the network is
free.
unspecified bit rate (UBR): does not guarantee any throughput
levels. This is used for applications, such as file transfer, that can tolerate
delays.

22) Network Address:

A network address serves as a unique identifier for a computer on a
network. When set up correctly, computers can determine the addresses of other
computers on the network and use these addresses to send messages to each
other.
One of the best known form of network addressing is the Internet
Protocol (IP) address. Another popular form of address is the Media Access
Control (MAC) address.
a) IP Address:
. An Internet Protocol Address is the address of a device connected to a
network. An IP Address can either be static or dynamic. (Server computers
-static addresses, Personal computer either static or dynamic IP
address. Every machine on the network has a unique identifying number,
called an IP Address. A typical IP address looks like this: 216.27.61.137The
four numbers in an IP address are called octets. So each octet can contain
any value between 0 and 255.
The octets are used to create classes of IP addresses that can be
assigned to a particular business, government or other entity based on size
and need.
The octets are split into two sections:
Net- The Net section always contains the first octet. It is used to
identify the network that a computer belongs to.
Host (Node)-identifies the actual computer on the network. The
Host section always contains the last octet.

There are five IP classes plus certain special addresses:

1. Class A - This class is for very large networks, such as a major
international company might have. IP addresses with a first octet from 1 to
126 are part of this class. The other three octets are used to identify each
host.
2. Class B - Class B is used for medium-sized networks. A good example is
a large college campus. IP addresses with a first octet from 128 to 191 are
part of this class. Class B addresses also include the second octet as part
of the Net identifier. The other two octets are used to identify each host.

3. Class C - Class C addresses are commonly used for small to mid-size

businesses. IP addresses with a first octet from 192 to 223 are part of this
class. Class C addresses also include the second and third octets as part
of the Net identifier. The last octet is used to identify each host.
4. Class D - Used for multicasts, Class D is slightly different from the first
three classes. It has a first bit value of 1, second bit value of 1, third bit
value of 1 and fourth bit value of 0. The other 28 bits are used to identify
the group of computers the multicast message is intended for.
5. Class E - Class E is used for experimental purposes only. Like Class D, it
is different from the first three classes. It has a first bit value of 1, second
bit value of 1, third bit value of 1 and fourth bit value of 1. The other 28 bits
are used to identify the group of computers the multicast message is
intended for.
 b) MAC Address:
The MAC address is a unique value associated with a network adapter. MAC
addresses are also known as hardware addresses or physical addresses. They
uniquely identify an adapter on a LAN.
MAC addresses are 12-digit hexadecimal numbers (48 bits in length). By
convention, MAC addresses are usually written in one of the following two
formats:
MM:MM:MM:SS:SS:SS OR MM-MM-MM-SS-SS-SS
The first half of a MAC address contains the ID number of the adapter
manufacturer. These IDs are regulated by an Internet standards body (see
sidebar). The second half of a MAC address represents the serial number
assigned to the adapter by the manufacturer. In the example,
00:A0:C9:14:C8:29
The prefix 00A0C9 indicates the manufacturer is Intel Corporation and the rest is
the serial number of the adapter.

Why MAC Addresses?

TCP/IP and other mainstream networking architectures generally adopt
the OSI model. In this model, network functionality is subdivided into layers. MAC
addresses function at the data link layer (layer 2 in the OSI model). They allow
computers to uniquely identify themselves on a network at this relatively low
level.

MAC vs. IP Addressing

MAC addressing works at the data link layer, IP addressing functions at the
network layer (layer 3). It's a slight oversimplification, but one can think of IP
addressing as supporting the software implementation and MAC addresses as
supporting the hardware implementation of the network stack. The MAC
address generally remains fixed and follows the network device, but the IP
address changes as the network device moves from one network to another.
23) VOIP- Voice over Internet Protocol:
VoIP stands for Voice over Internet Protocol. It is also referred to as
IP Telephony or Internet Telephony. It is another way of making phone calls, with
the difference of making the calls cheaper or completely free. The phone part is
not always present anymore, as you can communicate without a telephone set.
VoIP has a lot of advantages over the traditional phone system. The main reason
for which people are so massively turning to VoIP technology is the cost. VoIP is
said to be cheap, but most people use it for free. Yes, if you have a computer
with a microphone and speakers, and a good Internet connection, you can
communicate using VoIP for free. This can also be possible with your mobile and
home phone.
There are many ways of using VoIP technology. It all depends on where and how
you will be making the calls. It could be at home, at work, in your corporate
network, during a travel and even on the beach. The way you make calls varies
with the VoIP service you use.
VoIP is Often Free
The great thing about VoIP is that it taps additional value from the already
existing infrastructure without additional costs. VoIP transmits the sounds you
make over the standard Internet infrastructure, using the IP Protocol. This is how
you can communicate without paying for more than your monthly Internet
bill. Skype is the most popular example of services that allow you to make free
calls on your PC. There are many computer-based VoIP services out there, so
many that you will have a difficult choice. You can also make free calls using
traditional phones and mobile phones. See the different flavors of VoIP
service that allow you to do this.
24) Firewall:

Firewall is essentially a filter. It is either a software program or hardware device

used in computer systems to prohibit forbidden information for passing though,
while allowing approved information. The communication which the firewall
prevents from passing though could be
hackers trying to gain access to your
personal information stored on your
computer.

How do firewalls work?

The firewall inspects all the information
which is passed over the system and
determines if it is a threat or not based
upon a variety of factors. It then stops all Fig 14: Shows a firewall between LAN
potential threats from passing through. The and WAN
criteria which a firewall uses to determine
whether or not information in a threat or not is carefully determined.

Need of a firewall on personal computer?

Firewalls are important for anyone with online security concerns. Firewalls can
be used for businesses, known as a corporate firewall or by individuals, known
as a personal firewall. It has long been known the firewalls are a necessity for
businesses to protect their networks; however, the demand for personal firewalls
has increased dramatically.
The internet is full of individuals that are waiting for any signs vulnerability,
looking to take advantage of holes in our computer's security. Whether they are
looking to steal our private information, or damage our computer system, it is the
firewall's job to make sure they are denied access. The firewall acts as our
system's bouncer, making sure anyone you want to let in can pass without delay
while stopping all the other creeps at the door or in this case port.

Hardware & Software Firewall:

There are two types of firewalls the Hardware Firewall and the Software
Firewall. A Software Firewall is a software program and a Hardware Firewall is a
piece of hardware. Both have the same objective of filtering communications over
a system. Systems can use a Hardware Firewall, a Software Firewall, or a
combination of both.
Who needs a firewall?
If computers ports are open to the internet then there is a need of firewall
protection. That means, if internet is always connected for instance cable
internet or DSL, or if dial up is used for extended periods of time, then
computers must be protected with a firewall.

What is a proxy?
A proxy is either a router or a computer system that creates a break in the link
from the sender and receiver. All requests which are sent between the client and
the server are processed through the proxy. There is no longer a direct
connection between the client and internet as all requests are fielded by the
proxy and the proxy can refuse access to any unauthorized communications.

What techniques do firewalls use?

One technique firewalls use is a Proxy Server; this catches all communication,
in both directions. Another technique is Packet Filtering which checks all packets
going through a network and determines whether is allowed by specifications
determined by the user. Firewalls can also use an Application Gateway or a
Circuit Level Gateway.

What is Port 80?

Port 80 is the default port which HTTP transactions (web transactions) pass
through.

What should your firewall be doing?

What are the most important points to focus on when choosing a firewall?
A good firewall will ensure the security of ports that can be used to access
your system.
Your system should not just be protected from incoming communications;
your firewall should also make sure personal information is not leaving
your system unauthorized.
Your firewall should be monitoring your system for any suspicious
behavior.
A firewall should not be slowing you down. It should not send you any
unnecessary notices.
 Some of the things firewall cant prevent:
E-mail viruses
E-mail viruses are attached to e-mail messages. A firewall can't
determine the contents of e-mail, so it can't protect you from these types
of viruses. You should use an antivirus program to scan and delete
suspicious attachments from an e-mail before you open it. Even when you
have an antivirus program, you should not open an e-mail attachment if
you're not positive it's safe.

Phishing scams
Phishing is a technique used to trick computer users into revealing
personal or financial information, such as a bank account password. A
common online phishing scam starts with an e-mail message that appears
to come from a trusted source but actually directs recipients to provide
information to a fraudulent website. Firewalls can't determine the contents
of e-mail, so they can't protect you from this type of attack.

Types Of Firewalls:

Packet Filtering Firewalls-

Packet filtering firewalls are generally a part of a router and work by
filtering the packet which the router receives. When the router receives the
packet from a network the firewall checks it according to specific list of
rules and decides whether or not to forward it to the next network.
Circuit Level Gateways-
Circuit level gateways do not filter each packet but rather check that
each session is secure. They work at the session layer of the OSI model
and inspect the TCP handshaking between packets. If a session is
deemed secure then a connection is made.
Application Level Gateways (Proxies)-
Application level gateways, otherwise known as proxies, filter
packets from the application layer of the OSI model. Filtering at the
application layer enables them to differentiate between different
application commands.
Stateful Multilayer Inspection Firewalls-
Stateful multilayer inspection firewalls are the most complex of
firewalls. They are essentially an amalgamation of the other three types
of firewalls. They first evaluate packets at the network level, they then
check if the packets are allowed and inspect the packets contents at the
application level.
25) Antivirus:
A computer virus is a computer program that
can copy itself and infect a computer without
the knowledge or permission of the owner. A
virus can only be spread from one computer to
another through some form of executable
codes. Viruses can be sent over a network,
the Internet, floppy disk, CD, or USB drive.
Viruses can increase changes of spreading to other computers by infecting files
on a network system that is accessed by other computers.
The term computer virus is used to include all types or malware such as
computer viruses, trojan horses, most rootkits, spyware, dishonest adware,
crimeware, and other malicious unwanted software. Since most computers are
now connected to the Internet and local networks it is increasing the chance for
spreading malicious virus codes.

Computer viruses cause a number of symptoms such as:

Computer programs taking longer to load than normal.
The computer is slower than normal.
Computer stops responding or freezes frequently.
Computer crashes and restarts every few minutes.
The computer does not run as usual.
Applications on the computer do not work correctly.
Disks or disk drives are inaccessible.
Printing items is difficult.
Error messages appear rapidly.
Distorted menus and dialog boxes.
Double extensions on attachments that you have already opened
(jpg,vbs,gif, exe, and etc).
Antivirus programs get disabled for no reason, and cannot be restarted.
Antivirus programs will not start, and new programs cannot be installed.
Strange sounds plays from the speakers unexpectedly.
Programs disappear from the computer.
These symptoms are common signs of computer virus infection, and they are
also warning signs that you may be getting a computer virus. When you suspect
that you are getting a computer virus there are many ways to take care of it.
Before you can get a virus it is best to prevent them from getting into your
computer by having a antivirus software.
Antivirus Software
Antivirus software is used to prevent, detect, and remove malware and other
computer viruses. Antivirus software systems detections involve searching for
known malicious patterns in executable code. it is possible for a user to be
infected with new viruses that have no sign or symptoms or existence. To counter
this problem of zero day threats, anti virus systems can be used to detect these
viruses when you don't even know that they are there.

There are many different types of antivirus software that have been developed
over the years. Original products were just scanners that would search through
the hard disk looking for viruses. As viruses have become more common and
difficult, the more antivirus software is being made to keep up with current virus
issues. There are many different types of general virus scanners that are used on
PCs today:

Conventional Disk Scanner

This is the stand virus check program. It can be ran upon the users request, and
it scans the contents of the disks, directories or files that the users wants, for any
boot sectors or files that contain viruses that it recognizes. These are usually ran
manually by the user as a preventive maintenance activity or when they thing a
virus is suspected. The user can schedule automatic scanning through the use of
a program scheduler.

Memory Resident Scanners

An antivirus software that now come with a special program that sits in the
background while youre using your computer and it automatically scans for
viruses based on different triggers. These programs can automatically scan as
they run or scan floppy disks when you command a shutdown of your system.
This scanner offers increased protection and more chances of catching a virus
before it does damage to your computer.

Behavior Based Detection

Some products offer an option where they will sit in memory and look for virus
like behavior and suspicious activity. Behavior based detection is looking for the
types of actions taken on files or boot sectors that might be performed by viruses
trying to spread. This type of antivirus software will look for a trap, and will
generically catch viruses red handed.

Start up Scanners
This type of antivirus scanner is designed to be run every time the PC is booted
up. It performs a quick scan of the disks boot sectors and critical system files. the
idea is to catch these viruses before the PC boots up reducing the chance of it to
spread.
Inoculation
Instead of scanning for viruses this type of antivirus software looks for changes
that the viruses make to files and boot sectors. With a clean system the software
will get a snap shot of information in each boot sector about its content and size.
Periodically it will re examine these files to see if anything has changed.
Top Anti Virus Software

The Shield Deluxe 2009 Antivirus & Antispyware

Webroot Antivirus with Antispyware 6.0
BitDefender Antivirus 2009
CA Anti-Virus Plus 2009
McAfee Virus Scan Plus 2009
Norton Antivirus 2009
ESET NOD 32 3.0

26) UTM-Unified Threat Management:

UTM solutions emerged out of the need to stem the increasing number
of attacks on corporate information systems a hacking / cracking, viruses,
worms - mostly an outcome of blended threats and insider threats. Data
security and unauthorized employee access have become major business
concerns for enterprises today. This is because malicious intent and the
resultant loss of confidential data can lead to huge financial losses as well

as corresponding legal liabilities.

Fig 15: Contents of UTM

 How UTM secures the network?
A single UTM appliance makes it very easy to manage a company's security
strategy, with just one device to worry about, one source of support and a single
way to maintain every aspect of your security solution. The UTM can prove to be
more effective a solution as its strength lies in the bundle of solutions which are
integrated and designed to work together. Also from one single centralized
console, all the security solutions can be monitored and configured. Thus it
tweaks the solutions to perfection.
In this context, UTMs represent all-in-one security appliances that carry a variety
of security capabilities including firewall, VPN, gateway anti-virus, gateway anti-
spam, intrusion prevention, content filtering, bandwidth management, application
control and centralized reporting as basic features. The UTM is thus, a highly
integrated quiver of security solutions, working in tandem that systematically
provides network security to organizations. As there is a customized OS holding
all these security features at one place, they tend to work in unison, providing a
very high throughput. The UTM can prove highly effective because its strength
lies in the bundle of solutions which are integrated and designed to work together
without treading on each others toes.
For enterprises with remote networks or distantly located offices, UTMs are the
only means to provide centralized security with complete control over their
globally distributed networks. Enterprises, thus get zero-hour protection at branch
offices against security attacks despite the lack of technical resources at these
locations.

Earlier, the enterprise security

scenario was divided into traditional
firewalls & targeted applications like
Antivirus, Anti spam & Intrusion
Detection Systems.

Fig 16: Previous view of security system

 However in 2004, a new trend
emerged which combined multiple
security features into one single
hardware platforms thereby
eliminating the need of machine to
machine protection
Since its inception, UTMs are one of
the fastest growing segment in the
security appliance sector.
Fig 17: Shows that UTM has replaced all
security systems by one device

Why UTM?
i. Reduced complexity: Single security solution. Single Vendor. Single AMC.
ii. Simplicity: Avoidance of multiple software installation and maintenance,
The integrated approach allows the administrator to worry about only one
device, not the whole flurry of firewalls, antivirus & IDS/IPS.
iii. Easy Management: Plug & Play Architecture, Web-based GUI for easy
management.
iv. Performance: Zero-hour protection without degrading the network
performance
v. Troubleshooting: Single point of contact 24 7 vendor support.
vi. Reduced technical training requirements, one product to learn.
vii. Cost effective.

Cyberoam UTM delivers enterprise-class network

security with crateful inspection firewall, VPN and
IPS, offering the Human Layer 8 identity-based
controls and Layer 7 application controls. It
ensures high levels of network security, network
connectivity, continuous availability and secure remote access with controlled
network access to road warriors, telecommuters, partners, customers.

Shift from Firewall to UTM Security Cyberoam offers Stateful Inspection

Firewall that is tightly integrated with VPN (IPSec & SSLVPN), Intrusion
Prevention System, Anti-Virus & Anti-Spyware, Anti-Spam, Web Filtering,
Bandwidth Management, Multiple Link Management to provide unified security.

Layer 1 to Human Layer 8 Firewall Cyberoam UTMs Stateful Inspection

Firewall implements policies based on the Physical Layer 1 to Application Layer 7
and Human Layer 8 with User Identity in addition to source, destination zone, IP
address and application. It enables organizations to control access to network
resources based on the user identity, work profile and application access
requirement of external users like customers and partners, internal LAN users
and employees outside the perimeter like road warriors, telecommuters. It also
offers user identity-based security in dynamic Wi-Fi, DHCP and shared endpoint
environments.

VPN Cyberoam UTM offers VPNC-certified IPSec and SSL VPN over the UTM
appliance, ensuring easy-to-manage secure remote access with high business
flexibility while lowering the capital and operating expense involved in deploying
dedicated VPN appliances.

IPS Cyberoam offers advanced Intrusion Prevention System (IPS) carrying

thousands of signatures applicable with human and application layer policies to
automatically detect and block intrusions, IM and P2P exploits, backdoor attacks
and other malware. Cyberoams IPS carries HTTP proxy signatures and custom
signature capability, offering customized protection to meet the unique security
requirements of each organization.

Advanced Network Security Cyberoam offers advanced network security

features to deliver business continuity, faster uptimes, higher network throughput,
rapid network growth, meeting the security and regulatory compliance
requirements through the following capabilities
High Availability with stateful failover
Dynamic routing
Multiple VLAN zones to create work-profile based groups across
distributed locations
Virtual host capability, enabling secure hosting of services inside the LAN
and DMZ
Centralized management and logging-reporting

27) IP Based Printer/ Network Printer:

Some printers, commonly known as network printers, have built-
in network interfaces, typically wireless and/or Ethernet based, and can serve
as a hard copy device for any user on the network. A network printer is shared by
more than one computer.
Network printing is having the ability to print over the
network. In other words, you dont need to have the
printer directly connected to your computer. For example,
if you have your computer and youre sitting in your office
and need to print to the printer at the front desk, you dont
need to send the document to the front desk computer Fig 18: Network Printer
or take your computer over to the printer and plug it in.
Instead, because the front desk printer is on the
network, you can simply click print, choose that printer, and print whatever it is
you need to print over the network.
A networked printer is a printer that is hooked up to your computer network with a
network cable or with a wireless networking adapter. Networked printers have
what is called a print server attached to them. The print server can be external to
the printer, a plug-in JetDirect card, or built-in to the formatter of the printer.

28) IP Camera:
An Internet protocol camera, or IP camera, is a type of digital video camera
commonly employed for surveillance, and which unlike analog closed circuit
television (CCTV) cameras can send and receive data via a
computer network and the Internet. Although most cameras that do
this are webcams, the term "IP camera" is usually applied only to
those used for surveillance.
Fig 19:Cisco PVC300
There are two kinds of IP cameras: Ip camera
Centralized IP cameras, which require a
central Network Video Recorder (NVR) to handle the
recording, video and alarm management.
Decentralized IP cameras, do not require a central Network Video
Recorder (NVR), as the cameras have recording functionality built-in and
can thus record directly to digital storage media, such as flash
drives, hard disk drives or network attached storage.
Potential advantages:

Two-way audio via a single network cable allows users to communicate with what
they are seeing (e.g. gas station clerk assisting a customer on how to use the
prepay pumps)
Higher image resolution: IP cameras have a resolution of at least 640x480
and can provide multi-megapixel resolution and HDTV image quality at 30
frames per second.
Flexibility: IP cameras can be moved around anywhere on an IP network
(including wireless).
Distributed intelligence: with IP cameras, video analytics can be placed in
the camera itself allowing scalability in analytics solutions.
Transmission of commands for PTZ (pan, tilt, zoom) cameras via a single
network cable.
Encryption & authentication: IP cameras offer secure data transmission
through encryption and authentication methods .
Remote accessibility: live video from selected cameras can be viewed
from any computer, anywhere, and also from many mobile smart
phones and other devices.
Cost-advantage for larger systems. Studies show that for systems with
fewer than 16 cameras, analog technology is cheaper, between 16 and 32
they are equal, and beyond 32 cameras, IP-based systems are more cost-
effective.
IP cameras are able to function on a wireless network. Initial configuration
has to be done through a router; after the IP camera is installed it can then
be used on the wireless network. These cameras are used in navigation
purpose in defense forces.
PoE - Power over Ethernet. Modern IP cameras have the ability to operate
without an additional power supply. They can work with the PoE-protocol
which gives power via the Ethernet-cable.

Potential disadvantages:
Higher initial cost per camera, except where cheap webcams are used.
(Note - IP cameras are becoming cheaper as demand increases and are
already available below 50usd and compete favorably with analogue
cameras).
High network bandwidth requirements: a typical CCTV camera with
resolution of 640x480 pixels and 10 frames per second (10 frame/s) in
MJPEG mode requires about 3 Mb/s.
Technical barrier. Most security systems including both CCTV and IP
camera systems may require a professional technician to install the
 system, although a competent person can install an IP camera very easily,
depending on make.
As with a CCTV/DVR system, if the video is transmitted over the public
Internet rather than a private IP LAN, the system becomes open to
hacking and hoaxing via internet. Criminals can hack into a CCTV system
to observe security measures and personnel, thereby facilitating criminal
acts and rendering the IP technology counterproductive.

29) Optic Fibre Cable

Fiber-optic lines are strands of optically pure glass as thin as a human hair that
carry digital information over long distances. They are also used in medical
imaging and mechanical engineering inspection.
Fiber optics (optical fibers) are long, thin strands of very pure glass about the
diameter of a human hair. They are arranged in bundles called optical cables and
used to transmit light signals over long distances.

It consists of the following parts:

1. Core - Thin glass center of the fiber where the light travels
2. Cladding - Outer optical material surrounding the core that reflects the
light back into the core
3. Buffer coating - Plastic coating that protects the fiber from damage and
moisture

Hundreds or thousands of these optical fibers are arranged in bundles in optical

cables. The bundles are protected by the cable's outer covering, called a jacket.
Optical fibers come in two types:
1. Single-mode fibers
2. Multi-mode fibers

Single-mode fibers have small cores (about 3.5 x 10-4 inches or 9 microns in
diameter) and transmit infrared laser light (wavelength = 1,300 to 1,550
nanometers).

Multi-mode fibers have larger cores (about 2.5 x 10-3 inches or 62.5 microns in
diameter) and transmit infrared light (wavelength = 850 to 1,300 nm) from light-
emitting diodes (LEDs).
Some optical fibers can be made from plastic. These fibers have a large core
(0.04 inches or 1 mm diameter) and transmit visible red light (wavelength = 650
nm) from LEDs.
Transmission Of Light In Optic Fibre:
The light in a fiber-optic cable travels through the core (hallway) by constantly
bouncing from the cladding (mirror-lined walls), a principle called total internal
reflection. Because the cladding does not absorb any light from the core, the light
wave can travel great distances.
However, some of the
light signal degrades
within the fiber, mostly
due to impurities in the
glass. The extent that the
signal degrades depends
on the purity of the glass
and the wavelength of the
transmitted light (for
example, 850 nm = 60 to
75 percent/km; 1,300 nm
= 50 to 60 percent/km; 1,550 nm is Fig 20: Diagram of total internal
greater than 50 percent/km). Some reflection in an optical fiber
premium optical fibers show much
less signal degradation -- less than 10 percent/km at 1,550 nm.

Advantages of Fiber Optics

Some advantages of optical fibers are:
1. Less expensive - Several miles of optical cable can be made cheaper
than equivalent lengths of copper wire. This saves your provider (cable
TV, Internet) and you money.
2. Thinner - Optical fibers can be drawn to smaller diameters than copper
wire.
3. Higher carrying capacity - Because optical fibers are thinner than copper
wires, more fibers can be bundled into a given-diameter cable than copper
wires. This allows more phone lines to go over the same cable or more
channels to come through the cable into your cable TV box.
4. Less signal degradation - The loss of signal in optical fiber is less than in
copper wire.
5. Light signals - Unlike electrical signals in copper wires, light signals from
one fiber do not interfere with those of other fibers in the same cable. This
means clearer phone conversations or TV reception.
6. Low power - Because signals in optical fibers degrade less, lower-power
transmitters can be used instead of the high-voltage electrical transmitters
needed for copper wires. Again, this saves your provider and you money.
 7. Digital signals - Optical fibers are ideally suited for carrying digital
information, which is especially useful in computer networks.
8. Non-flammable - Because no electricity is passed through optical fibers,
there is no fire hazard.
9. Lightweight - An optical cable weighs less than a comparable copper wire
cable. Fiber-optic cables take up less space in the ground.
10. Flexible - Because fiber optics are so flexible and can transmit and
receive light, they are used in many flexible digital cameras for the
following purposes:
11. Medical imaging - in bronchoscopes, endoscopes, laparoscopes
12. Mechanical imaging - inspecting mechanical welds in pipes and engines
(in airplanes, rockets, space shuttles, cars)
13. Plumbing - to inspect sewer line.
Safety:
Because the infrared light used in communications cannot be seen, there is a
potential laser safety hazard to technicians. In some cases the power levels
are high enough to damage eyes, particularly when lenses or microscopes
are used to inspect fibers which are inadvertently emitting invisible IR.
Inspection microscopes with optical safety filters are available to guard
against this.
Small glass fragments can also be a problem if they get under someone's
skin, so care is needed to ensure that fragments produced
when cleaving fiber are properly picked up and disposed of.

30) RJ45 vs CAT5 :

When it comes to wired networking, RJ45 and CAT5 are two of the most
common terms being thrown around. What most people dont know is that
although these terms are often used to refer to the same cables, they are not the
same.
RJ45 is the electrical interconnection standard that defines
the connector and how the wires are arranged at the end of
the cable while CAT5 is a standard regarding Ethernet
cables.
RJ45, with the acronym RJ standing for registered jack,
started out as an interconnection standard intended for
telephones and looks pretty much like a bigger version of
the RJ11 used in our landlines. It never saw widespread Fig 21: Rj45 Cable and
connector
use in telephony but has flourished in computer networking
where it became the standard for wired networking. Some
homes do have RJ45 wall outlets but these are often used to connect VoIP
phones rather than for connecting a laptop.
CAT5, a common contraction for category 5, is a classification of cables
that are used for Ethernet networks. A single CAT5 cable contains four twisted
pairs of color coded cables. The twisting of the wires reduces the amount of
crosstalk and cancels out EMI. CAT5 cables rely on the twisting for noise
reduction and are not shielded. This can be problematic in some areas where
electrical noise is great. CAT5, or to be
more accurate
CAT5e, cables are currently the ones that
are being used in most networks
nowadays. It provides adequate bandwidth
for the 100mbps connections of LAN
cards. Due to ever increasing network
speeds and the need to be prepared for
future technologies, it is slowly being
Fig 22: cat 5 cable and replaced by CAT6 cables though as CAT5
connector is inadequate for gigabit speeds. Maximum
length of cat 5 cable 328 feets(100 metres)
and 2800 m with four repeaters

So, RJ45 and CAT5 are two parts of wired networking that are non-competing.
RJ45 dictates how the cables are wired while CAT5 dictates the maximum speed
you can attain with the cables used. CAT5 is easily replaceable and that is whats
basically happening in certain parts of the world. RJ45 is more difficult to replace
as that is whats being used by hardware manufacturers around the world; and,
there is really no reason to replace RJ45.

Summary:
1. RJ45 is the electrical interconnection standard while CAT5 is the
cable standard.
2. RJ45 dictates with what you can use the cable for while CAT5
determines how large a bandwidth you have.
31) Copper Wire:
The attractive properties which made copper so useful then - good corrosion
resistance, attractive colour, excellent workability and good mechanical
properties - are relevant today and, in addition, copper has the best electrical and
thermal conductivity of any commercial metal. Today, over half of the copper
produced is used in electrical and electronic applications and this leads to a
convenient classification of the types of copper into:

electrical (high conductivity)

Non-electrical (engineering).

The low hardness of copper partly explains its high electrical

6
(59.610 S/m) and thus also high thermal conductivity, which are the second
highest among pure metals at room temperature
Properties of Copper

An excellent electrical conductor tough

An excellent thermal conductor non-magnetic
corrosion resistant an attractive colour
anti-bacterial easy to alloy
easily joined recyclable
ductile catalytic

Electrical conductivity
Copper has the best electrical conductivity of any metal, except silver. A good
electrical conductivity is the same as a small electrical resistance.
Applications
Copper wires allow electric current to flow without much loss of energy. This is
why copper wires are used in mains cables in houses and underground (although
overhead cables tend be aluminium because it is less dense). However, where
size rather than weight is important, copper is the best choice. Thick copper strip
is used for lightning conductors on tall buildings like church spires. The cable has
to be thick so that it can carry a large current without melting.
How copper conducts
Copper is a metal. It is made up of copper atoms closely packed together.
If we could look closely enough, we would see that there are electrons moving
about between the copper atoms. Each copper atom has lost one electron and
become a positive ion. So copper is a lattice of positive copper ions with free
electrons moving between them. (The electrons are a bit like the particles of a
gas that is free to move within the edges of the wire).
The electrons can move freely through the metal. For this reason, they are
known as free electrons. They are also known as conduction electrons, because
they help copper to be a good conductor of heat and electricity.
The copper ions are vibrating. Notice that they vibrate around the same place
whereas the electrons can move through the lattice. This is very important when
we connect the wire to a battery.

Conducting electricity
We can connect a copper wire to a battery and a switch. Normally, the free
electrons move about randomly in the metal. When we close the switch, an
electric current flows. Now the free electrons flow through the wire (here, they are
moving from left to right - although they still move randomly as well).
Electrons have a negative charge. They are attracted to the positive end of the
battery. The free electrons move through the copper, flowing from the negative to
positive terminal of the battery (note that they flow in the opposite direction to
conventional current; this is because they have a negative charge).
The copper ions in the wire vibrate. Sometimes an ion blocks the path of a
moving electron. The electron collides with the ion and bounces off it. This slows
down the electron. Some of its energy has been transferred to the ion,
which vibrates faster.

In this way, energy is transferred from the moving electrons to the copper ions.
The copper gets hotter. This explains why:
metals have electrical resistance;
metals get hot when a current flows through them.
32) Satellite Communication:
A Satellite is a solid object which revolves around some heavenly body due to
the effect of gravitational forces which are mutual in nature. .
A satellite communications system uses satellites to relay radio transmissions
between earth terminals. The two types of communications satellites are ACTIVE
and PASSIVE. . A passive satellite only reflects received radio signals back to
earth. An active satellite acts as a REPEATER; it amplifies signals received and
then retransmits them back to earth .This increases signal strength at the
receiving terminal to a higher level than would be available from a passive
satellite.

Fig 23: Satellite Communication

How do satellites work?

Two Stations on Earth want to communicate through radio broadcast but are too
far away to use conventional means. The two stations can use a satellite as a
relay station for their communication .
A typical operational link involves an active satellite and two or more earth
terminals. One station transmits to the satellite on a frequency called the UP-
LINK frequency. The satellite then amplifies the signal, converts it to the DOWN-
LINK frequency, and transmits it back to earth. The signal is next picked up by
the receiving terminal.
One Earth Station sends a transmission to the satellite. This is called a Uplink.
The satellite Transponder converts the signal and sends it down to the second
earth station. This is called a Downlink.
 The term Satellite communication is very frequently used, but what is
satellite communication?
It is simply the communication of the satellite in space with large number of
earth stations on the ground. Users are the ones who generate baseband
signals, which is processed at the earth station and then transmitted to the
satellite through dish antennas. Now the user is connected to the earth station
via some telephone switch or some dedicated link. The satellite receives the
uplink frequency and the transponder present inside the satellite does the
processing function and frequency down conversion in order to transmit the
downlink signal at different frequency.
The earth station then receives the signal from the satellite through parabolic
dish antenna and processes it to get back the baseband signal. This baseband
signal is then transmitted to the respective user via dedicated link or other
terrestrial system.

The advantages of satellite communication over terrestrial communication

are:
The coverage area of a satellite greatly exceeds that of a terrestrial system.
Transmission cost of a satellite is independent of the distance from the
center of the coverage area.
Satellite to Satellite communication is very precise.
Higher Bandwidths are available for use.
Very good for file and data transfer.

The disadvantages of satellite communication:

Launching satellites into orbit is costly.
Satellite bandwidth is gradually becoming used up.
There is a larger propagation delay in satellite communication than in
terrestrial communication.
Time consuming.
Not fit for voice transfer.

Equipments used in SATELLITE communication:

Satellite modem
EMR: The Edge Media Router (EMR) series of satellite receivers and
routers are versatile and powerful networking platforms that receive and
manage content at the network edge for small office/home office (SOHO),
enterprise, government agency and service provider deployments. The
EMR series provides a complete satellite Internet solution.
The Micro-EMR-1600 is a compact satellite receiver and media router for
cost-effective satellite connectivity to the SOHO environment.
The EMR 5520S and 5540S offer service providers a powerful platform to
deliver mission-critical real-time information to users over broadcast and
broadband networks for applications including distance-learning; real-time
data dissemination; remote site IP video distribution; Internet over Satellite
services; broadcast content, file and data distribution and global IP
network connectivity. Residing at the edge of the data delivery network,
the EMR series can extract or pass through encrypted IP content from
incoming DVB MPEG-2 transport streams. It decrypts and routes content
to edge networks for delivery over 10/100 Fast Ethernet connections.
RFT: Frequency transmitter and Receiver
SSPA: A solid state power amplifier (SSPA) is a transmitter power
amplifier that uses semiconductor devices (transistors) for all
amplification. In a transmitter, a power amplifier is used to drive the
antenna.
LNA: Low-noise amplifier (LNA) is an electronic amplifier used to
amplify very weak signals (for example, captured by an antenna).
Using a LNA, the effect of noise from subsequent stages of the
receive chain is reduced by the gain of the LNA, while the noise of
the LNA itself is injected directly into the received signal. Thus, it is
necessary for a LNA to boost the desired signal power while adding
as little noise and distortion as possible, so that the retrieval of this
signal is possible in the later stages in the system.
Feed Horn: The feedhorn is the part of a satellite dish system
which gathers the reflected signal from the dish and focuses it
towards the LNB. The feedhorn also does the job of attenuating
unwanted signals from sources like adjacent channels. This is done
by selection of the polarity of the waves that are to be received. As
an accessory located at the focal point of a satellite dish system or
a paraboloid antenna, it gathers the reflected signal from the dish
and focuses it towards the Low Noise Block (LNB), which is usually
affixed in or on the dish.
33) Protecting the Receiver:
Receiver is the receiving end of a communications channel.
If you experience erratic behavior that seems like a radio glitch, it could be
from receiver damage. Fuel, oil, water, snow, mud, and even a spilled soda can
seep into the receiver and create malfunctions that cause erratic behavior or
permanent damage. Vibration from normal operation or, especially, a sudden jolt
(such as from a crash, a hard landing after a jump, or being dropped) can
dislodge the crystal or knock antenna wires loose causing erratic behavior or
make the RC stop working entirely. One specific way to protect your receiver
from both moisture and the effects of vibration is using a receiver cover or
balloon.
Use a Receiver Cover or Balloon

A fitted receiver cover helps protect the receiver from moisture and may provide
a small amount of vibration protection. If your RC didn't come with a cover you
can purchase one, or just use a balloon. A simple balloon (yes, like you blow up
for parties or use as water balloons) over the receiver is an inexpensive way to
protect the receiver from damage. Use a zip tie to seal the open end of the
balloon.

34) Radio Frequency:

Radio frequency (abbreviated RF, rf, orr.f.) is a term that refers to alternating
current (AC) having characteristics such that, if the current is input to an antenna,
an electromagnetic (EM) field is generated suitable for wireless broadcasting
and/or communications. These frequencies cover a significant portion of
the electromagnetic radiation spectrum, extending from nine kilohertz (9 kHz),the
lowest allocated wireless communications frequency (it's within the range of
human hearing), to thousands of gigahertz(GHz).
When an RF current is supplied to an antenna, it gives rise to an electromagnetic
field that propagates through space. This field is sometimes called an RF field; in
less technical jargon it is a "radio wave." Any RF field has a wavelength that is
inversely proportional to the frequency. In the atmosphere or in outer space, if f is
the frequency in megahertz and sis the wavelength in meters, then
s = 300/f.
The frequency of an RF signal is inversely proportional to the wavelength of the
EM field to which it corresponds. At 9
kHz, the free-space wavelength is approximately 33 kilometers (km) or 21 miles
(mi). At the highest radio frequencies, the EM wavelengths measure
approximately one millimeter (1 mm). As the frequency isincreased beyond that
of the RF spectrum, EM energy takes the form of infrared (IR), visible, ultraviolet
(UV), X rays, and gamma rays.
Many types of wireless devices make use of RF fields. Cordless and cellular
telephone, radio and television broadcast stations, satellite communications
systems, and two-way radio services all operate in the RF spectrum. Some
wireless devices operate at IR or visible-light frequencies, whose electromagnetic
wavelengths are shorter than those of RFfields. Examples include most
television-set remote-control boxes, some cordless computer keyboards and
mice, and a few wireless hi-fi stereo headsets.
The RF spectrum is divided into several ranges, orbands. With the exception of
the lowest-frequency segment, each band represents an increase of frequency
corresponding to an order of magnitude (power of 10). The table depicts the eight
bands in the RF spectrum, showing frequency and bandwidth ranges. TheSHF
and EHFbands are often referred to as the microwave spectrum.

Free-space
Designation AbbreviationFrequencies
Wavelengths
Very Low Frequency VLF 9 kHz - 30 kHz 33 km - 10 km
Low Frequency LF 30 kHz - 300 kHz 10 km - 1 km
Medium Frequency MF 300 kHz - 3 MHz 1 km - 100 m
High Frequency HF 3 MHz - 30 MHz 100 m - 10 m
30 MHz - 300
Very High Frequency VHF 10 m - 1 m
MHz
Ultra High Frequency UHF 300 MHz - 3 GHz 1 m - 100 mm
Super High Frequency SHF 3 GHz - 30 GHz 100 mm - 10 mm
Extremely High 30 GHz - 300
EHF 10 mm - 1 mm
Frequency GHz

Table 1: List of frequencies

Although radio frequency is a rate of oscillation, the term "radio frequency"

or its acronym "RF" is also used as a synonym for radio i.e. to describe the use
of wireless communication, as opposed to communication via an electrical
connector
The energy in an RF current can radiate off a conductor into space
as electromagnetic waves (radio waves); this is the basis of radio technology. RF
current does not penetrate deeply into electrical conductors but flows along their
surfaces; this is known as the skin effect. For this reason, when the human body
comes in contact with high power RF currents it can cause superficial but serious
burns called RF burns. RF current can easily ionize air, creating a conductive
path through it.
 In order to receive radio signals an antenna must be used. However, since
the antenna will pick up thousands of radio signals at a time, a radio tuner is
necessary to tune in to a particular frequency

35) Masts - Tower:

Radio masts and towers are, typically, tall structures designed to
support antennas (also known as aerials) for
telecommunications and broadcasting, including television. They are among the
tallest man-made structures.
a tower is an antenna structure attached to the ground, whereas a mast is a
vertical antenna support mounted on some other structure (which itself may be a
tower, a building, or a vehicle). Masts (to use the civil engineering terminology)
tend to be cheaper to build but require an extended area surrounding them to
accommodate the guy wires. Towers are more commonly used in cities where
land is in short supply.
a tower is an antenna structure attached to the ground, whereas a mast is a
vertical antenna support mounted on some other structure (which itself may be a
tower, a building, or a vehicle). Masts (to use the civil engineering terminology)
tend to be cheaper to build but require an extended area surrounding them to
accommodate the guy wires. Towers are more commonly used in cities where
land is in short supply.

36) Antenna:
An antenna (or aerial) is an electrical device which couples radio waves in free
space to an electrical current used by a radio receiver or transmitter. In reception,
the antenna intercepts some of the power of an electromagnetic wave in order to
produce a tiny voltage that the radio receiver can amplify. Alternatively, a radio
transmitter will produce a large radio frequency current that may be applied to the
terminals of the same antenna in order to convert it into an electromagnetic wave
(radio wave) radiated into free space. Antennas are thus essential to the
operation of all radio equipment, both transmitters and receivers. They are used
in systems such as radio and television broadcasting, two-way radio, wireless
LAN, mobile telephony, radar, and satellite communications.
37) VPN-Virtual Private Networks:
A VPN utilizes public telecommunications networks to conduct private data
communications. Most VPN implementations use the Internet as the public
infrastructure and a variety of specialized protocols to support private
communications through the Internet.
VPN follows a client and server approach. VPN clients authenticate users,
encrypt data, and otherwise manage sessions with VPN servers utilizing a
technique called tunneling.

VPN clients and VPN servers are typically used in these three scenarios:
1.to support remote access to an intranet,
2. to support connections between multiple intranets within the same
organization, and
3. to join networks between two organizations, forming an extranet.

VPN servers can also connect directly to other VPN servers. A VPN server-to-
server connection extends the intranet or extranet to span multiple networks.

Types of VPN Tunneling:

VPN supports two types of tunneling - voluntary and compulsory. Both

types of tunneling are commonly used.
In voluntary tunneling, the VPN client manages connection setup. The client
first makes a connection to the carrier network provider (an ISP in the case of
Internet VPNs). Then, the VPN client application creates the tunnel to a VPN
server over this live connection.
In compulsory tunneling, the carrier network provider manages VPN
connection setup. When the client first makes an ordinary connection to the
carrier, the carrier in turn immediately brokers a VPN connection between that
client and a VPN server. From the client point of view, VPN connections are set
up in just one step compared to the two-step procedure required for voluntary
tunnels.
VPN offers two main advantages over alternative technologies: cost savings, and
network scalability. To the clients accessing these networks, VPNs also bring
some benefits of ease of use.
Cost Savings with a VPN: A VPN can save an organization money in
several situations:
eliminating the need for expensive long-distance leased lines
reducing long-distance telephone charges
offloading support costs
VPN Network Scalability:

The cost to an organization of building a dedicated private network may be

reasonable at first but increases exponentially as the organization grows.
nternet based VPNs avoid this scalability problem by simply tapping into the the
public lines and network capability readily available. Particularly for remote and
international locations, an Internet VPN offers superior reach and quality of
service.

Fig 24 : VPN Network

38) Comparison between TCP and UDP:
Transmission Control Protocol: TCP (Transmission Control Protocol) is a set
of rules (protocol) used along with the Internet Protocol (IP) to send data in the
form of message units between computers over the Internet. While IP takes care
of handling the actual delivery of the data, TCP takes care of keeping track of the
individual units of data (called packets) that a message is divided into for efficient
routing through the Internet.
TCP is known as a connection-oriented protocol, which means that a connection
is established and maintained until such time as the message or messages to be
exchanged by the application programs at each end have been exchanged. TCP
is responsible for ensuring that a message is divided into the packets that IP
manages and for reassembling the packets back into the complete message at
the other end. In the Open Systems Interconnection (OSI) communication model,
TCP is in layer 4, the Transport Layer.

User Datagram Protocol (UDP): UDP is a communications protocol that offers a

limited amount of service when messages are exchanged between computers in
a network that uses the Internet Protocol (IP). UDP is an alternative to the
Transmission Control Protocol (TCP) and, together with IP, is sometimes referred
to as UDP/IP. Like the Transmission Control Protocol, UDP uses the Internet
Protocol to actually get a data unit (called a datagram) from one computer to
another. Unlike TCP, however, UDP does not provide the service of dividing a
message into packets (datagrams) and reassembling it at the other end.
Specifically, UDP doesn't provide sequencing of the packets that the data arrives
in. This means that the application program that uses UDP must be able to make
sure that the entire message has arrived and is in the right order. Network
applications that want to save processing time because they have very small
data units to exchange (and therefore very little message reassembling to do)
may prefer UDP to TCP. The Trivial File Transfer Protocol (TFTP) uses UDP
instead of TCP.
UDP provides two services not provided by the IP layer. It provides port
numbers to help distinguish different user requests and, optionally, a checksum
capability to verify that the data arrived intact.
TCP UDP
Reliability: TCP is connection-orientedReliability: UDP is connectionless protocol.
protocol. When a file or message send it will When you a send a data or message, you
get delivered unless connections fails. If don't know if it'll get there, it could get lost on
connection lost, the server will request the the way. There may be corruption while
lost part. There is no corruption while transferring a message.
transferring a message.
Ordered: If you send two messages along a Ordered: If you send two messages out,
connection, one after the other, you know the you don't know what order they'll arrive in
first message will get there first. You don't i.e. no ordered
have to worry about data arriving in the wrong
order.
Heavyweight: - when the low level parts of Lightweight: No ordering of messages, no
the TCP "stream" arrive in the wrong order,tracking connections, etc. It's just fire and
resend requests have to be sent, and all the forget! This means it's a lot quicker, and the
out of sequence parts have to be put back network card / OS have to do very little work
together, so requires a bit of work to piece to translate the data back from the packets.
together.
Streaming: Data is read as a "stream," with Datagrams:
S.No Packets
NAME are sent individually
Port Number
nothing distinguishing where one packet ends and are guaranteed to be whole if they
1 FTP
and another begins. There may be multiple arrive. One packet per one20/21
read call.
packets per read call. 2 SSH 22

Examples: World Wide Web (Apache TCPExamples: 3 Domain

Telnet Name23System (DNS
port 80), e-mail (SMTP TCP port 25 Postfix UDP port 53), streaming media applications
MTA), File Transfer Protocol (FTP port 21)such as 4 IPTVSMTP or movies,25Voice over IP
and Secure Shell (OpenSSH port 22) etc. (VoIP),5Trivial File
DNS Transfer 53
Protocol (TFTP)
and online multiplayer games etc
6 BOOTP 67/68
Speed of transfer: The speed for TCP inSpeed 7of transfer
TFTP :UDP is69faster because
comparison with UDP is slower. there is no error-checking for packets.
8 HTTP 80

9 POP3 110
Header Size: TCP header size is 20 bytes. Header Size: UDP Header size is 8 bytes.
10 NNTP 119
Function: As a message makes its wayFunction: 11 UDPNTP is also a protocol
123 used in
across the internet from one computer tomessage transport or transfer. This is not
another. This is connection based. connection
12 based
SNMPwhich means
161 that one
program can send a load of packets to
13 LDAP 389
another and that would be the end of the
relationship.
14 RIP 520

15 DHCP 546/547
Table 2: Comparison between
16
TCP and UDP
WINS 1512
39) Ports:
17 L2TP 1701

18 PPTP 1723

19 RADIUS 1812/13
In TCP/IP and UDP networks, a port is an endpoint to a logical connection and
the way a client program specifies a specific server program on a computer in a
network. Some ports have numbers that are pre-assigned to them by the IANA
(Internet Assigned Numbers Authority).
Port numbers range from 0 to 65536, but only ports numbers 0 to 1024 are
reserved for privileged services and designated as well-known ports.
Any server machine makes its services available to the Internet using
numbered ports, one for each service that is available on the server. For
example, if a server machine is running a Web server and an FTP server, the
Web server would typically be available on port 80, and the FTP server would be
available on port 21. Clients connect to a service at a specific IP address and on
a specific port.
Each of the most well-known services is available at a well-known port number.
Here are some common port numbers:
If the server machine accepts connections on a port from the outside world, and
if a firewall is not protecting the port, you can connect to the port from anywhere
on the Internet and use the service

Table 3: Well Known Port Numbers

40) Routing Information Protocol (RIP):
The Routing Information Protocol (RIP) provides the standard IGP protocol for
local area networks, and provides great network stability, guaranteeing that if one
network connection goes down the network can quickly adapt to send packets
through another connection. What makes RIP work is a routing database that
stores information on the fastest route from computer to computer, an update
process that enables each router to tell other routers which route is the fastest
from its point of view, and an update algorithm that enables each router to update
its database with the fastest route communicated from neighboring routers:
Database. Each RIP router on a given network keeps a database that
stores the following information for every computer in that network:
o IP Address. The Internet Protocol address of the computer.
o Gateway. The best gateway to send a message addressed to that
IP address.
o Distance: The number of routers between this router and the router
that can send the message directly to that IP address.
o Route change flag. A flag that indicates that this information has
changed, used by other routers to update their own databases.
o Timers. Various timers.
Algorithm. The RIP algorithm works like this:
Update. At regular intervals each router sends an update message describing its
routing database to all the other routers that it is directly connected to. Some
routers will send this message as often as every 30 seconds, so that the network
will always have up-to-date information to quickly adapt to changes as computers
and routers come on and off the network.

Propagation. When a router X finds that a router Y has a shorter and faster path
to a router Z, then it will update its own routing database to indicate that fact. Any
faster path is quickly propagated to neighboring routers through the update
process, until it is spread across the entire RIP network.

Limitations:
Metric: Hop Count: Since RIP calculates the best route to a destination
based solely on how many hops it is to the destination network, RIP tends
to be inefficient in network using more than one LAN protocol. his is
because RIP prefers paths with the shortest hop count. The path with the
shortest hop count might be over the slowest link in the network.
 Hop Count Limit: RIP cannot handle more than 15 hops. Anything more
than 15 hops away is considered unreachable by RIP. This fact is used by
RIP to prevent routing loops.
41) OSPF-Open Shortest Path First:
OSPF is an interior gateway protocol that routes Internet Protocol (IP) packets
solely within a single routing domain (autonomous system). It gathers link state
information from available routers and constructs a topology map of the network.
The topology determines the routing table presented to the Internet Layer which
makes routing decisions based solely on the destination IP address found in IP
packets.
OSPF detects changes in the topology, such as link failures, very quickly
and converges on a new loop-free routing structure within seconds. It computes
the shortest path tree for each route
The link-state information is maintained on each router as a link-state database
(LSDB) which is a tree-image of the entire network topology. Identical copies of
the LSDB are periodically updated through flooding on all OSPF routers.

42) Border Gateway Protocol:

The Border Gateway Protocol (BGP) is the routing protocol used to exchange
routing information across the Internet. It makes it possible for ISPs to connect to
each other and for end-users to connect to more than one ISP. BGP is the only
protocol that is designed to deal with a network of the Internet's size, and the only
protocol that can deal well with having multiple connections to unrelated routing
domains.
BGP4 provides a set of mechanisms for supporting Classless Inter-Domain
Routing (CIDR) defined in RFC 4632. These mechanisms include support for
advertising a set of destinations as an IP prefix and eliminating the concept of
network "class" within BGP. BGP version 4 also introduces mechanisms which
allow aggregation of routes, including aggregation of AS paths.
Routing information exchanged via BGP supports only the destination-based
forwarding paradigm, which assumes that a router forwards a packet based
solely on the destination address carried in the IP header of the packet. This, in
turn, reflects the set of policy decisions that can (and cannot) be enforced
using BGP.BGP can support only the policies conforming to the destination-
based forwarding paradigm.
A unique AS number (ASN) is allocated to each AS for use inBGP routing. The
numbers are assigned by IANA and the Regional Internet Registries (RIR), the
same authorities that allocate IP addresses. There are public numbers, which
may be used on the Internet and range from 1 to 64511, and private numbers
from 64512 to 65535, which can be used within an organization.

43) Telnet:
Telnet is an old computer protocol (set of programmatic rules). Telnet is famous
for being the original Internet when the Net first launched in 1969. Telnet stands
for 'telecommunications network', and was built to be form of remote control to
manage mainframe computers from distant terminals. In those original days of
large mainframe computers, telnet enabled research students and professors to
'log in' to the university mainframe from any terminal in the building. This remote
login saved researchers hours of walking each semester.
While telnet pales in comparison to modern networking technology, it was
revolutionary in 1969, and telnet helped pave the way for the eventual World
Wide Web in 1989. While telnet technology is very old, it is still in some use
today by purists.Telnet has evolved into a new modern version of remote control
called 'SSH', something that many modern network administrators use today to
manage linux and unix computers from a distance.

Telnet is a text-based computer protocol. Unlike Firefox or Google Chrome

screens, telnet screens are very dull to look at. Very different from Web pages
that sport fancy images, animation, and hyperlinks, telnet is about typing on a
keyboard. Telnet commands can be rather cryptic commands, with example
commands being 'z' and 'prompt% fg'. Most modern users would find telnet
screens to be very archaic and slow.
A terminal emulation that enables a user to connect to a
remote host or device using a telnet client, usually over over port 23. For
example, typing telnet hostname would connect a user to a host
named hostname. Telnet enables a user to manage an account or device
remotely. For example, a user may telnet into a computer that hosts
their website to manage his or her filesremotely. The image to the right is an
example of what a telnet session may look like. As can be seen from the example
to the right a telnet session is a command line interface.
Telnet is considered insecure because it transfers all data in clear text. Which
means if a user was sniffing a network, it's very possible they could easily grab
your username andpassword as they were being transmitted. Users who are
concerned about the data being transmitted should consider SSH as opposed to
telnet.
 44) HTTP
HTTP (Hypertext Transfer Protocol) is the set of rules for transferring files (text,
graphic images, sound, video, and other multimedia files) on the World Wide
Web. As soon as a Web user opens their Web browser, the user is indirectly
making use of HTTP. HTTP is an application protocol that runs on top of the
TCP/IP suite of protocols (the foundation protocols for the Internet).
HTTP concepts include (as the Hypertext part of the name implies) the idea that
files can contain references to other files whose selection will elicit additional
transfer requests. Any Web server machine contains, in addition to the Web page
files it can serve, an HTTP daemon, a program that is designed to wait for HTTP
requests and handle them when they arrive. Your Web browser is an HTTP
client, sending requests to server machines. When the browser user enters file
requests by either "opening" a Web file (typing in a Uniform Resource Locator or
URL) or clicking on a hypertext link, the browser builds an HTTP request and
sends it to the Internet Protocol address (IP address) indicated by the URL. The
HTTP daemon in the destination server machine receives the request and sends
back the requested file or files associated with the request. (A Web page often
consists of more than one file). The latest version of HTTP is HTTP 1.1.
Chapter 4: Observation and Findings
4.1 Need of networking in Organization:
 4.2 Network design:

Fig 25: Full View of the network design for an organization

This network setup satisfies a very basic need of communication and information
sharing of any big or small organization. As we have already seen the
requirements of an organization, so to fulfill that need, this setup is designed with
the latest gadgets available. Specific purpose gadgets are not included in the
diagram, it just show the most common needs that any enterprise would want to
have in their setup in order to communicate and share the information in and
around.
Setup consists of two network connections-Virtual Private Network, especially for
direct communication with the company server, and other internet connection
through an ISP.
Lets say, in our setup, head office is the main office of Royal Enfield Bullets, and
the branch is OM Sai Automobiles, in Raipur. Branch deals with the workshop, 5
bullets showroom and spare parts shop. So Om Sai Automobiles wants itself
always connected with the main office, so that it can be updated 24x7 with whats
happening in the Royal Enfield, What are new offers, new technology, any other
information, etc. Also head office also wants to maintain a continuous check on
the branch offices.
Therefore a VPN (mechanism for providing secure, reliable transport over
Internet) is established between any two branches, head office and branch office
or all the royal Enfield offices are connected to each other. This way they
maintain their own private network through public network.

Thus VPN is helpful:

1. To support remote access to an intranet
2. To support connections between multiple intranets within the same
organization,
3. To join networks between two organizations, forming an extranet.

VPN is established by the ISP, but maintenance can be done by the company
itself or it can give this task to sum third party.
Company contacts to its ISP to create a VPN connection between various offices,
then ISP creates VPN connection through world wide web. As we can see in the
diagram, OFC (optical fiber cable) comes to the ISP exchange. Here OFC
converts to copper cable which reaches to the branch offices premises. Cable
reaches to NOC-Network Operation centre. It is the room which is maintained at
very cool temperature because this room consists of all important gadgets like
router, switch, modems, server computers etc.
Copper cable is attached to a small device known as OFC to Fiber Media
converter. This device converts the copper cable to fast Ethernet cable-cat5
cable/cat6 (whichever is required) and vice-versa. Then cable goes to routers
LAN port (here we have taken Cisco 1721 router).Then router is connected to a
device Unified Threat management, which represents all-in-one security
appliances that carry a variety of security capabilities including firewall, VPN,
gateway anti-virus, gateway anti-spam, intrusion prevention, content filtering,
bandwidth management, application control and centralized reporting as basic
features.
From the UTM (a device which is a combination of applications like Antivirus, Anti
spam & Intrusion Detection Systems) cables goes to the uplink port of switch
(here, we are using Cisco 2950 catalyst series Managed switch).Switch connects
different network devices and terminals. All the terminals are now in Virtual
Private Network.

This was VPN connection (private network), an organization also needs an

internet connection (public network).For this purpose we have taken an internet
connection through an ISP. Internet can be taken through a telephone
connection. Telephone line is connected to DSL Cable Modem Router (a device
which has function of both a modem and a router).Then Ethernet cable goes to
the UTM device and then to the servers LANcard .Server is connected to one of
the switchs port.
Since we need both VPN as well as public Internet connection work
simultaneously, we attach two LAN cards to server.LANcard2 is connected to
modem (which gives public internet connection) and LANcard1 connects with the
switch for VPN connection.
But DNS gateway is to be set for both the connections, for this purpose. Suppose
IP address of DSL modem Router is 172.16.3.1, LANcard1: 192.16.3.1, LANcard:
172.16.3.2. So IP address of the devices attached to the switch, must be set to
192.16.3.2, 192.16.3.3, 192.16.3.4 and so on. This will enable the VPN
connection throughout the network. In order to set internet settings we need to
add one more IP address in DNS tab for every device, but gateway will be same
for everyone. Lets say as LANcard2 :172.16.3.2,so other devices (in DNS tab)
add more and IP address can be set to:172.16.3.3, 172.16.3.4, 172.16.3.5 and
so on, but gateway will be set to same as LANcard2s IP address.

(In Windows ,to configure TCP/IP settings)

1. control panel --> open Network Connections.
2. Right-click the connection that you want to change, and then click
Properties.
If you are prompted for an administrator password or confirmation, type
the pa/ssword or provide confirmation.

3. Click the Networking tab. Under This connection uses the following items,
click either Internet Protocol Version 4 (TCP/IPv4) or Internet Protocol
Version 6 (TCP/IPv6), and then click Properties.
4. To specify IPv4 IP address settings, do one of the following:

o To obtain IP settings automatically, click Obtain an IP address

automatically, and then click OK.

o To specify an IP address, click Use the following IP address, and

then, in the IP address, Subnet mask, and Default gateway boxes,
type the IP address settings.

5. To specify IPv6 IP address settings, do one of the following:

o To obtain IP settings automatically, click Obtain an IPv6 address

automatically, and then click OK.

o To specify an IP address, click Use the following IPv6 address, and

then, in the IPv6 address, Subnet prefix length, and Default
gateway boxes, type the IP address settings.

6. To specify DNS server address settings, do one of the following:

o To obtain a DNS server address automatically, click Obtain DNS

server address automatically, and then click OK.
 o To specify a DNS server address, click Use the following DNS
server addresses, and then, in the Preferred DNS server and
Alternate DNS server boxes, type the addresses of the primary and
secondary DNS servers.

7. To change DNS, WINS, and IP settings, click Advanced.

 Switch connection

Fig 26: Connection of devices to switch

Now lets us see, how devices are connected to the switch.

Generally first and last ports of switch are uplink port, and in some cases it is
given separately. So the cable which comes from UTM is attached to the uplink
port of the switch. This will enable the switch to use VPN.

Cisco 2950 Managed switch has 24 ports. It is divided into 3 blocks each
consists of 8 ports. Managed switch is used because it lets us prioritize the traffic
traveling across our network so that the most important information gets through
first. In addition, we can control who has access to our network.
With a managed switch, we can configure, manage, and monitor our network.
Managed switches use SNMP (Simple Network Management Protocol) to show
how well our network is running and if any of the devices on our network are
broken or failing. SNMP also provides remote management capabilities, enabling
us to make changes to the devices on our network and repair any problems
through the Web-based interface, without having to directly connect to the switch
itself.
Managed switches also provide redundancy and VLAN (virtual LAN) capabilities
to help improve our networks performance. Redundancy allows the switch to
keep network traffic flowing even if a network connection fails. In other words, our
network wont go down.
VLANs let us create groups within our company to isolate different kinds of traffic
on the network. For example, we can segment traffic between finance and sales
groups so that mission-critical financial information has priority over sales data.
VLANs also provide an additional layer of security by letting us hide sensitive
company information from guests we have allowed accessing our network.
Finally, a managed switch can support us as our business and technology needs
grow. For example, if we decide to adopt an IP-based phone system(VOIP),
having a managed switch with QOS (Quality of Service) support allows us to
assign a higher priority to voice traffic so that call quality isnt affected by other
traffic on our network. Additionally, a managed switch that includes secure
wireless connectivity lets you add usersemployees and gueststo your
network at any time and allow them to access your network and the Internet from
any office or conference room in the building.

After uplink port is connected, rest of the ports can be connected to the devices
that are required. In this setup, we are using WIFI Modem(for wireless devices,
mobile phones .and guests who come to our premises), Network Attached
Storage(new method of utilizing computer networks for data storage),an IP based
Telephone (VOIP-through this calls can be made to other office free of cost), a
network Printer(Network printing is having the ability to print over the network), IP
based camera(for surveillance ), unmanaged switch(which is used for connecting
number of network devices) and computers.

For wireless communication terminals need to install a network adapter and their
driver in the same terminals while today almost all the computers have an inbuilt
network adapter.

Here we have divided the devices in 4 parts- finance, sales, inventory &
workshop and owner & billing section. We havent created any VLANs; we can
create it by configuring the switch. Every section needs different types of devices.
And according to the need, devices are attached.

An unmanaged switch has fewer features than its managed counterpart, so it

requires little technical know-how to add to network. Theres no software to install
and nothing to configure, making an unmanaged switch ideal for small
businesses that are just getting their network started or that have no in-house IT
support.
Unmanaged switches have a fixed configuration and are ready to communicate
with PCs, network printers, and other devices right out of the box. All we have to
do is plug in the switch, connect computers and other devices to it, and connect
the switch to the Internet. Thats all there is to it.
Therefore we have used two unmanaged switches to connect two groups of
devices.
More unmanaged switch can be added as and when required.
Chapter 5: Recommendations
Chapter 6:conclusion and Future Scope of Work