UNIT-1
Distributed processing.
In a computer network, is a method that involves dividing a complex task
into segments and distributing them across multiple machines in a
network. Each machine or node them completes its part of the task and
send it to back to be compiled into a single output.
Computer networking.
A computer network is a collection of interconnected devices that share
the sources and information. This device can include computer servers,
printers, or hardware. The network allow for the efficient exchange of data,
enabling various applications such as e-mail, file sharing and Internet
browsing.
Computer networking is very important in modern technology, enabling
the interconnected systems that power the Internet, business
communication and everyday digital instruction.
( Medium)
Sender ———————— Receiver
(Caries a message)
Types of computer networking
1. LAN –
local area network is a network that covers a small area such as
an. Office or a home. LANS are typically used to connect
computers and other devices within a building or a campus.
It is less costs costly as it is bold with inexpensive hardware such
as herbs, network adapters and Ethernet cables.
The data is transferred at an extremely faster rate in local area
network.
It provides higher security.
2. WAN-
Wide area network. Is a network that covers a large geographic
area such as city, country, or even the entire world. WANs are
used to connect LANs together and are typically used for long
distance communication.
A white area network is quite big a network then the local area
network.
A wide area network is not limited to a single location, but it is
pence over a large geographical area through a telephone line,
fibre optic cable and satellite links.
The Internet is one of the biggest Wan in the world.
A wide area network is widely used in the field of business,
government and education.
3. Cloud Network. Cloud networks can be visualised with a wide area
network as they. Can be hosted on public or private cloud service
providers and cloud networks are available if there is a demand. Cloud
networks consist of virtual routers, firewalls, etc.
4. PAN
Personal area network is a network arranged within a individual
person, typically within a range of 10 metres.
Personal area network is used for connecting the computer
devices of personal use is known as personal area network.
Personal. Area network covers an area of 30 feet.
Personal computer devices that are used to develop the personal
area network or the laptop, mobile phones, media player and
Playstations.
There are two types of personal area network. 1. Wired personal
area network. 2. Wireless personal area network.
5. MAN
Metropolitan Area network is a network that covers a large
geographic area by interconnecting a different LAN to form a
large network.
Government agency use MAN to connect the citizens and private
industry.
In MAN, various LAN are connected to each other through a
telephone exchange line.
It has Higher range then LAN.
Data transmission mode.
It is also known as communication mode. Is the mechanism of transferring
data between devices connected on a network. It defines a direction in
which information flows between the devices.
Data transmission model specifies the direction of information flow
between two communication devices via a communication channel that
includes an optical fibre, wireless channels, copper wires and other
storage media.
Buses and network are designed to allow communication to occur between
individual devices that are interconnected.
There are three types of transmission mode
1. Simplex Mode. A simplex communication system can transmit data in
One Direction only. Devices connected to such a circuit whether send or
receive only. In the simplex mode. The communication is uni
directional, as on a one way Street. Only one of the two devices on
Uplink can transmit the other only can receive. The simplex mode can
use the entire capacity of the channel to send data in One Direction.
Example. Keyboard and traditional monitors. The keyboard can only
introduce input, the monitor can only keep the output.
2. Half duplex mode- I have two plus communication system can transmit
data in both direction but only One Direction at a time. Hence it can
alternately send and receive data. It required 2 wires. It is most
suitable for voice communication using telephones in which one person
can speak at a time. The hearts duplex mode is used in cases where
there is no need for communication in board direction. At the same
time, the entire capacity of the channel can be utilised for each
direction. Example. Walkie-talkie in which message is sent one at a
time and messages are sent in both directions.
3. Full duplex mode – In full to play small, both stations can transmit and
receive simultaneously. In full duplex mode, signals going in One
Direction share the capacity of the link with signals going in other
direction. This sharing can occur in two ways-
I don’t the link must contain two physical separate transmission
path, one for sending and other for receiving.
Or the capacity is divided between signals travelling in both
direction.
Full duplex mode is used when communication in bold direction is
required all the time. The capacity of the channel however, must be
divided between the two direction. Example. Telephone networks in
which there is a communication between two persons by a
telephone line through which both can talk and listen at the same
time.
Components of data communication
1. Message.
2. Sender.
3. Receivers.
4. Transmission Media.
5. Set of Rules.
Network Topology-
Topology of a network reference to the way in which the network nodes
(computer or other devices need to communicate )are linked together.
It is the Way devices are connected in a network. It defines how these
components are connected and how data transfer between the network.
Characteristic of network topology
i. It determines various data paths available between any pair of
nodes in the network
ii. Choose a topology for a computer network depends on a
combination of factors such as:
a. Desired performance of the system.
b. Reliability of the system size
c. Size ( number of notes and their geographical distribution )
d. Cost of components and services like to required implement
network.
e. Ability of communication lines.
Point to point Network contains hosts such as a computer, switches or
routers. In this type of network, nodes are connected back-to-back using a
single piece of cable. If the host are connected point to point logically,
then may have multiple intermediate device. In this network, the end
hosts are unaware of underline network and see each other as they are
connected directly.
Types of topology
1. Bus topology – In case of bus topology all devices share single
communication line or cable. Bus topology may have problem while
multiple host sending data at the same time. It is. One of the simple
form of networking where a failure of a device does just affect the
other device, but failure of the shared communication line can make
all other devices stop functioning. Both ends of the shared channel
have line transmitter. The data is sent in only One Direction and as
soon as it reaches the extreme and the task transmitter removes
the data from the line.
