5/10/2024

UNIT-II

Wireless Networking, Wireless LAN Overview- MAC issues, IEEE 802.11,

MOBILE COMPUTING (KCA051)
Blue Tooth, Wireless multiple access protocols, TCP over wireless, Wireless

by- applications, Data broadcasting, Mobile IP, WAP architecture, Protocol stack,
Ashutosh Pandey
Assistant Professor application environnent, applications.
UIM (011)

By: Ashutosh Pandey, Department of Computer Application, UIM (011)

Wireless Networking Wireless Networking

 Wireless networking is a computer network that uses radio frequency (RF)  Wireless networking refers to the communication between devices such as

connections between devices. This allows devices to connect to a network computers, smartphones, tablets, and other hardware using radio

while still moving around, unlike wired networks, which use cables. frequency signals instead of traditional wired connections.

 Wireless networking is popular in homes, businesses, and  This technology allows users to access networks and the internet without

telecommunications networks. the constraints of physical cables, providing flexibility and mobility.

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 3 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 4

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Introduction of WLAN Advantages of WLAN

 The most prominent specification for wireless LANs (WLANs) was  Mobility
developed by the IEEE 802.11 working group.
 Low Implementation Cost
 It is a network that allows devices to connect and communicate wirelessly.
 Installation Speed and Simplicity
 Unlike a traditional wired LAN, in which devices communicate
 Network Expansion
over Ethernet cables, devices on a WLAN communicate via Wi-Fi.
 Reduced Cost-of-Ownership
 Mobile users can access information and network resources through
wireless LAN as they attend meetings, collaborate with other users, or  Reliability
move to other locations in the premises.
 Usage of ISM band
 WLAN is not a replacement for the wired infrastructure. It implemented
as an extension to a wired LAN within a building or campus. *ISM stands for Industrial, Scientific, and Medical, and ISM bands
are radio frequency (RF) bands reserved for non-telecommunications uses.
By: Ashutosh Pandey, Department of Computer Application, UIM (011) 5 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 6

Key Aspects of Wireless Networking Wireless Standard

Wireless networking operates based on various standards developed by
1. Wireless Standards organizations like the Institute of Electrical and Electronics Engineers (IEEE). The
most common standards include:
2. Components of Wireless Networks  IEEE 802.11: This standard family encompasses different versions, such as
802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, and 802.11ax (Wi-Fi 6 and Wi-
3. Wireless Security Fi 6E). Each version offers different data rates, frequencies, and features,
with newer versions typically providing faster speeds and better reliability.
4. Challenges and Considerations
 Other standards include Bluetooth for short-range communication between
devices, Zigbee for low-power, low-data-rate applications, and cellular
standards like 3G, 4G, and 5G for mobile broadband communication.
By: Ashutosh Pandey, Department of Computer Application, UIM (011) 7 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 8

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Components of Wireless Standard Components of Wireless Standard

 Access Points (APs): These are devices that facilitate wireless communication
between client devices (such as laptops or smartphones) and the wired network
infrastructure.
 Wireless Clients: These are devices that connect to wireless networks, such as
laptops, smartphones, tablets, IoT devices, and more.
 Wireless Routers: These devices combine the functionality of a router with that
of an access point, allowing multiple devices to connect to the internet wirelessly.
 Antennas: Antennas are used to transmit and receive wireless signals. They
come in various types and configurations, such as omni-directional antennas that
radiate signals in all directions and directional antennas that focus signals in
specific directions.

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 9 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 10

Wireless Security Challenges & Consideration

 Encryption: Wireless networks use encryption protocols like WPA2 Interference: Wireless networks can be susceptible to interference from
(Wi-Fi Protected Access 2) or WPA3 to secure data transmission between other devices operating on the same frequency band, such as microwave
devices and prevent unauthorized access. ovens, cordless phones, or neighboring Wi-Fi networks.

 Authentication: Users and devices are authenticated before being Range and Coverage: The range of a wireless network depends on factors
granted access to the network, typically through passwords, digital like the transmission power of the devices, obstacles in the environment,
certificates, or other authentication methods. and the frequency band used. Extenders or mesh networking systems can be
used to extend coverage in large or challenging environments.
 Access Control: Access control mechanisms, such as MAC address
filtering and network segmentation, help control which devices can Performance: Factors like network congestion, signal strength, and the
connect to the wireless network and what resources they can access. number of connected devices can impact the performance of a wireless
network. Proper network design, channel planning, and Quality of Service
(QoS) configurations can help optimize performance.

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 11 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 12

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Issues in TCP over Wireless

The Transmission Control Protocol (TCP) has several issues when
implemented in wireless networks, including:
High packet loss
Delay
Issues in TCP over Wireless Bit errors
Handoff errors
Congestion
Re-ordering errors

13 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 14

Overview of MAC issues

 In mobile computing, Media Access Control (MAC) is a sub-layer of the

data link layer that controls how data packets are transmitted over a
shared network medium.
Overview of MAC issues  MAC is responsible for: Flow control, Multiplexing, Data packets
transmission, Collision resolution, and Retransmission initiation.

15 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 16

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Overview of MAC issues Overview of MAC issues

1. Collision Avoidance Collision Avoidance: In wireless LANs, multiple devices share the same
2. Hidden Terminal Problem medium for transmission. To avoid collisions where two or more devices
3. MAC Address Filtering transmit data simultaneously, a mechanism known as Carrier Sense
4. Quality of Service (QoS) Multiple Access with Collision Avoidance (CSMA/CA) is employed.
5. Channel Allocation However, collisions can still occur due to hidden terminal problems or other
issues, leading to degraded network performance.

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 17 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 18

Overview of MAC issues Overview of MAC issues

Hidden Terminal Problem: This occurs when two nodes within the network MAC Address Filtering: Wireless LANs often implement MAC address
are out of range of each other but are within the range of a common filtering as a security measure, allowing only devices with approved MAC
access point. As a result, they may not be able to detect each other's addresses to connect to the network. However, managing a large number of
transmissions and may inadvertently transmit simultaneously, leading to MAC addresses can be cumbersome, and spoofing MAC addresses is
collisions. relatively easy for determined attackers.

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 19 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 20

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Overview of MAC issues Overview of MAC issues

Quality of Service (QoS): MAC layer protocols often include mechanisms Channel Allocation: Wi-Fi networks operate on different channels within
for prioritizing certain types of traffic over others to ensure that real-time the RF spectrum. Proper channel allocation is essential to minimize
applications such as voice or video streaming receive adequate bandwidth interference between neighboring access points and maximize the available
and minimal latency. However, misconfigurations or improper QoS bandwidth. However, overlapping channels or insufficient channel separation
settings can lead to suboptimal performance for critical applications. can lead to co-channel interference, reducing network performance.

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 21 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 22

Wireless multiple access protocols

Wireless multiple access protocols

23 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 24

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IEEE 802.11
 The IEEE 802.11 standard, commonly known as Wi-Fi.

 IEEE 802.11 is a family of standards for wireless local area networking

(WLAN) developed by the Institute of Electrical and Electronics
Engineers (IEEE).
IEEE 802.11
 It defines the protocols and technologies used for wireless communication
within a limited area, typically within a building, campus, or metropolitan
area.

25 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 26

IEEE Standards IEEE 802.15 (WPAN)

WPAN / Bluetooth. It is based on Bluetooth technology.
IEEE 802.11 Wireless LAN It defines physical layer (PHY) and medium access control (MAC)
IEEE 802.15 Wireless Personal Area Network(WPAN)
specification for wireless connectivity with fixed, portable and moving
IEEE 802.16 Broadband Wireless Access (BBWA)
IEEE 802.20 Mobile Broadband Wireless Access (MBWA)
devices within or entering personal operating space.

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 27 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 28

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IEEE 802.16 (BBWA) WiFi vs WiMAX

The IEEE 802.16 standard, commonly known as Broadband Wireless
Access.

The IEEE Standards Board established a working group in 1999 to create

standards for broadband for wireless metropolitan area networks.

The IEEE 802.16 architecture defines specifications for wireless broadband

technology, including standards for the physical layer and medium access
control (MAC).

It has been commercialized as Worldwide Interoperability for Microwave

Access (WiMAX).

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 29 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 30

Bluetooth
 Bluetooth technology plays a significant role in mobile computing, enabling
wireless communication between devices over short distances using a band
of 2.4 to 2.485 GHz..
Bluetooth  Bluetooth is also known as IEEE 802.15 standard or specification that uses
low power radio communications to link phones, computers and other
network devices over a short distance without using any type of connecting
wires.

31 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 32

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Bluetooth Bluetooth Protocol Stack

 In Bluetooth technology, the wireless signals transmit data and files over a
short distance, typically up to 30 feet or 10 meters.
 Bluetooth technology was developed by a group of 5 companies known as
Special Interest Group formed in 1998.
 The companies are Ericsson, Intel, Nokia, IBM, and Toshiba.

Baseband Layer /

Radio Layer /

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 33 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 34

Bluetooth Protocol Stack Bluetooth Protocol Stack

 Physical Layer : Using this layer, BLE offers data rates of 1 Mbps  GAP : This layer directly interfaces with the application layer and/or
(Bluetooth v4.2)/2 Mbps (Bluetooth v5.0). profiles on it. It handles device discovery and connection related services for
 Link Layer : It is responsible for advertising, scanning, and BLE devices.
creating/maintaining connections.  GATT : This layer is a service framework which specifies sub-procedures
 HCI : It provides communication between controller and host through to use ATT. Data communications between two BLE devices are handled
standard interface types. through these sub-procedures.
 L2CAP :This layer offers data encapsulation services to upper layers. This  ATT : This layer allows BLE devices to expose certain pieces of data or
allows logical end to end data communication. attributes.
 SMP :This security Manager layer provides methods for device pairing and  Application Layer : It helps to interact with applications and profiles as
key distributions. desired. It handles device discovery and connection related services for the
BLE device.

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 35 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 36

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Radio Layer & Baseband Layer

The Bluetooth radio layer and baseband layer are both part of the
Bluetooth protocol stack's physical layer.

The radio layer defines the air interface's details, including frequency,
transmit power, and frequency hopping.
Wireless Application Protocol
The baseband layer defines the addressing scheme, packet frame format,
timing, and power control algorithms. The baseband layer also establishes the
ACL link, defines master/slave relationships, and controls the radio signal
strength.

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 37 38

Wireless Application Protocol LANs, MANs and WANs

WAP is an application communication protocol.
It is designed for access to Internet and
advanced telephony services from mobile phones
Full-form Local Area Network Metropolitan Area Network Wide Area Network
It is a protocol designed for micro-browsers and Transmission speed High comparatively Average comparatively Low comparatively
it enables the access of internet in the mobile Propagation delay Short Moderate High
devices Congestion Low comparatively Average comparatively High comparatively
Maintenance Easy Difficult than LAN Difficult than MAN and LAN
WAP uses mark-up language – WML
Scope Small (1 to 10 Km) Multiple Building or Society Multiple city or country
WAP can be used from variety of 2G and 3G e.g. Small building, cluster or in a city.(upto 100 Km (beyone 100Km)
of building, organization area)
networks
Ownership Private Private or public Private or public
GPRS and 3G are more suited for these Medium Cable Telephone lines Telephone lines, satellite
applications.
By: Ashutosh Pandey, Department of Computer Application, UIM (011) 39 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 40

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Mobile IP
Mobile IP is a communication protocol
(created by extending Internet Protocol,
IP) that allows the users to move from one
network to another with the same IP
Mobile IP address.
It ensures that the communication will
continue without user’s sessions or
connections being dropped.

41 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 42

Mobile IP Topology Mobile IP Topology

 The term “Mobile” in Mobile IP signifies that, while a user is connected to
applications across the Internet and the user’s point of attachment changes
dynamically, all connections are maintained despite the change in underlying network
properties.
 Similar to the handoff/roaming situation in a cellular network.
 Mobile IP allows the mobile node to use two IP addresses called home address and
care of address.
 The home address is static and known to everybody as the identity of the host.
 The care of address changes at each new point of attachment and can be thought of as
the mobile node’s location specific address.
By: Ashutosh Pandey, Department of Computer Application, UIM (011) 43 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 44

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Mobile IP Architecture Working of Mobile IP

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topology or routers  Tunneling - Tunneling procedure is used to forward IP datagram's
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By: Ashutosh Pandey, Department of Computer Application, UIM (011) 45 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 46

Working of Mobile IP : Discovery Working of Mobile IP : Registration

 Discovery - A mobile node uses a discovery procedure Registration - A mobile node uses a registration procedure to inform its home
to identify prospective home agents and foreign
agents. agent of its care-of address.
 Agent Discovery
 HA’s and FA’s broadcast their presence on each network to
which they are attached
 Beacon messages via ICMP (Internet Control Message
Protocol)and RDP (Router Discovery Protocol)
 MN’s listen for advertisement and then initiate registration

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 47 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 48

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Working of Mobile IP : Tunneling Mobile IP : Features

Tunneling - Tunneling procedure is used to forward IP datagrams from a home  Enables hosts to stay connected to the Internet regardless of their
address to a care of address. location
 Enables hosts to be tracked without needing to change their IP address
 Requires no changes to software of non-mobile hosts/routers
 Requires addition of some infrastructure
 Has no geographical limitations
 Requires no modifications to IP addresses or IP address format
 Supports security

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 49 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 50

WAP Protocol Stack WAP Protocol Stack

 Enables hosts to stay connected to the Internet regardless of their Application Layer (WAE) Other Services and
Applications
location Session Layer (WSP)

 Enables hosts to be tracked without needing to change their IP address Transaction Layer (WTP)

 Requires no changes to software of non-mobile hosts/routers Security Layer (WTLS)

 Requires addition of some infrastructure Transport Layer (WDP)

 Has no geographical limitations Bearers:

GSM IS-136 CDMA PHS CDPD PDC-P IDEN FLEX etc…

 Requires no modifications to IP addresses or IP address format

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By: Ashutosh Pandey, Department of Computer Application, UIM (011) 51 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 52

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Comparing with Internet Model WAP Architecture

HTML Client Web Server

WAP Gateway
HTTP
WML

with WML-Script
TLS/SSL WML Encoder CGI

WML Decks
TCP/IP WML- Scripts
WSP/WTP WMLScript
HTTP etc.
Script
Compiler
WTAI
Protocol Adapters Content
Etc.

By: Ashutosh Pandey, Department of Computer Application, UIM (011) 53 By: Ashutosh Pandey, Department of Computer Application, UIM (011) 54

By: Ashutosh Pandey, Department of Computer Application, UIM (011)

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