Breifly Discuss WLAN Architecture.

1. VISHAL VERMA
02BTD5050063
SHUBHAM
02BTD5050056
7TH SEM
CSE

2. Wireless Local Area Network(WLAN)
 WLAN is a local area data network without wires.
 Mobile user can access information and network
resources through wireless LAN as they attend
meeting ,collaborate with other users or move to other
locations in the premises.
 WLAN is not a replacement for the wired
infrastructure. It is implemented as an extension to a
wired LAN within a building or campus.

3.  Wireless LAN is commercially known as WiFi or
Wi-Fi.
 Wi-Fi is an acronym for Wireless Fidelity.
 IEEE creates some standards and protocols for
connectivity.
 IEEE creates some specification for wireless LANs
which covers the Physical and Data Link Layer.

4. Advantages of WLAN
 Mobility
 Low Implementation Costs
 Installation Speed and Simplicity
 Network Expansion
 Reduced Cost-of-Ownership
 Reliability
 Scalability
 Usage of ISM band

5. Applications of WLAN
 Office/Campus Environment
 Factory Shop Floor
 Homes
 Workgroup Environment
 Heritage Buildings
 Public Places
 War/Defense Sites

6. Architecture of WLAN
Components of Architecture:
• Stations
• Access Points
• Basic Service Set(BSS)
• Extended Service Set(ESS)
• Distributed System

7. Stations
 All components that can connect into a wireless
medium in a network are referred to as stations.
 Wireless stations can be mobile devices such as
laptops, personal digital assistants, IP phones and
other smartphones, or non-portable devices such
as desktop computers, printers, and workstations that
are equipped with a wireless network interface.

8. Access Points
 Access points (APs), normally wireless routers, are
base stations for the wireless network.
 APs transmit and receive radio frequencies for wireless
enabled devices to communicate with.
 It uses as Central Device in WLAN architecture.

9. Access Point

10. Basic Service Set
 Basic Service Set(BSS) is the building block of WLAN.
 BSS is a set of all stations that can communicate with
each other at physical layer.
 Every BSS has an identification (ID) called the BSSID,
which is the MAC address of the access point servicing
the BSS.
 In BSS ,there wireless stations could be Mobile or
Stationary .

11.  There are two types of BSS Architecture in
WLAN:
 Adhoc Network Architecture
 Infrastructure Network Architecture

12. Adhoc Network Architecture
 There is no access point in WLAN architecture, then it
will be adhoc architecture.
 It have stand alone network.
 It cannot sends the data to other BSS.
 In Adhoc architecture, stations can locate the another
stations in same BSS but can communicate only if they
have agreement between them.
 It is peer to peer network topology.

13. Adhoc Network Architecture

14. Infrastructure Network Architecture
 It have access point with basic service set.
 In infrastructure mode, a base station acts as a wireless
access point hub, and nodes communicate through the
hub.
 It is Star Topology.
 In this architecture, signal come first to central device
then passes to all stations.
 Wireless access points are usually fixed, and provide
service to their client nodes within range.

15. Infrastructure Network Architecture

16. Extended Service Set
 An extended service set (ESS) is a set of connected
BSSs that communicate with each other.
 Access points in an ESS are connected by a
distribution system.
 Each ESS has an ID called the SSID which is a 32-byte
(maximum) character string.

17. WLAN Architecture

18. Distributed System
 A distribution system (DS) connects access points in
an extended service set.
 The concept of a distributed system can be used to
increase network coverage through roaming between
cells.
 It can be wired or wireless.
 Current wireless distribution systems are mostly based
on WDS or MESH protocols, though other systems are
in use.