In WLAN formation I will show you basic definition and explanations of abbreviations you have heard hundred of times.
WLAN networks consist of: 1) Distribution system - combination of bridging engine and backbone network.
2) Access Point (AP) - performs wireless to wired bridging function.
3) Wireless Medium - for exchanging frames between stations and backbone.
4) Station - PCs, laptops and other devices with wireless network card.
The basic block of 802.
11 networks is BSS - Basic Service Set.
This is group of stations that communicate only between them.
There are 2 types of BSS: Independent BSS networks or ad hoc.
Only stations without Access Point.
You can setup your WLAN home network, even without AP.
Infrastructure BSS networks - stations use AP for communication between them.
Why do we actually use Access Point, if it is not essential? There are few reasons for that: - AP bridges wireless word to wired.
So without AP you do not have a connection to the rest of the world.
- Longer range.
Range of Infrastructure BSS is defined by the distance between station and AP.
In Ad-Hoc network range is defined by distance between stations.
- With AP, stations save power.
When station enters a power-saving mode, access point buffers frames for it.
Extended Service areas- ESS -connects BSSs with backbone network.
ESS connects stations with rest of the word - Internet.
From user's prospective, WLAN is Wireless Ethernet.
Network administrators have to know that frame delivery is unreliable, comparing to wired networks.
Because that, 802.
11 standard requires a numbers of additional services and more complex framing.