User's Manual

Appendix B

About Wireless LANs

This Appendix provides some background information about using Wireless

LANs (WLANs).

Modes

Wireless LANs can work in either of two (2) modes:

• Ad-hoc

• Infrastructure

Ad -hoc Mode

Ad-hoc mode does not require an Access Point or a wired (Ethernet) LAN. Wireless Sta-

tions (e.g. notebook PCs with wireless cards) communicate directly with each other.

Infrastructure Mode

In Infrastructure Mode, one or more Access Points are used to connect Wireless Stations

(e.g. Notebook PCs with wireless cards) to a wired (Ethernet) LAN. The Wireless Stations

can then access all LAN resources.

Access Points can only function in "Infrastructure" mode, and

can communicate only with Wireless Stations which are set

to "Infrastructure" mode.

BSS/ESS

BSS

A group of Wireless Stations and a single Access Point, all using the same ID (SSID), form a

Basic Service Set (BSS).

Generally, using the same SSID is essential. Devices with different SSIDs are on different

Wireless LANs, and may be unable to communicate with each other.

Note that some Access Points will broadcast their SSID, allowing Wireless stations to adopt the

correct SSID. This makes it easier for the clients to locate the correct AP. If the SSID is not

broadcast, the client can still connect to the AP by entering the correct SSID and other data.

ESS

A group of Wireless Stations, and multiple Access Points, all using the same ID (ESSID), form

an Extended Service Set (ESS).