What is WLAN? (802.11b/g)

Wireless LAN is a flexible datacommunications system implemented as an extension to, or as an alternative for, a wired LAN. Wireless LAN users can access shared information without looking for a place to plug in. Information can be accessed anywhere in the organization.
802.11b is operating in the 2.4 GHz band.

11 Mbps is the theoretical speed of 802.11b

Practical speed depends on installations, but in normal cases somewhere between 2-5 Mbps