WESM zl Management and Configuration Guide WT.01.28 and greater

1-53
Introduction
Radio Ports
The second radio on the RP 220 and on the RP 230 supports 802.11a.
802.11 Frames
In addition to Physical Layer standards, 802.11 defines Data Link Layer standards.
802.11 frame types include:
■ control frames, which wireless devices use to reserve the shared medium
■ management frames, which regulate communications between stations and RPs
and include:
• beacon frames, which the RP radio uses to announce itself to wireless
stations and which will be discussed in more detail in “Beaconing” on
page 1-58
• authentication frames, which wireless devices use to ensure that they are
connecting to the correct peer
• association frames, which stations use to negotiate the wireless connection
to an RP
A station cannot send or receive data until it associates to an RP.
■ data frames, which encapsulate all the higher layer packets the wireless connec-
tion is intended to carry (for example, a data frame might include an HTTP
request for a Web page)
BSS
A BSS is the set of wireless stations controlled by a single coordination function as
well as the RP to which they connect. In other words, the BSS consists of all stations
that share the same medium (the radio signal broadcast by an RP) to transmit and
receive data. (See Figure 1-18.)