11B (NON-ERP)FIGURE 6-2 11G CELL WITH AN 11B CLIENTNOW THA...

802.11b (Non-ERP)

Figure 6-2 802.11g Cell with an 802.11b Client

Now that the cell knows about the 802.11b clients, the way that data is sent within the cell

changes. When an 802.11g client sends a frame, it first must warn the 802.11b clients by

sending a request to send (RTS) message at 802.11b speed so the 802.11b clients can hear

and understand it. The RTS is not a broadcast as you might think, but rather a unicast that

is sent to the recipient of the frame that the 802.11g client wants to send to. The recipient

then responds with a clear to send (CTS) at 802.11b speed. Figure 6-3 illustrates this

process.

In Step 1, the client knows that the 802.11b client is present; therefore, before sending, it

issues an RTS at 802.11b speeds.

In Figure 6-4, the 802.11b client hears the RTS (Step 2), which includes the duration, and it

waits until the duration is over before sending its data even though it cannot hear the