IBM 22P6401, User Manual

Page: 27 / 58

Advanced
Request to send (RTS) Threshold: In some situations, not all clients in a WLAN
are aware of each other (hidden node problem). That can lead to different
WLAN clients transmitting to the Gateway at the same time, therefore
jamming each other’s transmission. RTS Threshold is a packet size above
which the Gateway will expect to use the RTS mechanism. This is negotiated
with the client.
The client issues an RTS signal (before data packets were sent) to advise the
Gateway nearby that it has a large packet to send. The Gateway then issues a
clear to send (CTS) signal to all clients, which keeps the other clients waiting
while the requesting client sends its data.
The default value for the IBM High Rate Wireless LAN Gateway is
2432
, which
is large so that RTS does not activate in most cases. In most network
environments, RTS is not necessary or desired, since it reduces performance.
The Fragmentation Threshold figure determines whether a long packet is split
into several shorter packets. This is done for efficiency reasons. Packets longer
than the Fragmentation Threshold are split, resulting in better network
performance.
Part 4: Setting up the access point in the IBM High Rate Wireless LAN Gateway
4-3