User`s manual

164
DWS-1008 User’s Manual
D-Link Systems, Inc.
Conguring DWL-8220AP Access Points
Disabling 802.11b Client Associations on 802.11b/g Radios
By default, an 802.11b/g radio allows associations from 802.11b clients as well as 802.11g
clients. The radio requires a client to support the 802.11b data rates but client support for
the higher 802.11g rates is optional. This radio conguration allows both types of clients
to associate with the radio and is useful in networks that have a mixture of both types of
clients.
When 802.11b trafc is detected by an 802.11b/g radio, the radio enters protection mode.
Protection mode guards against 802.11b interference with 802.11g trafc that is at data rates
higher than the 802.11b rates. Because 802.11b clients cannot detect the trafc at data rates
higher than are supported by 802.11b, the clients might cause interference by sending trafc
while 802.11g access points or clients also are sending trafc.
To guard against interference, an 802.11b/g radio in protection mode sends messages while
802.11g trafc at higher data rates is being sent, to inform 802.11b devices about the 802.11g
trafc and reserve bandwidth for the trafc. Protection mode remains in effect until 60 seconds
after the last 802.11b trafc is detected by the 802.11b/g radio.
Protection mode lowers overall trafc throughput due to the additional messages sent by
802.11b/g radios. You can congure the 802.11b/g radios in a radio prole to reject association
attempts by 802.11b clients so that protection mode is less likely to be required. In this case,
the 802.11b/g radios require a client to support all the 802.11g rates.
Note: Even when association of 802.11b clients is disabled, if an 802.11b/g radio detects
a beacon from an 802.11b network, the radio enters protection mode to protect against
interference.
To congure 802.11b/g radios to reject association attempts from 802.11b clients, use the
following command:
set radio-prole name 11g-only {enable | disable}
To congure the 802.11b/g radios in radio prole rp1 to allow associations from 802.11g
clients only, type the following command:
DWS-1008# set radio-prole rp1 11g-only enable
success: change accepted.
Changing the Preamble Length
By default, 802.11b/g radios advertise support for frames with short preambles and can
support frames with short or long preambles.
An 802.11b/g radio generates unicast frames to send to a client with the preamble length
specied by the client. An 802.11b/g radio always uses a long preamble in beacons, probe
responses, and other broadcast or multicast trafc.