D-Link DWS-1008 User Manual page 169

DWS-1008 User's Manual
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 configuration 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 traffic is detected by an 802.11b/g radio, the radio enters protection mode.
Protection mode guards against 802.11b interference with 802.11g traffic that is at data rates
higher than the 802.11b rates. Because 802.11b clients cannot detect the traffic at data rates
higher than are supported by 802.11b, the clients might cause interference by sending traffic
while 802.11g access points or clients also are sending traffic.
To guard against interference, an 802.11b/g radio in protection mode sends messages while
802.11g traffic at higher data rates is being sent, to inform 802.11b devices about the 802.11g
traffic and reserve bandwidth for the traffic. Protection mode remains in effect until 60 seconds
after the last 802.11b traffic is detected by the 802.11b/g radio.
Protection mode lowers overall traffic throughput due to the additional messages sent by
802.11b/g radios. You can configure the 802.11b/g radios in a radio profile 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 configure 802.11b/g radios to reject association attempts from 802.11b clients, use the
following command:
set radio-profile name 11g-only {enable | disable}
To configure the 802.11b/g radios in radio profile rp1 to allow associations from 802.11g
clients only, type the following command:
DWS-1008# set radio-profile 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
specified by the client. An 802.11b/g radio always uses a long preamble in beacons, probe
responses, and other broadcast or multicast traffic.
D-Link Systems, Inc.
Configuring DWL-8220AP Access Points
164