3com WX4400 3CRWX440095A Manual De Usuario

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C
HAPTER
 10: C
ONFIGURING
 MAP A
CCESS
 P
OINTS
Changing the Maximum Transmit Threshold
The maximum 
transmission threshold specifies the number of milliseconds a frame 
scheduled to be transmitted by a radio can remain in buffer memory. To 
change the maximum transmit lifetime, use the following command:
set radio-profile name max-tx-lifetime time
The time can be from 500 ms (0.5 second) through 250,000 ms 
(250 seconds). The default is 2000 ms (2 seconds).
To change the maximum transmit threshold for radio profile rp1 to 
4000 ms, type the following command:
WX1200# set radio-profile rp1 max-tx-lifetime 4000
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.
Generally, clients assume access points require long preambles and 
request to use short preambles only if the access point with which they 
are associated advertises support for short preambles. You can disable 
the advertisement of support for short preambles by setting the preamble 
length value to long. In this case, clients assume that the access point 
supports long preambles only and the clients request long preambles.
Changing the preamble length value affects only the support advertised 
by the radio. Regardless of the preamble length setting (short or long), 
an 802.11b/g radio accepts and can generate 802.11b/g frames with 
either short or long preambles.
If any client associated with an 802.11b/g radio uses long preambles for 
unicast traffic, the MAP still accepts frames with short preambles but 
does not transmit any frames with short preambles. This change also 
occurs if the access point overhears a beacon from an 802.11b/g radio on 
another access point that indicates the radio has clients that require long 
preambles.