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27 Chapter 3
The “Advanced” drop-down menu identifies several parameters that are
related to the 802.11b wireless network. We suggested the default set-
tings are not changed unless necessary.
Beacon Interval
In infrastructure networks, the access point periodically sends beacons.
You can set the beacon interval with the access point configuration
screen. In general, the beacon interval is set to 100 ms, which provides
good performance for most applications.
In ad hoc networks, there are no access points. As a result, one of the peer
stations assumes the responsibility for sending the beacon. After receiv-
ing a beacon frame, each station waits for the beacon interval and then
sends a beacon if no other station does so after a random time delay. This
ensures that at least one station will send a beacon, and the random delay
rotates the responsibility for sending beacons.
By increasing the beacon interval, you can reduce the number of beacons
and associated overhead, but that will likely delay the association and
roaming process because stations scanning for available access points
may miss the beacons. You can decrease the beacon interval, which
increases the rate of beacons. This will make the association and roaming
process very responsive; however, the network will incur additional over-
head and throughput will go down. In addition, stations using power save
mode will need to consume more power because they'll need to awaken
more often, which reduces power saving mode benefits.
Table 3.2: Advanced Parameters’ Default Value and Range
Parameters Default Value Range
Beacon Interval 100 0~65535
RTS Threshold 2347 0~2347
Fragment Threshold 2346 256~2346
Preamble Long Long/Short