User Manual

Chapter 16: Configuring Radio Settings
Configuring Radio Settings
158
Psion Teklogix 9160 Wireless Gateway User Manual
Beacon Interval Beacon frames are transmitted by an access point at regular intervals to announce the existence of
the wireless network. The default behaviour is to send a beacon frame once every
100 milliseconds
(or 10 per second).
The Beacon Interval value is set in milliseconds. Enter a value from
20 to 2000 .
DTIM Period The Delivery Traffic Information Map ( DTIM ) message is an element included in some Beacon
frames. It indicates which client stations, currently sleeping in low-power mode, have data buffered on
the access point awaiting pick-up.
The DTIM period you specify here indicates how often the clients served by this access point should
check for buffered data still on the AP awaiting pickup.
Specify a DTIM period within the given range ( 1 - 255 ).
The measurement is in beacons. For example, if you set this to
1 , clients will check for buffered data
on the AP at every beacon. If you set this to
2 , clients will check on every other beacon. If you set this
to
10 , clients will check on every 10th beacon.
Fragmentation
Threshold
Specify a number between 256 and 2,346 to set the frame size threshold in bytes.
The fragmentation threshold is a way of limiting the size of packets (frames) transmitted over the net-
work. If a packet exceeds the fragmentation threshold set here, the fragmentation function will be acti-
vated and the packet will be sent as multiple 802.11 frames.
If the packet being transmitted is equal to or less than the threshold, fragmentation will not be used.
Setting the threshold to the largest value (
2,346 bytes) effectively disables fragmentation.
Fragmentation involves more overhead both because of the extra work of dividing up and reassem-
bling of frames it requires, and because it increases message traffic on the network. However,
fragmentation can help improve network performance and reliability if properly configured.
Sending smaller frames (by using lower fragmentation threshold) may help with some interference
problems; for example, with microwave ovens.
By default, fragmentation is
off . We recommend not using fragmentation unless you suspect radio
interference. The additional headers applied to each fragment increase the overhead on the network
and can greatly reduce throughput.
Field Description
Table 16.1 Radio Settings