D-Link DWL-3600AP Administrator's Manual page 62

Unified Access Point Administrator's Guide
Field Description
Protection The protection feature contains rules to guarantee that 802.11n transmissions do not
cause interference with legacy stations or APs. By default, these protection mechanisms
are enabled (Auto). With protection enabled, protection mechanisms will be invoked if
legacy devices are within range of the AP. This causes more overhead on every
transmission, which will impact performance. However, there is no impact on
performance if there are no legacy devices within range of the AP.
You can disable (Off) these protection mechanisms; however, when 802.11n protection
is off, legacy clients or APs within range can be affected by 802.11n transmissions. The
802.11 protection feature is also available when the mode is 802.11b/g. When
protection is enabled in this mode, it protects 802.11b clients and APs from 802.11g
transmissions.
Note: This setting does not affect the ability of the client to associate with the AP.
Beacon Interval Beacon frames are transmitted by an AP at regular intervals to announce the existence
of the wireless network. The default behavior is to send a beacon frame once every 100
milliseconds (or 10 per second).
Enter a value from 20 to 2000 milliseconds.
DTIM Period Specify a DTIM period from 1 to 255 beacons.
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 AP awaiting pick‐up.
The DTIM period you specify indicates how often the clients served by this AP should
check for buffered data still on the AP awaiting pickup.
The measurement is in beacons. For example, if you set this field to 1, clients will check
for buffered data on the AP at every beacon. If you set this field to 10, clients will check
on every 10th beacon.
Fragmentation Specify a number between 256 and 2,346 to set the frame size threshold in bytes.
Threshold
The fragmentation threshold is a way of limiting the size of packets (frames) transmitted
over the network. If a packet exceeds the fragmentation threshold you set, the
fragmentation function is activated and the packet is sent as multiple 802.11 frames.
If the packet being transmitted is equal to or less than the threshold, fragmentation is not
used.
Setting the threshold to the largest value (2,346 bytes) effectively disables
fragmentation. Fragmentation plays no role when Aggregation is enabled.
Fragmentation involves more overhead both because of the extra work of dividing up
and reassembling 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) might 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.
D-Link
November 2011
Table 19: Radio Settings (Cont.)
Modifying Radio Settings
Unified Access Point Administrator's Guide
Page 62