Cisco WAP371, Руководство администратора

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Wireless
Radio
Cisco Small Business WAP371 Wireless Access Point Administration Guide 61
5
You can disable protection (Off); however, legacy clients or WAP devices within range
can be affected by 802.11n transmissions. Protection is also available when the mode is
802.11b/g. When protection is enabled in this mode, it protects 802.11b clients and
WAP devices from 802.11g transmissions.
NOTE
This setting does not affect the ability of the client to associate with the WAP
device.
• Beacon Interval—The interval between the transmission of beacon frames. The WAP
device transmits these 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 an integer from 20 to 2000 milliseconds. The default is 100 milliseconds.
• DTIM Period—The Delivery Traffic Information Map (DTIM) period. Enter an integer
from 1 to 255 beacons. The default is 2 beacons.
The 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 WAP
device awaiting pickup.
The DTIM period that you specify indicates how often the clients served by this WAP
device should check for buffered data still on the WAP device awaiting pickup.
The measurement is in beacons. For example, if you set this field to 1, clients check for
buffered data on the WAP device at every beacon. If you set this field to 10, clients
check on every 10th beacon.
• Fragmentation Threshold—The frame size threshold in bytes. The valid integer must be
even and in the range of 256 to 2346. The default is 2346.
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, which is the default)
effectively disables fragmentation.
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.