D-Link DWC-2000 User Manual page 90

Section 4 - Advanced WLAN Configuration
Field
Load Balancing
Channel Bandwidth
Protection
Space Time Block Code
No Ack
DTIM Period
Beacon Interval
Automatic Channel
D-Link DWC-2000 User Manual
If you enable load balancing, you can control the amount of traffic that is allowed on the
AP.
The 802.11n specification allows the use of a 40‐MHz‐wide channel in addition to the
legacy 20‐MHz channel available with other modes. The 40‐MHz channel enables
higher data rates but leaves fewer channels available for use by other 2.4 GHz and 5 GHz
devices. The 40‐MHz option is enabled by default for 802.11a/n modes and 20 MHz for
802.11b/g/n modes. You can use this setting to restrict the use of the channel bandwidth
to a 20‐MHz channel.
The protection feature contains rules to guarantee that 802.11 transmissions do not
cause interference with legacy stations or applications. 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. 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. 802.11 protection 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.
Space Time Block Coding (STBC) is an 802.11n technique intended to improve the
reliability of data transmissions. The data stream is transmitted on multiple antennas so
the receiving system has a better chance of detecting at least one of the data streams.
Select one of the following options:
• ON=The AP transmits the same data stream on multiple antennas at the same time.
• OFF=The AP does not transmits the same data on multiple antennas.
Select Enable to specify that the AP should not acknowledge frames with QosNoAck as
the service class value.
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 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 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.
Beacon frames are transmitted by an access point 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). The Beacon Interval value is set in milliseconds.
Enter a value from 20 to 2000.
The channel defines the portion of the radio spectrum that the radio uses for transmitting
and receiving. The range of channels and the default channel are determined by the
Mode of the radio interface. When the AP boots, the AP scans the RF area for occupied
channels and selects a channel from the available non‐interfering or clear channels.
However, channel conditions can change during operation.
Enabling the Automatic Channel makes APs assigned to this profile eligible for auto‐
channel selection. You can automatically or manually run the auto‐channel selection
algorithm to allow the controller to adjust the channel on APs as WLAN conditions
change.
By default, the global auto‐channel mode is set to manual. To enable the automatic
channel selection mode, go to the AP Management > RF Management page and select
Fixed or Interval for the Channel Plan mode. You can also run the automatic channel
selection algorithm manually from the Manual Channel Plan page.
Note: If you assign a static channel to an AP in the Valid AP database or on the Advanced
AP Management page, the AP will not participate in the auto‐channel selection.
Description
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