D-Link DWC-2000-AP32-LIC 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 Description 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. D-Link DWC-2000 User Manual 90