D-Link AirPremier DWL-2210AP Manual page 99

Configuring Queues for Qualty of Service (QoS)
A different type of data is associated with each queue. The queue and associated
priorities and parameters for transmission are as follows:
• Data 0 (bulk). Lowest priority queue, high throughput. Bulk data that requires
maximum throughput and is not time-sensitive is sent to this queue (FTP data,
for example).
Data 1 (best effort). Medium priority queue, medium throughput and delay. Most
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traditional IP data is sent to this queue.
• Data 2 (interactive). Highest priority queue, minimum delay. Time-sensitive data
such as VoIP and streaming media are automatically sent to this queue.
Data 3 (not used)
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Packets in a higher priority queue will be transmitted before packets in a lower priority
queue. Interactive data in the queue labeled "Data 2" is always sent first, best effort data
in "Data 1" is sent next, and bulk data in "Data 0" is sent last. Each lower priority queue
(class of traffic) gets bandwidth that is left over after the higher classes of traffic have
been sent. At an extreme end if you have enough interactive data to keep the access
point busy all the time, low priority traffic would never get sent.
Using the QoS settings on the Administration UI, you can configure parameters that
determine how each queue is treated when it is sent by the access point.
Wireless traffic travels:
• Downstream from the access point to the client station
• Upstream from client station to access point
• Upstream from access point to network
• Downstream from network to access point
QoS settings on the D-Link DWL-2210AP affect only the first of these; downstream traffic flowing
from the access point to client station. The other phases of the traffic flow are not under control
of the QoS settings on the AP.
DCF Control of Data Frames and Interframe Spaces
Data is transmitted over 802.11 wireless networks in frames. A Frame consists of a
discrete portion of data along with some descriptive meta-information packaged for
transmission on a wireless network.
A Frame is similar in concept to a Packet, the difference being that a packet operates on the
Network layer (layer 3 in the OSI model) whereas a frame operates on the Data-Link layer
(layer 2 in the OSI model).
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