Allied Telesis AT-WA7400/NA - Manual (Page 164)

Chapter 15: Configuring Quality of Service (QoS)
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ˆ Data 2 (Best Effort). Medium priority queue, medium throughput and
delay. Most traditional IP data is sent to this queue.
ˆ Data 3 (Background). 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).
Packets in a higher priority queue will be transmitted before packets in a
lower priority queue. Interactive data in the queues labeled Data 0 and
Data 1 is always sent first, best effort data in Data 2 is sent next, and
Background (bulk) data in Data 3 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 web UI, you can configure Enhanced
Distributed Channel Access (EDCA) parameters that determine how each
queue is treated when it is sent by the access point to the client or by the
client to the access point.
Note
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
With WMM enabled, QoS settings on the AT-WA7400 Wireless
Access Point affect the first two of these; downstream traffic flowing
from the access point to client station (AP EDCA parameters) and
the upstream traffic flowing from the station to the access point
(station EDCA parameters).
With WMM disabled, you can still set some parameters on the
downstream traffic flowing from the access point to the client station
(AP EDCA parameters).
The other phases of the traffic flow (to and from the network) are not
under control of the QoS settings on the access point.
EDCF Control of Data Frames and Arbitration 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.