D-Link DWS-1008 Product Manual - Page 211

WMM QoS on an AP, SVP QoS Mode

Page 211 highlights

WMM QoS on an AP Access points use forwarding queues to prioritize traffic for wireless clients. For a packet received by the AP from a client, the AP classifies the packet based on the service type in the 802.11 header and maps the service type value to an internal CoS value. The AP then marks the DSCP value in the IP tunnel header to the switch based on the internal CoS value. For a packet received from a DWS-1008 switch and addressed to a client, the AP classifies the packet by mapping the DSCP value in the IP tunnel header to an internal CoS value. The AP then assigns the packet to a forwarding queue based on the internal CoS value. The AP also marks the service type in the 802.11 header based on the internal CoS value. An AP uses the DSCP-to-CoS and CoS-to-DSCP mappings of the switch that is managing it. If you change mappings on a switch, the change also applies to the AP. Likewise, if an AP changes to another switch (for example, after an AP restart), the AP uses the mappings in effect on the new switch. The table below lists the default mappings between an AP's internal CoS values and its forwarding queues. CoS 1 or 2 0 or 3 4 or 5 6 or 7 AP Forwarding Queue Background Best Effort Video Voice SVP QoS Mode The SVP QoS mode optimizes forwarding of SVP traffic by setting the random wait time an AP radio waits before transmitting the traffic to 0 microseconds. Normally, an AP radio waits an additional number of microseconds following the fixed wait time, before forwarding a queued packet or frame. Each forwarding queue has a different range of possible random wait times. The Voice queue has the narrowest range, whereas the Background and Best Effort queues have the widest range. The random wait times ensure that the Voice queue gets statistically more access to the air than the other queues. By setting the random wait time to 0 for SVP, the SVP QoS mode provides SVP traffic the greatest possible access to the air, on a statistical basis. The QoS mode affects forwarding of SVP traffic only. The random wait times for other types of traffic are the same as those used when the QoS mode is WMM. D-Link DWS-1008 User Manual 192

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D-Link DWS-1008 User Manual
1·±
WMM QoS on an AP
Access points use forwarding queues to prioritize traffic for wireless clients.
For a packet received by the AP from a client, the AP classifies the packet based on the service type in
the 802.11 header and maps the service type value to an internal CoS value. The AP then marks the
DSCP value in the IP tunnel header to the switch based on the internal CoS value.
For a packet received from a DWS-1008 switch and addressed to a client, the AP classifies the packet
by mapping the DSCP value in the IP tunnel header to an internal CoS value. The AP then assigns the
packet to a forwarding queue based on the internal CoS value. The AP also marks the service type in
the 802.11 header based on the internal CoS value.
An AP uses the DSCP-to-CoS and CoS-to-DSCP mappings of the switch that is managing it. If you
change mappings on a switch, the change also applies to the AP. Likewise, if an AP changes to another
switch (for example, after an AP restart), the AP uses the mappings in effect on the new switch.
The table below lists the default mappings between an AP’s internal CoS values and its forwarding
queues.
CoS
AP Forwarding Queue
1 or 2
Background
0 or 3
Best Effort
4 or 5
Video
6 or 7
Voice
SVP QoS Mode
The SVP QoS mode optimizes forwarding of SVP traffic by setting the random wait time an AP radio
waits before transmitting the traffic to 0 microseconds.
Normally, an AP radio waits an additional number of microseconds following the fixed wait time, before
forwarding a queued packet or frame. Each forwarding queue has a different range of possible random
wait times. The Voice queue has the narrowest range, whereas the Background and Best Effort queues
have the widest range. The random wait times ensure that the Voice queue gets statistically more
access to the air than the other queues.
By setting the random wait time to 0 for SVP, the SVP QoS mode provides SVP traffic the greatest
possible access to the air, on a statistical basis. The QoS mode affects forwarding of SVP traffic only.
The random wait times for other types of traffic are the same as those used when the QoS mode is
WMM.