User Guide

Table Of Contents
Wi-Fi Multimedia 307
Nortel WLAN Security Switch 2300 Series Configuration Guide
QoS on an AP
AP access ports use forwarding queues to prioritize traffic to wireless clients. When the AP receives a packet from an
WSS switch, the AP places the packet into one of four forwarding queues. The AP’s queue selection is based on the IP
ToS setting in the tunnel header of the encapsulated data packet received from the WSS. The AP has the following
forwarding queues, listed from lowest priority to highest priority:
Background
Best effort
•Video
•Voice
Figure 15 shows an example of WMM providing high priority forwarding for voice traffic through the network.
Figure 15. WMM in a Nortel Network
This figure shows the following process:
1 A user sends voice traffic from a WMM VoIP phone. The phone marks the QoS field of the packet with
service type 7, indicating that the packet is for high priority (voice) traffic.
2 AP A receives the voice packet, encapsulates the data in an IP tunnel packet, and maps the service type to
the equivalent IP ToS value in the tunnel header. Then the AP sends the packet to the WSS switch.
Layer 3
WSS Switch
Srvc Type = 7 Voice Data . . .
IP ToS = 0xe0 Voice Data. . .
802.1p = 7
IP ToS = 0xe0 Voice Data. . .
802.1p = 7
Voice
Video
Best Effort
Bgrnd
WSS Switch A
AP A
AP B
4
1
2
3
5
6
Voice Data. . .
Tnl Hdr IP ToS = 0xe0
Voice Data. . .
Tnl Hdr IP ToS = 0xe0
Layer 3