User's Manual

Configuring Quality of Service
Installation and Configuration Guide: Airgo Access Point 111
Configuring Quality of Service
Under normal network conditions, traffic in the wireless network is routed on a best-effort basis,
and all types of traffic are treated with equal priority. Quality of Service (QoS) permits priority
setting for different types of traffic, which can be important for applications in which even minor
interruptions in packet transmission can have a deleterious effect on perceived results. Examples
include streaming media or voice-over-IP (VoIP). With a QoS process in place, multiple clients can
run applications with varying traffic delivery requirements over a single shared network.
Airgo supports QoS through hierarchical classes of service (COS) that control how network
bandwidth is shared among multiple entities. COS specifies a numeric class code with values
ranging from 0 (lowest priority) to 7 (highest priority). This method does not guarantee bandwidth
for different traffic types, but does assure that high COS traffic will be given preference.
For example, when Acme Works wanted to set up a video conference center, it was important to
provide a higher quality of service for the video conference application. The company accordingly
set up a structure of multiple SSIDs in which a higher COS value was assigned to the service
profile for the Video SSID (Figure 81).
Figure 81: Example Applications with Different COS Levels
The Airgo AP supports several options for assigning COS to the packets passing into the AP (the
ingress to the AP).
Rule Description
TCID-to-COS mapping Defines a COS mapping based on the Traffic Class Identifier (TCID), which
is part of the standard 802.11 frame header. Incoming packets with a TCID
value assigned can be mapped to COS.
VLAN-to-COS Defines a COS mapping for packets that are not VLAN-tagged upon arrival at
the AP.
Interface-to-COS Associates a COS value to each of the AP interfaces (eth0, wlan0, wlan1).
MAC Uses the COS value from the user group’s service profile (see “Configuring
SSID Parameters” on page 78).
A0043B
SSID="Corporate" SSID="Video"
10/100 Switched Ethernet
Corporate Video
COS=7COS=4