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CHAPTER
7-1
Cisco Wireless Router and HWIC Configuration Guide
OL-6415-03
7
Configuring QoS on an Access Point
This chapter describes how to configure quality of service (QoS) on an access point. QoS provides
preferential treatment to certain traffic at the expense of other traffic. Without QoS, the access point
offers best-effort service to each packet, regardless of the packet contents or size. It sends the packets
without any assurance of reliability, delay bounds, or throughput.
Recommended Reading
The following information is recommended for gaining a better understanding of QoS as it applies to
voice deployments in a wireless environment:
Wireless Quality-of-Service Deployment Guide
http://www.cisco.com/en/US/products/hw/wireless/ps430/prod_technical_reference09186a008014449
8.html
Cisco Wireless IP Phone 7920 Design and Deployment Guide
http://www.cisco.com/en/US/products/hw/phones/ps379/products_implementation_design_guide_boo
k09186a00802a029a.html
Understanding QoS for Wireless LANs
Typically, networks operate on a best-effort delivery basis that means that all traffic has equal priority
and an equal chance of being delivered in a timely manner. When congestion occurs, all traffic has an
equal chance of being dropped.
When QoS is configured on an access point, you can select specific network traffic, prioritize it, and use
congestion-management and congestion-avoidance techniques to provide preferential treatment.
Implementing QoS in a wireless LAN makes network performance more predictable and bandwidth
utilization more effective.
Configuring QoS creates and applies policies to the VLANs configured on the access point. If VLANs
are not used on the network, QoS policies can be applied to the Ethernet and radio ports.
QoS for Wireless LANs Versus QoS on Wired LANs
The QoS implementation for wireless LANs differs from QoS implementations on other Cisco devices.
With QoS enabled, access points perform the following:
• Does not classify packets; it prioritizes packets based on Differentiated Services Code Point (DSCP)
value, client type (such as a wireless phone), or the priority value in the 802.1q or 802.1p tag.