CHAPTER
22-1
ATM Switch Router Software Configuration Guide
OL-7396-01
22
Configuring Quality of Service
This chapter describes the quality of service (QoS) features built into your switch router and includes
information on how to configure the QoS functionality. This chapter includes the following sections:
About Quality of Service, page 22-1
About Layer 3 Switching Quality of Service, page 22-2
IP Precedence Based Class of Service (CoS), page 22-3
About IP QoS on the Enhanced Gigabit Ethernet and Enhanced ATM Router Module Interfaces,
page 22-6
IP QoS—Functional Differences Between Modules (Catalyst 8540 MSR), page 22-11
Configuring IP QoS on Enhanced Gigabit Ethernet and Enhanced ATM Router Module Interfaces,
page 22-17
Verifying the IP QoS Configuration, page 22-22
Note Unless otherwise noted, the information in this chapter appl ies to the Catalyst 8540 CSR, Catalyst 8510
CSR, and Catalyst 8540 MSR with Layer 3 functionality. For further information about the commands
used in this chapter, refer to the ATM and Layer 3 Switch Router Command Reference.

About Quality of Service

QoS refers to the capability of a network to provide better service to selected network traffic over various
technologies, including Frame Relay, Asynchronous Transfer Mode (ATM), Ethernet and 802.1
networks, SONET, and IP-routed networks that may use any or all of these underlying technologies.The
following sections describe the Best-Effort, Integrated, and Differentiated service models that the QoS
functionality offers.
Note For more information about Policy Based Routing, refer to the Layer 3 Switching Software and Feature
Configuration Guide.