CHAPT ER
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Catalyst 3750 SwitchSoftware Configuration Guide
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Configuring QoS
This chapter describes how to configure quality of service (QoS) by using automatic QoS (auto-QoS)
commands or by using standard QoS commands on the Catalyst3750 switch. With QoS, you can provide
preferential treatment to certain types of traffic at the expense of others. Without QoS, the switch 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. Unless otherwise noted, the term switch refers
to a standalone switch and a switch stack.
You can configure QoS on physical ports and on switch virtual interfaces (SVIs). Other than to apply
policy maps, you configure the QoS settings, such as classification, queueing, and scheduling, the same
way on physical ports and SVIs. When configuring QoS on a physical port, you apply a nonhierarchical
policy map to a port. When configuring QoS on an SVI, you apply a nonhierarchical or a hierarchical
policy map. In the Catalyst 3750 Metro switch documentation, nonhierarchical policy maps are referred
to as nonhierarchical single-level policy maps, and hierarchical policy maps are referred to as
hierarchical dual-level policy maps.
Note For complete syntax and usage information for the commands used in this chapter, see the command
reference for this release.
This chapter consists of these sections:
Understanding QoS, page35-2
Configuring Auto-QoS, page35-21
Displaying Auto-QoS Information, page35-34
Configuring Standard QoS, page35-35
Displaying Standard QoS Information, page35-85
The switch supports some of the modular QoS CLI (MQC) commands. For more information about the
MQC commands, see the “Modular Quality of Service Command-Line Interface Overview”:
http://www.cisco.com/en/US/docs/ios/12_2/qos/configuration/guide/qcfmcli2.html