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Catalyst 3750 Metro Switch Software Configuration Guide
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Chapter 26 Configuring QoS
Configuring Hierarchical QoS
Configuring Hierarchical QoS
You can configure hierarchical QoS (traffic classification, CBWFQ, LLQ, shaping, and two-rate,
three-color policing) and apply it to outbound traffic on an ES port.
Before configuring hierarchical QoS, you must have a thorough understanding of these items:
• The types of applications used and the traffic patterns on your network.
• Traffic characteristics and needs of your network. Is the traffic bursty? Do you need to reserve
bandwidth for voice and video streams?
• Bandwidth requirements and speed of the network.
• Location of congestion points in the network.
These sections describe how to configure hierarchical QoS on your switch. Read these sections if traffic
is flowing from a standard or an ES port to an ES port:
• Default Hierarchical QoS Configuration, page 26-76
• Hierarchical QoS Configuration Guidelines, page 26-76
• Configuring an Egress Hierarchical QoS Policy, page 26-77 (required)
Default Hierarchical QoS Configuration
QoS is disabled.
No traffic classes, class maps, policy maps, or policers are defined.
LLQ is disabled.
CBWFQ is disabled.
Tail drop is enabled.
WRED is disabled.
Average-rate traffic shaping is disabled.
Hierarchical QoS Configuration Guidelines
Before beginning the hierarchical QoS configuration, you should be aware of this information:
• QoS must be enabled with the mls qos global configuration command for any hierarchical
configuration to take effect. When enabled, QoS uses the default settings described in the “Default
Standard QoS Configuration” section on page 26-38 and the “Default Hierarchical QoS
Configuration” section on page 26-76. For detailed steps, see the “Enabling QoS Globally” section
on page 26-42.
• Because the switch does not support attaching a service policy to a logical interface (such as an
EtherChannel), if you have EtherChannel ports configured on your switch, you must configure QoS
classification, policing, mapping, and queueing on the individual physical ports that comprise the
EtherChannel.
• Class maps that contain ACLs are not supported in an egress policy attached to an ES port. You
cannot use the match access-group acl-index-or-name class-map configuration command.
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