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Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
Chapter27 Configuring Quality of Service
Configuring QoS
Configuring QoS
Before configuring 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 QoS on the Catalyst 4500 series sw itch:
Default QoS Configuration, page 27-23
Configuration Guidelines, page 27-25
Enabling QoS Globally, page 27-25
Configuring a Trusted Boundary to Ensure Port Security, page 27-26
Enabling Dynamic Buffer Limiting, page 27-27
Creating Named Aggregate Policers, page 27-27
Configuring a QoS Policy, page 27-29
Configuring User Based Rate Limiting, page 27-36
Enabling Per-Port Per-VLAN QoS, page 27-41
Enabling or Disabling QoS on an Interface, page 27-44
Configuring VLAN-Based QoS on Layer 2 Interfaces, page 27-45
Configuring the Trust State of Interfaces, page 27-46
Configuring the CoS Value for an Interface, page 27-47
Configuring DSCP Values for an Interface, page 27-47
Configuring Transmit Queues, page 27-48
Configuring DSCP Maps, page 27-51

Default QoS Configuration

Table27-3 shows the Qo S default configuration.
Table27-3 QoS Default Configuration
Feature Default Value
Global QoS configuration Disabled
Interface QoS configuration (port based) Enabled when QoS is globally enabled
Interface CoS value 0
Interface DSCP value 0