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Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
Chapter 27 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 switch:
• 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
Table 27-3 shows the QoS default configuration.
Table 27-3 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
