Quality of Service Commands

4-257

4

Quality of Service Commands

The commands described in this section are used to configure Differentiated
Services (DiffServ) classification criteria and service policies. You can classify traffic
based on access lists, IP Precedence or DSCP values, or VLANs. Using access lists
allows you select traffic based on Layer 2, Layer 3, or Layer 4 information contained
in each packet
Note: Due to a chip limitation, IP source guard and Quality of Service (for IP-related
QoS) cannot be enabled at the same time.
To create a service policy for a specific category of ingress traffic, follow these steps:
1. Use the class-map command to designate a class name for a specific category
of traffic, and enter the Class Map configuration mode.
2. Use the match command to select a specific type of traffic based on an access
list, a DSCP or IP Precedence value, or a VLAN.
3. Use the policy-map command to designate a policy name for a specific
manner in which ingress traffic will be handled, and enter the Policy Map
configuration mode.
4. Use the class command to identify the class map, and enter Policy Map Class
configuration mode. A policy map can contain multiple class statements.
Table 4-82 Quality of Service Commands
Command Function Mode Page
class-map Creates a class map for a type of traffic GC 4-258
match Defines the criteria used to classify traffic CM 4-259
rename Redefines the name of a class map CM 4-260
description Specifies the description of a class map CM 4-260
policy-map Creates a policy map for multiple interfaces GC 4-261
class Defines a traffic classification for the policy to act on PM 4-261
rename Redefines the name of a policy map PM 4-260
description Specifies the description of a policy map PM 4-260
set Classifies IP traffic by setting a CoS, DSCP, or IP-precedence
value in a packet
PM-C 4-262
police Defines an enforcer for classified traffic PM-C 4-263
service-policy Applies a policy map defined by the policy-map command to
the input of a particular interface
IC 4-264
show class-map Displays the QoS class maps which define matching criteria
used for classifying traffic
PE 4-264
show policy-map Displays the QoS policy maps which define classification
criteria for incoming traffic, and may include policers for
bandwidth limitations
PE 4-265
show policy-map interface Displays the configuration of all classes configured for all
service policies on the specified interface
PE 4-265