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56-1
Chapter 56: 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.
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 specify type of traffic based on an access
list, a DSCP or IP Precedence value, or a VLAN.
3. Set an ACL mask to enable filtering for the criteria specified in the match
command.
4. 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.
5. Use the class command to identify the class map, and enter Policy Map Class
configuration mode. A policy map can contain multiple class statements.
6. Use the set command to modify the QoS value for matching traffic class, and
use the policer command to monitor the average flow and burst rate, and drop
any traffic that exceeds the specified rate, or just reduce the DSCP service level
for traffic exceeding the specified rate.
7. Use the service-policy command to assign a policy map to a specific interface.
Table 56-1 Quality of Service Commands
Command Function Mode Page
class-map Creates a class map for a type of traffic GC 56-2
match Defines the criteria used to classify traffic CM 56-3
policy-map Creates a policy map for multiple interfaces GC 56-4
class Defines a traffic classification for the policy to act on PM 56-4
set Classifies IP traffic by setting a CoS, DSCP, or IP-precedence
value in a packet
PM-C 56-5
police Defines an enforcer for classified traffic PM-C 56-6
service-policy Applies a policy map defined by the policy-map command to
the input of a particular interface
IC 56-7
show class-map Displays the QoS class maps which define matching criteria
used for classifying traffic
PE 56-8
show policy-map Displays the QoS policy maps which define classification
criteria for incoming traffic, and may include policers for
bandwidth limitations
PE 56-8
show policy-map interface Displays the configuration of all classes configured for all
service policies on the specified interface
PE 56-9