Table Of Contents
QoS Child Service Policy for Priority Class
Prerequisites for QoS Child Service Policy for Priority Class
Restrictions for QoS Child Service Policy for Priority Class
Information About QoS Child Service Policy for Priority Class
Priority Class of a Parent Policy
How to Configure a Child Policy Under a Parent Priority Class
Configuring a Child Policy Under a Priority Class
Attaching a Hierarchical Service Policy to a Subinterface
Configuration Examples for Configuring a Child Policy Under a Priority Class
Configuring a Police-Based Child Policy Under a Priority Class: Example
Attaching a Bandwidth-Based Child Policy to a Priority Class—Invalid Configuration: Example
Attaching Bandwidth to a Child Policy Attached to a Priority Class—Invalid Configuration: Example
QoS Child Service Policy for Priority Class
First Published: November, 2006The QoS Child Service Policy for Priority Class feature allows you to configure a child service policy with nonqueuing-based features and attach the child policy to a priority class.
History of QoS Child Service Policy for Priority Class
Release Modification12.2(31)SB2
This feature was introduced and implemented on the Cisco 10000 series router for the PRE3.
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Contents
•Prerequisites for QoS Child Service Policy for Priority Class
•Restrictions for QoS Child Service Policy for Priority Class
•Information About QoS Child Service Policy for Priority Class
•How to Configure a Child Policy Under a Parent Priority Class
•Configuration Examples for Configuring a Child Policy Under a Priority Class
Prerequisites for QoS Child Service Policy for Priority Class
Traffic classes must be configured using the class-map command.
Restrictions for QoS Child Service Policy for Priority Class
The child policy that you attach to a priority class must be based on nonqueuing features. For example, if you attempt to do any of the following, an error message displays:
•Attach queuing-based child policy—You cannot attach a child service policy that is based on queuing features to a priority class. For example, you cannot attach a bandwidth-based child policy to a class with priority configured.
•Add queuing features to child policy—You cannot add queuing features (such as bandwidth) to a child policy that is already attached to a parent class with priority configured.
•Add priority to parent class—If a queuing-based child policy is already attached to a non-priority class of a parent policy, you cannot then configure the priority command for the parent class.
Information About QoS Child Service Policy for Priority Class
The QoS Child Service Policy for Priority Class feature allows you to configure a child service policy with nonqueuing-based features and attach the child policy to a priority class. In a three-level hierarchical policy, the priority class to which you attach the child policy must be in the middle-level policy. In a two-level hierarchical policy (nested policy), the priority class to which you attach the child policy is in the parent policy.
Prior to Cisco IOS Release 12.2(31)SB2, you could not attach a child service policy to a priority class even if the child policy contained nonqueuing-based commands. If you attempted to do so, an error message similar to the following displayed:
Please remove priority before attaching a child policy.Priority Class of a Parent Policy
A parent policy contains traffic classes with various queuing and nonqueuing features enabled on the classes. You can give priority to a traffic class by configuring the priority command under the class. The router processes the packets belonging to the priority class before processing nonpriority classes.
Hierarchical Policies
A hierarchical policy is a quality of service (QoS) model that enables you to specify QoS behavior at multiple levels of hierarchy. Depending on the type of hierarchical policy you configure, you can use hierarchical policies to:
•Specify multiple policy maps to shape multiple queues together
•Apply specific policy map actions on the aggregate traffic
•Apply class-specific policy map actions
•Restrict the maximum bandwidth of a virtual circuit (VC) while allowing policing and marking of traffic classes within the VC
All hierarchical policy types consist of a top-level parent policy and one or more child policies. The service-policy command is used to apply a policy to another policy, and a policy to an interface, subinterface, virtual circuit (VC), or virtual LAN (VLAN).
How to Configure a Child Policy Under a Parent Priority Class
To configure a child policy under a parent priority class, perform the following configuration tasks:
•Configuring a Child Policy Under a Priority Class
•Attaching a Hierarchical Service Policy to a Subinterface
Configuring a Child Policy Under a Priority Class
Use the following procedure to configure a child policy under a priority class.
SUMMARY STEPS
1. enable
2. configure terminal
3. policy-map policy-map-name
4. class class-map-name
5. police [cir] bps [bc] burst-normal [be] burst-excess [conform-action action] [exceed-action action] [violate-action action]
6. exit
7. policy-map policy-map-name
8. class class-map-name
9. priority
10. service-policy policy-map-name
DETAILED STEPS
Command or Action PurposeStep 1
enable
Example:Router> enable
Enables privileged EXEC mode.
•Enter your password if prompted.
Step 2
configure terminal
Example:Router# configure terminal
Enters global configuration mode.
Step 3
policy-map policy-map-name
Example:Router(config)# policy-map Business
Creates or modifies the child policy. Enters policy-map configuration mode.
•policy-map-name is the name of the child policy map. The name can be a maximum of 40 alphanumeric characters.
Step 4
class class-map-name
Example:Router(config-pmap)# class video
Assigns the traffic class you specify to the policy map. Enters policy-map class configuration mode.
•class-map-name is the name of a previously configured class map.
Step 5
police [cir] bps [Bc] burst-normal [Be] burst-excess [conform-action action] [exceed-action action] [violate-action action]Example:Router(config-pmap-c)# police 4000000 2000 5000 conform-action transmit exceed-action set-dscp-transmit 5
Configures traffic policing.
•cir is the committed information rate.
•bps specifies the average rate in bits per second (bps).
•Bc is the normal or committed burst (bc) size used by the first token bucket for policing.
•burst-normal specifies the committed burst size in bytes.
•Be is the excess burst (be) size used by the second token bucket for policing.
•burst-excess specifies the excess burst in bytes.
•conform-action action specifies the action to take on packets that conform to the rate limit.
•exceed-action action specifies the action to take on packets that exceed the rate limit, but not the peak information rate (PIR).
•violate-action action specifies the action to take on packets that continuously exceed the PIR limit.
Step 6
exit
Example:Router(config-pmap-c)# exit
Exits policy-map class configuration mode.
Step 7
policy-map policy-map-name
Example:Router(config-pmap)# policy-map Premium
Creates or modifies the top-level parent policy (nested policy), or the middle-level policy (three-level hierarchical policy).
•policy-map-name is the name of the parent or middle-level policy map. The name can be a maximum of 40 alphanumeric characters.
Step 8
class class-map-name
Example:Router(config-pmap)# class Gold
Assigns the traffic class you specify to the policy map. Enters policy-map class configuration mode.
•class-map-name is the name of a previously configured class map.
Step 9
priority
Example:Router(config-pmap-c)# priority
Assigns priority to the traffic class.
Step 10
service-policy policy-map-name
Example:Router(config-pmap-c)# service-policy Business
Applies a child policy to the parent or middle-level priority class.
•policy-map-name is the name of a previously configured child policy map.
Note For three-level hierarchical policies, after applying the child policy to the middle-level priority class, you must then apply the middle-level policy to the parent policy. For more information, see "Defining QoS for Multiple Policy Levels" in the Cisco 10000 Series Router Quality of Service Configuration Guide.
Attaching a Hierarchical Service Policy to a Subinterface
Use the following procedure to attach a hierarchical service policy to a subinterface.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface type slot/module/port.subinterface [point-to-point]
4. service-policy {input | output} policy-map-name
DETAILED STEPS
Configuration Examples for Configuring a Child Policy Under a Priority Class
This section provides the following configuration examples:
•Configuring a Police-Based Child Policy Under a Priority Class: Example
•Attaching a Bandwidth-Based Child Policy to a Priority Class—Invalid Configuration: Example
•Attaching Bandwidth to a Child Policy Attached to a Priority Class—Invalid Configuration: Example
Configuring a Police-Based Child Policy Under a Priority Class: Example
The following example configuration shows how to configure a child policy with policing enabled and attach it to a priority class of a parent policy.
policy-map Childclass class1police 10000!policy-map Parentclass P2priorityservice-policy ChildAttaching a Bandwidth-Based Child Policy to a Priority Class—Invalid Configuration: Example
As shown in the following example configuration, the router does not allow you to attach a bandwidth-based child policy to a priority class of a parent policy. This is an invalid configuration.
policy-map Childclass class1bandwidth 100!policy-map Parentclass P2priorityservice-policy ChildPlease remove priority before attaching a child policy.!!show policy-mappolicy-map Childclass class1bandwidth 100!policy-map Parentclass P2priorityAttaching Bandwidth to a Child Policy Attached to a Priority Class—Invalid Configuration: Example
As shown in the following example configuration, the router does not allow you to add the bandwidth command to a child policy that is already attached to a priority class of a parent policy. This is an invalid configuration.
policy-map Childclass class1police cir 10000 bc 1500 conform-action transmit exceed-action drop!policy-map Parentclass P2priorityservice-policy Child!!policy-map Childclass class1bandwidth 10Cannot configure `bandwidth' in child policy with `priority' in parent!!show policy-mappolicy-map Childclass class1police cir 10000 bc 1500 conform-action transmit exceed-action drop!policy-map Parentclass P2priorityservice-policy ChildAttaching Priority to a Parent Policy with a Queuing-Based Child Policy—Invalid Configuration: Example
As shown in the following example configuration, the router does not allow you to assign priority to a class of a parent policy when a queuing-based child policy is already attached to the parent class. This is an invalid configuration.
policy-map Childclass class1bandwidth 10!policy-map Parentclass P2police cir 10000 bc 1500 conform-action transmit exceed-action dropservice-policy Child!!policy-map Parentclass P2priorityCannot configure `priority' in parent policy with queuing-related child policy.!!show policy-mappolicy-map Childclass class1bandwidth 10!policy-map Parentclass P2police cir 10000 bc 1500 conform-action transmit exceed-action dropservice-policy ChildAdditional References
The following sections provide references related to the QoS Child Service Policy for Priority Class feature.
Related Documents
Related Topic Document TitleHierarchical policies
Cisco 10000 Series Router Quality of Service Configuration Guide
Policing and shaping
Cisco IOS Quality of Service Solutions Configuration Guide
Part 4: Policing and Shaping > Policing and Shaping Overview
Cisco 10000 Series Router Quality of Service Configuration Guide
Policy maps
Cisco 10000 Series Router Quality of Service Configuration Guide
Standards
Standard TitleNo new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
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MIBs
RFCs
RFC TitleNo new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.
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Technical Assistance
Command Reference
This feature uses no new or modified commands.
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