QoS: Congestion Management Configuration Guide, Cisco IOS XE Release 3S
QoS Hierarchical Queueing for ATM DSLAMs
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QoS Hierarchical Queueing for ATM DSLAMs

Contents

QoS Hierarchical Queueing for ATM DSLAMs

This feature module describes how to configure quality of service (QoS) hierarchical queueing policy maps on sessions and ATM VCs in ATM Digital Subscriber Line Access Multiplexer (A-DSLAM) applications on a Cisco ASR 1000 Series Aggregation Services Router.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Prerequisites for QoS Hierarchical Queueing for ATM DSLAMs

You must configure traffic classes using the class-map command.

Restrictions for QoS Hierarchical Queueing for ATM DSLAMs

The QoS Hierarchical Queueing for ATM DSLAMs feature is not supported in combination with load balancing when a session service policy is routed to a Layer 2 Tunnel Protocol (L2TP) tunnel. This feature is supported only with shaped ATM VCs, which means ATM VCs that are defined as constant bit rate (CBR), Variable bit rate (VBR) or shaped unspecified bit rate (UBR), (that is, UBR with a peak cell rate).

Information About QoS Hierarchical Queueing for ATM DSLAMs

Different Levels of QoS Provisioning

Traffic downstream from a Broadband Router Access Server (BRAS) requires different levels of QoS provisioning (for example, traffic shaping) depending on the network architecture between the BRAS and the subscriber. The figure below illustrates an ATM DSL access network. The sample network includes multiple entities where QoS provisioning is required for different reasons.

Figure 1. ATM DSL Access Network

Integrated Queueing Hierarchy

Different traffic shaping requirements result in QoS provisioning at multiple levels at the same time. The QoS-Hierarchical Queueing for ATM DSLAMs feature provides the ability to form one integrated queueing hierarchy that provides QoS provisioning at multiple levels with support for features such as bandwidth distribution at any of these levels.

The integrated queueing hierarchy is formed on the physical interface. When a service policy is instantiated on a session, the Subscriber Service Switch (SSS) infrastructure invokes the Modular QoS CLI (MQC) and a common queueing control plane sets up and enables the queueing features.

Session-to-ATM associations are resolved to determine the ATM VC on which the session QoS queues are built. QoS policies consisting of a shaper may also be applied simultaneously at the VC level.

Configuration Guidelines for Hierarchical Queueing on ATM DSLAMs

When configuring the QoS Hierarchical Queueing for ATM DSLAMs feature, note the following guidelines:

  • When an ATM VC is used to aggregate a number of sessions with queueing policies, a queueing policy at an ATM VC level must be a one-level policy map that is configured as class-default with only the shape feature enabled.
  • Both ATM VCs and sessions can be oversubscribed and controlled by shapers.

How to Configure QoS Hierarchical Queueing for ATM DSLAMs

Configuring and Applying QoS Hierarchical Queueing Policy Maps to Sessions

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    policy-map policy-map-name

    4.    class class-map-name

    5.    bandwidth {bandwidth-kbps | percentpercentage| remainingpercentpercentage}

    6.    exit

    7.    exit

    8.    policy-map policy-map-name

    9.    class class-default

    10.    shape average {cir| percentpercentage}

    11.    bandwidth remaining ratio ratio

    12.    service-polic ypolicy-map-name

    13.    exit

    14.    exit

    15.    interface virtual-template number

    16.    service-policy output policy-map-name

    17.    end


DETAILED STEPS
     Command or ActionPurpose
    Step 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 session-a-child
     

    Creates a child policy and enters policy-map configuration mode.

    • Enter the policy-map name.
     
    Step 4 class class-map-name


    Example:
    Router(config-pmap)# class voip
     

    Configures the traffic class that you specify and enters policy-map class configuration mode.

    • Enter the name of a previously configured class map .
     
    Step 5 bandwidth {bandwidth-kbps | percentpercentage| remainingpercentpercentage}

    Example:
    Router(config-pmap-c)# bandwidth 10000


    Example:
    
     
    		  
     

    (Optional) Enables class-based weighted fair queueing based on the keywords and arguments specified.

    • bandwidth-kbps--Specifies the minimum bandwidth allocated for a class belonging to a policy map. Valid values are from 1 to 2,000,000.
    • percent percentage--Specifies the minimum percentage of the link bandwidth allocated for a class belonging to a policy map. Valid values are from 1 to 100.
    • remaining percent percentage--Specifies the minimum percentage of unused link bandwidth allocated for a class belonging to a policy map. Valid values are from 1 to 99.
     
    Step 6 exit


    Example:
    Router(config-pmap-c)# exit
     

    Exits policy-map class configuration mode.

     
    Step 7 exit


    Example:
    Router(config-pmap)# exit
     

    Exits policy-map configuration mode.

     
    Step 8 policy-map policy-map-name


    Example:
    Router(config)# policy-map session_a_parent
     

    Creates a parent policy and enters policy-map configuration mode.

    • Enter the policy-map name.
     
    Step 9 class class-default


    Example:
    Router(config-pmap)# class class-default
     

    Configures the traffic class as class-default and enters policy-map class configuration mode.

    Note   

    Do not configure any other traffic class.

     
    Step 10 shape average {cir| percentpercentage}


    Example:
    Router(config-pmap-c)# shape average 10000000
     

    Specifies average-rate traffic shaping for all traffic that does not match any other traffic class.

    • Enter the average keyword followed by the committed information rate (CIR), in bits per second (bps), or enter the average keyword followed by percentage keyword to specify a percentage of the interface bandwidth for the CIR. Valid values are from 1 to 100.
     
    Step 11 bandwidth remaining ratio ratio


    Example:
    Router(config-pmap-c)# bandwidth remaining ratio 10
     

    Specifies the weight (ratio) for the ATM VC.

    • Enter the relative weight of this ATM VC (or class queue). This number (ratio) indicates the proportional relationship between the other ATM VCs or class queues.
     
    Step 12 service-polic ypolicy-map-name


    Example:
    Router(config-pmap-c)# service-policy session-a-child 
     

    Applies the child policy map to the parent class-default class.

    • Enter the name of a previously configured child policy map.
     
    Step 13 exit


    Example:
    Router(config-pmap-c)# exit
     

    Exits policy-map class configuration mode.

     
    Step 14 exit


    Example:
    Router(config-pmap)# exit
     

    Exits policy-map configuration mode.

     
    Step 15 interface virtual-template number


    Example:
    Router(config)# interface virtual-template 1
     

    Creates a virtual template and enters interface configuration mode.

    • Enter the virtual template number. Valid range is from 1 to 4095.
     
    Step 16 service-policy output policy-map-name


    Example:
    Router(config-if)# service-policy output session_a_parent
     

    Applies the service policy to the virtual interface.

    • Enter the name of the previously configured parent policy map.
    Note   

    You must specify the output keyword to apply the service policy to outbound traffic on the interface.

     
    Step 17 end


    Example:
    Router(config-if)# end
     

    (Optional) Returns to privileged EXEC mode.

     

    Examples

    The following is an example of how to configure and apply a QoS hierarchical queueing policy map to PPP/IP sessions by using a virtual template:

    Router> enable 
    Router# configure terminal 
    Router(config)# policy-map session-a-child 
    Router(config-pmap)# class voip 
    Router(config-pmap-c)# police 1000000 
    Router(config-pmap-c)# priority level 1
    Router(config-pmap-c)# exit
    Router(config-pmap)# class video 
    Router(config-pmap-c)# police 100000 
    Router(config-pmap-c)# priority level 2 
    Router(config-pmap-c)# exit
    Router(config-pmap)# class precedence_0 
    Router(config-pmap-c)# bandwidth remaining ratio 10 
    Router(config-pmap-c)# exit
    Router(config-pmap)# class precedence_1 
    Router(config-pmap-c)# bandwidth remaining ratio 20 
    Router(config-pmap-c)# exit 
    Router(config-pmap)# exit 
    Router(config)# policy-map session_a_parent 
    Router(config-pmap-c)# exit
    Router(config-pmap)# class class-default 
    Router(config-pmap-c)# shape average 10000000 
    Router(config-pmap-c)# bandwidth remaining ratio 10 
    Router(config-pmap-c)# service-policy session-a-child 
    Router(config-pmap-c)# exit 
    Router(config-pmap)# exit 
    Router(config)# interface virtual-template 20 
    Router(config-if)# service-policy output session_a_parent 
    Router(config-if)# end

    Configuring and Applying QoS Hierarchical Queueing Policy Maps to ATM VCs

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    policy-map policy-map-name

      4.    class class-default

      5.    shape average {cir| percentpercentage}

      6.    exit

      7.    exit

      8.    interface type slot/subslot/port.subinterface

      9.    pvc [name] vpi/vci [ces | ilmi | qsaal | smds| l2transport]

      10.    vbr-nrt peak-cell-rate average-cell-rate

      11.    service-policy output policy-map-name

      12.    end


    DETAILED STEPS
       Command or ActionPurpose
      Step 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 subint-1
       

      Creates a policy map and enters policy-map configuration mode.

      • policy-map-name--The name of the policy map.
       
      Step 4 class class-default


      Example:
      Router(config-pmap)# class class-default
       

      Configures the traffic class as class-default and enters policy-map class configuration mode.

      • Do not configure any other traffic class.
      Note   

      When an ATM VC aggregates a number of sessions with queueing policies, a queueing policy at an ATM VC level must be a one-level policy map that is configured as class-default.

       
      Step 5 shape average {cir| percentpercentage}


      Example:
      Router(config-pmap-c)# shape average 10000000 
       

      Specifies average-rate traffic shaping for all traffic that does not match any other traffic class.

      • Enter the average keyword followed by the CIR, in bps or enter the average keyword followed by percentage keyword to specify a percentage of the interface bandwidth for the CIR. Valid values are from 1 to 100.
      Note   

      When an ATM VC aggregates a number of sessions with queueing policies, a queueing policy at an ATM VC level must be a one-level policy map with only the shape feature enabled.

       
      Step 6 exit


      Example:
      Router(config-pmap-c)# exit
       

      Exits policy-map class configuration mode.

       
      Step 7 exit


      Example:
      Router(config-pmap)# exit
       

      Exits policy-map configuration mode.

       
      Step 8 interface type slot/subslot/port.subinterface

      Example:
      Router(config)# interface ATM 3/1/1.1
       

      Specifies the ATM VC on which you are attaching the policy map and enters ATM VC configuration mode.

      • Enter the interface type and slot number, subslot number, port number, and ATM VC number.
       
      Step 9 pvc [name] vpi/vci [ces | ilmi | qsaal | smds| l2transport]

      Example:
      Router(config-if-atm-vc)# pvc 2/100
       

      Selects the ATM VC to which the service policy is to be applied.

       
      Step 10 vbr-nrt peak-cell-rate average-cell-rate


      Example:
      Router(config-if-atm-vc)# vbr-nrt 800000 800000
       

      Sets the VC type to VBR with a peak and average cell rate.

       
      Step 11 service-policy output policy-map-name


      Example:
      Router(config-subif)# service-policy output subint-1 
       

      Attaches the service policy to the ATM VC.

      • policy-map-name--The name of the previously configured policy map.
      Note   

      You must specify the output keyword to apply the service policy to outbound traffic on the ATM VC.

       
      Step 12 end


      Example:
      Router(config-subif)# end
       

      (Optional) Returns to privileged EXEC mode.

       

      Examples

      The following is an example of how to configure and apply a QoS hierarchical queueing policy map to an ATM VC (and provide aggregate shaping for a large number of subscribers):

      Router> enable 
      Router# configure terminal
      Router(config)# policy-map subint-1
      Router(config-pmap)# class class-default
      Router(config-pmap-c)# shape average 10000000
      Router(config-pmap-c)# exit 
      Router(config-pmap)# exit 
      Router(config)# interface ATM 3/1/1.1
      Router(config-if-atm-vc)# pvc 2/100
      Router (config-if-atm-vc)# vbr-nrt 800000 800000
      Router(config-subif)# service-policy output subint-1
      Router(config-subif)# end 

      Displaying Policy-Map Information for Hierarchical Queueing

      SUMMARY STEPS

        1.    enable

        2.    show policy-map

        3.    show policy-map interface type number

        4.    show policy-map session

        5.    exit


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 enable


        Example:
        Router> enable
         

        Enables privileged EXEC mode.

        • Enter your password if prompted.
         
        Step 2 show policy-map


        Example:
        Router# show policy-map
         

        (Optional) Displays all information for all class maps.

         
        Step 3 show policy-map interface type number


        Example:
        Router# 
        show policy-map interface ATM 4/0/0.1
         

        (Optional) Displays the packet statistics of all classes that are configured for all service policies either on the specified interface or ATM VC or on a specific PVC on the interface.

        • Enter the interface type and number.
         
        Step 4 show policy-map session


        Example:
        Router# 
        show policy-map session
         

        (Optional) Displays the QoS policy map in effect for the SSS session.

         
        Step 5 exit


        Example:
        Router# exit
         

        (Optional) Exits privileged EXEC mode.

         

        Configuration Examples for QoS Hierarchical Queueing for ATM DSLAMs

        Example Policy Maps on Sessions

        The following example shows how to configure and apply QoS hierarchical queueing policy maps on sessions. A child queueing policy is applied to each parent subscriber line level policy.

        Router> enable
        Router# configure terminal
        Router(config)# policy-map service-a-out
        Router(config-pmap)# class voip
        Router(config-pmap-c)# priority
        Router(config-pmap-c)# set cos 1
        Router(config-pmap-c)# exit
        Router(config-pmap)# class video
        Router(config-pmap-c)# set cos 2
        Router(config-pmap-c)# exit
        Router(config-pmap)# class gaming
        Router(config-pmap-c)# bandwidth remaining percent 80
        Router(config-pmap-c)# set cos 3
        Router(config-pmap-c)# exit
        Router(config-pmap)# class class-default
        Router(config-pmap-c)# bandwidth remaining percent 20
        Router(config-pmap-c)# set cos 4
        Router(config-pmap-c)# exit
        Router(config-pmap)# exit
        !
        Router(config)# policy-map rate-1-service-a-out
        Router(config-pmap)# class class-default
        Router(config-pmap-c)# bandwidth remaining ratio 10
        Router(config-pmap-c)# shape average 100000
        Router(config-pmap-c)# service-policy service-a-out
        Router(config-pmap-c)# exit
        Router(config-pmap)# exit
        !
        Router(config)# policy-map rate-1-service-a-in
        Router(config-pmap)# class voip
        Router(config-pmap-c)# police percent 25
        Router(config-pmap-c)# exit
        Router(config-pmap)# class gaming
        Router(config-pmap-c)# police percent 50
        Router(config-pmap-c)# exit
        Router(config-pmap)# class class-default
        Router(config-pmap-c)# police percent 20
        Router(config-pmap-c)# exit
        Router(config-pmap)# exit
        !
        Router(config)# interface virtual-template 20
        Router(config-if)# service-policy output rate-1-service-a-out
        Router(config-if)# service-policy input rate-1-service-a-in
        Router(config-if)# end
        

        Example Policy Maps on Sessions with Aggregate Shaping

        The following example shows how to configure and apply QoS hierarchical queueing policy maps on sessions with multiple PPP/IP sessions per subscriber line. In this example, queueing is configured as in previous example. The VC is configured as follows:

        Router(config)# policy-map isp_A_out
        Router(config-pmap)# class class-default
        Router(config-pmap-c)# shape average 500000
        Router(config-pmap-c)# exit
        Router(config-pmap)# exit
        Router(config)# interface ATM 1/0/0.1
        Router(config-subif)# pvc 10/100
        Router(config-if-atm-vc)# vbr-nrt 800000 800000
        Router(config-if-atm-vc)# service-policy output isp-A-out
        Router(config-if-atm-vc)# exit
        Router(config-subif)# exit

        Additional References

        Related Documents

        Related Topic

        Document Title

        QoS commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

        Cisco IOS Quality of Service Solutions Command Reference

        Traffic shaping

        "Regulating Traffic Flow Using Traffic Shaping" module

        MQC

        "Applying QoS Features Using the MQC" module

        Standards

        Standard

        Title

        No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

        --

        MIBs

        MIB

        MIBs Link

        No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

        To locate and download MIBs for selected platforms, Cisco IOS XE Software releases, and feature sets, use Cisco MIB Locator found at the following URL:

        http:/​/​www.cisco.com/​go/​mibs

        RFCs

        RFC

        Title

        No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

        --

        Technical Assistance

        Description

        Link

        The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

        http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

        Feature Information for QoS Hierarchical Queueing for ATM DSLAMs

        The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

        Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

        Table 1 Feature Information for QoS Hierarchical Queueing for ATM DSLAMs

        Feature Name

        Releases

        Feature Information

        QoS Hierarchical Queueing for ATM DSLAMs

        Cisco IOS XE Release 2.4 Cisco IOS XE Release 2.5

        This feature module describes how to configure QoS hierarchical queueing policy maps on sessions and ATM VCs in ATM Digital Subscriber Line Access Multiplexer (A-DSLAM) applications.

        This feature was implemented on Cisco ASR 1000 Series Aggregation Services Routers.