IP Routing: Protocol-Independent Configuration Guide, Cisco IOS XE Release 3S
QoS Policy Propagation via BGP
Download this chapter
QoS Policy Propagation via BGPQoS Policy Propagation via BGP
Download the complete book
IP Routing: Protocol-Independent Configuration Guide, Cisco IOS XE Release 3SIP Routing: Protocol-Independent Configuration Guide, Cisco IOS XE Release 3S (PDF - 4 MB)
 Feedback

QoS Policy Propagation via BGP

The QoS Policy Propagation via BGP feature allows you to classify packets by IP precedence based on the Border Gateway Protocol (BGP) community lists, BGP autonomous system paths, and access lists. After packets have been classified, you can use other quality of service (QoS) features such as committed access rate (CAR) and Weighted Random Early Detection (WRED) to specify and enforce policies to fit your business model.

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 Policy Propagation via BGP

  • Enable the Border Gateway Protocol (BGP) and Cisco Express Forwarding (CEF) or distributed CEF (dCEF) on the device. Subinterfaces on an ATM interface that have the bgp-policy command enabled must use CEF mode because dCEF is not supported. dCEF uses the Versatile Interface Processor (VIP) rather than the Route Switch Processor (RSP) to perform forwarding functions.
  • Define the policy.
  • Apply the policy through BGP.
  • Configure the BGP community list, BGP autonomous system path, or access list and enable the policy on an interface.
  • Enable committed access rate (CAR) or Weighted Random Early Detection (WRED) to use the policy.

Information About QoS Policy Propagation via BGP

Benefits of QoS Policy Propagation via BGP

The QoS Policy Propagation via BGP feature allows you to classify packets by IP precedence based on Border Gateway Protocol (BGP) community lists, BGP autonomous system paths, and access lists. After a packet has been classified, you can use other quality of service (QoS) features such as committed access rate (CAR) and Weighted Random Early Detection (WRED) to specify and enforce policies to fit your business model.

How to Configure QoS Policy Propagation via BGP

Configuring QoS Policy Propagation via BGP Based on Community Lists

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    route-map route-map-name [permit | deny [sequence-number]]

    4.    match community {standard-list-number | expanded-list-number | community-list-name [exact]}

    5.    set ip precedence [number | name]

    6.    exit

    7.    router bgp autonomous-system

    8.    table-map route-map-name

    9.    exit

    10.    ip community-list standard-list-number {permit | deny} [community-number]

    11.    interface type number

    12.    bgp-policy {source | destination} ip-prec-map

    13.    exit

    14.    ip bgp-community new-format

    15.    end


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Device> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.
     
    Step 2 configure terminal


    Example:
    Device# configure terminal
     

    Enters global configuration mode.

     
    Step 3 route-map route-map-name [permit | deny [sequence-number]]


    Example:
    Device(config)# route-map rm1
     

    Defines a route map to control redistribution and enters route-map configuration mode.

     
    Step 4 match community {standard-list-number | expanded-list-number | community-list-name [exact]}


    Example:
    Device(config-route-map)# match community 1
     

    Matches a Border Gateway Protocol (BGP) community list.

     
    Step 5 set ip precedence [number | name]


    Example:
    Device(config-route-map)# set ip precedence 5
     

    Sets the IP Precedence field when the community list matches.

    Note   

    You can specify either a precedence number or a precedence name.

     
    Step 6 exit


    Example:
    Device(config-route-map)# exit
     

    Exits route-map configuration mode and returns to global configuration mode.

     
    Step 7router bgp autonomous-system


    Example:
    Device(config)# router bgp 45000
     

    Enables a BGP process and enters router configuration mode.

     
    Step 8 table-map route-map-name


    Example:
    Device(config-router)# table-map rm1
     

    Modifies the metric and tag values when the IP routing table is updated with BGP learned routes.

     
    Step 9 exit


    Example:
    Device(config-router)# exit
     

    Exits router configuration mode and returns to global configuration mode.

     
    Step 10ip community-list standard-list-number {permit | deny} [community-number]


    Example:
    Device(config)# ip community-list 1 permit 2
     

    Creates a community list for BGP and controls access to it.

     
    Step 11interface type number


    Example:
    Device(config)# interface gigabitethernet 0/0/0
     

    Specifies the interface (or subinterface) and enters interface configuration mode.

     
    Step 12 bgp-policy {source | destination} ip-prec-map


    Example:
    Device(config-if)# bgp-policy source ip-prec-map
     

    Classifies packets using IP precedence.

     
    Step 13 exit


    Example:
    Device(config-if)# exit
     

    Exits interface configuration mode and returns to global configuration mode.

     
    Step 14 ip bgp-community new-format


    Example:
    Device(config)# ip bgp-community new-format
     

    (Optional) Displays the BGP community number in AA:NN (autonomous system:community number/4-byte number) format.

     
    Step 15 end


    Example:
    Device(config)# end
     

    Exits global configuration mode and returns to privileged EXEC mode.

     

    Configuring QoS Policy Propagation via BGP Based on the Autonomous System Path Attribute

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    route-map route-map-name [permit | deny [sequence-number]]

      4.    match as-path path-list-number

      5.    set ip precedence [number | name]

      6.    exit

      7.    router bgp autonomous-system

      8.    table-map route-map-name

      9.    exit

      10.    ip as-path access-list access-list-number {permit | deny} as-regular-expression

      11.    interface type number

      12.    bgp-policy {source | destination} ip-prec-map

      13.    end


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 enable


      Example:
      Device> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.
       
      Step 2 configure terminal


      Example:
      Device# configure terminal
       

      Enters global configuration mode.

       
      Step 3 route-map route-map-name [permit | deny [sequence-number]]


      Example:
      Device(config)# route-map rm1
       

      Defines a route map to control redistribution and enters route-map configuration mode.

       
      Step 4match as-path path-list-number


      Example:
      Device(config-route-map)# match as-path 2
       

      Matches a Border Gateway Protocol (BGP) autonomous system path access list.

       
      Step 5set ip precedence [number | name]


      Example:
      Device(config-route-map)# set ip precedence 5
       

      Sets the IP Precedence field when the autonomous-system path matches.

      Note   

      You can specify either a precedence number or a precedence name.

       
      Step 6 exit


      Example:
      Device(config-route-map)# exit
       

      Exits route-map configuration mode and returns to global configuration mode.

       
      Step 7 router bgp autonomous-system


      Example:
      Device(config)# router bgp 45000
       

      Enables a BGP process and enters router configuration mode.

       
      Step 8table-map route-map-name


      Example:
      Device(config-router)# table-map rm1
       

      Modifies the metric and tag values when the IP routing table is updated with BGP learned routes.

       
      Step 9 exit


      Example:
      Device(config-router)# exit
       

      Exits router configuration mode and returns to global configuration mode.

       
      Step 10ip as-path access-list access-list-number {permit | deny} as-regular-expression


      Example:
      Device(config)# ip as-path access-list 500 permit 45000
       

      Defines an autonomous system path access list.

       
      Step 11 interface type number


      Example:
      Device(config)# interface gigabitethernet 0/0/0
       

      Specifies the interface (or subinterface) and enters interface configuration mode.

       
      Step 12bgp-policy {source | destination} ip-prec-map


      Example:
      Device(config-if)# bgp-policy source ip-prec-map
       

      Classifies packets using IP precedence.

       
      Step 13 end


      Example:
      Device(config-if)# end
       

      Exits interface configuration mode and returns to privileged EXEC mode.

       

      Configuring QoS Policy Propagation via BGP Based on an Access List

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    route-map route-map-name [permit | deny [sequence-number]]

        4.    match ip address access-list-number

        5.    set ip precedence [number | name]

        6.    exit

        7.    router bgp autonomous-system

        8.    table-map route-map-name

        9.    exit

        10.    access-list access-list-number {permit | deny} source

        11.    interface type number

        12.    bgp-policy {source | destination} ip-prec-map

        13.    end


      DETAILED STEPS
         Command or ActionPurpose
        Step 1enable


        Example:
        Device> enable
         

        Enables privileged EXEC mode.

        • Enter your password if prompted.
         
        Step 2 configure terminal


        Example:
        Device# configure terminal
         

        Enters global configuration mode.

         
        Step 3 route-map route-map-name [permit | deny [sequence-number]]


        Example:
        Device(config)# route-map rm1
         

        Defines a route map to control redistribution and enters route-map configuration mode.

         
        Step 4 match ip address access-list-number


        Example:
        Device(config-route-map)# match ip address 69
         

        Matches an access list.

         
        Step 5set ip precedence [number | name]


        Example:
        Device(config-route-map)# set ip precedence routine
         

        Sets the IP precedence field when the autonomous system path matches.

         
        Step 6 exit


        Example:
        Device(config-route-map)# exit
         

        Exits route-map configuration mode and returns to global configuration mode.

         
        Step 7 router bgp autonomous-system


        Example:
        Device(config)# router bgp 45000
         

        Enables a Border Gateway Protocol (BGP) process and enters router configuration mode.

         
        Step 8table-map route-map-name


        Example:
        Device(config-router)# table-map rm1
         

        Modifies the metric and tag values when the IP routing table is updated with BGP learned routes.

         
        Step 9 exit


        Example:
        Device(config-router)# exit
         

        Exits router configuration mode and returns to global configuration mode.

         
        Step 10access-list access-list-number {permit | deny} source


        Example:
        Device(config)# access-list 69 permit 10.69.0.0
         

        Defines an access list.

         
        Step 11 interface type number


        Example:
        Device(config)# interface gigabitethernet 0/0/0
         

        Specifies the interfaces (or subinterface) and enters interface configuration mode.

         
        Step 12bgp-policy {source | destination} ip-prec-map


        Example:
        Device(config-if)# bgp-policy source ip-prec-map
         

        Classifies packets using IP Precedence.

         
        Step 13 end


        Example:
        Device(config-if)# end
         

        Exits interface configuration mode and returns to privileged EXEC mode.

         

        Monitoring QoS Policy Propagation via BGP

        To monitor the QoS Policy Propagation via the BGP feature configuration, use the following optional commands.

        Command or Action

        Purpose 

        show ip bgp

        Displays entries in the Border Gateway Protocol (BGP) routing table to verify whether the correct community is set on the prefixes. 

        show ip bgp community-list community-list-number

        Displays routes permitted by the BGP community to verify whether correct prefixes are selected. 

        show ip cef network

        Displays entries in the forwarding information base (FIB) table based on the specified IP address to verify whether Cisco Express Forwarding has the correct precedence value for the prefix. 

        show ip interface

        Displays information about the interface. 

        show ip route prefix

        Displays the current status of the routing table to verify whether correct precedence values are set on the prefixes.

        Configuration Examples for QoS Policy Propagation via BGP

        Example: Configuring QoS Policy Propagation via BGP

        The following example shows how to create route maps to match access lists, Border Gateway Protocol (BGP) community lists, and BGP autonomous system paths, and apply IP precedence to routes learned from neighbors.

        In the figure below, Device A learns routes from autonomous system 10 and autonomous system 60. The quality of service (QoS) policy is applied to all packets that match defined route maps. Any packets from Device A to autonomous system 10 or autonomous system 60 are sent the appropriate QoS policy, as the numbered steps in the figure indicate.

        Figure 1. Device Learning Routes and Applying QoS Policy

        Device A Configuration

        interface serial 5/0/0/1:0
ip address 10.28.38.2 255.255.255.0
bgp-policy destination ip-prec-map
no ip mroute-cache
no cdp enable
frame-relay interface-dlci 20 IETF
router bgp 30
 table-map precedence-map
 neighbor 10.20.20.1 remote-as 10
 neighbor 10.20.20.1 send-community
!
ip bgp-community new-format
!
! Match community 1 and set the IP precedence to priority
route-map precedence-map permit 10
 match community 1
 set ip precedence priority
!
! Match community 2 and set the IP precedence to immediate
route-map precedence-map permit 20
 match community 2
 set ip precedence immediate
!
! Match community 3 and set the IP precedence to flash
route-map precedence-map permit 30
 match community 3
 set ip precedence flash
!
! Match community 4 and set the IP precedence to flash-override
route-map precedence-map permit 40
 match community 4
 set ip precedence flash-override
!
! Match community 5 and set the IP precedence to critical
route-map precedence-map permit 50
 match community 5
 set ip precedence critical
!
! Match community 6 and set the IP precedence to internet
route-map precedence-map permit 60
 match community 6
 set ip precedence internet
!
! Match community 7 and set the IP precedence to network
route-map precedence-map permit 70
 match community 7
 set ip precedence network
!
! Match ip address access list 69 or match autonomous system path 1
! and set the IP precedence to critical
route-map precedence-map permit 75
 match ip address 69
 match as-path 1
 set ip precedence critical
!
! For everything else, set the IP precedence to routine
route-map precedence-map permit 80
 set ip precedence routine
!
! Define community lists 
ip community-list 1 permit 60:1
ip community-list 2 permit 60:2
ip community-list 3 permit 60:3
ip community-list 4 permit 60:4
ip community-list 5 permit 60:5
ip community-list 6 permit 60:6
ip community-list 7 permit 60:7
!
! Define the AS path
ip as-path access-list 1 permit ^10_60
!
! Define the access list
access-list 69 permit 10.69.0.0

        Device B Configuration

        router bgp 10
 neighbor 10.30.30.1 remote-as 30
 neighbor 10.30.30.1 send-community
 neighbor 10.30.30.1 route-map send_community out
!
ip bgp-community new-format
!
! Match prefix 10 and set community to 60:1
route-map send_community permit 10
 match ip address 10
 set community 60:1
!
! Match prefix 20 and set community to 60:2
route-map send_community permit 20
 match ip address 20
 set community 60:2
!
! Match prefix 30 and set community to 60:3
route-map send_community permit 30
 match ip address 30
 set community 60:3
!
! Match prefix 40 and set community to 60:4
route-map send_community permit 40
 match ip address 40
 set community 60:4
!
! Match prefix 50 and set community to 60:5
route-map send_community permit 50
 match ip address 50
 set community 60:5
!
! Match prefix 60 and set community to 60:6
route-map send_community permit 60
 match ip address 60
 set community 60:6
!
! Match prefix 70 and set community to 60:7
route-map send_community permit 70
 match ip address 70
 set community 60:7
!
! For all others, set community to 60:8
route-map send_community permit 80
 set community 60:8
!
! Define access lists
access-list 10 permit 10.61.0.0
access-list 20 permit 10.62.0.0
access-list 30 permit 10.63.0.0
access-list 40 permit 10.64.0.0
access-list 50 permit 10.65.0.0
access-list 60 permit 10.66.0.0
access-list 70 permit 10.67.0.0

        Additional References

        Related Documents

        Related Topic

        Document Title

        Cisco IOS commands

        Cisco IOS Master Command List, All Releases

        IP routing protocol-independent commands

        Cisco IOS IP Routing: Protocol-Independent Command Reference

        BGP configuration

        BGP Configuration Guide

        Cisco Express Forwarding configuration

        Cisco Express Forwarding Configuration Guide

        Committed access rate configuration

        “Configuring Committed Access Rate” module in the QoS: Classification Configuration Guide (part of the Quality of Service Solutions Configuration Guide Library)

        Weighted Random Early Detection configuration

        “Configuring Weighted Random Early Detection” module in the QoS: Congestion Avoidance Configuration Guide (part of the Quality of Service Solutions Configuration Guide Library)

        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 Policy Propagation via BGP

        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 Policy Propagation via BGP

        Feature Name

        Releases

        Feature Information

        QoS Policy Propagation via BGP

        The QoS Policy Propagation via BGP feature allows you to classify packets by IP precedence based on Border Gateway Protocol (BGP) community lists, BGP autonomous system paths, and access lists. After a packet has been classified, you can use other quality of service (QoS) features such as committed access rate (CAR) and Weighted Random Early Detection (WRED) to specify and enforce policies to fit your business model.

        Policy Routing Infrastructure

        The Policy Routing Infrastructure feature provides full support of IP policy-based routing with Cisco Express Forwarding (CEF). As CEF gradually obsoletes fast switching, policy routing is integrated with CEF to increase customer performance requirements. When policy routing is enabled, redundant processing is avoided.