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IP Routing: BGP Configuration Guide, Cisco IOS XE Release 3E

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Book Title

IP Routing: BGP Configuration Guide, Cisco IOS XE Release 3E

Chapter Title

IPv6 Routing: Multiprotocol BGP Extensions for IPv6

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Updated:
January 15, 2018

Chapter: IPv6 Routing: Multiprotocol BGP Extensions for IPv6

IPv6 Routing: Multiprotocol BGP Extensions for IPv6

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.

Information About IPv6 Routing: Multiprotocol BGP Extensions for IPv6

Multiprotocol BGP Extensions for IPv6

Multiprotocol BGP is the supported Exterior Gateway Protocol (EGP) for IPv6. Multiprotocol BGP extensions for IPv6 supports many of the same features and functionality as IPv4 BGP. IPv6 enhancements to multiprotocol BGP include support for an IPv6 address family and Network Layer Reachability Information (NLRI) and next hop (the next device in the path to the destination) attributes that use IPv6 addresses.

How to Implement Multiprotocol BGP for IPv6

Configuring an IPv6 BGP Routing Process and BGP Router ID

Perform this task to configure an IPv6 BGP routing process and an optional BGP router ID for a BGP-speaking device.

BGP uses a router ID to identify BGP-speaking peers. The BGP router ID is 32-bit value that is often represented by an IPv4 address. By default, the router ID is set to the IPv4 address of a loopback interface on the device. If no loopback interface is configured on the device, then the software chooses the highest IPv4 address configured to a physical interface on the device to represent the BGP router ID.

When configuring BGP on a device that is enabled only for IPv6 (that is, the device does not have an IPv4 address), you must manually configure the BGP router ID for the device. The BGP router ID, which is represented as a 32-bit value using an IPv4 address syntax, must be unique to the BGP peers of the device.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    router bgp as-number

    4.    no bgp default ipv4-unicast

    5.    bgp router-id ip-address


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 router bgp as-number


    Example: 
    Device(config)# router bgp 65000
     

    Configures a BGP routing process, and enters router configuration mode for the specified routing process.

     
    Step 4 no bgp default ipv4-unicast


    Example: 
    Device(config-router)# no bgp default ipv4-unicast
     

    Disables the IPv4 unicast address family for the BGP routing process specified in the previous step.

    Note    Routing information for the IPv4 unicast address family is advertised by default for each BGP routing session configured with the neighbor remote-as command unless you configure the no bgp default ipv4-unicast command before configuring the neighbor remote-as command.
     
    Step 5 bgp router-id ip-address


    Example: 
    Device(config-router)# bgp router-id 192.168.99.70
     

    (Optional) Configures a fixed 32-bit router ID as the identifier of the local device running BGP.

    Note    Configuring a router ID using the bgp router-id command resets all active BGP peering sessions.
     

    Configuring IPv6 Multiprotocol BGP Between Two Peers

    By default, neighbors that are defined using the neighbor remote-as command in router configuration mode exchange only IPv4 unicast address prefixes. To exchange other address prefix types, such as IPv6 prefixes, neighbors must also be activated using the neighbor activate command in address family configuration mode for the other prefix types, as shown for IPv6 prefixes.

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    router bgp as-number

      4.    neighbor {ip-address | ipv6-address [%] | peer-group-name} remote-as autonomous-system-number [alternate-as autonomous-system-number ...]

      5.    address-family ipv6 [unicast | multicast]

      6.    neighbor {ip-address | peer-group-name | ipv6-address %} activate


    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 router bgp as-number


      Example: 
      Device(config)# router bgp 65000
       

      Enters router configuration mode for the specified routing process.

       
      Step 4 neighbor {ip-address | ipv6-address [%] | peer-group-name} remote-as autonomous-system-number [alternate-as autonomous-system-number ...]


      Example: 
      Device(config-router)# neighbor 2001:DB8:0:CC00::1 remote-as 64600
       

      Adds the IPv6 address of the neighbor in the specified autonomous system to the IPv6 multiprotocol BGP neighbor table of the local device.

       
      Step 5 address-family ipv6 [unicast | multicast]


      Example: 
      Device(config-router)# address-family ipv6
       

      Specifies the IPv6 address family and enters address family configuration mode.

      • The unicast keyword specifies the IPv6 unicast address family. By default, the device is placed in configuration mode for the IPv6 unicast address family if a keyword is not specified with the address-family ipv6 command.
      • The multicast keyword specifies IPv6 multicast address prefixes.
       
      Step 6 neighbor {ip-address | peer-group-name | ipv6-address %} activate


      Example: 
      Device(config-router-af)# neighbor 2001:DB8:0:CC00::1 activate
       

      Enables the neighbor to exchange prefixes for the IPv6 address family with the local device.

       

      Advertising Routes into IPv6 Multiprotocol BGP

      By default, networks that are defined in router configuration mode using the network command are injected into the IPv4 unicast database. To inject a network into another database, such as the IPv6 BGP database, you must define the network using the network command in address family configuration mode for the other database, as shown for the IPv6 BGP database.

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    router bgp as-number

        4.    address-family ipv6 [vrf vrf-name] [unicast | multicast | vpnv6]

        5.    network {network-number [mask network-mask] | nsap-prefix} [route-map map-tag]

        6.    exit


      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 router bgp as-number


        Example:
        Device(config)# router bgp 65000
         

        Enters router configuration mode for the specified BGP routing process.

         
        Step 4 address-family ipv6 [vrf vrf-name] [unicast | multicast | vpnv6]


        Example:
        Device(config-router)# address-family ipv6 unicast
         

        Specifies the IPv6 address family, and enters address family configuration mode.

        • The unicast keyword specifies the IPv6 unicast address family. By default, the device is placed in configuration mode for the IPv6 unicast address family if a keyword is not specified with the address-family ipv6 command.

        • The multicast keyword specifies IPv6 multicast address prefixes.

         
        Step 5 network {network-number [mask network-mask] | nsap-prefix} [route-map map-tag]


        Example:
        Device(config-router-af)# network 2001:DB8::/24
         

        Advertises (injects) the specified prefix into the IPv6 BGP database (the routes must first be found in the IPv6 unicast routing table).

        • The prefix is injected into the database for the address family specified in the previous step.

        • Routes are tagged from the specified prefix as “local origin.”

        • The ipv6-prefix argument in the network command must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

        • The prefix-length argument is a decimal value that indicates how many of the high-order contiguous bits of the address comprise the prefix (the network portion of the address). A slash mark must precede the decimal value.

         
        Step 6 exit


        Example:
        Device(config-router-af)# exit
         

        Exits address family configuration mode, and returns the device to router configuration mode.

        • Repeat this step to exit router configuration mode and return the device to global configuration mode.

         

        Configuring a Route Map for IPv6 Multiprotocol BGP Prefixes

        • By default, neighbors that are defined using the neighbor remote-as command in router configuration mode exchange only IPv4 unicast address prefixes. To exchange other address prefix types, such as IPv6 prefixes, neighbors must also be activated using the neighbor activate command in address family configuration mode for the other prefix types, as shown for IPv6 prefixes.
        • By default, route maps that are applied in router configuration mode using the neighbor route-map command are applied to only IPv4 unicast address prefixes. Route maps for other address families must be applied in address family configuration mode using the neighbor route-map command, as shown for the IPv6 address family. The route maps are applied either as the inbound or outbound routing policy for neighbors under the specified address family. Configuring separate route maps under each address family type simplifies managing complicated or different policies for each address family.
        SUMMARY STEPS

          1.    enable

          2.    configure terminal

          3.    router bgp as-number

          4.    neighbor {ip-address | ipv6-address[%] | peer-group-name} remote-as autonomous-system-number [alternate-as autonomous-system-number ...]

          5.    address-family ipv6 [vrf vrf-name] [unicast | multicast | vpnv6]

          6.    neighbor {ip-address | peer-group-name | ipv6-address %} activate

          7.    neighbor {ip-address | peer-group-name | ipv6-address [%]} route-map map-name {in | out}

          8.    exit

          9.    exit

          10.    route-map map-tag [permit | deny] [sequence-number]

          11.    match ipv6 address {prefix-list prefix-list-name | access-list-name}


        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 router bgp as-number


          Example: 
          Device(config)# router bgp 65000
           

          Enters router configuration mode for the specified routing process.

           
          Step 4 neighbor {ip-address | ipv6-address[%] | peer-group-name} remote-as autonomous-system-number [alternate-as autonomous-system-number ...]


          Example: 
          Device(config-router)# neighbor 2001:DB8:0:cc00::1 remote-as 64600
           

          Adds the link-local IPv6 address of the neighbor in the specified remote autonomous system to the IPv6 multiprotocol BGP neighbor table of the local device.

           
          Step 5 address-family ipv6 [vrf vrf-name] [unicast | multicast | vpnv6]


          Example: 
          Device(config-router)# address-family ipv6
           

          Specifies the IPv6 address family, and enters address family configuration mode.

          • The unicast keyword specifies the IPv6 unicast address family. By default, the device is placed in configuration mode for the IPv6 unicast address family if the unicast keyword is not specified with the address-family ipv6 command.
          • The multicast keyword specifies IPv6 multicast address prefixes.
           
          Step 6 neighbor {ip-address | peer-group-name | ipv6-address %} activate


          Example: 
          Device(config-router-af)# neighbor 2001:DB8:0:cc00::1 activate
           

          Enables the neighbor to exchange prefixes for the IPv6 address family with the local device using the specified link-local addresses.

           
          Step 7 neighbor {ip-address | peer-group-name | ipv6-address [%]} route-map map-name {in | out}


          Example: 
          Device(config-router-af)# neighbor 2001:DB8:0:cc00::1 route-map rtp in
           

          Applies a route map to incoming or outgoing routes.

          • Changes to the route map will not take effect for existing peers until the peering is reset or a soft reset is performed. Using the clear bgp ipv6 command with the soft and in keywords will perform a soft reset.
           
          Step 8 exit


          Example: 
          Device(config-router-af)# exit
           

          Exits address family configuration mode, and returns the device to router configuration mode.

           
          Step 9 exit


          Example: 
          Device(config-router)# exit
           

          Exits router configuration mode, and returns the device to global configuration mode.

           
          Step 10 route-map map-tag [permit | deny] [sequence-number]


          Example: 
          Device(config)# route-map rtp permit 10
           

          Defines a route map and enters route-map configuration mode.

          • Follow this step with a match command.
           
          Step 11 match ipv6 address {prefix-list prefix-list-name | access-list-name}


          Example: 
          Device(config-route-map)# match ipv6 address prefix-list cisco
           

          Distributes any routes that have a destination IPv6 network number address permitted by a prefix list, or performs policy routing on packets.

           

          Redistributing Prefixes into IPv6 Multiprotocol BGP

          Redistribution is the process of redistributing, or injecting, prefixes from one routing protocol into another routing protocol. This task explains how to inject prefixes from a routing protocol into IPv6 multiprotocol BGP. Specifically, prefixes that are redistributed into IPv6 multiprotocol BGP using the redistribute router configuration command are injected into the IPv6 unicast database.

          SUMMARY STEPS

            1.    enable

            2.    configure terminal

            3.    router bgp as-number

            4.    address-family ipv6 [vrf vrf-name] [unicast | multicast | vpnv6]

            5.    redistribute bgp [process-id] [metric metric-value] [route-map map-name] [source-protocol-options]

            6.    exit


          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 router bgp as-number


            Example: 
            Device(config)# router bgp 65000
             

            Enters router configuration mode for the specified BGP routing process.

             
            Step 4 address-family ipv6 [vrf vrf-name] [unicast | multicast | vpnv6]


            Example: 
            Device(config-router)# address-family ipv6
             

            Specifies the IPv6 address family, and enters address family configuration mode.

            • The unicast keyword specifies the IPv6 unicast address family. By default, the device is placed in configuration mode for the IPv6 unicast address family if a keyword is not specified with the address-family ipv6 command.
            • The multicast keyword specifies IPv6 multicast address prefixes.
             
            Step 5 redistribute bgp [process-id] [metric metric-value] [route-map map-name] [source-protocol-options]


            Example: 
            Device(config-router-af)# redistribute bgp 64500 metric 5
             

            Redistributes IPv6 routes from one routing domain into another routing domain.

             
            Step 6 exit


            Example: 
            Device(config-router-af)# exit
             

            Exits address family configuration mode, and returns the device to router configuration mode.

            • Repeat this step to exit router configuration mode and return the device to global configuration mode.
             

            Clearing External BGP Peers

            SUMMARY STEPS

              1.    enable

              2.    clear bgp ipv6 {unicast | multicast} external [soft] [in | out]

              3.    clear bgp ipv6 {unicast | multicast} peer-group name


            DETAILED STEPS
               Command or ActionPurpose
              Step 1 enable


              Example:
              Device> enable
               

              Enables privileged EXEC mode.

              • Enter your password if prompted.

               
              Step 2 clear bgp ipv6 {unicast | multicast} external [soft] [in | out]


              Example:
              Device# clear bgp ipv6 unicast external soft in
               

              Clears external IPv6 BGP peers.

               
              Step 3 clear bgp ipv6 {unicast | multicast} peer-group name


              Example:
              Device# clear bgp ipv6 unicast peer-group marketing
               

              Clears all members of an IPv6 BGP peer group.

               

              Advertising IPv4 Routes Between IPv6 BGP Peers

              If an IPv6 network is connecting two separate IPv4 networks, IPv6 can be used to advertise the IPv4 routes. Configure the peering using the IPv6 addresses within the IPv4 address family. Set the next hop with a static route or with an inbound route map because the advertised next hop will usually be unreachable. Advertising IPv6 routes between two IPv4 peers is also possible using the same model.

              SUMMARY STEPS

                1.    enable

                2.    configure terminal

                3.    router bgp as-number

                4.    neighbor peer-group-name peer-group

                5.    neighbor {ip-address | ipv6-address[%] | peer-group-name} remote-as autonomous-system-number [alternate-as autonomous-system-number ...]

                6.    address-family ipv4 [mdt | multicast | tunnel | unicast [vrf vrf-name] | vrf vrf-name]

                7.    neighbor ipv6-address peer-group peer-group-name

                8.    neighbor {ip-address | peer-group-name | ipv6-address [%]} route-map map-name {in | out}

                9.    exit

                10.    exit

                11.    route-map map-tag [permit | deny] [sequence-number]

                12.    set ip next-hop ip-address [... ip-address] [peer-address]


              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 router bgp as-number


                Example: 
                Device(config)# router bgp 65000
                 

                Enters router configuration mode for the specified routing process.

                 
                Step 4 neighbor peer-group-name peer-group


                Example: 
                Device(config-router)# neighbor 6peers peer-group
                 

                Creates a multiprotocol BGP peer group.

                 
                Step 5 neighbor {ip-address | ipv6-address[%] | peer-group-name} remote-as autonomous-system-number [alternate-as autonomous-system-number ...]


                Example: 
                Device(config-router)# neighbor 6peers remote-as 65002
                 

                Adds the IPv6 address of the neighbor in the specified autonomous system to the IPv6 multiprotocol BGP neighbor table of the local device.

                 
                Step 6 address-family ipv4 [mdt | multicast | tunnel | unicast [vrf vrf-name] | vrf vrf-name]


                Example: 
                Device(config-router)# address-family ipv4
                 

                Enters address family configuration mode to configure a routing session using standard IPv4 address prefixes.

                 
                Step 7 neighbor ipv6-address peer-group peer-group-name


                Example: 
                Device(config-router-af)# neighbor 2001:DB8:1234::2 peer-group 6peers
                 

                Assigns the IPv6 address of a BGP neighbor to a peer group.

                 
                Step 8 neighbor {ip-address | peer-group-name | ipv6-address [%]} route-map map-name {in | out}


                Example: 
                Device(config-router-af)# neighbor 6peers route-map rmap out
                 

                Applies a route map to incoming or outgoing routes.

                • Changes to the route map will not take effect for existing peers until the peering is reset or a soft reset is performed. Using the clear bgp ipv6 command with the soft and in keywords will perform a soft reset.
                 
                Step 9 exit


                Example: 
                Device(config-router-af)# exit
                 

                Exits address family configuration mode, and returns the device to router configuration mode.

                 
                Step 10 exit


                Example: 
                Device(config-router)# exit
                 

                Exits router configuration mode, and returns the device to global configuration mode.

                 
                Step 11 route-map map-tag [permit | deny] [sequence-number]


                Example: 
                Device(config)# route-map rmap permit 10
                 

                Defines a route map and enters route-map configuration mode.

                 
                Step 12 set ip next-hop ip-address [... ip-address] [peer-address]


                Example: 
                Device(config-route-map)# set ip next-hop 10.21.8.10
                 

                Overrides the next hop advertised to the peer for IPv4 packets.

                 

                Configuration Examples for Multiprotocol BGP for IPv6

                Example: Configuring a BGP Process, BGP Router ID, and IPv6 Multiprotocol BGP Peer

                The following example enables IPv6 globally, configures a BGP process, and establishes a BGP router ID. Also, the IPv6 multiprotocol BGP peer 2001:DB8:0:CC00::1 is configured and activated. 

                ipv6 unicast-routing
!
router bgp 65000
 no bgp default ipv4-unicast
 bgp router-id 192.168.99.70
 neighbor 2001:DB8:0:CC00::1 remote-as 64600
 address-family ipv6 unicast
  neighbor 2001:DB8:0:CC00::1 activate

                Example: Configuring an IPv6 Multiprotocol BGP Peer Group

                The following example configures the IPv6 multiprotocol BGP peer group named group1: 

                router bgp 65000
no bgp default ipv4-unicast
neighbor group1 peer-group
neighbor 2001:DB8:0:CC00::1 remote-as 64600
address-family ipv6 unicast
 neighbor group1 activate
 neighbor 2001:DB8:0:CC00::1 peer-group group1

                Example: Advertising Routes into IPv6 Multiprotocol BGP

                The following example injects the IPv6 network 2001:DB8::/24 into the IPv6 unicast database of the local device. (BGP checks that a route for the network exists in the IPv6 unicast database of the local device before advertising the network.) 

                router bgp 65000
 no bgp default ipv4-unicast
address-family ipv6 unicast
  network 2001:DB8::/24

                Example: Configuring a Route Map for IPv6 Multiprotocol BGP Prefixes

                The following example configures the route map named rtp to permit IPv6 unicast routes from network 2001:DB8::/24 if they match the prefix list named cisco: 

                router bgp 64900
no bgp default ipv4-unicast
neighbor 2001:DB8:0:CC00::1 remote-as 64700
address-family ipv6 unicast
 neighbor 2001:DB8:0:CC00::1 activate
 neighbor 2001:DB8:0:CC00::1 route-map rtp in
ipv6 prefix-list cisco seq 10 permit 2001:DB8::/24
route-map rtp permit 10
 match ipv6 address prefix-list cisco

                Example: Redistributing Prefixes into IPv6 Multiprotocol BGP

                The following example redistributes RIP routes into the IPv6 unicast database of the local device: 

                router bgp 64900
no bgp default ipv4-unicast
address-family ipv6 unicast
 redistribute rip

                Example: Advertising IPv4 Routes Between IPv6 Peers

                The following example advertises IPv4 routes between IPv6 peers when the IPv6 network is connecting two separate IPv4 networks. Peering is configured using IPv6 addresses in the IPv4 address family configuration mode. The inbound route map named rmap sets the next hop because the advertised next hop is likely to be unreachable. 

                router bgp 65000
!
 neighbor 6peers peer-group
 neighbor 2001:DB8:1234::2 remote-as 65002
 address-family ipv4
 neighbor 6peers activate
 neighbor 6peers soft-reconfiguration inbound
 neighbor 2001:DB8:1234::2 peer-group 6peers
 neighbor 2001:DB8:1234::2 route-map rmap in
!   
route-map rmap permit 10
 set ip next-hop 10.21.8.10

                Additional References

                Related Documents

                Related Topic

                Document Title

                IPv6 addressing and connectivity

                IPv6 Configuration Guide

                Cisco IOS commands

                Cisco IOS Master Command List, All Releases

                IPv6 commands

                Cisco IOS IPv6 Command Reference

                Cisco IOS IPv6 features

                Cisco IOS IPv6 Feature Mapping

                Standards and RFCs

                Standard/RFC

                Title

                RFCs for IPv6

                IPv6 RFCs

                MIBs

                MIB

                MIBs Link

                —

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

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

                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 IPv6 Routing: Multiprotocol BGP Extensions for IPv6

                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 IPv6 Routing: Multiprotocol BGP Extensions for IPv6

                Feature Name

                Releases

                Feature Information

                IPv6 Routing: Multiprotocol BGP Extensions for IPv6

                Cisco IOS XE Release 3.3SE

                Multiprotocol BGP Extensions for IPv6 supports the same features and functionality as IPv4 BGP.

                In Cisco IOS XE Release 3.3SE, support was added for the Cisco Catalyst 3650 Series Switches and Cisco Catalyst 3850 Series Switches.

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