IS-IS IPv6 Client for BFD

When Bidirectional Forwarding Detection (BFD) support is configured with Intermediate System To Intermediate System (IS-IS) as a registered protocol with BFD, IS-IS receives forwarding path detection failure messages from BFD.

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Prerequisites for IS-IS IPv6 Client for BFD

  • IS-IS must be running on all participating devices.

  • The baseline parameters for BFD sessions must be configured on the interfaces that run BFD sessions to BFD neighbors.

Information About IS-IS IPv6 Client for BFD

IS-IS BFD Topology

When BFD support is configured with IS-IS as a registered protocol with BFD, IS-IS receives forwarding path detection failure messages from BFD. BFD support for IS-IS can be configured in either router address-family configuration mode or interface configuration mode. IS-IS IPv6 can run in single-topology or in Multi-Topology (MT) mode.

IS-IS BFD supports both IPv4 and IPv6 on the same adjacency for single-topology or multi-topology mode. If BFD is enabled for both IPv4 and IPv6, IS-IS sends two BFD session creation requests to BFD. For single-topology mode, the IS-IS adjacency state can only be UP if both BFD sessions are UP. If either of the BFD sessions is DOWN, the associated IS-IS adjacency state is also DOWN. For MT mode, the IS-IS adjacency state can be UP as long as one of topologies has a BFD session in an UP state.

IS-IS BFD IPv6 Session Creation

IS-IS requests a BFD session for the interface and IPv6 address of the neighboring device when all of the following conditions are met:

  • An IS-IS adjacency entry exists.

  • The Address Family Identifier (AFI) specific peer interface address is known.

  • IS-IS BFD is enabled for that AFI on an interface.

  • IS-IS is enabled for that AFI on the local interface.

  • If the neighboring device supports RFC 6213, BFD must be enabled for the specified Multi-Topology Identifier (MTID) or Network Layer Protocol Identifier (NLPID).

IS-IS BFD IPv6 Session Deletion

When IS-IS BFD IPv6 is disabled on an interface, IS-IS removes related BFD sessions for IPv6 from the adjacent device. When the IS-IS adjacency entry is deleted, all BFD sessions are also deleted. IS-IS requests BFD to remove each BFD session that it has requested when any of the following events occur:

  • The IS-IS instance is deleted or un-configured.

  • The IS-IS adjacency entry is deleted.

  • IS-IS BFD is disabled on the next hop interface for an address-family.

  • The neighboring device supports RFC 6213 and indicates that it no longer supports BFD for the specified MTID or NLPID.

How to Configure ISIS IPv6 Client for BFD

Configuring IS-IS IPv6 Client Support for BFD on an Interface

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    interface type number

    4.    isis ipv6 bfd

    5.    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 interface type number


    Example:
    Device(config)# interface gigabitethernet 6/0/0
     

    Enters interface configuration mode.

     
    Step 4 isis ipv6 bfd


    Example:
    Device(config-if)# isis ipv6 bfd
     

    Enables IPv6 BFD on a specific interface that is configured for IS-IS.

     
    Step 5 end


    Example:
    Device(config-if)# end
     

    Exits interface configuration mode and returns to privileged EXEC mode.

     

    Configuring IS-IS IPv6 Client Support for BFD on All Interfaces

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    router isis

      4.    metric-style wide

      5.    address-family ipv6

      6.    multi-topology

      7.    bfd all-interfaces

      8.    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 router isis


      Example:
      Device(config)# router isis
       

      Enables the IS-IS routing protocol and enters router configuration mode.

       
      Step 4 metric-style wide


      Example:
      Device(config-router)# metric-style wide
       

      (Optional) Configures a device that is running IS-IS so that it generates and accepts only new-style type, length, value objects (TLVs).

       
      Step 5 address-family ipv6


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

      Enters address family configuration mode for configuring IS-IS routing sessions that use standard IPv6 address prefixes.

       
      Step 6 multi-topology


      Example:
      Device(config-router-af)# multi-topology
       

      (Optional) Enables multi-topology IS-IS for IPv6.

       
      Step 7 bfd all-interfaces


      Example:
      Device(config-router-af)# bfd all-interfaces
       

      Enables BFD for all interfaces participating in the routing process.

       
      Step 8 end


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

      Exits address family configuration mode and returns to privileged EXEC mode.

       

      Configuration Examples for ISIS IPv6 Client for BFD

      Example: IS-IS IPv6 Client Support for BFD on a Single Interface

      Device> enable
Device# configure terminal
Device(config)# interface gigabitethernet 6/0/0
Device(config-if)# isis ipv6 bfd
Device(config-if)# end
     
      Device> enable
Device# configure terminal
Device(config)# interface gigabitethernet 6/0
Device(config-if)# isis ipv6 bfd
Device(config-if)# end

      Example: IS-IS IPv6 Client Support for BFD on All Interfaces

      Device> enable
Device# configure terminal
Device(config)# router isis
Device(config-router)# metric-style wide
Device(config-router)# address-family ipv6
Device(config-router-af)# multi-topology
Device(config-router-af)# bfd all-interfaces
Device(config-router-af)# end

      Additional References

      Related Documents

      Related Topic

      Document Title

      Cisco IOS commands

      Cisco IOS Master Command List, All Releases

      BFD commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples.

      Cisco IOS IP Routing: Protocol-Independent Command Reference

      Configuring and monitoring IS-IS

      “Configuring Integrated IS-IS” module of the IP Routing Protocols Configuration Guide

      Cisco IOS IPv6 features

      Cisco IOS IPv6 Feature Mapping

      IPv6 commands

      Cisco IOS IPv6 Command Reference

      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 IS-IS IPv6 Client for BFD

      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 IS-IS IPv6 Client for BFD

      Feature Name

      Releases

      Feature Information

      IS-IS IPv6 Client for BFD

      15.1(1)SY

      15.2(4)S

      15.3(1)T

      When BFD support is configured with IS-IS as a registered protocol with BFD, IS-IS receives forwarding path detection failure messages from BFD.

      The following commands were introduced or modified: bfd all-interfaces, isis ipv6 bfd.