MPLS Layer 2 VPNs Configuration Guide, Cisco IOS XE Release 3S
Pseudowire Group Switchover
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Pseudowire Group Switchover

Pseudowire Group Switchover

The Pseudowire Group Switchover feature allows all pseudowires in a group to be quickly switched over to backup pseudowires. This group switchover is triggered by a single “group down” status message received from a remote peer.

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 Pseudowire Group Switchover

  • The remote provider edge (PE) router must be capable of sending group status messages.
  • Label Distribution Protocol (LDP) must be implemented on the network.
  • Each xconnect must have a backup pseudowire configured.

Restrictions for Pseudowire Group Switchover

The Pseudowire Group Switchover feature is supported on Cisco IOS XE Release 3.10S and later releases. This feature is supported on Cisco ASR 903 Series routers on the following attachment circuits:

  • Ethernet VLAN
  • Asynchronous Transfer Mode (ATM)
  • Circuit Emulation over MPLS (CEM)

Information About Pseudowire Group Switchover

Introduction to Pseudowire Group Switchover

The Pseudowire Group Switchover feature allows you to reduce the switchover time from main pseudowires to backup pseudowires when a fault is encountered. The reduced switchover time is achieved by grouping Label Distribution Protocol (LDP) status messages and internal interprocess communication (IPC) messages.

When the remote peer detects an attachment circuit failure, it sends an LDP status message. When this status message is received, the designated backup pseudowires take over. Packets are then routed through the backup pseudowires.

Pseudowires can be grouped together by assigning a group ID. When an LDP status message is received by a pseudowire group, the entire group switches over, thus reducing switchover time.


Note


The Pseudowire Group Switchover feature is enabled by default and cannot be disabled.


Figure 1. Primary and Backup Pseudowire Groups

How to Configure Predictive Switchover

Predictive switchover allows switchovers from a main pseudowire to a backup pseudowire with a remote "standby" status, without waiting for an “up” status from the remote peer.

Predictive switchover is configured by enabling redundancy predictive mode in global configuration mode or xconnect configuration mode.

Configuring Predictive Switchover (Global Configuration Mode)

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    l2vpn

    4.    redundancy predictive enabled

    5.    end


DETAILED STEPS
      Command or Action Purpose
    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 l2vpn


    Example:
    Device(config)# l2vpn
     

    Enters l2vpn configuration mode.

     
    Step 4 redundancy predictive enabled


    Example:
    Device(config-l2vpn)# redundancy predictive enabled
     

    Enables redundancy predictive mode.

    • By default, redundancy predictive mode is disabled.
     
    Step 5 end


    Example:
    Device(config-l2vpn)# end
     

    Exits l2vpn configuration mode and returns to privileged EXEC mode.

     

    Configuring Predictive Switchover (Xconnect Configuration Mode)

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    l2vpn xconnect context context-name

      4.    redundancy predictive enabled

      5.    end


    DETAILED STEPS
        Command or Action Purpose
      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 l2vpn xconnect context context-name


      Example:
      Device(config)# l2vpn xconnect context con1
       

      Creates an L2VPN cross-connect context and enters xconnect configuration mode.

       
      Step 4 redundancy predictive enabled


      Example:
      Device(config-xconnect)# redundancy predictive enabled
       

      Enables redundancy predictive mode.

       
      Step 5 end


      Example:
      Device(config-xconnect)# end
       

      Exits xconnect configuration mode and returns to privileged EXEC mode.

       

      Verifying a Pseudowire Group Switchover Configuration

      You can use show commands to view information about a pseudowire group switchover configuration.

      The following example shows how to display information about Any Transport over MPLS (AToM) virtual circuits (VCs):

      Device# show l2vpn atom vc destination 2.1.1.2 group remote 6
      
                                              Service
      Interface  Dest Address     VC ID     Type     Name                   Status
      --------- --------------- ---------- ------ ------------------------ ----------
      pw100001   2.1.1.2         1234000    p2p      Et1/0.1-1001           UP

      The following example shows how to display the status of the pseudowire switching point:

      Device# show l2vpn atom vc destination 2.1.1.2 group remote 6 detail
      
      pseudowire100001 is up, VC status is up PW type: Ethernet
        Create time: 5d20h, last status change time: 5d20h
          Last label FSM state change time: 5d20h
        Destination address: 2.1.1.2 VC ID: 1234000
          Output interface: Et0/0, imposed label stack {2001}
        Preferred path: not configured
        Default path: active
        Next hop: 20.0.0.2
      Member of xconnect service Et1/0.1-1001, group right
        Associated member Et1/0.1 is up, status is up
        Interworking type is Ethernet
        Service id: 0x6d000002
      Signaling protocol: LDP, peer 2.1.1.2:0 up
        Targeted Hello: 1.1.1.1(LDP Id) -> 2.1.1.2, LDP is UP
        Graceful restart: not configured and not enabled
        Non stop routing: not configured and not enabled
        PWid FEC (128), VC ID: 1234000
        Status TLV support (local/remote) : enabled/supported
          LDP route watch : enabled
          Label/status state machine : established, LruRru
          Local dataplane status received : No fault
          BFD dataplane status received : Not sent
          BFD peer monitor status received : No fault
          Status received from access circuit : No fault
          Status sent to access circuit : No fault
          Status received from pseudowire i/f : No fault
          Status sent to network peer : No fault
          Status received from network peer : No fault
          Adjacency status of remote peer : No fault
      Sequencing: receive disabled, send disabled
      Bindings
      Parameter    Local                          Remote
      ------------ ------------------------------ ------------------------------
      Label        2007                           2001
      Group ID     0                              6
      Interface
      MTU          1500                           1500
      Control word on (configured: autosense)     on
      PW type      Ethernet                       Ethernet
      VCCV CV type 0x12                           0x12
                     LSPV [2], BFD/Raw [5]          LSPV [2], BFD/Raw [5]
      VCCV CC type 0x07                           0x07
                   CW [1], RA [2], TTL [3]        CW [1], RA [2], TTL [3]
      Status TLV   enabled                        supported
      Dataplane:
        SSM segment/switch IDs: 12309/4115 (used), PWID: 1
      Rx Counters
        106563 input transit packets, 9803650 bytes
        0 drops, 0 seq err
      Tx Counters
        0 output transit packets, 0 bytes
        0 drops

      The following example lists the active and standby segment pairs associated with each peer IP address and group identifier:

      Device# show ssm group
      
      Active              Standby
      IP Address       Group ID       Segment/Switch      Segment/Switch
      =========================================================================
      2.1.1.2               6            8215/4115           4116/8210

      The following example displays the number of active and standby segment pairs associated with each peer IP address and group identifier:

      Device# show ssm group 2.1.1.2 6 summary
      
      IP Address        Group ID      Group Members
      =============================================
      2.1.1.2                6               1
      

      The following example displays the number of pseudowires programmed in the hardware, with grouping information:

      Device# show platform hardware pp active pw eompls group brief
      
      Brief L2VPN EoMPLS Pseudo Wire Group Info
      
      IP address           Group ID            Count
      ------------------------------------------------------
      0x47474747           100695488            90

      Troubleshooting a Pseudowire Group Switchover Configuration

      Use the debug platform software atom brief command to view information about the following configurations:

      • Add Group
      • Delete From Group
      • Group Switchovers

      Note


      We recommend that you use the debug platform software atom brief command only under Cisco Technical Assistance Center (TAC) supervision.


      Configuration Examples for Predictive Switchover

      Example: Configuring Predictive Switchover (Global Configuration Mode)

      Device> enable
      Device# configure terminal
      Device(config)# l2vpn
      Device(config-l2vpn)# redundancy predictive enabled
      Device(config-l2vpn)# end

      Example: Configuring Predictive Switchover (Xconnect Configuration Mode)

      Device> enable
      Device# configure terminal
      Device(config)# l2vpn xconnect context con1
      Device(config-xconnect)# redundancy predictive enabled
      Device(config-xconnect)# end

      Additional References

      Related Documents

      Standards and RFCs

      Standard/RFC Title

      RFC 4447

      Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)

      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 Pseudowire Group Switchover

      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 Pseudowire Group Switchover

      Feature Name

      Releases

      Feature Information

      Pseudowire Group Switchover

      Cisco IOS XE Release 3.10S

      This feature allows all pseudowires in a group to be quickly switched over to backup pseudowires. This group switchover is triggered by a single “group down” status message received from a remote peer.

      The following commands were introduced or modified: redundancy predictive, show ssm group.