MPLS Layer 2 VPNs Configuration Guide, Cisco IOS XE Release 3S
L2VPN Multisegment Pseudowires
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Contents

L2VPN Multisegment Pseudowires

The L2VPN Multisegment Pseudowires feature enables you to configure two or more Layer 2 pseudowire segments that function as a single pseudowire. The L2VPN Multisegment Pseudowires feature span multiple cores or autonomous systems of the same or different carrier networks.

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 L2VPN Multisegment Pseudowires

Before configuring this feature, see the following documents:

Restrictions for L2VPN Multisegment Pseudowires

  • Only Mutliprotocol (MPLS) Layer 2 pseudowires are supported.
  • Only manual configuration of the pseudowires (including S-PE and T-PE routers) is supported.
  • The L2VPN Pseudowire Switching feature is supported for pseudowires advertised with FEC 128. FEC 129 is not supported.
  • The S-PE router is limited to 1600 pseudowires.

Information About L2VPN Multisegment Pseudowires

L2VPN Pseudowire Defined

An L2VPN pseudowire (PW) is a tunnel established between two provider edge (PE) routers across the core carrying the Layer 2 payload encapsulated as MPLS data, as shown in the figure below. This helps carriers migrate from traditional Layer 2 networks such as Frame Relay and ATM to an MPLS core. In the L2VPN pseudowire shown in the figure, the PWs between two PE routers are located within the same autonomous system. Routers PE1 and PE2 are called terminating PE routers (T-PEs). Attachment circuits are bounded to the PW on these PE routers.



L2VPN Multisegment Pseudowire Defined

An L2VPN multisegment pseudowire (MS-PW) is a set of two or more PW segments that function as a single PW. It is also known as switched PW. MS-PWs span multiple cores or autonomous systems of the same or different carrier networks. A L2VPN MS-PW can include up to 254 PW segments.

The figure below is an example of a Multisegment Pseudowire topology.



The end routers are called terminating PE routers (T-PEs), and the switching routers are called S-PE routers. The S-PE router terminates the tunnels of the preceding and succeeding PW segments in an MS-PW. The S-PE router can switch the control and data planes of the preceding and succeeding PW segments of the MS-PW. An MS-PW is declared to be up when all the single-segment PWs are up. For more information, see the L2VPN Pseudowire Switching document.

How to Configure L2VPN Multisegment Pseudowires

Configuring L2VPN Multisegment Pseudowires

Perform the following steps on the S-PE routers to create L2VPN Multisegment Pseudowires.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    mpls label protocol ldp

    4.    mpls ldp router-id interface force

    5.    pseudowire-class name

    6.    encapsulation mpls

    7.    switching tlv

    8.    exit

    9.    l2 vfi name point-to-point

    10.    description string

    11.    neighbor ip-address vcid { encapsulation mpls pw-class pw-class-name}


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 mpls label protocol ldp

    Example:
    Router(config)# mpls label protocol ldp
     

    Configures the use of Label Distribution Protocol (LDP) on all interfaces.

     
    Step 4 mpls ldp router-id interface force


    Example:
    Router(config)# mpls ldp router-id loopback0 force
     

    Specifies the preferred interface for determining the LDP router ID.

     
    Step 5 pseudowire-class name


    Example:
    Router(config)# pseudowire-class atom
     

    Establishes a pseudowire class with a name that you specify, and enters pseudowire class configuration mode.

     
    Step 6 encapsulation mpls


    Example:
    Router(config-pw-class)# encapsulation mpls
     

    Specifies the tunneling encapsulation.

    • For MPLS L2VPNs, the encapsulation type is mpls.
     
    Step 7 switching tlv


    Example:
    Router(config-pw-class)# switching tlv
     

    (Optional) Enables the advertisement of the switching point type-length variable (TLV) in the label binding.

    • This command is enabled by default.
     
    Step 8 exit


    Example:
    Router(config-pw-class)# exit
     

    Exits pseudowire class configuration mode.

     
    Step 9 l2 vfi name point-to-point


    Example:
    Router(config)# l2 vfi atomtunnel point-to-point
     

    Creates a point-to-point Layer 2 virtual forwarding interface (VFI) and enters VFI configuration mode.

     
    Step 10 description string


    Example:
    Router(config-vfi)# description segment1
     

    Provides a description of the switching provider edge router for a multisegment pseudowire.

     
    Step 11 neighbor ip-address vcid { encapsulation mpls pw-class pw-class-name}


    Example:
    Router(config-vfi)# neighbor 10.0.0.1 100 pw-class mpls
     

    Sets up an emulated VC.

    • Specify the IP address and the VC ID of the peer router. Also specify the pseudowire class to use for the emulated VC.
    Note   

    Only two neighborcommands are allowed for each l2 vfi point-to-point command.

     

    Configuring L2VPN Multisegment Pseudowires using the commands associated with the L2VPN Protocol-Based CLIs feature

    Perform this task on the S-PE routers to create L2VPN multisegment pseudowires.

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    mpls label protocol ldp

      4.    mpls ldp router-id interface force

      5.    interface pseudowire number

      6.    encapsulation mpls

      7.    switching tlv

      8.    neighbor peer-address vcid-value

      9.    exit

      10.    l2vpn xconnect context context-name

      11.    description string

      12.    member ip-address vcid encapsulation mpls


    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 mpls label protocol ldp


      Example:
      Device(config)# mpls label protocol ldp
       

      Configures the use of Label Distribution Protocol (LDP) on all interfaces.

       
      Step 4 mpls ldp router-id interface force


      Example:
      Device(config)# mpls ldp router-id loopback0 force
       

      Specifies the preferred interface for determining the LDP router ID.

       
      Step 5 interface pseudowire number


      Example:
      Device(config)# interface pseudowire 1
       

      Establishes an interface pseudowire with a value that you specify, and enters pseudowire configuration mode.

       
      Step 6 encapsulation mpls


      Example:
      Device(config-pw)# encapsulation mpls
       

      Specifies the tunneling encapsulation.

      • For MPLS L2VPNs, the encapsulation type is mpls.
       
      Step 7 switching tlv


      Example:
      Device(config-pw)# switching tlv
       

      (Optional) Enables the advertisement of the switching point type-length variable (TLV) in the label binding.

      • This command is enabled by default.
       
      Step 8 neighbor peer-address vcid-value


      Example:
      Router(config-pw)#  neighbor 10.0.0.1 123
       

      Specifies the peer IP address and virtual circuit (VC) ID value of a Layer 2 VPN (L2VPN) pseudowire.

       
      Step 9 exit


      Example:
      Device(config-pw)# exit
       

      Exits pseudowire configuration mode.

       
      Step 10 l2vpn xconnect context context-name


      Example:
      Device(config)# l2vpn xconnect context con1
       

      Creates a Layer 2 VPN (L2VPN) cross connect context and enters xconnect configuration mode.

       
      Step 11 description string


      Example:
      Device(config-xconnect)# description segment1
       

      Provides a description of the switching provider edge router for a multisegment pseudowire.

       
      Step 12 member ip-address vcid encapsulation mpls


      Example:
      Device(config-xconnect)# member 10.10.10.10 1 encapsulation mpls
       

      Specifies the devices that form a point-to-point Layer 2 VPN (L2VPN) virtual forwarding interface (VFI) connection.

      Note   

      Only two membercommands are allowed for each l2vpn xconnect context command.

       

      Displaying Information About the L2VPN Multisegment Pseudowires

      SUMMARY STEPS

        1.    show mpls l2transport binding

        2.    show mpls l2transport vc detail


      DETAILED STEPS
        Step 1   show mpls l2transport binding

        Use the show mpls l2transport binding command to display information about the pseudowire switching point, as shown in bold in the output. (In the following examples PE1 and PE4 are the T-PE routers.)



        Example:
        Router# show mpls l2transport binding
 
  Destination Address: 10.1.1.1,  VC ID: 102
    Local Label:  17
        Cbit: 1,    VC Type: FastEthernet,    GroupID: 0
        MTU: 1500,   Interface Desc: n/a
        VCCV: CC Type: CW [1], RA [2], TTL [3]
              CV Type: LSPV [2]
    Remote Label: 16
        Cbit: 1,    VC Type: FastEthernet,    GroupID: 0
        MTU: 1500,   Interface Desc: n/a
        VCCV: CC Type: CW [1], RA [2], TTL [3]
              CV Type: LSPV [2]
        PW Switching Point:
             Vcid   local IP addr      remote IP addr      Description
             101    10.11.11.11        10.20.20.20         PW Switching Point PE3
             100    10.20.20.20        10.11.11.11         PW Switching Point PE2

        Step 2   show mpls l2transport vc detail

        Use the show mpls l2transport vc detail command to display status of the pseudowire switching point. In the following example, the output (shown in bold) displays the segment that is the source of the fault of the multisegment pseudowire:



        Example:
        Router# show mpls l2transport vc detail
Local interface: Se3/0/0 up, line protocol up, HDLC up
  Destination address: 12.1.1.1, VC ID: 100, VC status: down
    Output interface: Se2/0, imposed label stack {23}
    Preferred path: not configured  
    Default path: active
    Next hop: point2point
  Create time: 00:03:02, last status change time: 00:01:41
  Signaling protocol: LDP, peer 10.1.1.1:0 up
    Targeted Hello: 10.1.1.4(LDP Id) -> 10.1.1.1, LDP is UP
    Status TLV support (local/remote)   : enabled/supported
      LDP route watch                   : enabled
      Label/status state machine        : established, LruRrd
      Last local dataplane   status rcvd: No fault
      Last local SSS circuit status rcvd: No fault
      Last local SSS circuit status sent: DOWN(PW-tx-fault)
      Last local  LDP TLV    status sent: No fault
      Last remote LDP TLV    status rcvd: DOWN(PW-tx-fault)
       PW Switching Point:
       Fault type  Vcid   local IP addr   remote IP addr   Description
       PW-tx-fault  101   10.1.1.1        10.1.1.1         S-PE2
      Last remote LDP ADJ    status rcvd: No fault
    MPLS VC labels: local 19, remote 23 
    Group ID: local 0, remote 0
    MTU: local 1500, remote 1500
    Remote interface description: 
  Sequencing: receive disabled, send disabled
  VC statistics:
    packet totals: receive 16, send 27
    byte totals:   receive 2506, send 3098
    packet drops:  receive 0, seq error 0, send 0

        Displaying Information About the L2VPN Multisegment Pseudowires using the commands associated with the L2VPN Protocol-Based CLIs feature

        SUMMARY STEPS

          1.    show l2vpn atom binding

          2.    show l2vpn atom vc detail


        DETAILED STEPS
          Step 1   show l2vpn atom binding

          Use the show l2vpn atom binding command to display information about the pseudowire switching point, as shown in bold in the output. (In the following examples PE1 and PE4 are the T-PE routers.)



          Example:
          Device# show l2vpn atom binding
 
  Destination Address: 10.1.1.1,  VC ID: 102
    Local Label:  17
        Cbit: 1,    VC Type: FastEthernet,    GroupID: 0
        MTU: 1500,   Interface Desc: n/a
        VCCV: CC Type: CW [1], RA [2], TTL [3]
              CV Type: LSPV [2]
    Remote Label: 16
        Cbit: 1,    VC Type: FastEthernet,    GroupID: 0
        MTU: 1500,   Interface Desc: n/a
        VCCV: CC Type: CW [1], RA [2], TTL [3]
              CV Type: LSPV [2]
        PW Switching Point:
             Vcid   local IP addr      remote IP addr      Description
             101    10.11.11.11        10.20.20.20         PW Switching Point PE3
             100    10.20.20.20        10.11.11.11         PW Switching Point PE2

          Step 2   show l2vpn atom vc detail

          Use the show l2vpn atom vc detail command to display status of the pseudowire switching point. In the following example, the output (shown in bold) displays the segment that is the source of the fault of the multisegment pseudowire:



          Example:
          Device# show l2vpn atom vc detail
Local interface: Se3/0/0 up, line protocol up, HDLC up
  Destination address: 12.1.1.1, VC ID: 100, VC status: down
    Output interface: Se2/0, imposed label stack {23}
    Preferred path: not configured  
    Default path: active
    Next hop: point2point
  Create time: 00:03:02, last status change time: 00:01:41
  Signaling protocol: LDP, peer 10.1.1.1:0 up
    Targeted Hello: 10.1.1.4(LDP Id) -> 10.1.1.1, LDP is UP
    Status TLV support (local/remote)   : enabled/supported
      LDP route watch                   : enabled
      Label/status state machine        : established, LruRrd
      Last local dataplane   status rcvd: No fault
      Last local SSS circuit status rcvd: No fault
      Last local SSS circuit status sent: DOWN(PW-tx-fault)
      Last local  LDP TLV    status sent: No fault
      Last remote LDP TLV    status rcvd: DOWN(PW-tx-fault)
       PW Switching Point:
       Fault type  Vcid   local IP addr   remote IP addr   Description
       PW-tx-fault  101   10.1.1.1        10.1.1.1         S-PE2
      Last remote LDP ADJ    status rcvd: No fault
    MPLS VC labels: local 19, remote 23 
    Group ID: local 0, remote 0
    MTU: local 1500, remote 1500
    Remote interface description: 
  Sequencing: receive disabled, send disabled
  VC statistics:
    packet totals: receive 16, send 27
    byte totals:   receive 2506, send 3098
    packet drops:  receive 0, seq error 0, send 0

          Performing ping mpls and trace mpls Operations on the L2VPN Multisegment Pseudowires

          You can use the ping mpls and trace mplscommands to verify that all the segments of the MPLS multisegment pseudowire are operating.

          You can use the ping mpls command to verify connectivity at the following pseudowire points:

          • From one end of the pseudowire to the other
          • From one of the pseudowires to a specific segment
          • The segment between two adjacent S-PE routers

          You can use the trace mplscommand to verify connectivity at the following pseudowire points:

          • From one end of the pseudowire to the other
          • From one of the pseudowires to a specific segment
          • The segment between two adjacent S-PE routers
          • A range of segments
          SUMMARY STEPS

            1.    ping mpls pseudowire destination-address vc-id [segment segment-number]

            2.    trace mpls pseudowire destination-address vc-id segment segment-number segment-number


          DETAILED STEPS
            Step 1   ping mpls pseudowire destination-address vc-id [segment segment-number]

            Where:

            • destination-address is the address of the S-PE router, which is the end of the segment from the direction of the source.
            • vc-id is the VC ID of the segment from the source to the next PE router.
            • segment segment-number is optional and specifies the segment you want to ping.

            The following examples use the topology shown in the second figure above :

            • To perform an end-to-end ping operation from T-PE1 to T-PE2, enter the following command:

            ping mpls pseudowire <addr-of-S-PE1> <vc-id between T-PE1 and S-PE1>

            • To perform a ping operation from T-PE1 to segment 2, enter the following command:

            ping mpls pseudowire <addr-of-S-PE1> <vc-id between T-PE1 and S-PE1> segment 2



            Example:
            
 
		  
            

            

            Step 2  
              
			  
				trace 
				mpls 
				pseudowire 
			  
			  
				destination-address 
				vc-id 
			  
			  
				segment 
			  
			  
				segment-number 
			  
			  
				segment-number 
			  
		  
              
			 
             Where: 
			 
            
 
			 
            •  
				   
					 destination-address 
				   
				   
					  
					  
					 is 
					 the 
					 address 
					 of 
					 the 
					 next 
					 S-PE 
					 router 
					 from 
					 the 
					 original 
					 of 
					 the 
					 trace. 
				   
				

              • 

            •  
				   
					 vc-id 
				   is the VC ID of the segment from which the 
				  trace command is issued. 
				

              • 

            •  
				   
					 segment-number 
				   indicates the segment upon which the trace operation will act. If you enter two segment numbers, the traceroute operation will perform a trace on that range of routers. 
				

              • 

            
 
			 
             The following examples use the topology shown in the second figure above : 
			 
            
 
			 
            •  To perform a trace operation from T-PE1 to segment 2 of the multisegment pseudowire, enter the following command: 
				

              • 

            
 
			 
             
				 
				  trace 
				  mpls 
				  pseudowire 
				 <addr-of-S-PE1> <vc-id 
				  between 
				  T-PE1 
				  and 
				  S-PE1> 
				segment 
				2 
			 
            
 
			 
             This example performs a trace from T-PE1 to S-PE2. 
			 
            
 
			 
            •  To perform a trace operation on a range of segments, enter the following command. This example performs a trace from S-PE2 to T-PE2. 
				

              • 

            
 
			 
             
				 
				  trace 
				  mpls 
				  pseudowire 
				 <addr-of-S-PE1> <vc-id 
				  between 
				  T-PE1 
				  and 
				  S-PE1> 
				segment 
				2 
				4 
			 
            
 
			 
             The following command performs a trace operation on S-PE router 10.10.10.9, on segment 1 and then on segment 2: 
			 
            
 
		   

            Example:
             
			 
            router# trace mpls pseudowire 10.10.10.9 220 segment 1
Tracing MS-PW segments within range [1-1] peer address 10.10.10.9 and timeout 2 seconds
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
  'L' - labeled output interface, 'B' - unlabeled output interface,
  'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
  'M' - malformed request, 'm' - unsupported tlvs, 'N' - no label entry,
  'P' - no rx intf label prot, 'p' - premature termination of LSP,
  'R' - transit router, 'I' - unknown upstream index,
  'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
L 1 10.10.9.9 0 ms [Labels: 18 Exp: 0]
    local 10.10.10.22 remote 10.10.10.9 vc id 220
router# trace mpls pseudowire 10.10.10.9 220 segment 2
Tracing MS-PW segments within range [1-2] peer address 10.10.10.9 and timeout 2 seconds
Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
  'L' - labeled output interface, 'B' - unlabeled output interface,
  'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
  'M' - malformed request, 'm' - unsupported tlvs, 'N' - no label entry,
  'P' - no rx intf label prot, 'p' - premature termination of LSP,
  'R' - transit router, 'I' - unknown upstream index,
  'X' - unknown return code, 'x' - return code 0
Type escape sequence to abort.
L 1 10.10.9.9 4 ms [Labels: 18 Exp: 0]
    local 10.10.10.22 remote 10.10.10.9 vc id 220
! 2 10.10.3.3 4 ms [Labels: 16 Exp: 0]
    local 10.10.10.9 remote 10.10.10.3 vc id 220
            
 
		  
            

            

            

            

            

            

            Additional References
            

             
	 
            

            Related Documents
             
		 
		

             
					 
             Related Topic
					 
            
 
				              		
 
					 
             Document Title
					 
            
 
				              		

            
            

             
					 
             Cisco IOS commands
					 
            
 
				              		
 
					 
             
						Cisco IOS Master Commands List, All Releases 
					 
            
 
				              		

            

             
					 
             Description of commands associated with MPLS and MPLS applications
					 
            
 
				              		
 
					 
            Cisco IOS Multiprotocol Label Switching Command Reference 
						 
					 
            
 
				              		

            

             
					 
             Layer 2 VPNS
					 
            
 
				              		

             
					 
            •  Any Transport over MPLS 
						

              • 

            •  
						  L2VPN Pseudowire Switching 
						

              • 

            •  MPLS LSP Ping/Traceroute for LDP/TE, and LSP Ping for VCCV 
						

              • 

            
 
				  
            
            		

            
            

            

            
 
	 
            

            Standards
             
		 
		

             
					 
             Standard
					 
            
 
				              		
 
					 
             Title
					 
            
 
				              		

            
            

             
					 
             RFC 4777
					 
            
 
				              		
 
					 
             
						Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP) 
					 
            
 
				              		

            
            

            

            
 
	 
            

            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 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 L2VPN Multisegment Pseudowires
            

             
		
            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 L2VPN Multisegment Pseudowires
             
				  
             Feature Name 
				  
            
 
				            		
 
				  
             Releases 
				  
            
 
				            		
 
				  
             Feature Information 
				  
            
 
				            		

            
            

             
				  
             MPLS OAM Support for Multisegment Pseudowires
 
				  
            
 
				   
				            		
 
				  
             Cisco IOS XE Release 2.3 
				  
            

            Cisco IOS XE Release 3.5S
            
 
				            		
 
				  
             The L2VPN Multisegment Pseudowires feature enables you to configure two or more Layer 2 pseudowire segments that function as a single pseudowire. The L2VPN Multisegment Pseudowires feature span multiple cores or autonomous systems of the same or different carrier networks. 
				  
            

            In isco IOS XE Release 2.3, this feature was introduced and implemented on the Cisco ASR 1000 Series Routers.

            

            In Cisco IOS XE Release 3.5S, support was added for the Cisco ASR 903 Router.

            
 
				  
             The following commands were introduced or modified: 
					 description (l2 vfi), 
					 ping 
						mpls, 
					 show 
						mpls 
						l2transport 
						binding, 
					 show 
						mpls 
						l2transport 
						vc, 
					 switching 
						tlv, 
					 trace 
						mpls.