Contents

L2VPN Pseudowire Switching

This feature module explains how to configure L2VPN Pseudowire Switching, which extends Layer 2 Virtual Private Network (L2VPN) pseudowires across an interautonomous system (inter-AS) boundary or across two separate Multiprotocol Label Switching (MPLS) networks. The feature supports ATM and time-division multiplexing (TDM) attachment circuits (ACs) and Ethernet ACs.

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 Pseudowire Switching

For the Cisco 12000 series routers, the L2VPN Pseudowire Switching feature for Any Transport over MPLS (AToM) is supported on the following engines:

  • E2

  • E3

  • E4+

  • E5

  • E6

For engines that do not support this feature, the packets are sent to the software and forwarded through the slow path.


Note

Engines E1 and E4 do not support L2VPN Pseudowire Switching, even in the slow path.

Restrictions for L2VPN Pseudowire Switching

  • L2VPN Pseudowire Switching is supported with AToM.

  • Only static, on-box provisioning is supported.

  • Sequencing numbers in AToM packets are not processed by L2VPN Pseudowire Switching. The feature blindly passes the sequencing data through the xconnect packet paths, a process that is called transparent sequencing. The endpoint provider-edge (PE) to customer-edge (CE) connections enforce the sequencing.

  • You can ping the adjacent next-hop PE router. End-to-end label switched path (LSP) pings are not supported.

  • Do not configure IP or Ethernet interworking on a router where L2VPN Pseudowire Switching is enabled. Instead, configure interworking on the routers at the edge PEs of the network.

  • The control word negotiation results must match. If either segment does not negotiate the control word, the control word is disabled for both segments.

  • AToM Graceful Restart is negotiated independently on each pseudowire segment. If there is a transient loss of the label distribution protocol (LDP) session between two AToM PE routers, packets continue to flow.

  • Per-pseudowire quality of service (QoS) is not supported. Traffic engineering (TE) tunnel selection is supported.

  • Attachment circuit interworking is not supported.

Information About L2VPN Pseudowire Switching

How L2VPN Pseudowire Switching Works

L2VPN Pseudowire Switching allows the user to extend L2VPN pseudowires across two separate MPLS networks or across an inter-AS boundary, as shown in the two figures below.

L2VPN Pseudowire Switching connects two or more contiguous pseudowire segments to form an end-to-end multihop pseudowire. This end-to-end pseudowire functions as a single point-to-point pseudowire.

As shown in the second figure below, L2VPN Pseudowire Switching enables you to keep the IP addresses of the edge PE routers private across inter-AS boundaries. You can use the IP address of the Autonomous System Boundary Routers (ASBRs) and treat them as pseudowire aggregation (PE-agg) routers. The ASBRs join the pseudowires of the two domains.

L2VPN Pseudowire Switching also enables you to keep different administrative or provisioning domains to manage the end-to-end service. At the boundaries of these networks, PE-agg routers delineate the management responsibilities.

Figure 1. L2VPN Pseudowire Switching in an Intra-AS Topology

Figure 2. L2VPN Pseudowire Switching in an Inter-AS Topology

How Packets Are Manipulated at the L2VPN Pseudowire Switching Aggregation Point

Switching AToM packets between two AToM pseudowires is the same as switching any MPLS packet. The MPLS switching data path switches AToM packets between two AToM pseudowires. The following list explains exceptions:

  • The outgoing virtual circuit (VC) label replaces the incoming VC label in the packet. New Internal Gateway Protocol (IGP) labels and Layer 2 encapsulation are added.

  • The incoming VC label time-to-live (TTL) field is decremented by one and copied to the outgoing VC label TTL field.

  • The incoming VC label EXP value is copied to the outgoing VC label EXP field.

  • The outgoing VC label “Bottom of Stack” S bit in the outgoing VC label is set to 1.

  • AToM control word processing is not performed at the L2VPN Pseudowire Switching aggregation point. Sequence numbers are not validated. Use the Router Alert label for LSP Ping; do not require control word inspection to determine an LSP Ping packet.

How to Configure L2VPN Pseudowire Switching

Use the following procedure to configure L2VPN Pseudowire Switching on each of the PE-agg routers. In this configuration, you are limited to two neighborcommands after entering the l2 vficommand.

Before You Begin

  • This procedure assumes that you have configured basic AToM L2VPNs. This procedure does not explain how to configure basic AToM L2VPNs that transport Layer 2 packets over an MPLS backbone. For information on the basic configuration, see Any Transport over MPLS .

  • For interautonomous configurations, ASBRs require a labeled interface.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    l2 vfi name point-to-point

    4.    neighbor ip-address vcid [encapsulation mpls | pw-class pw-class-name]

    5.    exit

    6.    exit

    7.    show mpls l2transport vc [vcid [vc-id | vc-id-min vc-id-max]] [interface name[local-circuit-id]] [destination ip-address | name] [detail]

    8.    show vfi [vfi-name]

    9.    ping [protocol] [tag] {host-name| system-address}


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 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 4 neighbor ip-address vcid [encapsulation mpls | pw-class pw-class-name]


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

    Configures an emulated VC.

    • Specify the IP address and the VC ID of the remote 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.

     
    Step 5 exit


    Example:
    Router(config-vfi)# exit
     

    Exits VFI configuration mode.

     
    Step 6 exit


    Example:
    Router(config)# exit
     

    Exits global configuration mode.

     
    Step 7 show mpls l2transport vc [vcid [vc-id | vc-id-min vc-id-max]] [interface name[local-circuit-id]] [destination ip-address | name] [detail]


    Example:
    Router# show mpls l2transport vc
     

    Verifies that the L2VPN Pseudowire Switching session has been established.

     
    Step 8 show vfi [vfi-name]


    Example:
    Router# show vfi atomtunnel
     

    Verifies that a point-to-point VFI has been established.

     
    Step 9 ping [protocol] [tag] {host-name| system-address}


    Example:
    Router# ping 10.1.1.1
     

    When issued from the CE routers, verifies end-to-end connectivity.

     

    Examples

    The following example displays output from the show mpls l2transport vc command:

    Router# show mpls l2transport vc
Local intf     Local circuit              Dest address    VC ID Status   
-------------  -------------------------- --------------- ----- ---- 
MPLS PW        10.0.1.1:100               10.0.1.1        100   UP 
MPLS PW        10.0.1.1:100               10.0.1.1        100   UP

    The following example displays output from the show vficommand:

    Router# show vfi
VFI name: test, type: point-to-point
 Neighbors connected via pseudowires:
   Router ID        Pseudowire ID
   10.0.1.1         100      
   10.0.1.1         100

    Configuration Examples for L2VPN Pseudowire Switching

    L2VPN Pseudowire Switching in an Inter-AS Configuration Example

    Two separate autonomous systems are able to pass L2VPN packets, because the two PE-agg routers have been configured with L2VPN Pseudowire Switching. This example configuration is shown in the figure below.

    Figure 3. L2VPN Pseudowire Switching in an Interautonomous System

    PE-agg-1

    PE-agg-2 

    version 12.0
    service timestamps debug uptime
    service timestamps log uptime
    service password-encryption
    !
    hostname [pe-agg1]
    !
    boot-start-marker
    boot-end-marker
    !
    enable secret 5 $1$Q0Bb$32sIU82pHRgyddWaeB4zs/
    !
    ip subnet-zero
    ip cef
    no ip domain-lookup
    mpls label protocol ldp
    pseudowire-class SW-PW
     encapsulation mpls
    !
    l2 vfi PW-SWITCH-1 point-to-point
     neighbor 172.17.255.3 100 pw-class SW-PW
     neighbor 172.16.255.1 16 pw-class SW-PW
    !
    interface Loopback0
     ip address 172.16.255.3 255.255.255.255
     no ip directed-broadcast
    !
    interface Serial0/0
     ip address 172.16.0.6 255.255.255.252
     no ip directed-broadcast
     mpls ip
    !
    interface Serial1/0
     ip address 192.168.0.1 255.255.255.252
     no ip directed-broadcast
     mpls bgp forwarding
    !
    router ospf 16
     log-adjacency-changes
     network 172.16.0.0 0.0.255.255 area 0
    !
    router bgp 65016
     no synchronization
     bgp log-neighbor-changes
     network 172.16.255.3 mask 255.255.255.255
     neighbor 192.168.0.2 remote-as 65017
     neighbor 192.168.0.2 send-label
     no auto-summary
    !
    ip classless
    control-plane
    !
    line con 0
     exec-timeout 0 0
    line aux 0
    line vty 0 4
     login
    !
    no cns aaa enable
    end
    		 
    version 12.0
    service timestamps debug uptime
    service timestamps log uptime
    service password-encryption
    !
    hostname [pe-agg2]
    !
    boot-start-marker
    boot-end-marker
    !
    enable secret 5 $1$32jd$zQRfxXzjstr4llV9DcWf7/
    !
    ip subnet-zero
    ip cef
    no ip domain-lookup
    mpls label protocol ldp
    pseudowire-class SW-PW
     encapsulation mpls
    !
    l2 vfi PW-SWITCH-1 point-to-point
     neighbor 172.16.255.3 100 pw-class SW-PW
     neighbor 172.17.255.1 17 pw-class SW-PW
    !
    interface Loopback0
     ip address 172.17.255.3 255.255.255.255
     no ip directed-broadcast
    !
    interface Serial0/0
     ip address 172.17.0.6 255.255.255.252
     no ip directed-broadcast
     mpls ip
    !
    interface Serial1/0
     ip address 192.168.0.2 255.255.255.252
     no ip directed-broadcast
     mpls bgp forwarding
    !
    router ospf 17
     log-adjacency-changes
     network 172.17.0.0 0.0.255.255 area 0
    !
    router bgp 65017
     no synchronization
     bgp log-neighbor-changes
     network 172.17.255.3 mask 255.255.255.255
     neighbor 192.168.0.1 remote-as 65016
     neighbor 192.168.0.1 send-label
     no auto-summary
    !
    ip classless
    control-plane
    !
    line con 0
     exec-timeout 0 0
    line aux 0
    line vty 0 4
     login
    !
    no cns aaa enable
    end

    A-P1

    B-P1 

    version 12.0
    service timestamps debug uptime
    service timestamps log uptime
    service password-encryption
    !
    hostname [a-p1]
    !
    boot-start-marker
    boot-end-marker
    !
    enable secret 5 $1$eiUn$rTMnZiYnJxtMTpO0NKpQQ/
    !
    ip subnet-zero
    ip cef
    no ip domain-lookup
    mpls label protocol ldp
    !
    interface Loopback0
     ip address 172.16.255.2 255.255.255.255
     no ip directed-broadcast
    !
    interface Serial0/0
     ip address 172.16.0.5 255.255.255.252
     no ip directed-broadcast
     mpls ip
    !
    interface Serial1/0
     ip address 172.16.0.2 255.255.255.252
     no ip directed-broadcast
     mpls ip
    !
    router ospf 16
     log-adjacency-changes
     network 172.16.0.0 0.0.255.255 area 0
    !
    ip classless
    !
    control-plane
    !
    line con 0
     exec-timeout 0 0
    line aux 0
    line vty 0 4
     login
    !
    no cns aaa enable
    end
    		 
    version 12.0
    service timestamps debug uptime
    service timestamps log uptime
    service password-encryption
    !
    hostname [b-p1]
    !
    boot-start-marker
    boot-end-marker
    !
    enable secret 5 $1$svU/$2JmJZ/5gxlW4nVXVniIJe1
    !
    ip subnet-zero
    ip cef
    no ip domain-lookup
    mpls label protocol ldp
    !
    interface Loopback0
     ip address 172.17.255.2 255.255.255.255
     no ip directed-broadcast
    !
    interface Serial0/0
     ip address 172.17.0.5 255.255.255.252
     no ip directed-broadcast
     mpls ip
    !
    interface Serial1/0
     ip address 172.17.0.2 255.255.255.252
     no ip directed-broadcast
     mpls ip
    !
    router ospf 17
     log-adjacency-changes
     network 172.17.0.0 0.0.255.255 area 0
    !
    ip classless
    !
    control-plane
    !
    line con 0
     exec-timeout 0 0
    line aux 0
    line vty 0 4
     login
    !
    no cns aaa enable
    end

    PE1

    PE2 

    version 12.0
    service timestamps debug uptime
    service timestamps log uptime
    service password-encryption
    !
    hostname [pe1]
    !
    boot-start-marker
    boot-end-marker
    !
    enable secret 5 $1$9z8F$2A1/YLc6NB6d.WLQXF0Bz1
    !
    ip subnet-zero
    ip cef
    no ip domain-lookup
    mpls label protocol ldp
    pseudowire-class ETH-PW
     encapsulation mpls
    !
    interface Loopback0
     ip address 172.16.255.1 255.255.255.255
     no ip directed-broadcast
    !
    interface Ethernet0/0
     no ip address
     no ip directed-broadcast
     no cdp enable
     xconnect 172.16.255.3 16 pw-class ETH-PW
    !
    interface Serial1/0
     ip address 172.16.0.1 255.255.255.252
     no ip directed-broadcast
     mpls ip
    !
    router ospf 16
     log-adjacency-changes
     network 172.16.0.0 0.0.255.255 area 0
    !
    ip classless
    !
    control-plane
    !
    line con 0
     exec-timeout 0 0
    line aux 0
    line vty 0 4
     login
    !
    no cns aaa enable
    end
    		 
    version 12.0
    service timestamps debug uptime
    service timestamps log uptime
    service password-encryption
    !
    hostname [pe2]
    !
    boot-start-marker
    boot-end-marker
    !
    enable secret 5 $1$rT.V$8Z6Dy/r8/eaRdx2TR/O5r/
    !
    ip subnet-zero
    ip cef
    no ip domain-lookup
    mpls label protocol ldp
    pseudowire-class ETH-PW
     encapsulation mpls
    !
    interface Loopback0
     ip address 172.17.255.1 255.255.255.255
     no ip directed-broadcast
    !
    interface Ethernet0/0
     no ip address
     no ip directed-broadcast
     no cdp enable
     xconnect 172.17.255.3 17 pw-class ETH-PW
    !
    interface Serial1/0
     ip address 172.17.0.1 255.255.255.252
     no ip directed-broadcast
     mpls ip
    !
    router ospf 17
     log-adjacency-changes
     network 172.17.0.0 0.0.255.255 area 0
    !
    ip classless
    !
    control-plane
    !
    line con 0
     exec-timeout 0 0
    line aux 0
    line vty 0 4
     login
    !
    no cns aaa enable
    end

    CE1

    CE2 

    version 12.0
    service timestamps debug uptime
    service timestamps log uptime
    service password-encryption
    !
    hostname [ce1]
    !
    boot-start-marker
    boot-end-marker
    !
    enable secret 5 $1$o9N6$LSrxHufTn0vjCY0nW8hQX.
    !
    ip subnet-zero
    ip cef
    no ip domain-lookup
    !
    interface Ethernet0/0
     ip address 10.0.0.1 255.255.255.252
     no ip directed-broadcast
    !
    ip classless
    !
    control-plane
    !
    line con 0
     exec-timeout 0 0
    line aux 0
    line vty 0 4
     login
    !
    no cns aaa enable
    end
    		 
    version 12.0
    service timestamps debug uptime
    service timestamps log uptime
    service password-encryption
    !
    hostname [ce2]
    !
    boot-start-marker
    boot-end-marker
    !
    enable secret 5 $1$YHo6$LQ4z5PdrF5B9dnL75Xvvm1
    !
    ip subnet-zero
    ip cef
    no ip domain-lookup
    !
    interface Ethernet0/0
     ip address 10.0.0.2 255.255.255.252
     no ip directed-broadcast
    !
    ip classless
    !
    control-plane
    !
    line con 0
     exec-timeout 0 0
    line aux 0
    line vty 0 4
     login
    !
    no cns aaa enable
    end

    Additional References

    Related Documents

    Related Topic

    Document Title

    Any Transport over MPLS

    Any Transport over MPLS

    Pseudowire redundancy

    http:/​/​www.cisco.com/​univercd/​cc/​td/​doc/​product/​software/​ios120/​120newft/​120limit/​120s/​120s31/​fsstitch.htm L2VPN Pseudowire Redundancy

    High availability for AToM

    AToM Graceful Restart

    L2VPN interworking

    L2VPN Interworking

    Layer 2 local switching

    Layer 2 Local Switching

    PWE3 MIB

    Pseudowire Emulation Edge-to-Edge MIBs for Ethernet and Frame Relay Services

    Packet sequencing

    Any Transport over MPLS (AToM) Sequencing Support

    Standards

    Standard

    Title

    draft-ietf-pwe3-control-protocol-14.txt

    Pseudowire Setup and Maintenance using LDP

    draft-martini-pwe3-pw-switching-01.txt

    Pseudo Wire Switching

    MIBs

    MIB

    MIBs Link

    • CISCO-IETF-PW-MIB

    • CISCO-IETF-PW-MPLS-MIB

    • CISCO-IETF-PW-ENET-MIB

    • CISCO-IETF-PW-FR-MIB

    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

    RFCs

    RFCs

    Title

    None

    —

    Technical Assistance

    Description

    Link

    The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

    To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

    Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

    http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

    Feature Information for L2VPN Pseudowire Switching

    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 Pseudowire Switching

    Feature Name

    Releases

    Feature Information

    L2VPN Pseudowire Switching

    12.0(31)S, 12.2(28)SB, 12.2(33)SRB, 12.2(33)SRD2, 12.2(33)SRE

    This feature configures L2VPN Pseudowire Switching, which extends L2VPN pseudowires across an interautonomous system (inter-AS) boundary or across two separate MPLS networks.

    In Cisco IOS Release 12.2(28)SB, support was added for the Cisco 7200 and 7301 series routers.

    In 12.2(33)SRD2, support was added for ATM and TDM ACs.

    The following commands were introduced or modified: l2 vfi point-to-point, neighbor(L2VPN Pseudowire Switching), show vfi. 

    
 
	 
    

    

    

    


    














L2VPN Pseudowire Switching

                              

    


    L2VPN Pseudowire Switching
    

     
	 
    

     This feature module explains how to configure L2VPN Pseudowire Switching, which extends Layer 2 Virtual Private Network (L2VPN) pseudowires across an interautonomous system (inter-AS) boundary or across two separate Multiprotocol Label Switching (MPLS) networks. The feature supports ATM and time-division multiplexing (TDM) attachment circuits (ACs) and Ethernet ACs.
	 
    

    

    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 Pseudowire Switching
    

    
For the Cisco 12000 series routers, the L2VPN Pseudowire Switching feature for Any Transport over MPLS (AToM) is supported on the following engines:
    

    • 
E2
      

      • 

    • 
E3
      

      • 

    • 
E4+
      

      • 

    • 
E5
      

      • 

    • 
E6
      

      • 

    

    
For engines that do not support this feature, the packets are sent to the software and forwarded through the slow path.
    


    Note
    
Engines E1 and E4 do not support L2VPN Pseudowire Switching, even in the slow path.
    

    

    

    

    Restrictions for L2VPN Pseudowire Switching
    

    • 
L2VPN Pseudowire Switching is supported with AToM.
      

      • 

    • 
Only static, on-box provisioning is supported. 
      

      • 

    • 
Sequencing numbers in AToM packets are not processed by L2VPN Pseudowire Switching. The feature blindly passes the sequencing data through the xconnect packet paths, a process that is called transparent sequencing. The endpoint provider-edge (PE) to customer-edge (CE) connections enforce the sequencing. 
      

      • 

    • 
You can ping the adjacent next-hop PE router. End-to-end label switched path (LSP) pings are not supported. 
      

      • 

    • 
Do not configure IP or Ethernet interworking on a router where L2VPN Pseudowire Switching is enabled. Instead, configure interworking on the routers at the edge PEs of the network. 
      

      • 

    • 
The control word negotiation results must match. If either segment does not negotiate the control word, the control word is disabled for both segments.
      

      • 

    • 
AToM Graceful Restart is negotiated independently on each pseudowire segment. If there is a transient loss of the label distribution protocol (LDP) session between two AToM PE routers, packets continue to flow. 
      

      • 

    • 
Per-pseudowire quality of service (QoS) is not supported. Traffic engineering (TE) tunnel selection is supported.
      

      • 

    • 
Attachment circuit interworking is not supported.
      

      • 

    

    

    

    Information About L2VPN Pseudowire Switching
    

    

    How L2VPN Pseudowire Switching Works
    

     L2VPN Pseudowire Switching allows the user to extend L2VPN pseudowires
		across two separate MPLS networks or across an inter-AS boundary, as shown in
		the two figures below.
	 
    

     L2VPN Pseudowire Switching connects two or more contiguous pseudowire
		segments to form an end-to-end multihop pseudowire. This end-to-end pseudowire
		functions as a single point-to-point pseudowire. 
	 
    

     As shown in the second figure below, L2VPN Pseudowire Switching enables
		you to keep the IP addresses of the edge PE routers private across inter-AS
		boundaries. You can use the IP address of the Autonomous System Boundary
		Routers (ASBRs) and treat them as pseudowire aggregation (PE-agg) routers. The
		ASBRs join the pseudowires of the two domains. 
	 
    

     L2VPN Pseudowire Switching also enables you to keep different
		administrative or provisioning domains to manage the end-to-end service. At the
		boundaries of these networks, PE-agg routers delineate the management
		responsibilities.
	 
    

    Figure 1. L2VPN Pseudowire Switching in an Intra-AS Topology

    

    Figure 2. L2VPN Pseudowire Switching in an Inter-AS Topology

    

    

    

    How Packets Are Manipulated at the L2VPN Pseudowire Switching Aggregation Point
    

    
Switching AToM packets between two AToM pseudowires is the same as switching any MPLS packet. The MPLS switching data path switches AToM packets between two AToM pseudowires. The following list explains exceptions:
    

    • 
The outgoing virtual circuit (VC) label replaces the incoming VC label in the packet. New Internal Gateway Protocol (IGP) labels and Layer 2 encapsulation are added.
      

      • 

    • 
The incoming VC label time-to-live (TTL) field is decremented by one and copied to the outgoing VC label TTL field. 
      

      • 

    • 
The incoming VC label EXP value is copied to the outgoing VC label EXP field.
      

      • 

    • 
The outgoing VC label “Bottom of Stack” S bit in the outgoing VC label is set to 1.
      

      • 

    • 
AToM control word processing is not performed at the L2VPN Pseudowire Switching aggregation point. Sequence numbers are not validated. Use the Router Alert label for LSP Ping; do not require control word inspection to determine an LSP Ping packet.
      

      • 

    

    

    

    

    How to Configure L2VPN Pseudowire Switching
    

     
		
     Use the following procedure to configure L2VPN Pseudowire Switching on each of the PE-agg routers. In this configuration, you are limited to two 
		  neighborcommands after entering the 
			 l2 
			 vficommand. 
		
    
 
	 
    

    Before You Begin
     
		
    •  This procedure assumes that you have configured basic AToM L2VPNs. This procedure does not explain how to configure basic AToM L2VPNs that transport Layer 2 packets over an MPLS backbone. For information on the basic configuration, see Any Transport over MPLS .
		  
      

      • 

    •  For interautonomous configurations, ASBRs require a labeled interface.
		  
      

      • 

    
 
	 
    

    
SUMMARY STEPS
      1.   
       
			  
				enable 
			  
		  
      

      2.   
       
			  
				configure 
			  
			  
				terminal 
			  
		  
      

      3.   
       
			  
				l2 
				vfi 
			  
			  
				name 
			  
			  
				point-to-point 
			  
		  
      

      4.   
       
			  
				neighbor 
			  
			  
				ip-address 
			  
			  
				vcid 
			  [encapsulation 
				mpls 
			 | 
			 pw-class 
			 pw-class-name]
		  
      

      5.   
       
			  
				exit 
			  
		  
      

      6.   
       
			  
				exit 
			  
		  
      

      7.   
       
			  
				show 
				mpls 
				l2transport 
				vc 
			  [vcid [vc-id | 
			 vc-id-min 
				vc-id-max]] [interface 
			 name[local-circuit-id]] [destination 
			 ip-address | 
			 name] [detail]
		  
      

      8.   
       
			  
				show 
				vfi 
			 [vfi-name]
		  
      

      9.   
       
			  
				ping 
			  [protocol] [tag] {host-name| 
			 system-address} 
		  
      


    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 
			  
				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 4 
			  
				neighbor 
			  
			  
				ip-address 
			  
			  
				vcid 
			  [encapsulation 
				mpls 
			 | 
			 pw-class 
			 pw-class-name]
		  
       

      Example:
       
			 
      Router(config-vfi)# neighbor 10.0.0.1 100 pw-class mpls
      
 
		  
      
 
            		  
			 
       Configures an emulated VC. 
			 
      
 
			 
      •  Specify the IP address and the VC ID of the remote 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.
			 
      

      
 
		   
      
      

      Step 5 
			  
				exit 
			  
		  
       

      Example:
       
			 
      Router(config-vfi)# exit
      
 
		  
      
 
            		  
			 
       Exits VFI configuration mode.
			 
      
 
		   
      
      

      Step 6 
			  
				exit 
			  
		  
       

      Example:
       
			 
      Router(config)# exit
      
 
		  
      
 
            		  
			 
       Exits global configuration mode. 
			 
      
 
		   
      
      

      Step 7 
			  
				show 
				mpls 
				l2transport 
				vc 
			  [vcid [vc-id | 
			 vc-id-min 
				vc-id-max]] [interface 
			 name[local-circuit-id]] [destination 
			 ip-address | 
			 name] [detail]
		  
       

      Example:
       
			 
      Router# show mpls l2transport vc
      
 
		  
      
 
            		  
			 
       Verifies that the L2VPN Pseudowire Switching session has been established. 
			 
      
 
		   
      
      

      Step 8 
			  
				show 
				vfi 
			 [vfi-name]
		  
       

      Example:
       
			 
      Router# show vfi atomtunnel
      
 
		  
      
 
            		  
			 
       Verifies that a point-to-point VFI has been established. 
			 
      
 
		   
      
      

      Step 9 
			  
				ping 
			  [protocol] [tag] {host-name| 
			 system-address} 
		  
       

      Example:
       
			 
      Router# ping 10.1.1.1
      
 
		  
      
 
            		  
			 
       When issued from the CE routers, verifies end-to-end connectivity. 
			 
      
 
		   
      
      

      

      

      Examples
      

      
The following example displays output from the show mpls l2transport vc command:
      

      Router# show mpls l2transport vc
Local intf     Local circuit              Dest address    VC ID Status   
-------------  -------------------------- --------------- ----- ---- 
MPLS PW        10.0.1.1:100               10.0.1.1        100   UP 
MPLS PW        10.0.1.1:100               10.0.1.1        100   UP 

      

      
The following example displays output from the show vficommand:
      

      Router# show vfi
VFI name: test, type: point-to-point
 Neighbors connected via pseudowires:
   Router ID        Pseudowire ID
   10.0.1.1         100      
   10.0.1.1         100 
      

      

      

      

      Configuration Examples for L2VPN Pseudowire Switching
      

      

      L2VPN Pseudowire Switching in an Inter-AS Configuration     Example
      

       Two separate autonomous systems are able to pass L2VPN packets, because
		the two PE-agg routers have been configured with L2VPN Pseudowire Switching.
		This example configuration is shown in the figure below. 
	 
      

      Figure 3. L2VPN Pseudowire Switching in an Interautonomous System 

      


      
              
       PE-agg-1 
				  
      

                  		

              
       PE-agg-2 
				  
      

                  		

      
      

      
              
      version 12.0
      

              
      service timestamps debug uptime
      

              
      service timestamps log uptime
      

              
      service password-encryption
      

              
      !
      

              
      hostname [pe-agg1]
      

              
      !
      

              
      boot-start-marker
      

              
      boot-end-marker
      

              
      !
      

              
      enable secret 5 $1$Q0Bb$32sIU82pHRgyddWaeB4zs/
      

              
      !
      

              
      ip subnet-zero
      

              
      ip cef
      

              
      no ip domain-lookup
      

              
      mpls label protocol ldp
      

              
      pseudowire-class SW-PW
      

              
       encapsulation mpls
      

              
      !
      

              
      l2 vfi PW-SWITCH-1 point-to-point
      

              
       neighbor 172.17.255.3 100 pw-class SW-PW
      

              
       neighbor 172.16.255.1 16 pw-class SW-PW
      

              
      !
      

              
      interface Loopback0
      

              
       ip address 172.16.255.3 255.255.255.255
      

              
       no ip directed-broadcast
      

              
      !
      

              
      interface Serial0/0
      

              
       ip address 172.16.0.6 255.255.255.252
      

              
       no ip directed-broadcast
      

              
       mpls ip
      

              
      !
      

              
      interface Serial1/0
      

              
       ip address 192.168.0.1 255.255.255.252
      

              
       no ip directed-broadcast
      

              
       mpls bgp forwarding
      

              
      !
      

              
      router ospf 16
      

              
       log-adjacency-changes
      

              
       network 172.16.0.0 0.0.255.255 area 0
      

              
      !
      

              
      router bgp 65016
      

              
       no synchronization
      

              
       bgp log-neighbor-changes
      

              
       network 172.16.255.3 mask 255.255.255.255
      

              
       neighbor 192.168.0.2 remote-as 65017
      

              
       neighbor 192.168.0.2 send-label
      

              
       no auto-summary
      

              
      !
      

              
      ip classless
      

              
      control-plane
      

              
      !
      

              
      line con 0
      

              
       exec-timeout 0 0
      

              
      line aux 0
      

              
      line vty 0 4
      

              
       login
      

              
      !
      

              
      no cns aaa enable
      

              
      end
      

            
      
      		

      
              
      version 12.0
      

              
      service timestamps debug uptime
      

              
      service timestamps log uptime
      

              
      service password-encryption
      

              
      !
      

              
      hostname [pe-agg2]
      

              
      !
      

              
      boot-start-marker
      

              
      boot-end-marker
      

              
      !
      

              
      enable secret 5 $1$32jd$zQRfxXzjstr4llV9DcWf7/
      

              
      !
      

              
      ip subnet-zero
      

              
      ip cef
      

              
      no ip domain-lookup
      

              
      mpls label protocol ldp
      

              
      pseudowire-class SW-PW
      

              
       encapsulation mpls
      

              
      !
      

              
      l2 vfi PW-SWITCH-1 point-to-point
      

              
       neighbor 172.16.255.3 100 pw-class SW-PW
      

              
       neighbor 172.17.255.1 17 pw-class SW-PW
      

              
      !
      

              
      interface Loopback0
      

              
       ip address 172.17.255.3 255.255.255.255
      

              
       no ip directed-broadcast
      

              
      !
      

              
      interface Serial0/0
      

              
       ip address 172.17.0.6 255.255.255.252
      

              
       no ip directed-broadcast
      

              
       mpls ip
      

              
      !
      

              
      interface Serial1/0
      

              
       ip address 192.168.0.2 255.255.255.252
      

              
       no ip directed-broadcast
      

              
       mpls bgp forwarding
      

              
      !
      

              
      router ospf 17
      

              
       log-adjacency-changes
      

              
       network 172.17.0.0 0.0.255.255 area 0
      

              
      !
      

              
      router bgp 65017
      

              
       no synchronization
      

              
       bgp log-neighbor-changes
      

              
       network 172.17.255.3 mask 255.255.255.255
      

              
       neighbor 192.168.0.1 remote-as 65016
      

              
       neighbor 192.168.0.1 send-label
      

              
       no auto-summary
      

              
      !
      

              
      ip classless
      

              
      control-plane
      

              
      !
      

              
      line con 0
      

              
       exec-timeout 0 0
      

              
      line aux 0
      

              
      line vty 0 4
      

              
       login
      

              
      !
      

              
      no cns aaa enable
      

              
      end
      

            
      
      		

      
      

      

      


      
              
       A-P1 
				  
      

                  		

              
       B-P1 
				  
      

                  		

      
      

      
              
      version 12.0
      

              
      service timestamps debug uptime
      

              
      service timestamps log uptime
      

              
      service password-encryption
      

              
      !
      

              
      hostname [a-p1]
      

              
      !
      

              
      boot-start-marker
      

              
      boot-end-marker
      

              
      !
      

              
      enable secret 5 $1$eiUn$rTMnZiYnJxtMTpO0NKpQQ/
      

              
      !
      

              
      ip subnet-zero
      

              
      ip cef
      

              
      no ip domain-lookup
      

              
      mpls label protocol ldp
      

              
      !
      

              
      interface Loopback0
      

              
       ip address 172.16.255.2 255.255.255.255
      

              
       no ip directed-broadcast
      

              
      !
      

              
      interface Serial0/0
      

              
       ip address 172.16.0.5 255.255.255.252
      

              
       no ip directed-broadcast
      

              
       mpls ip
      

              
      !
      

              
      interface Serial1/0
      

              
       ip address 172.16.0.2 255.255.255.252
      

              
       no ip directed-broadcast
      

              
       mpls ip
      

              
      !
      

              
      router ospf 16
      

              
       log-adjacency-changes
      

              
       network 172.16.0.0 0.0.255.255 area 0
      

              
      !
      

              
      ip classless
      

              
      !
      

              
      control-plane
      

              
      !
      

              
      line con 0
      

              
       exec-timeout 0 0
      

              
      line aux 0
      

              
      line vty 0 4
      

              
       login
      

              
      !
      

              
      no cns aaa enable
      

              
      end
      

            
      
      		

      
              
      version 12.0
      

              
      service timestamps debug uptime
      

              
      service timestamps log uptime
      

              
      service password-encryption
      

              
      !
      

              
      hostname [b-p1]
      

              
      !
      

              
      boot-start-marker
      

              
      boot-end-marker
      

              
      !
      

              
      enable secret 5 $1$svU/$2JmJZ/5gxlW4nVXVniIJe1
      

              
      !
      

              
      ip subnet-zero
      

              
      ip cef
      

              
      no ip domain-lookup
      

              
      mpls label protocol ldp
      

              
      !
      

              
      interface Loopback0
      

              
       ip address 172.17.255.2 255.255.255.255
      

              
       no ip directed-broadcast
      

              
      !
      

              
      interface Serial0/0
      

              
       ip address 172.17.0.5 255.255.255.252
      

              
       no ip directed-broadcast
      

              
       mpls ip
      

              
      !
      

              
      interface Serial1/0
      

              
       ip address 172.17.0.2 255.255.255.252
      

              
       no ip directed-broadcast
      

              
       mpls ip
      

              
      !
      

              
      router ospf 17
      

              
       log-adjacency-changes
      

              
       network 172.17.0.0 0.0.255.255 area 0
      

              
      !
      

              
      ip classless
      

              
      !
      

              
      control-plane
      

              
      !
      

              
      line con 0
      

              
       exec-timeout 0 0
      

              
      line aux 0
      

              
      line vty 0 4
      

              
       login
      

              
      !
      

              
      no cns aaa enable
      

              
      end
      

            
      
      		

      
      

      

      


      
              
       PE1 
				  
      

                  		

              
       PE2 
				  
      

                  		

      
      

      
              
      version 12.0
      

              
      service timestamps debug uptime
      

              
      service timestamps log uptime
      

              
      service password-encryption
      

              
      !
      

              
      hostname [pe1]
      

              
      !
      

              
      boot-start-marker
      

              
      boot-end-marker
      

              
      !
      

              
      enable secret 5 $1$9z8F$2A1/YLc6NB6d.WLQXF0Bz1
      

              
      !
      

              
      ip subnet-zero
      

              
      ip cef
      

              
      no ip domain-lookup
      

              
      mpls label protocol ldp
      

              
      pseudowire-class ETH-PW
      

              
       encapsulation mpls
      

              
      !
      

              
      interface Loopback0
      

              
       ip address 172.16.255.1 255.255.255.255
      

              
       no ip directed-broadcast
      

              
      !
      

              
      interface Ethernet0/0
      

              
       no ip address
      

              
       no ip directed-broadcast
      

              
       no cdp enable
      

              
       xconnect 172.16.255.3 16 pw-class ETH-PW
      

              
      !
      

              
      interface Serial1/0
      

              
       ip address 172.16.0.1 255.255.255.252
      

              
       no ip directed-broadcast
      

              
       mpls ip
      

              
      !
      

              
      router ospf 16
      

              
       log-adjacency-changes
      

              
       network 172.16.0.0 0.0.255.255 area 0
      

              
      !
      

              
      ip classless
      

              
      !
      

              
      control-plane
      

              
      !
      

              
      line con 0
      

              
       exec-timeout 0 0
      

              
      line aux 0
      

              
      line vty 0 4
      

              
       login
      

              
      !
      

              
      no cns aaa enable
      

              
      end
      

            
      
      		

      
              
      version 12.0
      

              
      service timestamps debug uptime
      

              
      service timestamps log uptime
      

              
      service password-encryption
      

              
      !
      

              
      hostname [pe2]
      

              
      !
      

              
      boot-start-marker
      

              
      boot-end-marker
      

              
      !
      

              
      enable secret 5 $1$rT.V$8Z6Dy/r8/eaRdx2TR/O5r/
      

              
      !
      

              
      ip subnet-zero
      

              
      ip cef
      

              
      no ip domain-lookup
      

              
      mpls label protocol ldp
      

              
      pseudowire-class ETH-PW
      

              
       encapsulation mpls
      

              
      !
      

              
      interface Loopback0
      

              
       ip address 172.17.255.1 255.255.255.255
      

              
       no ip directed-broadcast
      

              
      !
      

              
      interface Ethernet0/0
      

              
       no ip address
      

              
       no ip directed-broadcast
      

              
       no cdp enable
      

              
       xconnect 172.17.255.3 17 pw-class ETH-PW
      

              
      !
      

              
      interface Serial1/0
      

              
       ip address 172.17.0.1 255.255.255.252
      

              
       no ip directed-broadcast
      

              
       mpls ip
      

              
      !
      

              
      router ospf 17
      

              
       log-adjacency-changes
      

              
       network 172.17.0.0 0.0.255.255 area 0
      

              
      !
      

              
      ip classless
      

              
      !
      

              
      control-plane
      

              
      !
      

              
      line con 0
      

              
       exec-timeout 0 0
      

              
      line aux 0
      

              
      line vty 0 4
      

              
       login
      

              
      !
      

              
      no cns aaa enable
      

              
      end
      

            
      
      		

      
      

      

      


      
              
       CE1 
				  
      

                  		

              
       CE2 
				  
      

                  		

      
      

      
              
      version 12.0
      

              
      service timestamps debug uptime
      

              
      service timestamps log uptime
      

              
      service password-encryption
      

              
      !
      

              
      hostname [ce1]
      

              
      !
      

              
      boot-start-marker
      

              
      boot-end-marker
      

              
      !
      

              
      enable secret 5 $1$o9N6$LSrxHufTn0vjCY0nW8hQX.
      

              
      !
      

              
      ip subnet-zero
      

              
      ip cef
      

              
      no ip domain-lookup
      

              
      !
      

              
      interface Ethernet0/0
      

              
       ip address 10.0.0.1 255.255.255.252
      

              
       no ip directed-broadcast
      

              
      !
      

              
      ip classless
      

              
      !
      

              
      control-plane
      

              
      !
      

              
      line con 0
      

              
       exec-timeout 0 0
      

              
      line aux 0
      

              
      line vty 0 4
      

              
       login
      

              
      !
      

              
      no cns aaa enable
      

              
      end
      

            
      
      		

      
              
      version 12.0
      

              
      service timestamps debug uptime
      

              
      service timestamps log uptime
      

              
      service password-encryption
      

              
      !
      

              
      hostname [ce2]
      

              
      !
      

              
      boot-start-marker
      

              
      boot-end-marker
      

              
      !
      

              
      enable secret 5 $1$YHo6$LQ4z5PdrF5B9dnL75Xvvm1
      

              
      !
      

              
      ip subnet-zero
      

              
      ip cef
      

              
      no ip domain-lookup
      

              
      !
      

              
      interface Ethernet0/0
      

              
       ip address 10.0.0.2 255.255.255.252
      

              
       no ip directed-broadcast
      

              
      !
      

              
      ip classless
      

              
      !
      

              
      control-plane
      

              
      !
      

              
      line con 0
      

              
       exec-timeout 0 0
      

              
      line aux 0
      

              
      line vty 0 4
      

              
       login
      

              
      !
      

              
      no cns aaa enable
      

              
      end
      

            
      
      		

      
      

      

      

      

      

      

      Additional References
      

      
    
      

      Related Documents
      
      
      

      
                
      
Related Topic
      

                    		

                
      
Document Title
      

                    		

      
      

      
                
      
Any Transport over MPLS
      

                    		

                
      
                  Any Transport over MPLS
                
      

                    		

      

      
                
      
Pseudowire redundancy
      

                    		

                
      
                  http:/​/​www.cisco.com/​univercd/​cc/​td/​doc/​product/​software/​ios120/​120newft/​120limit/​120s/​120s31/​fsstitch.htm
                  L2VPN Pseudowire Redundancy
                
      

                    		

      

      
                
      
High availability for AToM
      

                    		

                
      
                  AToM Graceful Restart
                
      

                    		

      

      
                
      
L2VPN interworking 
      

                    		

                
      
                  L2VPN Interworking
                
      

                    		

      

      
                
      
Layer 2 local switching 
      

                    		

                
      
                  Layer 2 Local Switching
                  
                    
                    
                  
                
      

                    		

      

      
                
      
PWE3 MIB
      

                    		

                
      
                  Pseudowire Emulation Edge-to-Edge MIBs for Ethernet and Frame Relay Services
                  
                    
                    
                  
                
      

                    		

      

      
                
      
Packet sequencing
      

                    		

                
      
                  Any Transport over MPLS (AToM) Sequencing Support
                
      

                    		

      
      

      

      

    
      

      Standards
      
      
      

      
                
      
Standard
      

                    		

                
      
Title
      

                    		

      
      

      
                
      
draft-ietf-pwe3-control-protocol-14.txt
      

                    		

                
      
                  
                    Pseudowire
                    Setup
                    and
                    Maintenance
                    using
                    LDP
                  
                
      

                    		

      

      
                
      
draft-martini-pwe3-pw-switching-01.txt
      

                    		

                
      
                  
                    Pseudo
                    Wire
                    Switching
                  
                
      

                    		

      
      

      

      

    
      

      MIBs
      
      
      

      
                
      
MIB
      

                    		

                
      
MIBs Link
      

                    		

      
      

      
                
      • 
CISCO-IETF-PW-MIB
        

        • 

      • 
CISCO-IETF-PW-MPLS-MIB
        

        • 

      • 
CISCO-IETF-PW-ENET-MIB
        

        • 

      • 
CISCO-IETF-PW-FR-MIB
        

        • 

      

              
      
      		

                
      
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
                
      

                    		

      
      

      

      

    
      

      RFCs
      
      
      

      
                
      
RFCs
      

                    		

                
      
Title
      

                    		

      
      

      
                
      
None
      

                    		

                
      
                  —
                
      

                    		

      
      

      

      

    
      

      Technical Assistance
      
      
      

      
                
      
Description
      

                    		

                
      
Link
      

                    		

      
      

      
                
      
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.
      

                
      
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      Feature Information for L2VPN Pseudowire Switching
      

       
		
      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 Pseudowire Switching 
       
				  
       Feature Name 
				  
      
 
				      		
 
				  
       Releases 
				  
      
 
				      		
 
				  
       Feature Information 
				  
      
 
				      		

      
      

       
				  
       L2VPN Pseudowire Switching 
				  
      
 
				      		
 
				  
       12.0(31)S, 12.2(28)SB, 12.2(33)SRB, 12.2(33)SRD2, 12.2(33)SRE 
				  
      
 
				      		
 
				  
       This feature configures L2VPN Pseudowire Switching, which extends L2VPN pseudowires across an interautonomous system (inter-AS) boundary or across two separate MPLS networks. 
				  
      
 
				  
       In Cisco IOS Release 12.2(28)SB, support was added for the Cisco 7200 and 7301 series routers. 
				  
      
 
				  
       In 12.2(33)SRD2, support was added for ATM and TDM ACs. 
				  
      
 
				  
       The following commands were introduced or modified: 
					 l2 
						vfi 
						point-to-point, 
						neighbor(L2VPN Pseudowire Switching), 
					 show 
						vfi.