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

Table Of Contents

L2VPN Multisegment Pseudowires

Finding Feature Information

Contents

Prerequisites for L2VPN Multisegment Pseudowires

Restrictions for L2VPN Multisegment Pseudowires

Information About L2VPN Multisegment Pseudowires

L2VPN Pseudowire Defined

L2VPN Multisegment Pseudowire Defined

How to Configure L2VPN Multisegment Pseudowires

Configuring L2VPN Multisegment Pseudowires

Displaying Information About the L2VPN Multisegment Pseudowires

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

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for L2VPN Multisegment Pseudowires


L2VPN Multisegment Pseudowires


First Published: February 27, 2009
Last Updated: May 4, 2009

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

For the latest feature information and caveats, see 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 for L2VPN Multisegment Pseudowires" section.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS XE software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Contents

Prerequisites for L2VPN Multisegment Pseudowires

Restrictions for L2VPN Multisegment Pseudowires

Information About L2VPN Multisegment Pseudowires

How to Configure L2VPN Multisegment Pseudowires

Additional References

Feature Information for L2VPN Multisegment Pseudowires

Prerequisites for L2VPN Multisegment Pseudowires

Before configuring this feature, see the following documents:

Any Transport over MPLS

L2VPN Pseudowire Switching

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

Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP) (RFC 4447)

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

L2VPN Multisegment Pseudowire Defined

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 Figure 1. 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 Figure 1, 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.

Figure 1 An L2VPN Pseudowire

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.

Figure 2 is an example of a Multisegment Pseudowire topology.

Figure 2 A Multisegment Pseudowire

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 (required)

Displaying Information About the L2VPN Multisegment Pseudowires (optional)

Performing ping mpls and trace mpls Operations on the L2VPN Multisegment Pseudowires (optional)

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 Action
Purpose

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 neighbor commands are allowed for each l2 vfi point-to-point 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.)

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:

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

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

You can use the ping mpls and trace mpls commands 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 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

A range of segments

SUMMARY STEPS

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

2. trace mpls pseudowire peer-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 Figure 2:

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


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 Figure 2:

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:


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


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

Table 1 lists the release history for this feature and provides links to specific configuration information.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS XE software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.


Note Table 1 lists only the Cisco IOS XE software release that introduced support for a given feature in a given Cisco IOS XE software release train. Unless noted otherwise, subsequent releases of that Cisco IOS XE software release train also support that feature.


Table 1 Feature Information for L2VPN Multisegment Pseudowires 

Feature Name
Releases
Feature Information

MPLS Support for Multisegment PWs-MPLS OAM/VCCV

Cisco IOS XE Release 2.3

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.

The following sections provide information about this feature:

Information About L2VPN Multisegment Pseudowires

How to Configure L2VPN Multisegment Pseudowires

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