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L2VPN Multisegment Pseudowires

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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 L2VPN Multisegment Pseudowires

Restrictions

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: November 20, 2009

The L2VPN Multisegment Pseudowires feature enables you to configure two or more Layer 2 pseudowire segments that function as a single pseudowire. The feature spans 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 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 and Catalyst OS 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 Multiprotocol Label Switching (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. See the "Restrictions" section for specific restrictions on ping mpls and trace mpls operations.

•The S-PE router is limited to 1600 pseudowires.

Information About L2VPN Multisegment Pseudowires

Before configuring the L2VPN Multisegment Pseudowires feature, you should understand the following concepts:

•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 2, 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. An L2VPN MS-PW can include up to 254 PW segments.

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.

Figure 2 A Multisegment Pseudowire

How to Configure L2VPN Multisegment Pseudowires

The following sections outline the tasks for creating and maintaining L2VPN multisegment pseudowires:

•Configuring L2VPN Multisegment Pseudowires (required)

•Displaying Information About the L2VPN Multisegment Pseudowires (optional)

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

Configuring L2VPN Multisegment Pseudowires

Perform the following steps on the S-PE routers to create L2VPN multisegment pseudowires.

Cisco 7600 Router-Specific Instructions

If the Cisco 7600 router is the penultimate hop router connected to the S-PE or T-PE router, issue the following commands on the S-PE or T-PE routers:

•mpls ldp explicit-null

•no mls mpls explicit-null propagate-ttl

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

Perform the following task to display the status of 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: Ethernet,    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: Ethernet,    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 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 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

Restrictions

Some ping mpls and trace mpls keywords that are available with IPv4 LDP or traffic engineering (TE), are not available with pseudowire.

The following keywords are not available with the ping mpls pseudowire command:

•dsmap

•flags

•force-explicit-null

•output

•revision

•ttl

The following keywords are not available with the trace mpls pseudowire command:

•flags

•force-explicit-null

•output

•revision

•ttl

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 Figure 2:

•To perform an end-to-end ping operation from T-PE1 to T-PE2, enter the following command. destination-address is S-PE1 and vc-id is the VC between T-PE1 and S-PE1.

ping mpls pseudowiredestination-address vc-id

•To perform a ping operation from T-PE1 to segment 2, enter the following command. destination-address is S-PE1 and vc-id is the VC between T-PE1 and S-PE1.

ping mpls pseudowire destination-address vc-id 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 origin 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. destination-address is S-PE1 and vc-id is the VC between T-PE1 and S-PE1.

trace mpls pseudowire destination-address vc-id 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. destination-address is S-PE1 and vc-id is the VC between T-PE1 and S-PE1.

trace mpls pseudowire destination-address vc-id segment 2 4

The following commands perform trace operations on S-PE router 10.10.10.9, first on segment 1, then on segment 2.

Segment 1 trace: 


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


Segment 2 trace:


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

The following sections provide references related to the L2VPN multisegment pseudowires feature.

Related Documents


Standards

Standard
Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

—


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 IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs


RFCs

RFC
Title

RFC 4447

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

RFC5085

Pseudowire Virtual Circuit Connectivity Verification (VCCV)

RFC4379

Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures


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 Multisegment Pseudowires

Table 1 lists the release history for this feature.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS 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 software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.

Table 1 Feature Information for L2VPN Multisegment Pseudowires 

Feature Name
Releases
Feature Information

L2VPN Multisegment Pseudowires

12.2(33)SRE

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


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