Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?

Example: Configuring a Multisegment Pseudowire

 

This example shows how to configure a dynamic multisegment pseudowire (MS-PW), where the stitching provider edge (S-PE) devices are automatically and dynamically discovered by BGP, and pseudowires are signaled by LDP using FEC 129. This arrangement requires minimum provisioning on the S-PEs, thereby reducing the configuration burden that is associated with statically configured Layer 2 circuits while still using LDP as the underlying signaling protocol.

Requirements

This example uses the following hardware and software components:

  • Six routers that can be a combination of M Series Multiservice Edge Routers, MX Series 5G Universal Routing Platforms, T Series Core Routers, or PTX Series Packet Transport Routers.

    • Two remote PE devices configured as terminating PEs (T-PEs).

    • Two S-PEs configured as:

      • Route reflectors, in the case of interarea configuration.

      • AS boundary routers or route reflectors, in the case of inter-AS configuration.

  • Junos OS Release 13.3 or later running on all the devices.

Before you begin:

  1. Configure the device interfaces.

  2. Configure OSPF or any other IGP protocol.

  3. Configure BGP.

  4. Configure LDP.

  5. Configure MPLS.

Overview

Starting with Junos OS Release 13.3, you can configure an MS-PW using FEC 129 with LDP signaling and BGP autodiscovery in an MPLS packet-switched network (PSN). The MS-PW feature also provides operation, administration, and management (OAM) capabilities, such as ping, traceroute, and BFD, from the T-PE devices.

To enable autodiscovery of S-PEs in an MS-PW, include the auto-discovery-mspw statement at the [edit protocols bgp group group-name family l2vpn] hierarchy level.

The automatic selection of S-PE and dynamic setting up of an MS-PW rely heavily on BGP. BGP network layer reachability information (NLRI) constructed for the FEC 129 pseudowire to autodiscover the S-PE is called an MS-PW NLRI [draft-ietf-pwe3-dynamic-ms-pw-15.txt]. The MS-PW NLRI is essentially a prefix consisting of a route distinguisher (RD) and FEC 129 source attachment identifier (SAII). It is referred to as a BGP autodiscovery (BGP-AD) route and is encoded as RD:SAII.

Only T-PEs that are provisioned with type 2 AIIs initiate their own MS-PW NLRI respectively. Since a type 2 AII is globally unique, an MS-PW NLRI is used to identify a PE device to which the type 2 AII is provisioned. The difference between a type 1 AII and a type 2 AII requires that a new address family indicator (AFI) and subsequent address family identifier (SAFI) be defined in BGP to support an MS-PW. The proposed AFI and SAFI value pair used to identify the MS-PW NLRI is 25 and 6, respectively (pending IANA allocation).

The AFI and SAFI values support autodiscovery of S-PEs and should be configured on both T-PEs that originate the routes, and the S-PEs that participate in the signaling.

Figure 1 illustrates an inter-area MS-PW setup between two remote PE routers—T-PE1 and T-PE2. The Provider (P) routers are P1 and P2, and the S-PE routers are S-PE1 and S-PE2. The MS-PW is established between T-PE1 and T-PE2, and all the devices belong to the same AS—AS 100. Since S-PE1 and S-PE2 belong to the same AS, they act as route reflectors and are also known as RR 1 and RR 2, respectively.

Figure 2 illustrates an inter-AS MS-PW setup. The MS-PW is established between T-PE1 and T-PE2, where T-PE1, P1, and S-PE1 belong to AS 1, and S-PE2, P2, and T-PE2 belong to AS 2. Since S-PE1 and S-PE2 belong to different ASs, they are configured as ASBR routers and are also known as ASBR 1 and ASBR 2, respectively.

Figure 1: Interarea Multisegment Pseudowire
Interarea Multisegment Pseudowire
Figure 2: Inter-AS Multisegment Pseudowire
Inter-AS Multisegment Pseudowire

The following sections provide information about how an MS-PW is established in an interarea and inter-AS scenario.

Minimum Configuration Requirements on S-PE

In order to dynamically discover both ends of an SS-PW and set up a T-LDP session dynamically, the following is required:

  • For interarea MS-PW, each S-PE plays both an ABR and BGP route reflector role.

    In the interarea case, as seen in Figure 1, the S-PE plays a BGP route reflector role and reflects the BGP-AD route to its client. A BGP-AD route advertised by one T-PE eventually reaches its remote T-PE. Because of the next-hop-self set by each S-PE, the S-PE or T-PE that receives a BGP-AD route can always discover the S-PE that advertises the BGP-AD in its local AS or local area through the BGP next hop.

  • For inter-AS MS-PW, each S-PE plays either an ASBR or a BGP route reflector role.

    In an MS-PW, the two T-PEs initiate a BGP-AD route respectively. When the S-PE receives the BGP-AD route through either the IBGP session with the T-PE or through a regular BGP-RR, it sets the next-hop-self before re-advertising the BGP-AD route to one or more of its EBGP peers in the inter-AS case, as seen in Figure 2.

  • Each S-PE must set next-hop-self when re-advertising or reflecting a BGP-AD route for the MS-PW.

Active and Passive Role of T-PE

To ensure that the same set of S-PEs are being used for a MS-PW in both directions, the two T-PEs play different roles in terms of FEC 129 signaling. This is to avoid different paths being chosen by T-PE1 and T-PE2 when each S-PE is dynamically selected for an MS-PW.

When an MS-PW is signaled using FEC 129, each T-PE might independently start signaling the MS-PW. The signaling procedure can result in an attempt to set up each direction of the MS-PW through different S-PEs.

To avoid this situation, one of the T-PEs must start the pseudowire signaling (active role), while the other waits to receive the LDP label mapping before sending the respective pseudowire LDP label mapping message (passive role). When the MS-PW path is dynamically placed, the active T-PE (the Source T-PE) and the passive T-PE (the Target T-PE) must be identified before signaling is initiated for a given MS-PW. The determination of which T-PE assumes the active role is done based on the SAII value, where the T-PE that has a larger SAII value plays the active role.

In this example, the SAII values of T-PE1 and T-PE 2 are 800:800:800 and 700:700:700, respectively. Since T-PE1 has a higher SAII value, it assumes the active role and T-PE2 assumes the passive role.

Directions for Establishing an MS-PW

The directions used by the S-PE for setting up the MS-PW are:

  • Forwarding direction—From an active T-PE to a passive T-PE.

    In this direction, the S-PEs perform a BGP-AD route lookup to determine the next-hop S-PE to send the label mapping message.

  • Reverse direction—From a passive T-PE to an active T-PE.

    In this direction, the S-PEs do not perform a BGP-AD route lookup, because the label mapping messages are received from the T-PEs, and the stitching routes are installed in the S-PEs.

In this example, the MS-PW is established in the forwarding direction from T-PE1 to T-PE2. When the MS-PW is placed from T-PE2 to T-PE1, the MS-PW is established in the reverse direction.

Autodiscovery and Dynamic Selection of S-PE

A new AFI and SAFI value is defined in BGP to support the MS-PWs based on type 2 AII. This new address family supports autodiscovery of S-PEs. This address family must be configured on both the TPEs and SPEs.

It is the responsibility of the Layer 2 VPN component to dynamically select the next S-PE to use along the MS-PW in the forwarding direction.

  • In the forwarding direction, the selection of the next S-PE is based on the BGP-AD route advertised by the BGP and pseudowire FEC information sent by the LDP. The BGP-AD route is initiated by the passive T-PE (T-PE2) in the reverse direction while the pseudowire FEC information is sent by LDP from the active T-PE (T-PE1) in the forwarding direction.

  • In the reverse direction, the next S-PE (S-PE2) or the active T-PE (T-PE1) is obtained by looking up the S-PE (S-PE1) that it used to set up the pseudowire in the forwarding direction.

Provisioning a T-PE

To support FEC 129 type 2 AII, the T-PE needs to configure its remote T-PE's IP address, a global ID, and an attachment circuit ID. Explicit paths where a set of S-PEs to use is explicitly specified on a T-PE is not supported. This eliminates the need to provision each S-PE with a type 2 AII.

Stitching an MS-PW

An S-PE performs the following MPLS label operations before forwarding the received label mapping message to the next S-PE:

  1. Pops the MPLS tunnel label.
  2. Pops the VC label.
  3. Pushes a new VC label.
  4. Pushes an MPLS tunnel label used for the next segment.

Establishing an MS-PW

After completing the necessary configuration, an MS-PW is established in the following manner:

  1. The SAII values are exchanged between T-PE1 and T-PE2 using BGP.

    T-PE1 assumes the active T-PE role, because it is configured with a higher SAII value. T-PE2 becomes the passive T-PE.

  2. T-PE1 receives the BGP-AD route originated by T-PE2. It compares the AII values obtained from T-PE2 in the received BGP-AD route against the AII values provisioned locally.
  3. If the AII values match, T-PE1 performs a BGP-AD route lookup to elect the first S-PE (S-PE1).
  4. T-PE1 sends an LDP label mapping message to S-PE1.
  5. Using the BGP-AD route originated from T-PE2, and the LDP label mapping message received from T-PE1, S-PE1 selects the next S-PE (S-PE2) in the forwarding direction.

    To do this, S-PE1 compares SAII obtained from the BGP-AD route against the TAI from the LDP label mapping message.

  6. If the AII values match, S-PE1 finds S-PE2 through the BGP next hop associated with the BGP-AD route.
  7. The process of selecting S-PE goes on until the last S-PE establishes a T-LDP session with T-PE2. When T-PE2 receives the LDP label mapping message from the last S-PE (S-PE2), it initiates its own label mapping message and sends it back to S-PE2.
  8. When all the label mapping messages are received on S-PE1 and S-PE2, the S-PEs install the stitching routes. Thus, when the MS-PW is established in the reverse direction, the S-PEs need not perform BGP-AD route lookup to determine its next hop as it did in the forwarding direction.

OAM Support for an MS-PW

After the MS-PW is established, the following OAM capabilities can be executed from the T-PE devices:

  • Ping

    • End-to-End Connectivity Verification Between T-PEs

      If T-PE1, S-PEs, and T-PE2 support Control Word (CW), the pseudowire control plane automatically negotiates the use of the CW. Virtual Circuit Connectivity Verification (VCCV) Control Channel (CC) Type 3 will function correctly whether or not the CW is enabled on the pseudowire. However, VCCV Type 1, which is used for end-to-end verification only, is only supported if the CW is enabled.

      The following is a sample:

      Ping from T-P1 to T-PE2

      user@T-PE1> ping mpls l2vpn fec129 instance instance-name local-id SAII of T-PE1 remote-pe-address address of T-PE2 remote-id TAII of T-PE2

      or

      user@T-PE1> ping mpls l2vpn fec129 interface CE1-facing interface
    • Partial Connectivity Verification from T-PE to Any S-PE

      To trace part of an MS-PW, the TTL of the pseudowire label can be used to force the VCCV message to pop out at an intermediate node. When the TTL expires, the S-PE can determine that the packet is a VCCV packet either by checking the CW or by checking for a valid IP header with UDP destination port 3502 (if the CW is not in use). The packet should then be diverted to VCCV processing.

      If T-PE1 sends a VCCV message with the TTL of the pseudowire label equal to 1, the TTL expires at the S-PE. T-PE1 can thus verify the first segment of the pseudowire.

      The VCCV packet is built according to RFC 4379. All the information necessary to build the VCCV LSP ping packet is collected by inspecting the S-PE TLVs. This use of the TTL is subject to the caution expressed in RFC 5085. If a penultimate LSR between S-PEs or between an S-PE and a T-PE manipulates the pseudowire label TTL, the VCCV message might not emerge from the MS-PW at the correct S-PE.

      The following is a sample:

      Ping from T-PE1 to S-PE

      user@T-PE1> ping mpls l2vpn fec129 interface CE1-facing interface bottom-label-ttl segment


      The bottom-label-ttl value is 1 for S-PE1 and 2 for S-PE2.

      The bottom-label-ttl statement sets the correct VC label TTL, so the packets are popped to the correct SS-PW for VCCV processing.

    Note

    Junos OS supports VCCV Type 1 and Type 3 for the MS-PW OAM capability. VCCV Type 2 is not supported.

  • Traceroute

    Traceroute tests each S-PE along the path of the MS-PW in a single operation similar to LSP trace. This operation is able to determine the actual data path of the MS-PW, and is used for dynamically signaled MS-PWs.

    user@T-PE1> traceroute mpls l2vpn fec129 interface CE1-facing interface
  • Bidirectional Forwarding Detection

    Bidirectional Forwarding Detection (BFD) is a detection protocol designed to provide fast forwarding path failure detection times for all media types, encapsulations, topologies, and routing protocols. In addition to fast forwarding path failure detection, BFD provides a consistent failure detection method for network administrators. The router or switch can be configured to log a system log (syslog) message when BFD goes down.

    user@T-PE1> show bfd session extensive

Configuration

Configuring an Interarea MS-PW

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.

T-PE1

P1

S-PE1 (RR 1)

S-PE2 (RR 2)

P2

T-PE2

Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode.

To configure T-PE1 in the interarea scenario:

Note

Repeat this procedure for the T-PE2 device in the MPLS domain, after modifying the appropriate interface names, addresses, and other parameters.

  1. Configure the T-PE1 interfaces.
  2. Set the autonomous system number.
  3. Enable MPLS on all the interfaces of T-PE1, excluding the management interface.
  4. Enable autodiscovery of intermediate S-PEs that make up the MS-PW using BGP.
  5. Configure the BGP group for T-PE1.
  6. Assign local and neighbor addresses to the mspw group for T-PE1 to peer with S-PE1.
  7. Configure OSPF on all the interfaces of T-PE1, excluding the management interface.
  8. Configure LDP on all the interfaces of T-PE1, excluding the management interface.
  9. Configure the Layer 2 VPN routing instance on T-PE1.
  10. Assign the interface name for the mspw routing instance.
  11. Configure the route distinguisher for the mspw routing instance.
  12. Configure the Layer 2 VPN ID community for FEC 129 MS-PW.
  13. Configure a VPN routing and forwarding (VRF) target for the mspw routing instance.
  14. Configure the source attachment identifier (SAI) value using Layer 2 VPN as the routing protocol for the mspw routing instance.
  15. Assign the interface name that connects the CE1 site to the VPN, and configure the target attachment identifier (TAI) value using Layer 2 VPN as the routing protocol for the mspw routing instance.
  16. (Optional) Configure T-PE1 to send MS-PW status TLVs.
  17. (Optional) Configure OAM capabilities for the VPN.

Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode.

To configure S-PE1 (RR 1) in the interarea scenario:

Note

Repeat this procedure for the S-PE2 (RR 2) device in the MPLS domain, after modifying the appropriate interface names, addresses, and other parameters.

  1. Configure the S-PE1 interfaces.
  2. Set the autonomous system number.
  3. Enable MPLS on all the interfaces of T-PE1, excluding the management interface.
  4. Enable autodiscovery of S-PE using BGP.
  5. Configure the BGP group for S-PE1.
  6. Configure S-PE1 to act as a route reflector.
  7. Assign local and neighbor addresses to the mspw group for S-PE1 to peer with T-PE1 and S-PE2.
  8. Configure OSPF on all the interfaces of S-PE1, excluding the management interface.
  9. Configure LDP on all the interfaces of S-PE1, excluding the management interface.
  10. Define the policy for enabling next-hop-self and accepting BGP traffic on S-PE1.

Results

From configuration mode, confirm your configuration by entering the show interfaces, show protocols, show routing-instances, show routing-options, and show policy-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.

T-PE1



S-PE1 (RR 1)

If you are done configuring the device, enter commit from configuration mode.

Configuring an Inter-AS MS-PW

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.

T-PE1

P1

S-PE1 (ASBR 1)

S-PE2 (ASBR 2)

P2

T-PE2

Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode.

To configure the T-PE1 router in the inter-AS scenario:

Note

Repeat this procedure for the T-PE2 device in the MPLS domain, after modifying the appropriate interface names, addresses, and other parameters.

  1. Configure the T-PE1 interfaces.
  2. Set the autonomous system number.
  3. Enable MPLS on all the interfaces of T-PE1, excluding the management interface.
  4. Enable autodiscovery of intermediate S-PEs that make up the MS-PW using BGP.
  5. Configure the BGP group for T-PE1.
  6. Assign local and neighbor addresses to the mspw group for T-PE1 to peer with S-PE1.
  7. Configure OSPF on all the interfaces of T-PE1, excluding the management interface.
  8. Configure LDP on all the interfaces of T-PE1, excluding the management interface.
  9. Configure the Layer 2 VPN routing instance on T-PE1.
  10. Assign the interface name for the mspw routing instance.
  11. Configure the route distinguisher for the mspw routing instance.
  12. Configure the Layer 2 VPN ID community for FEC 129 MS-PW.
  13. Configure a VPN routing and forwarding (VRF) target for the mspw routing instance.
  14. Configure the source attachment identifier (SAI) value using Layer 2 VPN as the routing protocol for the mspw routing instance.
  15. Assign the interface name that connects the CE1 site to the VPN, and configure the target attachment identifier (TAI) value using Layer 2 VPN as the routing protocol for the mspw routing instance.
  16. (Optional) Configure T-PE1 to send MS-PW status TLVs.
  17. (Optional) Configure OAM capabilities for the VPN.

Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode.

To configure S-PE1 (ASBR 1) in the inter-AS scenario:

Note

Repeat this procedure for the S-PE2 (ASBR 2) device in the MPLS domain, after modifying the appropriate interface names, addresses, and other parameters.

  1. Configure S-PE1 (ASBR 1) interfaces.
  2. Set the autonomous system number.
  3. Enable MPLS on all the interfaces of S-PE1 (ASBR 1), excluding the management interface.
  4. Enable autodiscovery of S-PE using BGP.
  5. Configure the IBGP group for S-PE1 (ASBR 1) to peer with T-PE1.
  6. Configure the IBGP group parameters.
  7. Configure the EBGP group for S-PE1 (ASBR 1) to peer with S-PE2 (ASBR 2).
  8. Configure the EBGP group parameters.
  9. Configure OSPF on all the interfaces of S-PE1 (ASBR 1), excluding the management interface.
  10. Configure LDP on all the interfaces of S-PE1 (ASBR 1), excluding the management interface.
  11. Define the policy for enabling next-hop-self on S-PE1 (ASBR 1).

Results

From configuration mode, confirm your configuration by entering the show interfaces, show protocols, show routing-instances, show routing-options, and show policy-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.

T-PE1



S-PE1 (RR 1)

If you are done configuring the device, enter commit from configuration mode.

Verification

Confirm that the configuration is working properly.

Verifying the Routes

Purpose

Verify that the expected routes are learned.

Action

From operational mode, run the show route command for the bgp.l2vpn.1, ldp.l2vpn.1, mpls.0, and ms-pw.l2vpn.1 routing tables.

From operational mode, run the show route table bgp.l2vpn.1 command.

user@T-PE1> show route table bgp.l2vpn.1

From operational mode, run the show route table ldp.l2vpn.1 command.

user@T-PE1> show route table ldp.l2vpn.1

From operational mode, run the show route table mpls.0 command.

user@T-PE1> show route table mpls.0

From operational mode, run the show route table ms-pw.l2vpn.1 command.

user@T-PE1> show route table ms-pw.l2vpn.1

Meaning

The output shows all the learned routes, including the autodiscovery (AD) routes.

The AD2 prefix format is RD:SAII-type2, where:

  • RD is the route distinguisher value.

  • SAII-type2 is the type 2 source attachment identifier value.

The PW2 prefix format is Neighbor_Addr:C:PWtype:l2vpn-id:SAII-type2:TAII-type2, where:

  • Neighbor_Addr is the loopback address of neighboring S-PE device.

  • C indicates if Control Word (CW) is enabled or not.

    • C is CtrlWord if CW is set.

    • C is NoCtrlWord if CW is not set.

  • PWtype indicates the type of the pseudowire.

    • PWtype is 4 if it is in Ethernet tagged mode.

    • PWtype is 5 if it is Ethernet only.

  • l2vpn-id is the Layer 2 VPN ID for the MS-PW routing instance.

  • SAII-type2 is the type 2 source attachment identifier value.

  • TAII-type2 is the type 2 target attachment identifier value.

Verifying the LDP Database

Purpose

Verify the MS-PW labels received by T-PE1 from S-PE1 and sent from T-PE1 to S-PE1.

Action

From operational mode, run the show ldp database command.

user@T-PE1> show ldp database

Meaning

The labels with FEC129 prefix are related to the MS-PW.

Checking the MS-PW Connections on T-PE1

Purpose

Make sure that all of the FEC 129 MS-PW connections come up correctly.

Action

From operational mode, run the show l2vpn connections extensive command.

user@T-PE1> show l2vpn connections extensive

Check the following fields in the output to verify that MS-PW is established between the T-PE devices:

  • Target-attachment-id—Check if the TAI value is the SAI value of T-PE2.

  • Remote PE—Check if the T-PE2 loopback address is listed.

  • Negotiated PW status TLV—Ensure that the value is Yes.

  • Pseudowire Switching Points—Check if the switching points are listed from S-PE1 to S-PE2 and from S-PE2 to T-PE2.

Meaning

MS-PW is established between T-PE1 and T-PE2 in the forwarding direction.

Checking the MS-PW Connections on S-PE1

Purpose

Make sure that all of the FEC 129 MS-PW connections come up correctly for the mspw routing instance.

Action

From operational mode, run the show l2vpn connections instance __MSPW__ extensive command.

user@S-PE1> show l2vpn connections instance __MSPW__ extensive

Check the following fields in the output to verify that MS-PW is established between the T-PE devices:

  • Target-attachment-id—Check if the TAI value is the SAI value of T-PE2.

  • Remote PE—Check if the T-PE1 and S-PE2 loopback addresses are listed.

  • Negotiated PW status TLV—Ensure that the value is Yes.

  • Pseudowire Switching Points—Check if the switching points are listed from S-PE2 to T-PE2.

Meaning

MS-PW is established between T-PE1 and T-PE2 in the forwarding direction.

Checking the MS-PW Connections on S-PE2

Purpose

Make sure that all of the FEC 129 MS-PW connections come up correctly for the mspw routing instance.

Action

From operational mode, run the show l2vpn connections instance __MSPW__ extensive command.

user@S-PE2> show l2vpn connections instance __MSPW__ extensive

Check the following fields in the output to verify that MS-PW is established between the T-PE devices:

  • Target-attachment-id—Check if the TAI value is the SAI value of T-PE1.

  • Remote PE—Check if the S-PE1 and T-PE2 loopback addresses are listed.

  • Negotiated PW status TLV—Ensure that the value is Yes.

  • Pseudowire Switching Points—Check if the switching points are listed from S-PE1 to T-PE1.

Meaning

MS-PW is established between T-PE1 and T-PE2 in the reverse direction.

Checking the MS-PW Connections on T-PE2

Purpose

Make sure that all of the FEC 129 MS-PW connections come up correctly.

Action

From operational mode, run the show l2vpn connections extensive command.

user@T-PE2> show l2vpn connections extensive

Check the following fields in the output to verify that MS-PW is established between the T-PE devices:

  • Target-attachment-id—Check if the TAI value is the SAI value of T-PE1.

  • Remote PE—Check if the T-PE1 loopback address is listed.

  • Negotiated PW status TLV—Ensure that the value is Yes.

  • Pseudowire Switching Points—Check if the switching points are listed from S-PE2 to S-PE1 and from S-PE1 to T-PE1.

Meaning

MS-PW is established between T-PE1 and T-PE2 in the reverse direction.

Troubleshooting

To troubleshoot the MS-PW connection, see:

Ping

Problem

How to check the connectivity between the T-PE devices and between a T-PE device and an intermediary device.

Solution

Verify that T-PE1 can ping T-PE2. The ping mpls l2vpn fec129 command accepts SAIs and TAIs as integers or IP addresses and also allows you to use the CE-facing interface instead of the other parameters (instance, local-id, remote-id, remote-pe-address).

Checking Connectivity Between T-PE1 and T-PE2

user@T-PE1> ping mpls l2vpn fec129 instance FEC129-VPWS local-id 800:800:800 remote-pe-address 10.255.14.1 remote-id 700:700:700
user@T-PE1> ping mpls l2vpn fec129 interface ge-3/1/2

Checking Connectivity Between T-PE1 and S-PE2

user@T-PE1> ping mpls l2vpn fec129 interface ge-3/1/2 bottom-label-ttl 2

Bidirectional Forwarding Detection

Problem

How to use BFD to troubleshoot the MS-PW connection from the T-PE device.

Solution

From operational mode, verify the show bfd session extensive command output.

user@T-PE1> show bfd session extensive

Traceroute

Problem

How to verify that MS-PW was established.

Solution

From operational mode, verify traceroute output.

user@T-PE1> traceroute mpls l2vpn fec129 interface interface