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Configuring Interoperability Between BGP Signaling and LDP Signaling in VPLS

A single VPLS routing instance can encompass one set of PE routers that use BGP for signaling and another set of PE routers that use LDP for signaling. Within each set, all of the PE routers are fully meshed in both the control and data planes and have a bidirectional pseudowire to each of the other routers in the set. However, the BGP-signaled routers cannot be directly connected to the LDP-signaled routers. To be able to manage the two separate sets of PE routers in a single VPLS routing instance, a border PE router must be configured to interconnect the two sets of routers.

The VPLS RFCs and Internet drafts require that all of the PE routers participating in a single VPLS routing instance must be fully meshed in the data plane. In the control plane, each fully meshed set of PE routers in a VPLS routing instance is called a PE router mesh group. The border PE router must be reachable by and have bidirectional pseudowires to all of the PE routers that are a part of the VPLS routing instance, both the LDP-signaled and BGP-signaled routers.

Note:

In the VPLS documentation, the word router in terms such as PE router is used to refer to any device that provides routing functions.

For LDP BGP interworking to function, LDP-signaled routers can be configured with forwarding equivalence class (FEC) 128 or FEC 129.

The following sections describe how to configure BGP LDP interworking for VPLS:

LDP BGP Interworking Platform Support

LDP BGP interworking is supported on the following Juniper Networks routers and routing platforms:

  • ACX5048

  • ACX5096

  • M7i

  • M10i

  • M40e

  • M120

  • M320

  • MX Series routers

  • T Series routers

  • TX Matrix routers

  • EX Series switches

Configuring FEC 128 VPLS Mesh Groups for LDP BGP Interworking

To configure FEC 128 LDP BGP interworking for VPLS, include the mesh-group statement in the VPLS routing instance configuration of the PE border router:

You can include this statement at the following hierarchy levels:

  • [edit routing-instances routing-instance-name protocols vpls]

  • [edit logical-systems logical-system-name routing-instances routing-instance-name protocols vpls]

Using the neighbor statement, configure each PE router that is a part of the mesh group. You must separate the LDP-signaled routers and the BGP-signaled routers into their own respective mesh groups. The LDP-signaled routers can be divided into multiple mesh groups. The BGP-signaled routers must be configured within a single mesh group for each routing instance.

Configuring FEC 129 VPLS Mesh Groups for LDP BGP Interworking

Configuration for a mesh group for FEC 129 is very similiar to the configuration for FEC 128.

Note the following differences for FEC 129:

  • Each user-defined mesh group must have a unique route distinguisher. Do not use the route distinguisher that is defined for the default mesh group at the [edit routing-intances] hierarchy level.

  • Each user-defined mesh group must have its own import and export route target.

  • Each user-defined mesh group can have a unique Layer 2 VPN ID. By default, all the mesh groups that are configured for the a VPLS routing-instance use the same Layer 2 VPN ID, the one that you configure at the [edit routing-instances] hierarchy level.

Configuring Switching Between Pseudowires Using VPLS Mesh Groups

To configure switching between Layer 2 circuit pseudowires using VPLS mesh groups, you can do either of the following:

  • Configure a mesh group for each Layer 2 circuit pseudowire terminating at a VPLS routing instance. The Junos OS can support up to 16 mesh groups on MX Series routers and up to 128 on M Series and T Series routers. However, two mesh groups are created by default, one for the CE routers and one for the PE routers. Therefore, the maximum number of user-defined mesh groups is 14 for MX Series routers and 126 for M Series and T Series routers.

  • Configure a single mesh group, terminate all the Layer 2 circuit pseudowires into it, and enable local switching between the pseudowires by including the local-switching statement at the [edit routing-instances routing-instance-name protocols vpls mesh-group mesh-group-name] hierarchy level. By default, you cannot configure local switching for mesh groups (except for the CE mesh group) because all of the VPLS PE routers must be configured in a full mesh. However, local switching is useful if you are terminating Layer 2 circuit pseudowires in a mesh group configured for an LDP signaled VPLS routing instance.

Note:

Do not include the local-switching statement on PE routers configured in a full mesh VPLS network.

To terminate multiple pseudowires at a single VPLS mesh group, include the local-switching statement:

You can include this statement at the following hierarchy levels:

  • [edit routing-instances routing-instance-name protocols vpls mesh-group mesh-group-name]

  • [edit logical-systems logical-system-name routing-instances routing-instance-name protocols vpls mesh-group mesh-group-name]

Configuring Integrated Routing and Bridging Support for LDP BGP Interworking with VPLS

Beginning with Junos OS Release 9.4, you can configure an integrated routing and bridging (IRB) interface on a router that functions as an autonomous system border router (ASBR) in an inter-AS VPLS environment between BGP-signaled VPLS and LDP-signaled VPLS. Previously, IRB interfaces were supported only on Provider Edge (PE) routers.

Note:

ACX Series routers do not support configuring IRB for LDP BGP Interworking with VPLS.

To configure a IRB support for LDP BGP Interworking with VPLS, include the routing-interface interface-name statement.

You can include this statement at the following hierarchy levels:

Configuring Inter-AS VPLS with MAC Processing at the ASBR

Inter-AS VPLS with MAC processing at the ASBR enables you to interconnect customer sites that are located in different ASs. In addition, you can configure the ASs with different signaling protocols. You can configure one of the ASs with BGP-signaled VPLS and the other with LDP-signaled VPLS. For more information about how to configure LDP-signaled and BGP signaled VPLS, see Configuring Interoperability Between BGP Signaling and LDP Signaling in VPLS.

For inter-AS VPLS to function properly, you need to configure IBGP peering between the PE routers, including the ASBRs in each AS, just as you do for a typical VPLS configuration. You also need to configure EBGP peering between the ASBRs in the separate ASs. The EBGP peering is needed between the ASBRs only. The link between the ASBR routers does not have to be Ethernet. You can also connect a CE router directly to one of the ASBRs, meaning you do not have to have a PE router between the ASBR and the CE router.

The configuration for the connection between the ASBRs makes inter-AS VPLS with MAC operations unique. The other elements of the configuration are described in other sections of this manual.

The following sections describe how to configure inter-AS VPLS with MAC operations:

Inter-AS VPLS with MAC Operations Configuration Summary

This section provides a summary of all of the elements which must be configured to enable inter-AS VPLS with MAC operations. These procedures are described in detail later in this chapter and in other parts of theJunos OS VPNs Library for Routing Devices.

The following lists all of major elements of an inter-AS VPLS with MAC operations configuration:

  • Configure IBGP between all of the routers within each AS, including the ASBRs.

  • Configure EBGP between the ASBRs in the separated ASs. The EBGP configuration includes the configuration that interconnects the ASs.

  • Configure a full mesh of LSPs between the ASBRs.

  • Configure a VPLS routing instance encompassing the ASBR routers. The ASBRs are VPLS peers and are linked by a single pseudowire. Multihoming between ASs is not supported. A full mesh of pseudowires is needed between the ASBR routers in all of the interconnected ASs.

  • Configure the VPLS routing instances using either BGP signaling or LDP signaling. LDP BGP interworking is supported for inter-AS VPLS with MAC operations, so it is possible to interconnect the BGP-signaled VPLS routing instances with the LDP-signaled VPLS routing instances.

  • Configure a single VPLS mesh group for all of the ASBRs interconnected using inter-AS VPLS.

Configuring the ASBRs for Inter-AS VPLS

This section describes the configuration on the ASBRs needed to enable inter-AS VPLS with MAC operations.

On each ASBR, you need to configure a VPLS mesh group within the VPLS routing instance which needs to include all of the PE routers within the AS, in addition to the ASBR. You need to configure the same mesh group for each of the ASs you want to interconnect using inter-AS VPLS. The mesh group name should be identical on each AS. You also must include the peer-as all statement. This statement enables the router to establish a single pseudowire to each of the other ASBRs.

To configure the mesh group on each ASBR, include the mesh-group and peer-as all statements:

You can include these statements at the following hierarchy levels:

  • [edit routing-instances routing-instance-name protocols vpls]

  • [edit logical-systems logical-system-name routing-instances routing-instance-name protocols vpls]

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