Configuring Point-to-Multipoint LSPs for Multicast VPNs

The JUNOS software supports point-to-multipoint label-switched paths (LSPs) for multicast VPNs. Point-to-multipoint LSPs for multicast VPNs are supported for intra-autonomous system (AS) environments (within an AS), but are not supported for inter-AS environments (between ASs). A point-to-multipoint LSP is an RSVP-signaled LSP with a single source and multiple destinations. For more information about point-to-multipoint LSPs, see the JUNOS MPLS Applications Configuration Guide.

You can configure point-to-multipoint LSPs for multicast VPNs as follows:

• Static point-to-multipoint LSPs—Configure static point-to-multipoint LSPs using the standard MPLS LSP statements specified at the [edit protocols mpls] hierarchy level. You manually configure each of the leaf nodes for the point-to-multipoint LSP.
• Dynamic point-to-multipoint LSPs using the default template—Configuring dynamic point-to-multipoint LSPs using the default-template option causes the leaf nodes to be discovered automatically. The leaf nodes are discovered through BGP intra-AS automatic discovery. The default-template option allows you to minimize the amount of configuration needed; however, it does not allow you to configure any of the standard MPLS options.
• Dynamic point-to-multipoint LSPs using a user-configured template—Configuring dynamic point-to-multipoint LSPs using a user-configured template also causes the leaf nodes to be discovered automatically. By creating your own template for the point-to-multipoint LSPs, all of the standard MPLS features (such as bandwidth allocation and traffic engineering) can be configured.

Be aware of the following properties for the egress PE router in a point-to-multipoint LSP configured for a multicast VPN:

• Penultimate hop-popping is not used by point-to-multipoint LSPs for multicast VPNs. Only ultimate hop-popping is used.
• You must configure either the vrf-table-label statement or a virtual loopback tunnel interface on the egress PE router.
• If you configure the vrf-table-label statement on the egress PE router and the egress PE router is also a transit router for the point-to-multipoint LSP, the penultimate hop router sends two copies of each packet over the link to the egress PE router.
• If you configure the vrf-table-label statement on the egress PE router and the egress PE router is not a transit router for the point-to-multipoint LSP, the penultimate hop router can send just one copy of each packet over the link to the egress PE router.
• If you configure a virtual loopback tunnel interface on the egress PE router and the egress PE router is also a transit router for the point-to-multipoint LSP, the penultimate hop router sends just one copy of each packet over the link to the egress PE router. A virtual loopback tunnel interface can perform two lookups on an incoming packet, one for the multicast MPLS lookup and one for the IP lookup.

The following sections describe how to configure point-to-multipoint LSPs for multicast VPNs:

• Configuring Inclusive Point-to-Multipoint LSPs
• Configuring Selective Point-to-Multipoint LSPs

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