Configuring Multicast Layer 3 VPNs
You can configure two types of multicast Layer 3 VPNs using the Junos OS:
- Draft Rosen multicast VPNs—Draft Rosen multicast VPNs are described in RFC 4364, BGP/MPLS IP Virtual Private Networks (VPNs) and based on Section Two of the IETF Internet draft draft-rosen-vpn-mcast-06.txt, Multicast in MPLS/BGP VPNs (expired April 2004).
- Next generation multicast VPNs—Next generation multicast VPNs are described in Internet drafts draft-ietf-l3vpn-2547bis-mcast-bgp-03.txt, BGP Encodings for Multicast in MPLS/BGP IP VPNs and draft-ietf-l3vpn-2547bis-mcast-02.txt, Multicast in MPLS/BGP IP VPNs.
This section describes how to configure draft Rosen multicast VPNs. This information is provided to you in case you already have dual PIM multicast VPNs configured on your network. For information about BGP MPLS multicast VPNs (also known as next generation multicast VPNs), see MBGP Multicast VPN Sites.
 | Note: Draft-rosen multicast VPNs are not supported in a logical system environment even though the configuration statements can be configured under the logical-systems hierarchy. |
You can configure a Layer 3 VPN to support multicast traffic using the Protocol Independent Multicast (PIM) routing protocol. To support multicast, you need to configure PIM on routers within the VPN and within the service provider’s network.
Each PE router configured to run multicast over Layer 3 VPNs must have a Tunnel Services PIC. A Tunnel Services PIC is also required on the P routers that act as rendezvous points (RPs). Tunnel Services PICs are also needed on all the CE routers acting as designated routers (first-hop/last-hop routers) or as RPs, just as they are in non-VPN PIM environments.
Configure the master PIM instance at the [edit protocols pim] hierarchy level on the CE and PE routers. This master PIM instance configuration on the PE router should match the configuration on the service providers core routers.
You also need to configure a PIM instance for the Layer 3 VPN at the [edit routing-instances routing-instance-name protocols pim] hierarchy level on the PE router. This creates a PIM instance for the indicated routing instance. The configuration of the PIM instance on the PE router should match the PIM instance configured on the CE router the PE router is connected to.
For information about how to configure PIM, see the Multicast Protocols Configuration Guide.
Include the vpn-apply-export statement to configure the group address designated for the VPN in the service provider’s network. This address must be unique for each VPN and configured on the VRF routing instance of all PE routers connecting to the same VPN. It ensures that multicast traffic is transmitted only to the specified VPN.
Include the vpn-apply-export statement:
For a list of hierarchy levels at which you can configure this statement, see the statement summary section for this statement.
You can include this statement at the following hierarchy levels:
- [edit routing-instances routing-instance-name protocols pim]
- [edit logical-systems logical-system-name routing-instances routing-instance-name protocols pim]
The rest of the Layer 3 VPN configuration for multicast is conventional and is described in other sections of this manual. Most of the specific configuration tasks needed to activate multicast in a VPN environment involve PIM. For more information about how to configure PIM and multicast in Junos, including an example of how to configure multicast over Layer 3 VPNs, see the Multicast Protocols Configuration Guide.
