Configuring Multicast for Layer 3 VPNs
The configuration syntax for PIM in a Layer 3 instance is available at the [edit routing-instances protocols pim] hierarchy level. It is similar to the global PIM configuration syntax found at the [edit protocols pim] hierarchy level.
The only new configuration command is vpn-group-address. This command is configured for PIM within the routing instance and specifies the multicast group address for a particular VPN. Only one vpn-group-address can be configured per VPN, and this address should be unique on a per-VPN basis. To review how the VPN group address is used within GRE packet headers, see Stage 2: PIM Join message.
Keep in mind that each PE router will contain two entries of PIM: one for the routing instance that connects to the CE router, and a second for master instance of PIM that connects through the service provider network. The RP listed within the routing instance is known as a VPN-RP, while the RP in the master instance is an SP-RP. Additionally, you must configure a unique loopback interface for the routing instance at the [edit interfaces lo0 unit] hierarchy level and include the loopback interface in the PIM-enabled VPN routing instance. The following sample configuration shows a PE router with PIM enabled for sparse-dense mode in the VPN instance and PIM sparse mode in the master instance:
[edit]
interfaces {
lo0 {
unit 1 {
family inet {
address 10.1.1.1;
}
}
}
}
protocols {
pim {
rp {
static {
address 10.254.71.47;
}
}
interface all {
mode sparse;
version 2;
}
interface fxp0.0 {
disable;
}
}
}
routing-instances {
VPN-A {
.....
protocols {
.....
pim {
vpn-group-address 239.1.1.1;
rp {
static {
address 10.254.245.91;
}
}
interface t1-1/0/0:0.0 {
mode sparse-dense;
version 2;
}
interface lo0.1 {
mode sparse-dense;
version 2;
}
}
}
}
}
