The following CLI options under the existing ldp command advertise an MLDP P2MP FEC to an upstream node using a T-LDP session. See the Classic CLI Command Reference Guide for command details.
configure router ldp prefer-mcast-tunnel-in-tunnel
configure router ldp targeted-session peer mcast-tunneling
The following apply when LDP mcast-tunneling is enabled on the ELER (downstream) and prefer-mcast-tunnel-in-tunnel and LDP mcast-tunneling are enabled on ILER (upstream):
On the upstream router, LDP resolves the nexthop using TTM using a P2P RSVP-TE LSP.
As shown in Figure: Configuring MLDP over RSVP P2P LSP, when the LSR 100.0.0.102 and LSR 100.0.0.101 nodes are directly connected, the T-LDP and link-LDP adjacencies share a common LDP session. The P2MP FEC is advertised over the LDP session and is received by LSR 100.0.0.102, which resolves it over the RSVP LSP if the mcast-tunneling option is enabled. The prefer-mcast-tunnel-in-tunnel option in LDP dictates if the MLDP FEC is resolved in preference to the tunnel or to the link.
Figure: Configuring MLDP over RSVP P2P LSP