Label Switched Multicast (LSM) Multicast Label Distribution Protocol (mLDP) based Multicast VPN (mVPN) Support
multicast VPN Routing and Forwarding (mVRF) on the receiver Provider Edge (PE) router or configure the
receiver mVRF on the source PE. MLDP MVPN is supported for both intranet and extranet.
Figure 10: MLDP based MPLS Network
P2MP and MP2MP Label Switched Paths
mLDP is an application that sets up Multipoint Label Switched Paths (MP LSPs) in MPLS networks without
requiring multicast routing protocols in the MPLS core. mLDP constructs the P2MP or MP2MP LSPs without
interacting with or relying upon any other multicast tree construction protocol. Using LDP extensions for MP
LSPs and Unicast IP routing, mLDP can setup MP LSPs. The two types of MP LSPs that can be setup are
Point-to-Multipoint (P2MP) and Multipoint-to-Multipoint (MP2MP) type LSPs.
A P2MP LSP allows traffic from a single root (ingress node) to be delivered to a number of leaves (egress
nodes), where each P2MP tree is uniquely identified with a 2-tuple (root node address, P2MP LSP identifier).
A P2MP LSP consists of a single root node, zero or more transit nodes, and one or more leaf nodes, where
typically root and leaf nodes are PEs and transit nodes are P routers. A P2MP LSP setup is receiver-driven
and is signaled using mLDP P2MP FEC, where LSP identifier is represented by the MP Opaque Value element.
MP Opaque Value carries information that is known to ingress LSRs and Leaf LSRs, but need not be interpreted
by transit LSRs. There can be several MP LSPs rooted at a given ingress node, each with its own identifier.
A MP2MP LSP allows traffic from multiple ingress nodes to be delivered to multiple egress nodes, where a
MP2MP tree is uniquely identified with a 2-tuple (root node address, MP2MP LSP identifier). For a MP2MP
LSP, all egress nodes, except the sending node, receive a packet sent from an ingress node.
A MP2MP LSP is similar to a P2MP LSP, but each leaf node acts as both an ingress and egress node. To
build an MP2MP LSP, you can setup a downstream path and an upstream path so that:
• Downstream path is setup just like a normal P2MP LSP
• Upstream path is setup like a P2P LSP towards the upstream router, but inherits the downstream labels
from the downstream P2MP LSP.
Cisco ASR 9000 Series Aggregation Services Router Multicast Configuration Guide, Release 6.0.x
Implementing Layer-3 Multicast Routing on Cisco IOS XR Software