Configuring an mLDP P2MP Tunnel

The mLDP P2MP LSP transmits multicast services over an IP/MPLS backbone network, which simplifies network deployment and efficiently uses network bandwidth resources.

Usage Scenario

Conventional core and backbone networks run IP/MPLS to transmit unicast packets and provide high reliability and traffic engineering (TE) capabilities. The proliferation of applications, such as IPTV, video conference, and massively multiplayer online role-playing games (MMORPGs), amplifies demands on multicast transmission over IP/MPLS networks. The existing P2P MPLS technology requires a transmit end to deliver the same data packet to each receive end, which wastes bandwidth resources.

To address this problem, configure an mLDP P2MP LSP. A tree-shaped mLDP P2MP LSP consists of sub-LSPs originating from the root node (ingress) and destined for leaf nodes. The root node directs multicast traffic to the P2MP LSP and sends packets to a branch node for replication. The branch node replicates the packets and forwards them to each leaf node connected to the branch node.

mLDP P2MP tunnels can be manually or automatically established. Table 1 compares the manual P2MP tunnels with the automatic P2MP tunnels.

**Table 1** Comparison between manual and automatic P2MP tunnels
Item	Manual P2MP Tunnel	Automatic P2MP Tunnel
Trigger method	Manually triggered by users	Automatically triggered by services
Usage scenario	Multicast services, excluding multicast VPN, are transmitted.	NG MVPN or multicast VPLS services are transmitted.
Traffic import method	QoS redirection is used to statically direct traffic to LSPs.	Services are automatically directed to LSPs.

Pre-configuration Tasks

Before configuring an mLDP P2MP LSP, complete the following tasks:

Configure network layer parameters to implement connectivity.
Configure MPLS LDP on each node to establish an LDP session.

mLDP P2MP tunnels can only be established in DU mode.

Configuring a Manual mLDP P2MP Tunnel: A manual mLDP P2MP tunnel can be manually triggered and transmit multicast services, excluding multicast VPN services.

Configuring an Automatic mLDP P2MP Tunnel: Automatic mLDP P2MP tunnels can only transmit NG MVPN and multicast VPLS traffic.

(Optional) Configuring the Reliability Enhancement Function for a P2MP Tunnel: Configure a function to improve service reliability as needed.

(Optional) Enabling the Capability of Establishing a Best-Effort Path for an mLDP P2MP Tunnel: The capability of establishing a best-effort path for an mLDP P2MP tunnel can be enabled to resolve a fault of a link to an interface, which helps speed up route convergence and reduce traffic loss.

(Optional) Configuring a Timer for mLDP P2MP Tunnel Re-optimization: A timer can be set so that mLDP P2MP tunnel re-optimization is triggered at the specified time if the network topology changes.

Verifying the Configuration of mLDP P2MP LSP: After configuring an mLDP P2MP LSP, verify mLDP P2MP LSP information on each node along the LSP and mLDP P2MP LSP connectivity on the root node (ingress).