multicast rpf multi-topology

Function

The multicast rpf multi-topology command enables multicast services to run in a specified multicast topology instance.

The undo multicast rpf multi-topology command disables multicast services from running in a multicast topology instance.

By default, multicast services do not run in a specified multicast topology instance.

Format

multicast rpf multi-topology

undo multicast rpf multi-topology

Parameters

None

Views

System view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
mcast-base	write

Usage Guidelines

Usage Scenario

With multicast multi-topologies, multicast services can run in a specified topology, which isolates multicast services from unicast services and eliminates the configuration conflict when both multicast services and unidirectional Traffic Engineering (TE) tunnel services are deployed.

Multicast services are isolated from unicast services.
On the current network, multicast services highly depend on unicast routes. During multicast routing, a router searches a unicast routing table for an optimal route. If the unicast optimal route, shared by both multicast services and unicast services, is faulty, the multicast services and unicast services will be interrupted and users fail to receive the multicast data.
With multicast multi-topologies, multicast services can run in a specified topology, which isolates multicast services from unicast services.
Multicast services are isolated from unidirectional TE tunnel services.
With both multicast services and unidirectional TE tunnel services deployed, if a unidirectional TE tunnel interface is chosen during multicast routing, the multicast data fails to pass the reverse path forwarding (RPF) check. A local multicast-topology (MT) feature can address this problem. However, in this situation, a separate Multicast Interior Gateway Protocol (MIGP) routing table has to be maintained, which consumes network resources.
With multicast multi-topologies, the system searches routes only in the unicast routing table, the static multicast routing table, and the Multicast Border Gateway Protocol (MBGP) routing table specified by the multicast topology. These routing tables contain no unidirectional TE tunnel interface, avoiding the problem that multicast data fails to pass the RPF check when a unidirectional TE tunnel interface is chosen. In addition, no separate MIGP routing table has to be maintained, so network resources can be properly planned.

Prerequisites

Global IPv4 multicast topology instance has been enabled.

Precautions

Multicast services can run in multicast multi-topologies in the public network instance.

Multicast topology instances support direct routes, static routes, IS-IS routes, and MBGP routes.

Example

# Enable multicast multi-topologies in the system view and enter the multicast multi-topology view of the public network instance.

<HUAWEI> system-view
[~HUAWEI] multicast routing-enable
[*HUAWEI] ip topology multicast
[*HUAWEI] multicast rpf multi-topology