local-mt enable

Function

The local-mt enable command enables IS-IS local MT.

The undo local-mt enable command disables IS-IS local MT.

By default, IS-IS local MT is not enabled.

Format

local-mt enable

undo local-mt enable

Parameters

None

Views

IS-IS view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
isis	write

Usage Guidelines

Usage Scenario

When multicast and an IGP Shortcut-enabled MPLS TE tunnel are configured on a network, the outbound interface of the route calculated by IS-IS may not be a physical interface but a TE tunnel interface. Multicast Join packets are transmitted over the tunnel, but these packets are transparent to routers through which the TE tunnel passes. Therefore, these routers cannot generate multicast forwarding entries.

Since the TE tunnel is unidirectional, multicast data packets from the multicast source are sent to a physical interface of routers through which the TE tunnel passes. These routers discard these packets because they have no multicast forwarding entry. As a result, services are interrupted.

To resolve this problem, enable local MT. If the outbound interface of a calculated route is an IGP Shortcut-enabled TE tunnel interface, the routing management (RM) module creates an independent Multicast IGP (MIGP) routing table. Multicast packets are then forwarded along the routes in the MIGP routing table.

Prerequisites

The IS-IS route cost type has been set to wide, wide-compatible, or compatible using the cost-style command, and the IS-IS TE tunnel function has been enabled using the traffic-eng command.

Example

# Enable IS-IS local MT.

<HUAWEI> system-view
[~HUAWEI] isis 1
[*HUAWEI-isis-1] cost-style compatible
[*HUAWEI-isis-1] traffic-eng
[*HUAWEI-isis-1] local-mt enable