ssm-mapping query dns

Function

The ssm-mapping query dns command enables DNS-based SSM mapping.

The undo ssm-mapping query dns command disables DNS-based SSM mapping.

By default, DNS-based SSM mapping is disabled.

Format

ssm-mapping query dns

undo ssm-mapping query dns

Parameters

None

Views

IGMP view, VPN instance IGMP view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
igmp	write

Usage Guidelines

Usage Scenario

The static SSM mapping function requires the configuration of multicast source-group mappings on the multicast device that runs IGMPv3, so that the device can provide the SSM service for users using a lower IGMP version. However, this mode brings huge configuration workloads and cannot be flexibly changed.

To solve this problem, you can run the ssm-mapping query dns command to enable the DNS-based SSM mapping function so that the multicast device can provide the SSM service for users through SSM mappings provided by a DNS server.

Prerequisites

The igmp command has been used.

Example

# In the public network instance, enable DNS-based SSM mapping.

<HUAWEI> system-view
[~HUAWEI] multicast routing-enable
[*HUAWEI] igmp
[*HUAWEI-igmp] ssm-mapping query dns