igmp-snooping ssm-mapping

Function

The igmp-snooping ssm-mapping command configures the mapping between a multicast group and a multicast source in a VLAN.

The undo igmp-snooping ssm-mapping command deletes the mapping between a multicast group and a multicast source in a VLAN.

By default, no mappings between multicast groups and multicast sources exist in a VLAN.

Format

igmp-snooping ssm-mapping group-address { group-mask | mask-length } source-address

undo igmp-snooping ssm-mapping group-address { group-mask | mask-length } source-address

Parameters

Parameter	Description	Value
group-address	Specifies the IP address of a multicast group.	The value is in dotted decimal notation, and the value range is specified by the igmp-snooping ssm-policy command.
group-mask	Specifies the mask of the multicast group address.	The value is in dotted decimal notation.
mask-length	Specifies the mask length of the multicast group address.	The value is an integer that ranges from 4 to 32.
source-address	Specifies the IP address of the multicast source mapped to a multicast group.	The value is in dotted decimal notation.

Views

VLAN view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

The SSM mapping mechanism converts IGMPv1 and IGMPv2 Report messages into messages with (S, G) information. This mechanism enables hosts that do not support IGMPv3 to work with SSM. To use this mechanism, enable SSM mapping and configure mappings between a multicast group G and multicast sources such as S1, S2 on the Layer 2 device connected to user hosts. When the Layer 2 device receives IGMPv1 and IGMPv2 Report messages for a multicast group, it checks the group address of the messages. If the group address is in the SSM group range, the Layer 2 device converts the messages into one or more IGMPv3 IS_IN (S1, S2...) messages with the group address G.

Prerequisites

IGMP snooping has been enabled globally using the igmp-snooping enable (system view) command.

Precautions

Before configuring the mapping between a multicast group and a multicast source:

IGMP snooping has been enabled in the specified VLAN using the igmp-snooping enable (VLAN view) command.
The IGMP message version is set to IGMPv3 using the igmp-snooping version command in the VLAN.
SSM mapping has been enabled using the igmp-snooping ssm-mapping enable command.
An SSM group policy has been configured using the igmp-snooping ssm-policy command in the VLAN to add the multicast group address to the SSM group range. This prerequisite is required when the multicast group address is an any-source multicast (ASM) address.

Example

# Map multicast groups 238.1.1.1 through 238.1.1.255 to multicast source 10.1.1.1 in VLAN 10.

<HUAWEI> system-view
[HUAWEI] igmp-snooping enable
[HUAWEI] vlan 10
[HUAWEI-vlan10] igmp-snooping enable
[HUAWEI-vlan10] igmp-snooping version 3
[HUAWEI-vlan10] igmp-snooping ssm-mapping enable
[HUAWEI-vlan10] igmp-snooping ssm-mapping 238.1.1.0 24 10.1.1.1