Configuring IPv6 SSM Mapping
Some hosts can run only MLDv1. To enable such hosts to obtain the MLDv2 service, configure SSM mapping.
Context
Compared to the traditional any-source multicast (ASM) technology, source-specific multicast (SSM) can conserve multicast addresses and has higher security, but MLDv2 only supports SSM. The majority of the latest multicast devices support MLDv2, but most legacy multicast terminals only support MLDv1 and hope to enjoy the MLDv2 multicast service. SSM mapping enables the compatibility in the SSM range by supporting hosts running MLDv1.
SSM mapping enables a Layer 2 device to map (*, G) information in MLDv1 data messages to (S, G) information in MLDv2 data messages. This allows hosts running MLDv1 to receive multicast data from an upstream Layer 3 device running MLDv2.
If a user joins a multicast group in the ASM range but wants to enjoy the SSM service of the multicast group, add the multicast group address to an SSM policy, and then configure SSM mapping.
Procedure
- Run system-view
The system view is displayed.
- Run acl { number basic-acl-number | name acl-name }
The ACL view is displayed.
- Run rule permit source source-ipv6-address source-wildcard
A basic ACL rule is configured.
- (Optional) Run rule deny source any
The device is configured to process other multicast group addresses as ASM ones.
Set permit in the rule command. Otherwise, the SSM group range configuration does not take effect. If you set deny or the specified address is not a multicast address, the configuration does not take effect either.
- Run quit
Return to the system view.
- Perform either of the following operations based on the VLAN or VPLS networking scenario:
- Run mld-snooping enable
MLD snooping is enabled for the VLAN/VSI.
- Run mld-snooping version 2
MLDv2 is set as the version of MLD snooping.
- Run mld-snooping ssm-policy { basic-acl6-number | acl6-name acl6-name }
The specified multicast address is added to the SSM group address range.
- Run mld-snooping ssm-mapping enable policy policy-name
SSM mapping is enabled for the VLAN/VSI.
- Run mld-snooping ssm-mapping ip-group-address { ip-group-mask | mask-length } ip-source-address
The multicast address in the specified range is mapped to a specified source address.
The specified multicast address is in the SSM address range.
- Run commit
The configuration is committed.