Configuring IGMPv2 SSM Mapping

The ip ssm-map command is used to enable the IGMPv2 mapping feature and to define the maps between IGMPv2 group addresses and multicast source addresses.

For standard ACLs, you must create an ACL with a permit clause and the ip-source-address variable must contain the group multicast address. This can be configured directly with a subnet mask or with the host keyword in which case a subnet mask of all zeros (0.0.0.0) is implied.

For extended ACLs, the ip-source-address variable must contain either 0.0.0.0 or the any keyword. Additionally, the extended ACL must be configured with a permit clause and the host keyword. This can be configured directly with a subnet mask or with the host keyword in which case a subnet mask of all zeros (0.0.0.0) is implied.

  1. Enter global configuration mode. 
    device# configure terminal
  2. Create a standard access-list with a permit statement for the group multicast address: 239.1.1.1 by including the host keyword. 
    device(config)# ip access-list standard 20 
device(config-std-ipacl-20)# permit host 239.1.1.1
  3. Create a permit statement in the same standard access-list for the group multicast address: 224.1.1.0 with a subnet mask of 0.0.0.255. 
    device(config-std-ipacl-20)# permit 224.1.1.0 0.0.0.225
device(config-std-ipacl-20)# exit
  4. Create an extended access-list for the group multicast address: 232.1.1.1 with a subnet mask of 0.0.0.255. 
    device(config)# ip access-list extended 100 
device(config-ext-ipacl-100)# permit ip any host 232.1.1.1
  5. Enable the IGMPv2 mapping feature, using the ip igmp ssm-map command. 
    device(config)# ip igmp ssm-map enable
  6. Configure a map between an IGMPv2 group address and a multicast source address using the ip igmp ssm-map static command. 
    device(config)# ip igmp ssm-map 20 1.1.1.1
    Repeat this step to map all the IGMPv2 group addresses and a multicast source address. The configuration example that follows this task displays other SSM mapping examples.

In the following example configuration, an extended ACL and a standard ACLs are defined with group multicast addresses. The ip igmp ssm-map commands are configured to map the ACLs to source addresses and to enable the feature on the router. 

device# configure terminal
device(config)# ip access-list standard 20 
device(config-std-ipacl-20)# permit host 239.1.1.1
device(config-std-ipacl-20)# permit 224.1.1.0 0.0.0.225
device(config-std-ipacl-20)# exit
device(config)# ip access-list extended 100 
device(config-ext-ipacl-100)# permit ip any host 232.1.1.1
device(config)# ip igmp ssm-map 20 1.1.1.1
device(config)# ip igmp ssm-map 20 2.2.2.2
device(config)# ip igmp ssm-map 100 1.1.1.1
device(config)# ip igmp ssm-map enable
Parent topic: IGMPv2 SSM Mapping