Example: Configuring SSM Mapping

SSM mapping does not require that all hosts support IGMPv3. SSM mapping translates IGMPv1 or IGMPv2 membership reports to an IGMPv3 report. This enables hosts running IGMPv1 or IGMPv2 to participate in SSM until the hosts transition to IGMPv3.

SSM mapping applies to all group addresses that match the policy, not just those that conform to SSM addressing conventions (232/8 for IPv4, ff30::/32 through ff3F::/32 for IPv6).

We recommend separate SSM maps for IPv4 and IPv6 if both address families require SSM support. If you apply an SSM map containing both IPv4 and IPv6 addresses to an interface in an IPv4 context (using IGMP), only the IPv4 addresses in the list are used. If there are no such addresses, no action is taken. Similarly, if you apply an SSM map containing both IPv4 and IPv6 addresses to an interface in an IPv6 context (using MLD), only the IPv6 addresses in the list are used. If there are no such addresses, no action is taken.

In this example, you create a policy to match the group addresses that you want to translate to IGMPv3. Then you define the SSM map that associates the policy with the source addresses where these group addresses are found. Finally, you apply the SSM map to one or more IGMP (for IPv4) or MLD (for IPv6) interfaces.

1. Create an SSM policy named ssm-policy-example. The policy terms match the IPv4 SSM group address 232.1.1.1/32 and the IPv6 SSM group address ff35::1/128. All other addresses are rejected.

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   user@router1# set policy-options policy-statement ssm-policy-example term A from route-filter 232.1.1.1/32 exact
   user@router1# set policy-options policy-statement ssm-policy-example term A then accept
   user@router1# set policy-options policy-statement ssm-policy-example term B from route-filter ff35::1/128 exact
   user@router1# set policy-options policy-statement ssm-policy-example term B then accept
   

2. After the configuration is committed, use the show configuration policy-options command to verify the policy configuration.

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   user@host> show configuration policy-options
   

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   [edit policy-options]
   policy-statement ssm-policy-example {
       term A {
           from {
               route-filter 232.1.1.1/32 exact;
           }
           then accept;
       }
       term B {
           from {
               route-filter ff35::1/128 exact;
           }
           then accept;
       }
       then reject;
   }
   

   The group addresses must match the configured policy for SSM mapping to occur.

3. Define two SSM maps, one called ssm-map-ipv6-example and one called ssm-map-ipv4-example, by applying the policy and configuring the source addresses as a multicast routing option.

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   user@host# set routing-options multicast ssm-map ssm-map-ipv6-example policy ssm-policy-example
   user@host# set routing-options multicast ssm-map ssm-map-ipv6-example source fec0::1 fec0::12
   user@host# set routing-options multicast ssm-map ssm-map-ipv4-example policy ssm-policy-example
   user@host# set routing-options multicast ssm-map ssm-map-ipv4-example source 10.10.10.4
   user@host# set routing-options multicast ssm-map ssm-map-ipv4-example source 192.168.43.66
   

4. After the configuration is committed, use the show configuration routing-options command to verify the policy configuration.

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   user@host> show configuration routing-options
   

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   [edit routing-options]
   multicast {
       ssm-map ssm-map-ipv6-example {
           policy ssm-policy-example;
           source [ fec0::1 fec0::12 ];
       }
       ssm-map ssm-map-ipv4-example {
           policy ssm-policy-example;
           source [ 10.10.10.4 192.168.43.66 ];
       }
   }
   

   We recommend separate SSM maps for IPv4 and IPv6.

5. Apply SSM maps for IPv4-to-IGMP interfaces and SSM maps for IPv6-to-MLD interfaces:

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   user@host# set protocols igmp interface fe-0/1/0.0 ssm-map ssm-map-ipv4-example
   user@host# set protocols mld interface fe-0/1/1.0 ssm-map ssm-map-ipv6-example
   

6. After the configuration is committed, use the show configuration protocol command to verify the IGMP and MLD protocol configuration.

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   user@router1> show configuration protocol
   

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   [edit protocols]
   igmp {
       interface fe-0/1/0.0 {
           ssm-map ssm-map-ipv4-example;
       }
   }
   mld {
       interface fe-/0/1/1.0 {
           ssm-map ssm-map-ipv6-example;
       }
   }
   

7. Use the show igmp interface and the show mld interface commands to verify that the SSM maps are applied to the interfaces.

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   user@host> show igmp interface fe-0/1/0.0
   Interface: fe-0/1/0.0
        Querier: 192.168.224.28
        State:         Up Timeout:    None Version:   2 Groups:   2 
        SSM Map: ssm-map-ipv4-example
   

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   user@host> show mld interface fe-0/1/1.0
   Interface: fe-0/1/1.0
        Querier: fec0:0:0:0:1::12
        State:         Up Timeout:    None Version:   2 Groups:   2 
        SSM Map: ssm-map-ipv6-example