# Configuring PIM SSM

Source Specific Multicast (SSM) is a datagram delivery model that best supports one-to-many applications, also known as broadcast applications. SSM is networking technology that targets audio and video broadcast application environments.

To use PIM SSM, MLDv2 must be configured on customer premises equipment (CPE)–facing interfaces to receivers, and PIM sparse mode must be configured on CPE-facing interfaces to sources and on core-facing interfaces. After configuring SSM, you can use the show ipv6 pim sparse-mode sg-state command to display SSM group membership information.

To configure PIM SSM, you enable PIM SSM on the router and define the SSM range of IP multicast addresses.

Figure 22 shows how PIM SSM is configured between a receiver and a source in the network. Interface 1 has MLDv2 enabled and all other interfaces towards the core or source have PIM SSM enabled.

Figure 22: Network on Which to Configure PIM SSM

To configure PIM SSM:

1. Enable PIM SSM on the E Series router. The IANA SSM range is configured by default. You can modify the SSM address range by using the access list.
   host1(config)#access-list 15 permit ip any host 239.0.0.2 host1(config)#access-list 15 permit ip any 232.0.0.0 0.225.225.225 host1(config)#ipv6 pim ssm range 15
2. Enable PIM sparse mode on the CPE-facing interface towards the source or core.
3. Enable MLDv2 on the CPE-facing interface towards the receiver.

PIM SSM also works with MLDv1 if you configure the ssm-map in MLD as in the following example:

host1(config)#ipv6 pim ssm host1(config)#ipv6 access-list ssm_map1 permit any host ff3e::1 host1(config)#ipv6 mld ssm-map enable host1(config)#ipv6 mld ssm-map static ssm_map1 51::1

The no version disables ssm-map:

host1(config)#no ipv6 mld ssm-map static ssm_map1 51::1

ipv6 pim ssm

- Use to enable PIM SSM and define the SSM range of IPv6 multicast addresses.
- Example 1—Enables SSM with addresses in the IANA range. The SSM address range is set as the default, which is limited to the IPv6 address range, and where x represents any valid scope.
  host1(config)#ipv6 pim ssm FF3 x ::/96
- Example 2—Configures Class D addresses outside of the default SSM range.
  host1(config)#ipv6 access-list alist permit any ff3e::1:0:0/96 host1(config)#ipv6 pim ssm range alist
- Example 3—Resets the SSM address range to the default.
  host1(config)#ipv6 pim ssm default
- Use the no version to disable SSM.
- See ipv6 pim ssm.