The address prefix FF3x::/32 is reserved by IANA for SSM use. All SSM addresses must have P=1, T=1 and plen=0. RFC 3306 mandates that the network prefix is zero, which results in the SSM address range to be in FF3x::/96 range. Since future documents may allow a non-zero network prefix, this feature allows the addresses in range FF3x::/32 in SSM map configuration. The default SSM range is FF3x::/96.
SSM address range is configured from the PIM context using the following command:
configure pim ipv6 ssm range default | policy policy_name
When this command is issued, PIM notifies MCMGR with the details of the SSM address range. MCMGR applies this range for the MLD SSM feature.