8. Source-Specific Multicast Block (232/8)

SSM [RFC4607] is an extension of IP Multicast in which traffic is forwarded to receivers from only those multicast sources for which the receivers have explicitly expressed interest and is primarily targeted at one-to-many (broadcast) applications. Note that this block was initially assigned to the Versatile Message Transaction Protocol (VMTP) transient groups [IANA].

8.1. Assignment Guidelines

Because the SSM model essentially makes the entire multicast address space local to the host, no IANA assignment policy is required. Note, however, that while no additional IANA assignment is required, addresses in the Source-Specific Multicast Block are explicitly for use by SSM and MUST NOT be used for other purposes.