RFC 3307 (rfc3307) - Page 3 of 8

Allocation Guidelines for IPv6 Multicast Addresses

RFC 3307          IPv6 Multicast Addresses Guidelines        August 2002


   bits (henceforth called the group ID) of the IPv6 multicast address
   and including them in the link-layer destination address.  Group IDs,
   less than or equal to, 32 bits long will generate unique link-layer
   addresses within a given multicast scope.

   These guidelines specify how the group ID of the IPv6 multicast
   address are chosen and assigned.  The guidelines specify several
   mechanisms that can be used to determine the group ID of the
   multicast address, based on the type of allocation being done.

3. Applicability

   These guidelines are designed to be used in any environment in which
   IPv6 multicast addresses are delegated, assigned, or selected.  These
   guidelines are not limited to use by MADCAP [RFC 2730] servers.  The
   following is a non-exhaustive list of applications of these
   guidelines:

      -  Source-specific multicast application servers can generate an
         SSM group address by generating a 96-bit multicast prefix, as
         defined in [UNIMCAST] (i.e. FF3x::/96) and concatenating that
         with a group ID, as defined in this document.

      -  A MADCAP server allocates IPv6 multicast addresses conforming
         to section 2.7 of [ADDRARCH], creating the group ID using the
         rules defined in this document.

      -  Nodes supplying multicast services in a zeroconf environment
         generate multicast addresses without the need of centralized
         control.

      -  IANA can assign permanent multicast addresses to fulfill
         requests via the protocol standardization process.

4. Group ID Selection Guidelines

   The Group ID selection process allows for three types of multicast
   address assignments.  These are permanent IPv6 multicast addresses,
   dynamic IPv6 multicast addresses, and permanent IPv6 multicast group
   IDs.  The following guidelines assume that the prefix of the
   multicast address has been initialized according to [ADDRARCH] or
   [UNIMCAST].









Haberman                    Standards Track