RFC 2776 (rfc2776) - Page 2 of 27

Multicast-Scope Zone Announcement Protocol (MZAP)

RFC 2776                          MZAP                     February 2000


   5.4 Not-Inside Message ........................................ 16
   6 Message Processing Rules .................................... 17
   6.1 Internal entities listening to MZAP messages .............. 17
   6.2 Sending ZAMs .............................................. 18
   6.3 Receiving ZAMs ............................................ 18
   6.4 Sending ZLEs .............................................. 20
   6.5 Receiving ZLEs ............................................ 20
   6.6 Sending ZCMs .............................................. 21
   6.7 Receiving ZCMs ............................................ 21
   6.8 Sending NIMs .............................................. 21
   6.9 Receiving NIMs ............................................ 22
   7 Constants ................................................... 22
   8 Security Considerations ..................................... 23
   9 Acknowledgements ............................................ 24
   10 References ................................................. 25
   11 Authors' Addresses ......................................... 26
   12 Full Copyright Statement ................................... 27

1.  Introduction

   The use of administratively-scoped IP multicast, as defined in RFC
   2365 [1], allows packets to be addressed to a specific range of
   multicast addresses (e.g., 239.0.0.0 to 239.255.255.255 for IPv4)
   such that the packets will not cross configured administrative
   boundaries, and also allows such addresses to be locally assigned and
   hence are not required to be unique across administrative boundaries.
   This property of logical naming both allows for address reuse, as
   well as provides the capability for infrastructure services such as
   address allocation, session advertisement, and service location to
   use well-known addresses which are guaranteed to have local
   significance within every organization.

   The range of administratively-scoped addresses can be subdivided by
   administrators so that multiple levels of administrative boundaries
   can be simultaneously supported.  As a result, a "multicast scope" is
   defined as a particular range of addresses which has been given some
   topological meaning.

   To support such usage, a router at an administrative boundary is
   configured with one or more per-interface filters, or "multicast
   scope boundaries".  Having such a boundary on an interface means that
   it will not forward packets matching a configured range of multicast
   addresses in either direction on the interface.

   A specific area of the network topology which is within a boundary
   for a given scope is known as a "multicast scope zone".  Since the
   same ranges can be reused within disjoint areas of the network, there
   may be many "multicast scope zones" for any given multicast scope.  A



Handley, et al.             Standards Track