RFC 2149 (rfc2149) - Page 2 of 18

Multicast Server Architectures for MARS-based ATM multicasting

RFC 2149             Multicast Server Architectures             May 1997


   In practice, a cluster is the set of endpoints that choose to use the
   same MARS to register their memberships and receive their updates
   from.

   A sender in the cluster has two options for multicasting data to the
   group members.  It can either get the list of ATM addresses
   constituting the group from the MARS, set up a point-to-multipoint
   virtual circuit (VC) with the group members as leaves, and then
   proceed to send data out on it.  Alternatively, the source can make
   use of a proxy Multicast Server (MCS).  The source transmits data to
   such an MCS, which in turn uses a point-to-multipoint VC to get the
   data to the group members.

   The MCS approach has been briefly introduced in [GA96].  This memo
   presents a detailed description of MCS architecture and proposes a
   simple mechanism for supporting multiple MCSs for fault tolerance.
   We assume an understanding of the IP multicasting over UNI 3.0/3.1
   ATM network concepts described in [GA96], and access to it.  This
   document is organized as follows.  Section 2 presents interactions
   with the local UNI 3.0/3.1 signaling entity that are used later in
   the document and have been originally described in [GA96].  Section 3
   presents an MCS architecture, along with a description of its
   interactions with the MARS. Section 4 describes the working of an
   MCS. The possibility of using multiple MCSs for the same layer 3
   group, and the mechanism needed to support such usage, is described
   in section 5.  A comparison of the VC Mesh approach and the MCS
   approach is presented in Appendix A.

2 Interaction with the local UNI 3.0/3.1 signaling entity

   The following generic signaling functions are presumed to be
   available to local AAL Users:

   LCALL-RQ - Establish a unicast VC to a specific endpoint.
   LMULTI-RQ - Establish multicast VC to a specific endpoint.
   LMULTI-ADD - Add new leaf node to previously established VC.
   LMULTI-DROP - Remove specific leaf node from established VC.
   LRELEASE - Release unicast VC, or all Leaves of a multicast VC.

   The following indications are assumed to be available to AAL Users,
   generated by by the local UNI 3.0/3.1 signaling entity:

   LACK - Succesful completion of a local request.
   LREMOTE-CALL - A new VC has been established to the AAL User.
   ERRL-RQFAILED - A remote ATM endpoint rejected an LCALLRQ,
                         LMULTIRQ, or L-MULTIADD.
   ERRL-DROP - A remote ATM endpoint dropped off an existing VC.
   ERRL-RELEASE - An existing VC was terminated.



Talpade & Ammar              Informational