RFC 2102 (rfc2102) - Page 2 of 23

Multicast Support for Nimrod : Requirements and Solution Approaches

RFC 2102                Nimrod Multicast Support           February 1997


1  Introduction

   The nature of emerging applications such as videoconferencing, remote
   classroom, etc.  makes the support for multicasting essential for any
   future routing architecture.  Multicasting is performed by using a
   multicast delivery tree whose leaves are the multicast destinations.

   Nimrod does not propose a solution for the multicasting problem.
   There are two chief reasons for this.  First, multicasting is a non-
   trivial problem whose requirements are still not well understood.
   Second, a number of groups (for instance the IDMR working group of
   the IETF) are studying the problem by itself and it is not our
   intention to duplicate those efforts.

   This attitude towards multicasting is consistent with Nimrod's
   general philosophy of flexibility, adaptability and incremental
   change.

   While a multicasting solution per se is not part of the "core" Nimrod
   architecture, Nimrod does require that the solution have certain
   characteristics.  It is the purpose of this document to discuss some
   of these requirements and evaluate approaches towards meeting them.

   This document is organized as follows.  In section 2 we discuss why
   multicasting is treated a little differently than unicast despite the
   fact that the former is essentially a generalization of the latter.
   Following that, in section 4 we discuss current approaches toward
   multicasting .  In section 5, we give an example of how Nimrod
   multicasting may be done using PIM [DEF+94a].  For readers who do not
   have the time to go through the entire document, a summary is given
   at the end.

   This document uses many terms and concepts from the Nimrod
   Architecture document [CCS96] and some terms and concepts (in section
   5) from the Nimrod Functionality document [RS96].  Much of the
   discussion assumes that you have read at least the Nimrod
   Architecture document [CCS96].














Ramanathan                   Informational