Browse Prior Art Database

Low Overhead Multicast on a Spanning Tree

IP.com Disclosure Number: IPCOM000108956D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Auerbach, J: AUTHOR [+3]

Abstract

A spanning tree joining the nodes of a computer network contains the minimum number of links, such that all of the nodes are connected. Thus, it is well suited for sending multicast messages, where a multicast message is a message which is transmitted to some subset of nodes which are interested in the subject of the message.

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This is the abbreviated version, containing approximately 55% of the total text.

Low Overhead Multicast on a Spanning Tree

       A spanning tree joining the nodes of a computer network
contains the minimum number of links, such that all of the nodes are
connected.  Thus, it is well suited for sending multicast messages,
where a multicast message is a message which is transmitted to some
subset of nodes which are interested in the subject of the message.

      When a link is added to such a spanning tree, it is marked with
a set of one or more tree addresses which are used to identify
different subsets of nodes.  A node can be a member of more than one
such subset.  A node forwards a received multicast message on the
spanning tree if the tree address in the message matches one of the
tree addresses marked on the spanning tree links.

      The problem with this approach is that it precludes dynamically
creating a new subset of nodes.  This is because all of the nodes in
the network need to know all of the tree addresses in advance in
order to mark them on links added to the spanning tree.

      This problem is solved by defining a special tree address which
consists of two parts.  The first part is fixed and identifies a
message containing this special tree address as a multicast message
intended for a dynamically created subset of nodes.  The second part
is variable and identifies the particular subset of nodes to which
the message is addressed; this is termed the subset identifier

      The special tree address is one of...