RFC 1075 (rfc1075) - Page 1 of 24
Distance Vector Multicast Routing Protocol
Alternative Format: Original Text Document
Network Working Group D. Waitzman
Request For Comments: 1075 C. Partridge
BBN STC
S. Deering
Stanford University
November 1988
Distance Vector Multicast Routing Protocol
1. Status of this Memo
This RFC describes a distance-vector-style routing protocol for
routing multicast datagrams through an internet. It is derived from
the Routing Information Protocol (RIP) [1], and implements
multicasting as described in RFC-1054. This is an experimental
protocol, and its implementation is not recommended at this time.
Distribution of this memo is unlimited.
2. Introduction
A draft standard for multicasting over IP networks now exists [2],
but no routing protocols to support internetwork multicasting are
available. This memo describes an experimental routing protocol,
named DVMRP, that implements internetwork multicasting. DVMRP
combines many of the features of RIP [1] with the Truncated Reverse
Path Broadcasting (TRPB) algorithm described by Deering [3].
DVMRP is an "interior gateway protocol"; suitable for use within an
autonomous system, but not between different autonomous systems.
DVMRP is not currently developed for use in routing non-multicast
datagrams, so a router that routes both multicast and unicast
datagrams must run two separate routing processes. DVMRP is designed
to be easily extensible and could be extended to route unicast
datagrams.
DVMRP was developed to experiment with the algorithms in [3]. RIP
was used as the starting point for the development because an
implementation was available and distance vector algorithms are
simple, as compared to link-state algorithms [4]. In addition, to
allow experiments to traverse networks that do not support
multicasting, a mechanism called "tunneling" was developed.
The multicast forwarding algorithm requires the building of trees
based on routing information. This tree building needs more state
information than RIP is designed to provide, so DVMRP is much more
complicated in some places than RIP. A link-state algorithm, which
already maintains much of the state needed, might prove a better
basis for Internet multicasting routing and forwarding.
Waitzman, Partridge & Deering
