Dvmrp - D-Link D-View 5.1 User Manual

D-View 5.1 User's Guide

DVMRP

DVMRP
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 data grams, so a router that routes both
multicast and unicast data grams must run two separate routing processes. DVMRP is
designed to be easily extensible and could be extended to route unicast data grams.
DVMRP was developed to experiment with the algorithms in 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. 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.
DVMRP differs from RIP in one very important way. RIP thinks in terms of routing and
forwarding data grams to a particular destination. The purpose of DVMRP is to keep
track of the return paths to the source of multicast data grams. To make explanation of
DVMRP more consistent with RIP, the word "destination" is used instead of the more
proper "source", but the reader must remember that data grams are not forwarded to
these destinations, but originate from them.
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