Subject: DDM & DSR

From: Webber Neil <[email-masked]>
Date: Mon, 13 Nov 2000 14:54:24 -0000

A fairly minor question...

In the DDM draft it is stated that the approach is motivated in part by
the work done on DSR. Is DDM intended to be a multicast addition to DSR,
in much the same way as TORA has LAM, or is it a stand alone protocol?

Thanks

Neil

Neil C Webber
Communications Dept.
DERA Malvern
Tel: +44 1684 89 7108
Fax: +44 1684 89 6166

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From: Dave Johnson <[email-masked]>
Date: Mon, 13 Nov 2000 11:27:23 -0600

Neil,

I can't speak as to what the authors of DDM intended for their
protocol, since the two groups are working separately.  DSR was
designed by the Monarch Project at Carnegie Mellon University (and
now at Rice University), whereas DDM was designed at the University
of Maryland.  However, in the Monarch Project, we have been working
for some time now on our own multicasting protocol, based on our
mechanisms in DSR.  We'll be submitting an Internet-Draft on that
sometime soon, once we get a chance to write up the design.  While,
as I said, our multicast protocol will be based on our mechanisms in
DSR, it will really be a standalone protocol that could be used with
any unicast routing protocol, since the two protocols operate
independently.

					Dave

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David B. Johnson, Associate Professor
of Computer Science and Electrical and Computer Engineering

Department of Computer Science - MS 132    [email-masked]
Rice University                            http://www.cs.rice.edu/~dbj/
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From: Lusheng Ji <[email-masked]>
Date: Mon, 13 Nov 2000 12:24:02 -0500 (EST)

Hi, Neil,

DDM is a stand alone protocol.  Although DDM requires the existence of A
unicast routing protocol (could be DSR), it does not care which one the
unicast protocol is.  As long as the unicasting provides the "next
hop" information, which is the common content of unicast routing table.
This is different from what TORA is to LAM.  LAM is designed as an
integrated component of the TORA-LAM unicast-multicast routing suite.

The connection between DDM and DSR is rather in part of the design
philosophy: inband, explicit routing information.  Of course because
of the difference between unicasting and multicasting, for DSR the routing
information is the route while for DDM the routing information is the
set of multicast receivers. 

Hope this answers your question.
Regards,

Lusheng