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From: sma@WRC.XEROX.COM
Newsgroups: comp.protocols.tcp-ip
Subject: Re:  Reliable Datagram ??? Protocols
Message-ID: <630@rocksanne.WRC.XEROX.COM>
Date: 1 Nov 90 22:12:43 GMT
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We have been doing some work on a reliable multicast transport protocol,
the "Multicast Transport Protocol".  MTP (or Empty Pea) attempts to satisfy
two of the goals discussed recently - 1) fast, reliable multicasting at the
transport level, and 2) agreement on order and delivery of "messages" built
on top of the transport data.

The transport layer is a NAK-based protocol that utilizes the multicast
capability of the lower layers (e.g. IP and Ethernet).  It provides reliable
delivery of messages, which are uninterpreted sequences of bytes terminated
by a end-of-message marker.  The ordering and agreement protocol uses a
token-based scheme to grant sending rights to producers of messages, to
guarentee that a given message will either be accepted by all processes or
not accepted by any, and to guarentee that all processes agree on the order
in which the messages will be processed.

Alan Freier at Apple and Keith Marzullo at Cornell have written a technical
report on MTP available from Cornell.  Ask marzullo@cs.cornell.edu for
information on getting a copy.

Cheers,
    Susie Armstrong
    Xerox Webster Research Center
    armstrong.wbst128@xerox.com