[comp.protocols.tcp-ip] What is VMTP?

hinton@netcom.UUCP (Greg Hinton) (05/30/90)

I've read bits & pieces about something called VMTP.  From what I've seen,
it appears to be a reliable counterpart of UDP.
Can someone explain in more depth exactly what VMTP is and/or provide
easily available references?
Are there any implementations under UNIX?

Thanks.
-- 

Greg Hinton
DOMAIN: hinton@netcom.uucp
UUCP: uunet!apple!netcom!hinton

kmeyer@wrl.dec.com (Kraig Meyer) (05/30/90)

In article <12637@netcom.UUCP> hinton@netcom.UUCP (Greg Hinton) writes:
||I've read bits & pieces about something called VMTP.  From what I've seen,
||it appears to be a reliable counterpart of UDP.
||Can someone explain in more depth exactly what VMTP is and/or provide
||easily available references?
||Are there any implementations under UNIX?

VMTP was developed as a transport protocol for the V distributed system
at Stanford.  Try "VMTP as the Transport Layer for High-Performance
Distributed Systems" by David Cheriton and Carey Williamson, IEEE
Communications Magazine, June 1989, p. 37.

****************************************************
Kraig Meyer                        kraig@wrl.dec.com
On parole from the University of Southern California
My views do not necessarily represent those of DEC.

postel@VENERA.ISI.EDU (05/31/90)

Hi.

See RFC-1045 and the papers by Cheriton in various places (e.g., Sigcomm
conference proceedings).

--jon.

deering@PESCADERO.STANFORD.EDU (Steve Deering) (05/31/90)

> I've read bits & pieces about something called VMTP.  From what I've seen,
> it appears to be a reliable counterpart of UDP.
> Can someone explain in more depth exactly what VMTP is and/or provide
> easily available references?

VMTP is a transport-layer protocol that provides a reliable request/response
or RPC style of service, rather than the reliable stream service of TCP or
the unreliable datagram service of UDP.  As others have pointed out, it
has been described in several papers by David Cheriton of Stanford; the
protocol specification can be found in RFC-1045.

> Are there any implementations under UNIX?

Yes, there is an implementation for 4.3BSD and derivitives (SunOS, Ultrix)
that may be obtained by anonymous FTP from host gregorio.stanford.edu,
in the vmtp-ip directory.  The software is free but covered by a
Stanford license agreement, which can be found in the file vmtp.LICENSE
in that directory.

Steve Deering