lmcl@ukc.UUCP (L.M.McLoughlin) (10/13/84)
I'm looking for an implementation of ISO level 4 (the transport level) to run under Unix. If you have any information on such a beastie please mail it to me. Its not for me, you understand, but for a friend! -- ...!ukc!lmcl ...!ukc!root44!west44!lee
gwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>) (10/16/84)
"ISO level 4 (the transport level)" is an abstraction. It can be realized in different ways, and has been on systems such as 4.2BSD. You need to find out just what your friend is really after.
barmar@mit-eddie.UUCP (Barry Margolin) (10/17/84)
In article <5313@brl-tgr.ARPA> gwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>) writes: >"ISO level 4 (the transport level)" is an abstraction. >It can be realized in different ways, and has been on systems >such as 4.2BSD. You need to find out just what your friend is >really after. ISO has defined a standard Transport Protocol. I believe that this is commonly referred to as TP4. It is quite similar to DoD's Internet Protocol (IP), I think. In any case, it is not just an abstraction any more. -- Barry Margolin ARPA: barmar@MIT-Multics UUCP: ..!genrad!mit-eddie!barmar
mccallum@opus.UUCP (Doug McCallum) (10/17/84)
> "ISO level 4 (the transport level)" is an abstraction. > It can be realized in different ways, and has been on systems > such as 4.2BSD. You need to find out just what your friend is > really after. ISO level 4 (NBS/ISO TP4) is also a real protocol that is very close to being an international standard. It is currently in DIS (Draft International Standard) form (ISO/DIS 8072 for the Transport service definition and ISO/DIS 8073 for the Connection oriented transport protocol specification). This is the protocol that was used at the NCC network demo. All 7 layers of the ISO Reference Model will have ISO protocols defined for them. Currently, Network is fairly stable but still a DP (Draft Proposal), Transport is being finalized, Session is in DIS form. The higher layers are in varying states depending on the application intended. Presentation is a ways from completion. There has also been some talk that the National Academy of Science is completing a study that will recommend that DoD adopt the ISO Class 4 protocol. NATO has already said they will adopt it. It will be interesting to see what happens over the next few years. Doug McCallum {allegra, btlunix, ucbvax, hao}!nbires!mccallum
gwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>) (10/19/84)
> ISO has defined a standard Transport Protocol. I believe that this is > commonly referred to as TP4. It is quite similar to DoD's Internet > Protocol (IP), I think. In any case, it is not just an abstraction any > more. Thanks for the information. Does TP4 have anything to do with the "TP" that is threatening to supplant TCP/IP on DOD nets?
schoff@cadtroy.UUCP (Martin Lee Schoffstall) (10/19/84)
> > ISO has defined a standard Transport Protocol. I believe that this is > > commonly referred to as TP4. It is quite similar to DoD's Internet > > Protocol (IP), I think. In any case, it is not just an abstraction any > > more. > From the United States Department of Commerce National Bureau of Standards Revised 9/20/84 The NBS/OSI Transport Class 4, the test system for transport, as well as the specification compiler for translating protocols formally described by the NBS specification technique can be obtained on magnetic tape from the National Technical Information Service US Department of Commerce Springfield, Virginia 22161 Telephone (703)487-4650 Telex: 89-9405 NTIS Order #: PB84-222918 Price Code: T14 Price: $985 U.S., $1585 Foreign ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ This code is written in C for a UNIX system (though a very non-standard one that traces its heritage back to V6). The price also includes some manuals. NBS is continuing to do fixes and work on the other levels including the network level. marty {bbncca,linus,seismo,wivax}!cadmus!schoff cadmus!schoff@seismo.ARPA
sylvain@lvbull.UUCP (Sylvain Langlois) (10/20/84)
Sorry Barry, but ISO Transport has nothing to do with DOD IP. What you should know about the "abstraction" is that there 5 different ISO Transport (for the moment!!): - Class 0: simple class for very reliable networks, - Class 1: basic error recovery class, - Class 2:multiplexing class, - Class 3: error recovery and multiplexing class, - Class 4: error detection and recovery class for unreliable nets. In fact, Transport Class 4 is somewhat similar to TCP. All of these classes are connection oriented and based on a connection oriented network service. I'm actually working on a Transport Class 4 based on a connectionless oriented network service. The code has been written in a V7 kernel environnement and I think about switching to a 4.2BSD implementation soon. I can tell that there is no abstraction there! --- Sylvain Langlois (....mcvax!vmucnam!lvbull!sylvain) ---
julian@deepthot.UUCP (Julian Davies) (10/22/84)
From: barmar@mit-eddie.UUCP (Barry Margolin) >ISO has defined a standard Transport Protocol. I believe that this is >commonly referred to as TP4. It is quite similar to DoD's Internet >Protocol (IP), I think. In any case, it is not just an abstraction any >more. True, but the resemblance between ISO/Transport protocol and DoD's IP is only 'generic'. Specific details are very different. BTW, the ISO recommendation in a draft form was printed a year or two ago in ACM Computer Communications newsletter, for anyone who wants to check it out. The final DIS (IS?) is probably slightly modified from that draft. Julian Davies uucp: deepthot!julian; uwo!julian Envoy: DJ.DAVIES