Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!mit-eddie!bloom-beacon!eru!hagbard!sunic!mcsun!unido!pbinfo!marc
From: marc@uni-paderborn.de (Marc Gumbold)
Newsgroups: comp.protocols.misc
Subject: Re: Realtime Protocols
Message-ID: <1990Oct2.095259.23485@uni-paderborn.de>
Date: 2 Oct 90 09:52:59 GMT
References: <24594@uflorida.cis.ufl.EDU> <1990Sep30.194033.16776@hellgate.utah.edu>
Organization: Uni-GH Paderborn, West Germany
Lines: 38

haas%basset.utah.edu@cs.utah.edu (Walt Haas) writes:

>In article <24594@uflorida.cis.ufl.EDU> wardc@banana () writes:
>>A friend just asked me an interesting question regarding network
>>protocols.  His company requires a "realtime" protcol.  By realtime they
>>are interested in ensuring that data arrived uncorrupted at the
>>destination within a certain period.  None of the protocols that I'm
>>aware of (TCP/IP, MAP etc.) provide this as an option.  About the only
>>suggestion I could make is to use MAP with token-ring.  Does anyone
>>know of any other protocols that might be appropriate.

>Actually I don't believe either MAP or token ring will qualify either.
>What you need is something based on time division.  A company called
>Applitech sells a line of Ethernet bridges using a proprietary protocol
>over a broadband network.  This protocol has time divisions, or "slots",
>which can be hard allocated or contended for according to the parameters
>set by the system administrator.  When you have a slot reserved for your
>exculsive use, you know that you will always get an opportunity to
>transmit in that slot.

>I think the 802.6 committee may be taking a similar approach
>(if I'm wrong someone will doubtless say so :-).

You're right. DQDB (802.6) should once provide isochronous service, too.
An isochronous service user will be guaranteed to transmit one byte every
125 microseconds. In the current version of the standard this is not
very clearly specified yet. 

Cheers, 
Marc




-- 

   Marc Gumbold    EMail: marc@uni-paderborn.de       Phone: +49 5251 60 3803
                   Snail: Uni-GH Paderborn, FB17i, 4790 Paderborn, W. Germany