Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!pdn!larry
From: larry@pdn.paradyne.com (Larry Swift)
Newsgroups: comp.dcom.lans
Subject: Re: What services does X.25 provide?
Keywords: x.25, services, login, e-mail, file transfer, IPC
Message-ID: <6669@pdn.paradyne.com>
Date: 18 Oct 89 12:35:45 GMT
References: <796@maxim.erbe.se> <3279@wasatch.utah.edu> <522@wet.UUCP> <6624@pdn.paradyne.com> <23189@cos.com> <1989Oct10.210812.13144@agate.berkeley.edu> <17899@bellcore.bellcore.com>
Sender: usenet@pdn.paradyne.com
Reply-To: larry@pdn.paradyne.com (Larry Swift)
Organization: AT&T Paradyne, Largo, Florida
Lines: 19

>>Why not just run TP4 everywhere?  It could run over X.25 just as well
>That's actually an extremely good question. The answer has to do with
>the *real* motivation behind OSI -- namely, the *thwarting* of true,
>interoperable internetworking by the European PTTs in order to protect
>their X.25 network monopolies. There can be no other explanation for the

This rabid, OSI-bashing statement aside, the answer to the question
is that TP4 over X.25 is a relatively poor performer for the resources
consumed (ie, protocol overhead in both layers for ACKing data units).  
TP2 over X.25 is at least more efficient.

I agree that OSI isn't perfect, and Layer 4 in particular is unlovely,
but to ascribe the *real* motivation behind OSI as above is pure nonsense.


Larry Swift                     larry@pdn.paradyne.com
AT&T Paradyne, LG-132           Phone: (813) 530-8605
8545 - 126th Avenue, North
Largo, FL, 34649-2826           She's old and she's creaky, but she holds!