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Path: utzoo!watmath!clyde!burl!we13!ihnp4!fortune!rpw3
From: rpw3@fortune.UUCP
Newsgroups: net.dcom
Subject: Re: Tymnet X.25 interface exists - (nf)
Message-ID: <3104@fortune.UUCP>
Date: Thu, 19-Apr-84 04:07:31 EST
Article-I.D.: fortune.3104
Posted: Thu Apr 19 04:07:31 1984
Date-Received: Fri, 20-Apr-84 00:42:26 EST
Sender: notes@fortune.UUCP
Organization: Fortune Systems, Redwood City, CA
Lines: 37

#R:utah-cs:-270400:fortune:3100004:000:1537
fortune!rpw3    Apr 18 20:34:00 1984

+--------------------
| "... Telenet is X.75 internally. ..."
| I don't understand this remark.  X.75 is a VC (connection-oriented)
| protocol for use between two half-gateways;  it actually looks very
| similar to X.25 in the packet formats used, but has some little
| twists to fit the needs of gateway organization.  Is this to say that
| Telenet treats every node as a separate subnetwork, with 'gateways'
| between them?
| 		Julian Davies
+--------------------

I don't know about Telenet, but when XTEN (R.I.P. *sigh*) was looking at
packet switches a few years ago, we looked at the Siemens EDX-P, and
that's EXACTLY what they do. Every node is a separate sub-net, and talks
X.75 to it's neighbors (but ONLY X.25 to "subscribers", puh-lease! ;-} ).

I was also very curious about that, since there are much more convenient
and efficient "internal" protocols for inter-nodal intra-network transport.

What I was told is, "Look, outside the U.S, our customers are the various
PTTs, and most countries that buy our gear are only big enough for one,
maybe two, nodes. They have to talk X.75 across the international borders,
so we just made it easy for ourselves and use it everywhere."

Now it would seem that Telenet is big enough to employ more efficient
ways of internal transport, but maybe they just decided to "make it easy"
and not bother, likewise.

Rob Warnock

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