[11902] in Commercialization & Privatization of the Internet
Re: X.25 with Internet?
daemon@ATHENA.MIT.EDU (Morten Reistad)
Sat Apr 23 19:38:15 1994
To: Miles R Fidelman <fidelman@civicnet.org>
Cc: com-priv@psi.com, mrr@galba.boers.no
In-Reply-To: Your message of "Sat, 23 Apr 1994 09:15:08 EDT."
<Pine.3.89.9404230909.A6568-0100000@world.std.com>
Date: Sat, 23 Apr 1994 22:38:44 +0200
From: Morten Reistad <mrr@galba.boers.no>
On Fri, 22 Apr 1994, Bruce Gingery wrote:
>Well for quite some time the Arpanent provided the primary long-haul
>connectivity for the Internet, and it ran X.25 during its later life
>(albeit a very fine-tuned form of X.25). Back in the days when 64kbps
>was fast, this worked fine.
Did the ARPAnet ever run X.25? I never heard this; I thought the
ARPAnet used the IMP style protocols to the very end. That said;
the IMP protocol and X.25 has a lot in common in terms of how they
behave as a platform for IP.
[clip clip]
>using a current day telco X.25 net (64kb if you're lucky) is not a
>great idea for connecting LANs together, though it could be ok for
>connecting individual machines to the Internet (if it weren't for
>per-packet charges)
X.25 nets are extremely sensitive to tuning. To acheive near link
throughput on > 19.2 lines you need to tune X.25 a lot. This means
you must have some clout with the owners of the networks, or design
them yourself. It does no mean it is impossible. I have to cope
daily with a dual X.25/ip network, and we are able to reduce the
overhead of X25 under IP to single-digit percentages on 64k lines.
Of course; the packet meters on X.25 are silly. Sad only a few
telco's have seen the light about that.
>Frame relay, on the other hand, is designed to run faster, and is a
>pretty good technology.
Amen. Frame relay is very far from X.25 in terms of performance.
It also fills in a gap in the Internet; The internet never had a
good link layer for the WAN part. This HDLC stuff Cisco uses;
or SLIP is rather rudimentrary. Frame Relay or PPP are better
choices for big networks. After all; IP is designed to run on
some other lan/wan/man/etc platform.
-- Morten Reistad <mrr@boers.no> speaking for self
