H. Craig McKee (mckee@mitre.ARPA)
Wed, 11 Mar 87 08:23:19 EST
I circulated the note from Phil ("...darker forces at play ...")
among several colleagues here at MITRE-Washington; herewith the
views of Steve Silverman.
*** Reply to note of 03/08/87 10:09
From: Steve Silverman
Subject: GOSIP vs TCP/IP
I would like to reply to your note on TCP/IP and its non-acceptance by the
commercial world. First of all, I doubt that there is any connection with
the various television standards other than the prevalence of the NIH
syndrome. This seems to be fairly prevalent in many places including the DOD.
As far as TCP/IP versus ISO, it must be recongnized that there are two ISO
suites being developed. One, the Connection-Based (CB), uses TP over X.25.
The second one, the Connectionless (CL) suite, uses IP between TP and X.25.
The CL suite is a datagram approach in the tradition of the ARPANET. This was
used in the first generation packet networks, but has significant costs
in comparison with the CB approach used by later generation commercial
packet networks. The CL approach means that each packet must contain
a larger header (TCP/IP = 40 bytes) than a CB packet (X.25 = 3 bytes).
The CL approach requires each switch to make a routing decision on each packet
while the CB approach allows transit switches to do a simple table lookup for
Each suite has its benefits; the CL approach is better for tactical networks
with very mobile nodes. The CB approach is much more economical for higher
data requirements. The public data networks are almost exclusively CB.
The design work being done today for future networks by the common carrier
network builders is almost exclusively CB based, although the OSI 7 layer
model is being downplayed (really discarded). To some of us, the use of
a CL stationary packet network is equivalent to forcing all military
ground vehicles to be armored and armed. If 495 (our local beltway) were
filled with tanks, it would be a major waste of money.
It is about time, in my opinion, that the military networkers realized that
the commercial data users are not stupid. They demand the same reliability
that the DOD requires. The Reconnect feature of X.25 prevents loss of
user data when a transit node fails. This has been widely deployed for
years. Meanwhile the cost of running the ARPANET is comparable to running
the Telenet public network which carries ten times as many user packets.
The reluctance of some people to embrace TCP/IP is not just based on NIH.
Some of us reject it on technical grounds.
:::GOSIP vs TCP/IP R
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