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
 following packets.

 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.
 Steve Silverman
 * Steve

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