Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!decvax!decwrl!pyramid!hplabs!ucbvax!nrtc-gremlin!mrose From: mrose@nrtc-gremlin.UUCP Newsgroups: mod.protocols.tcp-ip Subject: Re: rfc983 Message-ID: <20148.518994237@nrtc-gremlin.northrop.com> Date: Thu, 12-Jun-86 21:03:22 EDT Article-I.D.: nrtc-gre.20148.518994237 Posted: Thu Jun 12 21:03:22 1986 Date-Received: Fri, 13-Jun-86 06:41:22 EDT References: Sender: daemon@ucbvax.BERKELEY.EDU Organization: The ARPA Internet Lines: 41 Approved: tcp-ip@sri-nic.arpa As one of the authors of the RFC, I feel I should clear up some misconceptions you have regarding it. At no point in rfc983 is it said how to implement the interface to the TSAP. What is said is how you can build such an interface on top of the TCP. That is, given the abstract service definitions for the TP, instructions are given as to how one can map those onto the services provided by the TCP. From our perspective, a proper implementation of rfc983 exhibits the following properties: - it has the TSAP interface that you want on your host - it uses the protocol defined in the rfc We have such an implementation for Berkeley 4.2 UNIX. I imagine that an implementation for TOPS-20 would look entirely different, both in actual internal code (the protocol engine) and in the interface code (subroutine library). The same goes for VAX/VMS, obviously. But, they would all speak the same protocol (as defined in rfc983). Perhaps the problem here, is that it appears to you that rfc983 specifies an "ISO protocol". This is certainly not our intention. the rfc specifies a DDN-style protocol which provides ISO services. It is the intent of rfc983 to permit standard ISO protocols to run on top of the TCP. It is not the intent to build ISO-like protocols for the ARPA Internet. I completely agree with your statement that: "In general, it is important for one to produce good generic protocol interface design so that a particular protocol implementation or even the protocol itself can easily be replaced without affecting the code in the upper or lower layer." But I fail to see how rfc983 violates this concern. Quite the contrary: rfc983 rips out the ISO TP internals and substitutes calls to the services provided by the TCP! /mtr