Marshall Rose (mrose@nrtc-gremlin)
Thu, 12 Jun 86 14:03:57 -0700
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
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
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!
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