Implementation guide for the ISO Transport Protocol (RFC1008)
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2019-Feb-15
Internet Society Requests For Comment (RFCs)
This RFC is being distributed to members of the Internet community in order to solicit comments on the Implementors Guide. While this document may not be directly relevant to the research problems of the Internet, it may be of some interest to a number of researchers and implementors.
Network Working Group Wayne McCoy Request for Comments: 1008 June 1987
ISO TRANSPORT PROTOCOL
Status of this Memo
This RFC is being distributed to members of the Internet community in order to solicit comments on the Implementors Guide. While this document may not be directly relevant to the research problems of the Internet, it may be of some interest to a number of researchers and implementors. Distribution of this memo is unlimited.
IMPLEMENTATION GUIDE FOR THE ISO TRANSPORT PROTOCOL
1 Interpretation of formal description.
It is assumed that the reader is familiar with both the formal description technique, Estelle [ISO85a], and the transport protocol as described in IS 8073 [ISO84a] and in N3756 [ISO85b].
1.1 General interpretation guide.
The development of the formal description of the ISO Transport Protocol was guided by the three following assumptions.
1. A generality principle
The formal description is intended to express all of the behavior that any implementation is to demonstrate, while not being bound to the way that any particular implementation would realize that behavior within its operating context.
2. Preservation of the deliberate nondeterminism of IS 8073
The text description in the IS 8073 contains deliberate expressions of nondeterminism and indeterminism in the behavior of the transport protocol for the sake of flexibility in application. (Nondeterminism in this context means that the order of execution for a set of actions that can be taken is not specified. Indeterminism means that the execution of a given action cannot be predicted on the basis of system state or the executions of other actions.)
McCoy [Page 1]
RFC 1008 June 1987
3. Discipline in the usage of Estelle
A given feature of Estelle was to be used only if the nature of the mechanism to be described strongly indicates its usage, or to adhere to the generality principle, or to retain the nondeterminism of IS 8073.
Implementation efficiency was not a particular goal nor was there an attempt to directly correlate Estelle mechanisms and features to implementation mechanisms and features. Thus, the description does not represent optimal behavior for the implemented protocol.
These assumptions imply that the formal description contains higher levels of abstraction than would be expected in a description for a particular operating environment. Such abstraction is essential, because of the diversity of networks and network elements by which implementation and design decisions are influenced. Even when operating environments are essentially identical, design choice and originality in solving a technical problem must be allowed. The same behavior may be expressed in many different ways. The goal in producing the transport formal description was to attempt to capture this equivalence. Some mechanisms of transport are not fully described or appear to be overly complicated because of the adherence to the generality principle. Resolution of th...