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].
1.1General interpretation guide.The development of the formal description of the ISO Transport Protocol was guided by the three following assumptions.
A generality principleThe 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.
Preservation of the deliberate nondeterminism of IS 8073The 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.)