Estelle specification of MIL-STD-188-220A datalink layer

This paper presents ongoing results of a contract between US Army CECOM and the University of Delaware to develop a formal specification of the datalink layer of MIL-STD-188-220A using the ISO International Standard Formal Description Technique Estelle (ISO 9074). The Estelle specification aims at discovering and resolving ambiguities in the original English document that would cause interpretation problems for implementers. The proposed architecture closely models ISO 8802´s Logical Link Control for local area networks. The paper also presents the state tables and transitions which constitute the modules of this architecture. We have prevoiusly reported on our initial effort to specify an earlier version titled 188-220 with support from the Army Research Laboratory in Aberdeen Proving Ground. Several updates have been generated since then as a result of regular meetings of the Combat Net Radio (CNR) Implementation Working Group (WG), previously known as the MIL-STD-188-220 WG. Our current specification efforts are based on the most recent version dated 27 July 1995. Thus far, over 30 ambiguities or inconsistencies (some minor, some major) have been discovered and reported to the CNR working group for incorporation into the developing 188-220A standard