OSI PROTOCOL CHOICES FOR LAN ENVIRONMENTS

The many options in current open systems interconnection layer-protocol standards for each of the seven OSI layers has caused much confusion and many difficulties in protocol selection. This paper provides an in-depth analysis on the requirements of the complimentary services of connectionless versus connection-oriented functions for each layer in order to select a set of cooperative protocol suites appropriate for use in interconnected heterogeneous local area networks. The choice hinges on the adoption of either a connectionless or connection-oriented internetworking strategy. The two schools of thought have led to two probable schemes for LAN profiles: scheme 1 - TP4-IP-LLC1 (connectionless network service); and scheme 2 - TP1-X.25PLP-LLC1 (connection-oriented network service). Detailed analysis on the pros and cons of the two LAN profiles shows that scheme 1 is more efficient and versatile than scheme 2, and thus a preferred approach in local area networking. This is in line with the rationale of profile adoption of MAP, TOP, and other international bodies. © 1990.