Interprogram communication for PC/LAN-based collaborative applications: PLEXNET, a session level communications system.

Abstract

This dissertation describes the analysis, design, and implementation of a session level communication system referred to as PLEXNET. PLEXNET was developed specifically to provide communication services required by Computer Supported Cooperative Work (CSCW) applications but which are not currently available as part of commercially available LAN products. CSCW services include such things as: reliable broadcast communications, dynamic multicasting, and message queuing. Analysis of CSCW networking requirements entailed: reviewing CSCW applications and communications systems; synthesizing a data exchange model for collaborative tools; and defining a target system (PC-LAN). PLEXNET design provides a discussion of: networking tradeoffs, the relationship between PLEXNET and NETBIOS, PLEXNET queue structure, and PLEXNET implementation details. The design and implementation of PLEXNET were validated by performing discrete event simulations comparing response times and resource utilization for three communication paradigms and by developing four collaborative applications which employ PLEXNET for data communications. These applications are: Multi-User LAN Editor, Electronic Discussion System, Contracts Procurement, and Video Switcher.