Implications of Precedence and Preemption Requirements on Packet Based Transport Architectures

Over the last several years there have been various attempts to extend traditional Precedence enabled transport services to support all Command and Control (C2) applications. Traditional experience with Precedence based transport services support either circuit-switched, voice-based transport, e.g., the Defense Switched Network (DSN), or message-switched transport, e.g., the Defense Message System (DMS) and the Automated Message Handling System (AMHS). We believe these attempts to extend and define new Precedence enabled transport services have failed because of a lack of well defined requirements and an understanding of their implications. In this paper, we offer a core set of ten requirements for Precedence and Preemption enabled transport services which aim to support all C2 applications. We make no claim as to the originality of these requirements; others have proposed subsets of these in the past. Based upon these ten requirements, we then discuss and identify their implications on network architectures for packet-based transport services. In the process we hope to better clarify the implications of the requirements and the network mechanisms to be designed and developed for future military Precedence enabled communications networks. We conclude by identifying areas for future research and development in order to bring packet-based Precedence-enabled transport services to all C2 applications.