CVLAN: a requirements definition for a real-time local area network in land combat vehicles

Provides the framework from which to design and implement a realtime LAN architecture for combat vehicles. The focus of this effort was to define a realtime LAN architecture capable of adapting to fault induced variations in network loading, and still meet the time constraints of critical messages. We specified benefit based, dynamic scheduling as the means by which this can be accomplished. In order to facilitate meeting time constraints, we proposed a means to reduce uncertainty and processing time in a message's critical time segment through logical addressing and the use of a priori information. There is currently an implementation effort underway for this architecture. The first part of this effort is the design and implementation of a logical link sub-layer based on the requirements described herein. This effort will focus on developing a benefit based scheduling algorithm and metric to measure scheduler performance. Another significant aspect of this effort is the integration of the LLC functions in such a way that message set-up processing can be removed from the critical time segment of a message. In the second part we will analyze the performance of this sub-layer on the two variations of token passing protocols. The goal of this effort will be to assess the suitability of either protocol for the types of real-time message transmissions found in combat vehicles. The realization of this architecture will provide a means for the developers of combat vehicles, or any other LAN based system that operates in a harsh, non-deterministic environment, to attain a more maintainable system that is able to adapt to fault induced variations in network loading.