Stubborn: a medium access protocol for expert assistants indistributed control systems

摘要

A novel implementation is presented, the Stubborn protocol, whichprovides the right compromise to obtain a balanced and near-optimalperformance under both normal (control) operation and transient(emergency) conditions. It is based on the following simple principle:stations make access attempts as in the usual 1-persistent CSMA/CD(carrier-sense multiple-access with collision detection). In case ofcollision, a station with priority higher than zero will not interrupttransmission, but will exercise its right to extend the collision for aperiod proportional to its priority level. The station that persistslonger will be able to start `clean' transmission as soon as all othershave desisted. The algorithm is complemented with tie-breakingprocedures