We propose a process algebra for link layer protocols, featuring a unique mechanism for modelling frame collisions. We also formalise suitable liveness properties for link layer protocols specified in this framework. To show applicability we model and analyse two versions of the Carrier-Sense Multiple Access with Collision Avoidance (CSMA CA) protocol. Our analysis confirms the hidden station problem for the version without virtual carrier sensing. However, we show that the version with virtual carrier sensing not only overcomes this problem, but also the exposed station problem with probability 1. Yet the protocol cannot guarantee packet delivery, not even with probability 1.
@cite_5 use models of CSMA CD to compare the tools SPIN and . Their models are much more abstract than ours. It is proven that no collisions will ever occur, without stating the exact conditions under which this statement holds.
@cite_5
2345573725
This paper compares the tools SPIN and UPPAAL by modelling and verifying a Collision Avoidance Protocol for an Ethernet-like medium. We find that SPIN is well suited for modelling the untimed aspects of the protocol processes and for expressing the relevant (untimed) properties. However, the modelling of the media becomes awkward due to the lack of broadcast communication in the PROMELA language. On the other hand we find it easy to model the timed aspects using the UPPAAL tool. Especially, the notion of committed locations supports the modelling of broadcast communication. However, the property language of UPPAAL lacks some expressivity for verification of bounded liveness properties, and we indicate how timed testing automata may be constructed for such properties, inspired by the (untimed) checking automata of SPIN.