Modeling Temporal Aspects of Contract Net Protocol Using Timed Colored Petri Nets

Contract Net Protocol (CNP) is a high level communication protocol. It is one of the most widely used protocols in multi-agent system (MAS) to resolve decentralized task allocation problem. The main aim of the protocol is to facilitate contract negotiation between a manager agent and many contractor agents. A lot of work has been done for the verification of the protocol and its extensions, but there still a lack of a formalism for representing temporal interaction aspects which are an essential parameter in modeling the protocol. This paper proposes to use Timed Colored Petri Nets (TCPN) to model correctly and formally this temporal dimension often defined as interaction duration and message deadlines. We will use simulation techniques and state space analysis to verify important properties namely model correctness, deadline respect, absence of deadlocks and livelocks, absence of dead code, agent terminal states consistency, concurrency and validity.