Distributed Artificial Intelligence

Research Program - Results (5)

The B-Contract protocol

The concept of negociation is central to the agent systems. The most frequently used protocol is that of Contract-Net proposed by Smith and Davis. However, although the Contract-Net is a landmark in the world of protocols, it shows nevertheless some limits. Thus, some researchers either modified it (Conry, Gu and Ishida), or proposed other protocols altogether (Sandholm).

None of the proposed protocols satisfied our needs. Thus, we were led to propose a new protocol, B-Contract, based upon Contract-Net, but allowing free agents to work on some tasks in parallel with agents that were granted the contract. Free agents would work however at a lower priority level. This approach allows to have more robust systems in particular in case of failure of some agents. The approach has been first implemented on the OASCA platform (UNIX environment) then on the SMAS and OMAS platforms (MacIntosh and Microsoft-32 environments).

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Last modified 8/4/02