Existing electronic negotiation systems (ENSs) typically implement a single, fixed negotiation protocol, which restricts their use to negotiation problems that were anticipated and established a priori by the system designers. The single-protocol restriction limits ENSs' applicability in experiments and in many real-life negotiation situations. ENSs that allow for the use of different protocols also allow for the customization to users' needs and abilities. We present theoretical foundations for the design of flexible and highly customizable protocol-driven ENSs. Our design enables researchers and negotiators to map negotiation activities onto system components and to construct their own negotiation protocols by creating a sequence of layout programs invoking components and rules.

A major challenge in developing an e-negotiation system (ENS) is that the system should fit into the context which varies with negotiation cases. To mitigate context dependency, we propose to separate e-negotiation protocols from ENS and adopt a component-oriented approach. In this paper, we present a framework for e-negotiation protocols that implements this approach. The framework has been tested by developing several ENSs of which two had been tested in laboratory negotiation experiments with more than 100 participants.