Extended WS-Agreement Protocol to Support Multi-round Negotiations and Renegotiations

WS-Agreement is a well-established and widely adopted protocol that helps service providers and consumers to agree on constraints under which a service is made available. However, the original protocol is limited to a simple interaction pattern for establishing agreements: the requester suggests the Quality of Service (QoS) details, the responder either accepts or declines. This is no longer sufficient when several rounds of negotiations are needed before both parties agree on the QoS level to be provided, or when an already established agreement needs to be changed based on mutual consent (renegotiation). This paper presents an extension to WS-Agreement which jointly addresses these limitations.