The current Web Services Agreement specification draft proposes a simple requestresponse protocol for agreement creation only addressing bilateral offer exchanges. This paper proposes a framework augmenting this WSAgreement to enable negotiations according to a variety of bilateral and multilateral negotiation protocols. The framework design is based on a thorough analysis of taxonomies for negotiations from the literature in order to allow for capturing a variety of different negotiation models within a single, WS-Agreement compatible, framework. In order to provide for the intended flexibility, the proposed protocol takes a two-stage approach: a meta-protocol is conducted among interested parties to agree on a common negotiation protocol first before the real negotiation is carried out in the second step due to the protocol established in the first step.

Grid computing has recently become an important paradigm for managing computationally demanding applications, composed of a collection of services. The dynamic discovery of services, and the selection of a particular service instance providing the best value out of the discovered alternatives, poses a complex multiattribute n:m allocation decision problem, which is often solved using a central resource broker. However, decentralized approaches to this service allocation problem represent a much more flexible alternative, thus promising improvements in the efficiency of the resulting negotiations and W. Streitberger (B) · S. Hudert · T. Eymann service allocations. This paper compares centralized and decentralized service allocation mechanisms in Grid market scenarios according to a defined set of metrics.

The vision of an open and global Internet of Services (IoS)is driven by globalization and fast changing settings when trading on a world-wide scope. It requires automated online techniques for handling services and resources themselves, for advertising and discovery as well as for the onthe-fly negotiation of proper terms for their use. In such a setting covering completely different branches and traditions of business, a flexible infrastructure for negotiating service level agreements is mandatory. In this paper, we propose an extended service usage cycle suitable for IoS along with an expressive but still machine manageable protocol description language capable of specifying a multitude of different negotiation protocols. It supports the extended usage cycle and permits choosing services with appropriate SLA negotiation styles as well as performing SLA negotiations based on the style agreed by potential business partners.

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