1 Providing inter-domain QoS guaranteed services is a huge challenge for operators and will bring new revenues to them. But, establishing end-to-end services requires a level of resource management that does not exist yet, even locally to an operator. Due to confidentiality and independence reasons, operators are afraid to cooperate which can not be avoided in the inter-domain context. We consider the existence of an alliance framework wherein operators would agree to cooperate. In this article, we address the issues of negotiating inter-domain services and propose efficient algorithms to determine the end-to-end QoS contract that will satisfy the QoS demand for a service.