End-to-end QoS of X-domain pipes

Multi-media services and other critical multi-site services (e.g. VPN) are becoming mainstream, and require a guaranteed Quality of Service (QoS). Services need to be established across several domains, often to connect multi-domain end-users. Thus, provisioning and control of end-to-end QoS requirements arises as one of the main challenges in X-domain management. While the use of QoS contracts (Service Level Agreements, SLAs) is crucial, the problem of QoS guarantees goes beyond the scope of contracts between one server and one client. End-to-end QoS contracts are subject to cumulation effects that must be taken into account. Moreover, several paths of contracts may satisfy the user's QoS requirements. While our previous work studied negotiation of end-to-end QoS contracts for single service requests, we turn here to pipes that handle large numbers of requests, allocating from a variety of contract chains between a fixed source and a fixed target domain. For incoming requests, a pipe selects from a pre-established set of contract chains, rather then launching a new negotiation. This paper studies the optimization and constraint resolution problems arising in pipe negotiation.