SLA Calculus for End-to-End QoS of TCP-Based Applications in a Multi-Domain Environment

Next-generation communication services will be offered over distributed information and communication infrastructures consisting of a multitude of administrative domains, owned by different parties. This raises the problem for service providers to provide satisfactory levels of end-to-end Quality of Service (QoS), as experienced by the paying end user, in a cost-effective manner. Motivated by this, the authors consider the problem of end-to-end QoS provisioning for TCP-based applications that cross multiple network domains. To this end, the authors construct an analytical model that provides a so-called SLA calculus, i.e. a mapping between per-domain network QoS parameters defined in the involved Service Level Agreements (SLAs) and end-to-end QoS metrics like response times and file download times that determine the QoS perceived by the end users.