Admission control and path allocation for SLAs in DiffServ networks

In this paper we consider a Differentiated Service domain, in which the domain administrator has to decide whether to accept or to reject service level agreements (SLA) requested by users. After introducing the admission criteria which are used to verify if there are enough resources to satisfy the SLA request, we focus our attention to the problem of the SLA routing, i.e., the selection of paths along which traffic may flow. In particular, we show that the construction of an optimal set of paths is equivalent to the construction of a multicast tree, or a Steiner tree which is known to be an NP-hard problem. We therefore propose a class of simple heuristics, whose performance is assessed by simulations. Results show that it is possible to increase up to 40% the amount of capacity a network provider can reserve to SLA requests without violating the QoS constraints or to reduce the SLA blocking probability by a order of magnitude by using the proposed algorithms.