A Scalable CAC Algorithm Providing StrictEnd-to-End Delay Guarantees in Networks with Aggregate Scheduling

Aggregate scheduling has been proposed as a solution for achieving scalability in large-size networks. However,in order to enable the provisioning of real-time services, such as video delivery or voice conversations, in aggregate scheduling networks, end-to-end delay bounds for single flows are required. In this thesis, we derive per-flow end-to-end delay bounds in aggregate scheduling networks in which per-egress(or sink-tree)aggregation is in place, and flows traffic is aggregated according to a FIFO policy. The derivation process is based on Network Calculus, which is suitably extended to this purpose. We show that the bound is tight by deriving the scenario in which it is attained. After that we investigate the problem of scalable admission control for real-time traffic in sink-tree networks employing per-aggregate resource management policies. Every traffic flow entering the network at an ingress node, and flowing towards a given egress node, specifies its leaky-bucket parameters and a required delay bound for traversing the network. We propose an algorithm (based on results previously showed)that admits a new flow if a guarantee can be given that the required delay bound, besides those of other already established flows, are not exceeded.