A control architecture for quality of service and resource allocation in multiservice IP networks

A multiservice IP network based on the DiffServ paradigm is considered, composed by Edge Routers (ER) and Core Routers (CR), forming a domain that is supervised by a Bandwidth Broker (BB). The traffic in the network belongs to three basic categories: Expedited Forwarding (EF), Assured Forwarding (AF) and Best-Effort (BE). Consistently with the DiffServ environment, CRs only treat aggregate flows; on the other hand, ERs keep perflow information (from external sources or other network Domains), and convey it to the BB, which knows at each time instant the number (and the bandwidth requirements) of flows in progress within the domain for both EF and AF traffic categories. A global strategy for admission control, bandwidth allocation and routing within the domain is introduced and discussed in the paper. The approach adopted is based on the combination of analytical and simulation models of traffic with service guarantees and of TCP aggregated traffic. The global scheme (under different traffic patterns) is investigated and the results of its application under different traffic loads are studied on a test network with a ns-2 simulation tool.