Broadband networks design models and admission control algorithms

Abstract

The development of efficient provisioning methods is one of the remaining challenges for the successful deployment of telecommunication networks. In this thesis, two of the many problems involved in telecommunication networks design are addressed: the connection admission control problem (CAC), which refers to the set of actions, taken at connection time, to decide whether to accept or reject the request for a new call/connection. The second is the network-wide link sizing problem, which selects the topology of the (ideally) optimal network interconnecting the nodes, based on traffic characterization, nodal layout, routing and admission control procedures. These two problems are related since the CAC policy, together with the traffic characterization, nodal layout and routing, determines the internal traffic of the network which is used in the link sizing problem. Two location models for the design of telecommunications networks, with constrained buffer length at switches, are introduced and discussed, which find optimal locations of switches on a network, and allocate users to them so as to minimize overall cost. Also, for a given buffer length, the models keep the desired cell-loss probability P smaller than or equal to α. Four fault tolerant telecommunication networks design models are discussed. Relaxation techniques and heuristics are used to solve the models. The fundamental network design problem that is addressed consists in determining, given the location of the communication nodes, the traffic demands among pairs of origin-destination nodes, fault tolerance restrictions and the cost structure for the available technologies, the capacity to be assigned to each link, in such a way to satisfy the restriction while reaching a minimum cost network. The thesis also focuses on the use of genetic algorithms in the design of telecommunications networks satisfying bi-connectivity and delay constraints. The design of a biconnected telecommunication network, consists in the interconnection of a set of N nodes, in such a way there exist at least two alternative paths between any given pair of nodes and the cost of the network (considering routing, capacities and delay restrictions) is minimized. An admission control and a traffic shaping method for BISDN/ATM networks are proposed. The method operates at the burst connection level based on the Sustainable data-transfer rate concept. The model treats all cells equally regardless of their associated service requirements.