Providing accurate estimates of performance in large heterogeneous internetworks, for the purposes of network design and planning and for service provisioning has become a critical problem. This is due to the heterogeneity of the physical medium, the size of current and future networks and the different quality of service requirements for multimedia services. In this thesis we describe our work on the development of connection level mathematical models used for estimating network performance characteristics such as throughput, delay and blocking probability. These network models can also be used in estimating performance in general packet-switched networks using effective bandwidth concepts. In particular, these models are directly applicable in studying connection blocking for networks using QoS routing schemes.
Computational complexity is a serious usability bottleneck for such algorithms.
We describe even faster algorithms based on a hierarchical loss network model we have developed. The latter are well matched to networks that have a natural hierarchical architecture, or which use some form of hierarchical routing to further reduce computational cost. We also developed models for networks using delay-based QoS routing. An important objective of our work is to demonstrate the utility of these models for effective design and dimensioning of a large network so that a certain set of QoS requirements are met. We describe our research in the development of a general network design and dimensioning methodology by linking our performance models with Automatic Differentiation and multi-objective optimization algorithms and tools.