A Practical Approach to Traffic Engineering using an Unsplittable Multicommodity Flow Problem with QoS Constraints

Abstract

The paper presents a practical approach to calculating intra-domain paths within a domain of a content-aware network (CAN) that uses source routing. This approach was used in the prototype CAN constructed as a part of the Future Internet Engineering project outcome. The calculated paths must satisfy demands for capacity (capacity for a single connection and for aggregate connections using the given path are considered distinctly) and for a number of path-additive measures like delay, loss ratio. We state a suitable variant of QoS-aware unsplittable multicommodity ow problem and present the solving algorithm. The algorithm answers to the needs of its immediate application in the constructed system: a quick return within a short and fairly predictable time, simplicity and modiability, good behavior in the absence of a feasible solution (returning approximately-feasible solutions, showing how to modify demands to retain feasibility). On the other hand, a certain level of overdimensioning of the network is explored, unlike in a typical optimization algorithm. The algorithm is a mixture of: (i) shortest path techniques, (ii) simpli ed reference-level multicriteria techniques and parametric analysis applied to aggregate the QoS criteria (iii) penalty and mutation techniques to handle the common constraints. Numerical experiments assessing various aspects of the algorithm behavior are given.