A distributed approach to measure IP traffic matrices

The traffic matrix of a telecommunications network is an essential input for any kind of network design and capacity planning decision. In this paper we address a debate surrounding traffic matrix estimation, namely whether or not the costs of direct measurement are too prohibitive to be practical. We examine the feasibility of direct measurement by outlining the computation, communication and storage overheads, for traffic matrices defined at different granularity levels. We illustrate that today's technology, that necessitates a centralized solution, does indeed incur prohibitive costs. We explain what steps are necessary to move towards fully distributed solutions, that would drastically reduce many overheads. However, we illustrate that the basic distributed solution, in which flow monitors are on all the time, is excessive and unnecessary. By discovering and taking advantage of a key stability property underlying traffic matrices, we are able to propose a new scheme that is distributed and relies only on a limited use of flow measurement data. Our approach is simple, accurate and scalable. Furthermore, it significantly reduces the overheads above and beyond the basic distributed solution. Our results imply that direct measurement of traffic matrices should become feasible in the near future.