Flow on Data Network and a Positive Semidefinite Representable Delay Function

Data networks are subject to congestion, thereby the delay to go across the network may be large enough in order to dishearten customers to keep on using such a network. In this paper we address the problem of determining in a given network a routing which minimizes the delay or keeps it under a certain bound. This problem was already shown as NP complete. Our main contribution is to study it in the special context of the positive semidefinite programming and we present a column generation approach to solve the underlying problem.