Davide Cherubini - PhD Thesis - UniCA Eprints

Chapter 7LP Model Tests & ResultsThe first optimization model presented in the last chapter, makes use of IS-ISrouting protocol in combination with explicit MPLS LSPs in order to find the besttraffic flow distribution. The objective function minimization process involvesalso additional survivability constraints that guarantee the delivery of the trafficin case of single link failure, using the link restoration technique performed by theunderlying IS-IS protocol.In this chapter the results of tests performed over this model are shown and, asbenchmark networks, three different topologies have been used.Two of them are synthetic networks while the third is a real backbone network.At the beginning of the chapter a short description of the implementation and ofthe software used to solve the LP model is given.7.1 Model implementationThe pre-testing phase has required the implementation of a C++ code reproducingthe behaviour of the IS-IS routing protocol. The instances of the problemhave been prepared using the Jones Lustig format [14] and have been read usinga service class for Multicommodity Min Cost Flow solvers called “Graph”[11]. A C++ function has been also implemented, which prepares the matrixrepresenting the constraints of the MMCF problem passing it to an Open sourcesolver called OsiSolver [16]. A further C++ class to decompose the aggregatedper source flows has been implemented.65