The Design of Partially Survivable Networks

In cellular telecommunications networks, a mobile telephone switching office (MTSO) co-ordinates the activities of the mobile units either directly or through intermediate hubs. In order to increase reliability, cells often split their traffic via multiple hubs — this ensures partial survivability in the face of equipment failures. This chapter examines three related problems in the context of partial survivability. The first is a single-period model that addresses the question of assigning cells to hubs at minimum cost, while incorporating diversity requirements. The second extends the problem into a multi-period context, while the third incorporates capacity requirements at the hubs. Results from extensive computational tests are presented for the first two versions of the problem, while limited results are presented for the third.