Network reliability under mixed IP and optical protection

In this article, we extend previous work showing that DiffServ can provide some QoS guarantees to both realtime and non real-time traffic in the event of the failure of an optical component. Even though DiffServ cannot totally replace optical protection in a network, it might be able to do so to some degree. In this paper, we study a 4-node linear topology which can be protected by DiffServ, DiffProtect or even a combination of both (MixProtect). We evaluate the performance of all protection combinations which enables us to study the extent to which we could replace optical protection by DiffServ in a particular network. Results have shown that replacing optical protection by DiffServ cannot be done randomly, the number and positions of DiffServ protected links versus DiffProtect´s must be carefully chosen in order to guarantee maximum performance to all traffic types.