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.