Degraded services in mixed-line-rate networks using multipath routing

Traffic in optical backbone networks is increasing and becoming heterogeneous with respect to bandwidth and QoS requirements due to the popularity of high-bandwidth services such as cloud computing, e-science, telemedicine, etc. which need to coexist with traditional services (HTTP, etc.). Mixed-line-rate (MLR) networks which support lightpaths of different rates are being studied to support the heterogeneous traffic demands. Here, we study the important topic of degraded services in MLR networks, where a service can accept degradation in bandwidth to a certain extent in case of a failure for lower cost, a concept called partial protection. Network operators may wish to support degraded services to optimize network resources and reduce cost. We develop a multipath routing scheme to support degraded services in MLR networks, and our illustrative examples show that significant cost savings can be achieved vs. full protection.