Using resource pools for pre-signaled restoration lSP in ASON networks

When considering network restoration, the amount of reserved resources has an important impact on network performance in that it can restrict the acceptance of new connections. Thus, the use of shared resources to support restoration can improve overall network performance. However, efficient resource sharing searches in a global network require extensive computation and database updates. The restoration scheme proposed in this paper can be performed by more than one entity. For instance, one node can perform CPU- intensive computations and send updates to other nodes responsible for the admissions and establishment of new connections on the network. Thus only a small number of nodes are required to store large databases and perform complex path calculations. Within the IETF there are two groups that focus on restoration mechanisms and large-scale networks: CCAMP and PCE. The proposed restoration mechanism can be applied for networks based on the control plane defined by the CCAMP Group. It can also be implemented in GMPLS-based networks where the PCE architecture is present. Here, the scheme is defined for ASON GMPLS-based networks, where LSPs represent lightpaths between OXCs that comprise a control plane compliant with the GMPLS umbrella of protocols. The performance evaluation shows that the proposed scheme can provide improved resource savings compared to other restoration schemes and a high robustness for lightpaths that require degrees of protection up to 100%.