Research On Several Key Technologies Of PCE-Based Multi-Layer Multi-Region Intelligent Optical Networks

With the growing of data service, the optical networks have experienced the change of the peer-to-peer SDH transport system to mesh networks, and there are lager network scale, more network nodes and more complicated network topologies. It is the future development trend for the optical networks to provide a scalable multi-layer/multi-domain network structure supporting the transport of multi-granularity services. In the large-scale multi-layer/multi-domain optical networks, high performance CPU resources are needed to process complicated algorithms as there are always huge path computation tasks with complicated constraints, which is a huge challenge to the network devices. Thus the IETF workgroup proposed the concept of PCE, which realize the path computation function by arrange specific resource. It is now a hot research field that combine the advantages of PCE with other network technologies to provide rapid, right and reliable routing function for the network services.The research work of this paper is based on an 863 project named DREAMSCAPE, and combined with the PCE technology, mainly focuses on such research fields as network structure, multi-domain routing, resource reservation, traffic grooming and etc. The main work and innovative contributions of this paper can be summarized as follows:Firstly, an additional backup model for PCE is proposed in order to avoid the risk as the PCE does not work. In this model, the system can turn the function of PCE to other ones immediately as it is down, thus the network can work properly. Secondly, based on the research work on existing strategies for multi-domain routing, a hierarchical PCE-based multi-domain routing scheme is proposed. This scheme guarantees the optimal route and path setup delay considering TE information and utilizing multiple PCEs. Both the theoretical analysis and the test results show that the scheme can reduce the setup-delay and the network blocking probability obviously.Thirdly, three different wavelength assignment schemes are proposed to solve the reservation collision problem in the destination initialized reservation scenario. The first two are realized through an assistance unit located in PCE in the process of wavelength selection. The third one is realized through reserving an additional backup lambda for the connection requests to decrease the collision probability as there is enough resource. Simulation results show that, the three schemes have successfully avoided the collision between two or more concurrently connections that traverse the same link/links and performs much better than the two traditional schemes in decreasing total blocking probability.Fourthly, two PCE-based dynamic traffic grooming schemes are proposed, one of which is realized through setting a threshold for the hops of a path and the other is realized through integration of the physical topology and logical topology and considering the load balance on the physical topology to establish a LSP connection. Simulation results show that the proposed schemes have higher resource use rate and lower blocking probability than the traditional way.Lastly, the novel routing structure-DREAMSCAPE proposed by the 863 project that the author participated in is studied and analyzed. The experimental platform is constructed and a network management system is developed. Based on the platform, two proposed routing scheme namely DRE-FPC and HDRE-BRPC are tested compared to the traditional HR scheme and some of the testing results are given and analyzed.