Routing And Control Technology In Multi-Layer And Multi-Region Optical Networks

With the rapid development of Internet, many kinds of services such as Real-time Streaming media communication, large volume data transporting, and storage area network thrive in this climate. The demand of bandwidth is also rise sharply. It takes many opportunities and challenges to the optical network.In the large scale multi-layer and multi-region optical network, many computational resources will be consumed because of the complex constraint conditions. So the apparatus of the network will face the challenge of lacking in resources. Internet Engineering Task Force (IETF) proposed a new concept about path computation element. A Path Computation Element (PCE) is an entity that is capable of computing a network path, and of applying computational constraints during the computation. The PCE entity is an application which can be located within a network node, or on an out-of-network server. The main contributions of this article are listed as follows:Firstly, several algorithms are proposed in the article, such as hierarchical routing (HR), forward path computation with dual-routing-engine (DRE-FPC) and backward recursive path computation (BRPC). We compared the performance of these algorithms.Secondly, a hot standby model in the PCE architecture is proposed in the article. The mechanism of hot standby is also introduced. The PCEP is extended for this model. The network is robust by applying this hot standby mechanism.Thirdly, when the network traffic load is light it is not necessary to enable traffic engineer.Whether enable or disable traffic engineering, the blocking probability is keep in a low level. When the network traffic load is heavy, the performance with global TE is far better the counterpart without TE. So, we can set a threshold, when the number of occupied wavelength is littler than it, do not enable TE. Otherwise, enable TE. The performance of these two condition has been compared by using OMNeT++, and the result shows that we can reduce the routing protocol overhead, while still keeping the well performance.