The Research And Design Of Protection Mechanism In Optical Tranport Network

As a new transmission technology, optical transport network can satisfy the needs of transmission network, and it has begun a large-scale commercial application since2011. An Efficient and flexible optical transport network is playing an increasingly important role in economic and social development. Once a transport network fault occurs, it could cause incalculable economic losses, so the research of protection mechanism in OTN has a great significance both in theory and practical.With the introduction of distributed control plane, OTN can achieve more intelligent signaling protocols and routing strategies, so it can not only have a flexible protection mechanism in a complex topology, but also get a high resource utilization. The testing on the OTN protection mechanism is an important way to know the protection mechanism’s performance and actual needs in engineering applications. In the paper, we give a detailed description on the test of ODUk sub-network connection protection and control plane-based protection and restoration, and also analyzes the advantages and disadvantages among these protection mechanisms. Through the testing we found that the introduction of control plane brings flexibility of OTN protection mechanisms as well as makes its implementation becomes more complicated, so it is necessary to strengthen the research of the protection mechanisms based on control plane.The research of protection mechanism based on the control plane is belong to the survivability technical problems of the intelligent optical network. In the paper, we propose a shared protection mechanism based on the grade of services under the control plane. For the current algorithms rarely think of the difference among the network services, and the studies have not comprehensive enough, the algorithm will divided the services into high priority services and low priority services according to a certain criteria, and provide different protection schemes for the different grade of services. In the algorithm we put up the concept of sharing risks link group (SRLG) weigh factor, which is not only to meet the control plane requirements of SRLG separation, but also as far as guidance the service route to the path with less numbers of SRLG, so that can reduce the impact of SRLG on path selection. And it also put the network load balancing into consider, then we design two formulas to calculate the cost of work route and protection route. With the above aspects in mind, we put forward the shared protection mechanism based on the grade of services.The final simulation results based on MATLAB show that the algorithm can effectively reduce the rate of network congestion and improve the utilization of network resources.