Research On The Symmetrical Delay Service Path Protection Algorithm Of Automatic Switched Optical Network

With increasing requirements of data service, the traditional transport network needing human effects can not meet the demand of intelligent connection. Automatic Switched Optical Network is then becoming the key technology to the intelligent network. With the introduction of intelligent control and GMPLS, the automatic configuration and dynamic connection of optical network resources are realized. One of the functions in ASON control plane is about routing, where the constraint-based routing is especially used to meet the requirments of traffic engineering. As an example, the requirements of automatic electric power relay controlling services include one-way delay and delay between bidirectional paths, which can be taken as a kind of high reliability and delay-sensitive service. Therefore, this thesis focuses on the protection paths for delay constraint and high reliability.Firstly, this thesis discusses ASON network architecture and its survivability. Secondly, GMPLS-based constraint routing mechanism and time-delay requirement of automatic electric power relay controlling service are analyzed and researched. Finally, according to the analysis of time-delay requirement, a path-protection method for the bidirectional symmetrical time-delay path routing is proposed. This algorithm can utilize an approach of dynamic adjusting of link cost to obtain in an iterative manner the working paths and protection paths which are SRLG separation, and improve the services'reliability.In order to verify the effectiveness and reliability of the proposed algorithm, the simulator GLASS is used for simulation experiments. The algorithm is used on the 16-node NSFNET and bandwidth, SRLG and link cost are configured. The successful and unsuccessful calculation cases are described respectively. The simulatiosn results show that the algorithm is valid for the services with time-delay requirements. In addition, using the algorithm on networks which have different SRLG configuration parameters, the simulation results show that the proposed algorithm can solve SRLG separation and path separation problems.