Research And Simulated Implementation Of Multi-layer Protection Routing Mechanism In IP Over WDM Networks

With the rapid development of Internet, people put forward new requirements on the capacity and performance of the communication system. Wavelength Division Multiplexing (WDM) technology can provide huge transmission capacity and meet the demand for bandwidth of the Internet traffic. However, the occurrence of network failures will lead to a lot of traffic interrupted. At the same time, in order to reduce the network operating cost and improve the bandwidth resources utilization, the current transport network gradually evolves from traditional IP over ATM over SDH/SONET over WDM multi-overlapping structure to IP over WDM two-layer structure for bearing the IP traffic directly on the WDM optical network. Under this background, this thesis studies the multi-layer protection routing mechanism in IP over WDM networks.The mechanism designed in this thesis considers both unicast and multicast cases, and also distinguish the dedicated and shared protection resources. Multi-layer auxiliary graph is designed to deal with the multi-constraints, including sparse-incomplete wavelength conversion capability, number of optical transmitters and receivers, and sparse-incomplete splitting capability. The concept of load balancing is introduced into the mechanism in order to reduce the number of services blocked as a result of the failure. The Unicast multi-layer protection routing mechanism firstly grooms the request, establishes the working path and the protecting path in IP layer, and then provides the protection for heavy-load working lightpath in WDM layer. For the unicast case, utility based multi-layer coordinating mechanism is designed to consider protection resource utilization and protection switching time of both IP and WDM layer for determining based on utility which layer to be responsible for the failure recovery. The Multicast multi-layer protection routing mechanism firstly grooms the request, establishes the working multicast forest and the protecting multicast forest in IP layer, and then provides the protection for heavy-load working multicast forest in WDM layer. Therefore, sub-tree based multicast traffic grooming algorithm, multicast routing under multi-constraints algorithm and multicast shared segment protection algorithm are designed for multicast traffic grooming, WDM layer multicast routing and protection of light-tree, respectively. To evaluate the performance of designed mechanism, a simulation platform is designed and developed. And based on this platform, the performance of designed mechanism is evaluated. The simulation results show that the designed mechanism can solve the multi-layer protection routing problems in IP over WDM networks efficiently and effectively.