Design And Simulated Implementation Of Dynamic Multicast Traffic Grooming Algorithms In Multi-Granularity Optical Networks

With the development of network technology and the increasing of users’ requirements, multicast has become an important type of transmission. Since the Wavelength Division Multiplexing (WDM) optical network has the huge bandwidth capacity, it can provide a good network infrastructure for the various bandwidth requirements for multicast. In IP over WDM optical networks, although the required bandwidth granularity of each multicast connection is various, it is generally less than a full wavelength capacity, so that the direct use of an optical wavelength channel to transmit a low-speed multicast service will reduce the bandwidth resource utilization and lead to a higher network blocking probability. In order to achieve higher resource utilization and lower blocking probability as much as possible, it is necessary to use the traffic grooming technology to groom a lot of low-speed connections into a few of high-speed optical channels. Meanwhile, with the increase of optical network capacity, the port number of optical cross-connect device is enhanced such that the complexity and the cost are greatly increased. By using the waveband switching technology in which many wavelength channels can be grouped to several waveband tunnels each of which takes only one switching port. Thus, the consumed ports and the complexity of multi-granularity optical cross-connects can be greatly reduced.According to analysis above, it shows that how to effectively groom the dynamic multicast traffic is the research focus of multicast technology. Firstly, based on the multi-granularity IP over WDM optical networks, through integrating the traditional traffic grooming and waveband switching technologies, this thesis proposes a dynamic multicast multi-granularity mechanism; that is, dynamically providing the multi-level multicast grooming for sub-wavelength level, wavelength level and the waveband level. Then, this thesis designs a model for multicast multi-granularity traffic grooming and a node structure to support multicast multi-granularity traffic grooming. According to the different types of network applications, this thesis presents the definition of different types of blocking probability. Based on the designed multicast traffic grooming model and the different requirements of network application for different types of blocking probability, this thesis proposes two novel dynamic multicast multi-granularity grooming heuristic algorithms, where the first is called minimizing the mean blocking probability of requests heuristic algorithm for multicast multi-granularity traffic grooming and the second is called minimizing the mean blocking probability of users heuristic algorithm for multicast multi-granularity traffic grooming.In order to assess the performance of the designed heuristic algorithms, this thesis develops software by VC++6.0for simulation and analysis. Simulation results show that the designed dynamic multicast multi-granularity traffic grooming algorithms have better performances in reducing the blocking probability and the switching node cost.