Research On Linear Network Coding In All-Optical Multicasting Networks

With the rapid development of network traffic, optical network, which has the properties of high speed, large bandwidth capacity and more flexible ability for network management, has been considered as the inevitable trend to support many future point-to-multipoint bandwidth-intensive applications,such as high-definition television(HDTV), multimedia document distribution and distributed games and so on.Besides,optical multicast can provide more superiorities than IP multicast when there are more and more demands in multicasting traffic.These intriguing observations prompt further investigation into optical multicast networks.However, the traditional optical multicast networks still cannot reach the maximum mujticast flow, while network coding, as a recently arisen technology, enables better resource utilization and improved throughput in optical multicast networks.Network coding allows the data from different incoming ports to be encoded instead of the conventional store-and-forward processing scheme in the multicast networks,the theoretical max-flow bound can be achieved, which is determined by the well known max-flow min-cut theorem. Furthermore, to achieve this upper flow bound, linear network coding is sufficiently enough. Accordingly, adapting network coding to optical multicast networks will facilitate the future development of effective optical networks.However, most of the proposed network coding schemes so fa is designed for the Electrical Layer (EL). While in all-optical networks, due to the limited buffering capability and weak logic operation ability of the actual optical network, employing linear network coding in all-optical multicast networks is still a tough problem.This paper pays much attention on the related fundamental theories and systemic concepts of linear network coding and its implement in all-optical multicast networks.Specially, the problem of the assignment of encoding vectors in the construction process of network coding is thoroughly investigated. Meanwhile, two methods to assign the encoding vectors have been proposed: the reversed method and the dynamic method based on the Graph Coloring for the assignment of the encoding vectors in multicast networks.Furthermore, another novel arithmetic which involves the scheduling arithmetic of the encoding source has been proposed for the distributed networks.Moreover, a hardware experimental platform, introducing the XOR gate based on the XGM in SOA, is put up to support and the proposed novel scheme for linear network coding in the practical all-optical multicast networks.Moreover, the experimental demonstration indicates that it is feasible and efficient to employing network coding in optical-layer multicast traffic.