Research On The Store-and-forward Mechanisms In Multidomain Optical Networks

With the development of internet technology and data applications,the network presents new features.With the continuous expansion of the network scale,the multi-layer and multi-domain network has become the trend of large-scale networks in the future.How to fully and effectively utilize limited network resources to improve the transmission of the ever-increasing data has become the key to encourage the development of data services.Rapid growth of traffic leads to bottlenecks on inter-domain links,and the residual bandwidth on such links exhibits temporal and spatial variations.There may not be sufficient bandwidth for end-to-end inter-domain transmission upon the arrival of bulk data requests.The research on Store-and-Forward(SnF)for solving delay tolerant data transmission inspired us to combine SnF and hierarchical routing to mitigate bandwidth contention during peak hours through temporary storage.Therefore,this paper focus on introducing SnF into multi-domain networks to solve the transmission scheduling problem of delay tolerant inter-domain transfers,including the inter-layer scheduling strategy and the large search space size and high computational complexity problems caused by SnF.The detailed contents and results of our paper are discussed as follows:Firstly,the TS-MLG(time-shifted multilayer graph)routing framework is applied to the hierarchical routing structure for the problems of inter-level temporal-spatial resource maintenance and scheduling brought by the introduction of SnF into the multi-domain network.An updating strategy is proposed to realize temporal bandwidth information exchange between physical and logical layers.With this scheme,the inter-domain routing path,as well as the storage points and the time of transmission,can be determined through conventional routing computations.Numerical simulations reveal that SnF can improve the inter-domain bandwidth utilization and optimize the network performance at the practical cost of network states maintenance overhead and computational complexity.And then,aiming at the problem of large search size and high computational complexity after the introduction of storage,we study the compromise between transmission performance and computational complexity by constructing a three-layer hierarchical routing scheduling structure based on two-level hierarchical structure.The computational complexity of inter-domain services on the complete Logical TS-MLG(LTS-MLG)is O((VL_R)~2).In addition to L_R,the purpose of reducing the routing search space can be achieved by limiting the number of nodes V.We first calculate the intermediate domain of the source and destination nodes in advance on the third layer according to the principle of minimum number of domains,and then separate the relevant temporal-spatial links from the LTS-MLG of the second layer,and construct the new Partial LTS-MLG.In this way,the computation space of the abstraction layer routing can be reduced to(NL_R)~2,N<V.The simulation results show that the three-layer structure can reduce the search space size as well as the simulation time.A compromise between network performance and computational complexity can be achieved at the expense of a small amount of blocking rate difference.