Software Defined Hierarchical Optical Access Network And Its Applications

In recent years,with the construction of cyber physical systems(CPS)such as mobile communication,data center,Internet of Things and industrial Internet,it is necessary to rely on high-speed and large-capacity optical access network technology to achieve data collecting,merging,transmitting,switching and processing.Due to the multi-source,discretization and heterogeneity of the spatio-temporal distribution of the massive data generated by the access root node,the traditional optical access network has been unable to meet the demand.Based on these application requirements,researches on the optical access network architecture,nodes and switching technologies through software definition and hybrid optical-electrical switching technologies have been carried out,considering both the physical layer and media access control(MAC)layer to meet the needs of massive data accessing and processing.Firstly,the software defined hierarchical optical access network(SD-HOAN)scheme is proposed,realizing unified control of core and access network domains,using different wavebands for uplink,downlink and control channels,and implementing layered distributed hybrid optical-electrical switching for cluster,set,domain and core four-layer signals.This combines both the physical layer and MAC layer so as to support multi-source heterogeneous data convergence,layered switching and unified control.A network simulator is developed,and a periodic signaling transmission mechanism and a dense time slot scheduling algorithm are proposed based on the architecture of the SD-HOAN.Simulation results verify that SD-HOAN has high throughput and low latency.Then,the single-and dual-fiber bidirectional passive optical distribution nodes(PODNs),and the output port bandwidth reconfigurable hybrid optical-electrical core switching node(HOECSN)are presented.The PODN constitutes the transmission path among the HOECSN and the edge access nodes(EANs).The MACs for both PODN and HOECSN are studied,realizing massive heterogeneous data switching within the set,domain and the core layer.Based on traffic statistics,the output bandwidth of the HOECSN can be dynamically configured,which improves the output bandwidth utilization and reduces the power consumption.Next,the applications of SD-HOAN technology in two specific scenarios are studied.A large-scale data center SD-HOAN system is proposed,where the PODNs and inter-cluster switching nodes respectively form a passive optical access and an electrical access layer,realizing dual MAC layered switching,and the load-sensing dual-mode(LSDM)scheduling algorithm is presented to implement efficient intra-cluster communication.High scalability and low power consumption are achieved.On the other hand,an intelligent substation SD-HOAN system is designed,and the prototypes of edge and core nodes are developed with the functions of low-latency one-way multicast,protocol conversion and optical domain signal aggregation,respectively.The SD-HOAN prototype system for SV service of intelligent substation is realized.Field experiments were carried out with high real-time and high reliability characteristics.Finally,the summary and the future work are discussed.