The Research Of Wavelength Scheduling For Flexible And Efficient TWDM-PON System

The TWDM-PON system is considered as the most promising optical access solution for those reasons.It can meet the growing bandwidth demand day by day and be compatible with the TDM-PON system which is widely deployed now to realize a smooth upgrade.Besides,it also can schedule the resources in dimensions of time and space.In 2012,the FSAN clearly pointed out that the TWDM-PON is the choice for NG-PON2 in the future.For the new optical access network solution TWDM-PON,it is of great significance to put forward an algorithm which can adaptive this system and make full use of the feature that wavelength schedule.Combined with software defined and network coding,this paper put forward a forward the flexible and efficient architecture of TWDM-PON and then optimize the system on the on the levels of software and data.On the control level,a wavelength scheduling algorithm is proposed and the result of simulation can validate that this algorithm can bring effects of traffic grooming and energy saving.On the data forwarding level,it can achieve data forwarding through hardware acceleration and economization processing of flow.In this paper,the specific research work are as follows:(1)Proposed the flexible and efficient TWDM-PON system architecture.This architecture is a Software Defined TWDM-PON(SD-TWDM-PON based on OVS.The flexibility is embedded in flexible intelligent control after introducing the software defined.It makes all devices,such as OLT,ONU,ODN,under the control of central controller.Through the unified management for OLT and ONU,the architecture can schedule the wavelength of uplink and downlink flexible.By forming a OLT resource poll and ONU resource pool,it is highly dynamic allowing controller to change the connectivity of OLT and ONT.The efficiency is embedded in saving the downline bandwidth when there is peer communication between ONU under the same OLT after introducing network coding into TWDM-PON,up to 50%.Besides,implement the software defined data forwarding plane through the form of hardware will greatly accelerated the speed data forwarding.(2)Proposed scheduling algorithm wavelength on control surface.After introducing the software defined into system,the controller on the control plane can schedule the wavelength of uplink and downlink flexible and also control ODN to dynamic change the connectivity of OLT and ONU.According this feature,this paper proposed the scheduling algorithm to enhance the system performance.Due to the feature of SD-TWDM-PON,this paper presents the scheduling algorithm between OLTs and scheduling algorithm in the OLT.The schedule of OLT mainly uses the flexible control of ODN and the high security of network coding,it can make efficient channel between equivalent flows of ONU and QOS guarantee.The wavelength scheduling in OLT mainly uses the flexible distribution of wavelength in the system.The controller can achieve all the state information of ONUs and OLTs,to realize the wavelength scheduling of OLT under the complicated network state,and then achieve the goal of loading balancing and energy saving.Through the simulation,It can be seed that the algorithm can make full use of the bandwidth saving bring by network coding and achieve loading balancing and energy saving.(3)Hardware acceleration of data forwarding plane.Due to the scale of networks increased and complicating,the size of flow table becomes hugeness.The bottleneck of query in the software flow table is the query time.On the data forwarding plane,through implementing the core data structure of OVS by hardware,the data forwarding will accelerate and the data forwarding rate will be enhanced based on the flow,and the forwarding rules are stored in the flow table.Detailed rules of data forwarding can be formulated to achieve the flow economization.