Study On ONU Admission Management And Bandwidth Allocation Algorithm For Multi-Standard VPON

With the continuous development of Internet technology,many new network application scenarios appear.As a result,the users' demand for bandwidth and service quality is constantly improved.To cope with the upgrade demand,a variety of technology standards have appeared in the field of access network over the years.According to the requirement of smooth evolution,there will be multiple technology standards in the access network.Network virtualization can help solve the management and resource cooperative scheduling issues of multi-standard network coexistence scenario.Passive Optical Network(PON)is the mainstream technology of access network.The virtualization of the access network is the research of PON virtualization.Virtual Passive Optical Network(VPON)is a logical-level virtual topology network.It has open architecture and programmable features,which can break the access restrictions brought by physical separation of traditional network.VPON allows users to join different networks through virtual connections and provides users with flexible and customized services.Through the programmable central control platform,the construction of VPON can be scheduled and controlled,and multiple VPONs' resources can be coordinated and deployed.The architecture design of VPON will bring the problem of coexistence of multiple standard networks and equipment.The flexibility of Optical Network Unit(ONU)virtual access will also pose new challenges to VPON's load management.Therefore,research on VPON-oriented ONU admission management and dynamic bandwidth allocation algorithms is of great significance.This dissertation conducts in-depth analysis and research on VPON-oriented ONU admission management and dynamic bandwidth allocation algorithms.Based on different VPON scenarios,we build models,analyze data,and propose corresponding ONU management and dynamic bandwidth allocation strategies.The specific research content is as follows: 1)For the management issue of ONU virtual access in VPON,an admission decision mechanism based on network-service value is proposed,which combines bandwidth requirement and service level for evaluation and management.The network-service value model is established to supervise the bandwidth allocation to ensure that VPON provides high quality bandwidth service.A multi-stages dynamic bandwidth allocation algorithm is proposed to provide bandwidth allocation and ONU virtual access management solutions for different network scenarios based on the network-service value.2)For the VPON scenario where the ONU's tuning time is not zero and multiple standard ONUs coexist,an adaptive bandwidth allocation algorithm is proposed to solve the tuning delay problem.A load-based dynamic wavelength number selection mechanism is proposed to ensure high bandwidth utilization.A ONU time slot scheduling matrix is constructed.According to the different ONU tuning time and network parameters,an adaptive time slot scheduling scheme is adopted to avoid the delay caused by the ONU wavelength tuning.The scheduling scheme can also provide excellent load balancing performance.3)For the idle time issue caused by high Round Trip Time(RTT)in VPON scenario based on LR WDM/TDM PON,a multi-thread dynamic bandwidth allocation algorithm is proposed.A dynamic thread and wavelength selection mechanism is proposed to ensure high bandwidth utilization.Elastic thread window and bandwidth resource advance mechanism are proposed to strengthen the inter-thread collaboration ability.The multi-thread algorithm effectively utilizes idle time caused by high RTT in VPON scenario based on LR WDM/TDM PON.By constructing the ONU buffer area and using the time stamp,the ONU wavelength tuning and transmission conflict problems in the scenario where multi-standard tuning equipment coexist are solved.