| With the rapid development of network technology,new network services such as live video,virtual/augmented reality,and remote control have put forward lower latency,higher bandwidth,and higher reliability and other service quality requirements for the network.Traditional IP networks have pain points such as complex architecture,challenges to expand,long route convergence time,and low management and control efficiency.They cannot provide deterministic service quality assurance for the transmission of business traffic.In the next-generation Internet technology,Software Defined Networking(SDN)separates the control plane and the data plane,and SRv6(Segment Routing IPv6)realizes fast source routing and forwarding of the data plane.They provide new ideas to realize the quality of service.The China Education and Research Network IPv6 Backbone Network(CERNET2)is an important demonstration project for developing the next-generation Internet in China.This paper studies a deterministic delay control model based on SDN architecture and combined with SRv6 technology that provides a deterministic delay service guarantee for business flows in the CERNET2 network environment.The main work includes the following three parts:Firstly,the design and realization of delay’s upper bound analysis function are based on network calculus.In the beginning,the characteristics of the data plane in the SDN environment are analyzed in-depth,and then the traffic arrival curve and the service curve of the node are described.Finally,the delay and queue length boundary values are calculated using the deterministic network calculus tool based on the minimum and maximum addition algebra.It provides theoretical data support for the deterministic delay control model.Secondly,the design and implementation of the state information collection function based on inband telemetry technology.This paper proposes an in-band telemetry scheme because the SDN controller needs to obtain a global view of the entire network and monitor the dynamic performance changes such as delays in real-time.At first,the structural characteristics of CERNET2 are analyzed through graph theory,and the low-redundancy detection path covering the entire network is obtained.Then,the design and processing of telemetry data packets are realized based on the programmable characteristics of SRv6 and P4(Programming Protocol-independent Packet Processors).Finally,the collected telemetry data is stored in a time-series-based database.It provides real-time state information for the deterministic delay control model.Thirdly,the path planning function based on the multi-constraint shortest path algorithm is designed and implemented.Given the various constraints and deterministic service quality requirements proposed by the business,this paper designs an optimal path solution algorithm based on LARAC(La Grange Relaxation-based Aggregated Cost).Firstly,because of the deterministic Qo S requirements,this paper improves the LARAC algorithm to meet the multi-constraint objectives,the backup path solution,and the optimization of running time.Then this paper designs the SRv6 Policy to meet the deterministic Qo S requirements.The verification and test of the deterministic delay control model are completed on the experimental platform of the ONOS controller and Mininet.The experimental results prove the feasibility of the deterministic delay control model.Through the analysis of the results,suggestions for improving the topology of the CERNET2 backbone network are put forward. |
