Optimized Design And Implementation Of SDN-Based Segment Routing Network

The Segment Routing(SR)technology,which has received wide attention in the industry in the past two years,is considered to be a new generation of network technology after MPLS.It better combines the SDN centralized control idea with the distributed route calculation method.The data plane utilizes a mature routing protocol to establish an optimal path to other network elements based on the IP routing model.The control plane makes an optimal routing decision based on the global network view,and is responsible for indicating the key network element path points through which the traffic needs to pass.SR provides a stable,reliable,flexible and controllable traffic scheduling method,and has made a lot of efforts in routing and fault protection.This paper presents optimized designs and implementations of routing,fault handling and network telemetry for SDN-based Segment Routing networks.In terms of routing,this paper extended the flow steering capability of the SR network.Based on the P4 programmable data plane,a source routing scheme is designed to support two types of tunnel,both key path points and hop-by-hop path points.This enables the network to have fine-grained ability to plan end-to-end traffic paths,and to have ability to avoid potential fault points by specifying protection path exactly,which can prevent the transient state of the inconsistent routing information of each network element in the SR network from affecting the effectiveness of the fault protection.In the aspect of fault detection,a detection method based on neighbor keep-alive and passive detection is designed,which reduces the bandwidth overhead.The detection method is implemented in the device data plane,which reduces the performance overhead of detection and enhances the sensitivity of fault detection.It provides new methods and possibilities for achieving fault detection and fault protection goals of the SR network within 50 ms.In terms of fault protection,in order to achieve rapid emergency protection of traffic,a fault point approach protection scheme including three protection methods and a closed loop feedback mechanism of the protection process are designed,so that multiple protection schemes are backed up each other.A fault notification mechanism based on constrained broadcast delivery and a protection scheme for source tunnel switching are designed.The traffic portal device,e.g.provider edge router,ensures that traffic is still forwarded on the whole optimal path when it is protected.The protection process is autonomously enabled and executed by the device data plane,that improves the response speed and execution efficiency of the protection measures.In terms of network telemetry,for the problem that in-band telemetry is difficult to obtain enough data in time when the packet loss ratio is high,a tellemetry scheme combining hop-by-hop push and end push method is designed.The hop-by-hop push method improves the reliability of data collection,while the management plane only performs detailed anallysis of the data from end push method to maintain a low processing load.In addition,telemetry can be performed on different flows with different push cycles as needed,so that the telemetry function can be applied to multiple types of traffic while improving telemetry efficiency.