Research On Open-interface Technology Between Hierarchical Controllers In The Software-defined Optical Network

With the development of Software Defined Network in the computer network science in recent years, it has been gradually extended to the optical transport network and been called Software Defined Optical Network (SDON) technology. SDON achieves the unified control and schedules for all optical layer resources. It provide the way of software programming to control dynamically, it meet the demand of business diversification and expansibility. The key idea of SDON architecture is the concept of separation between network control plane and forwarding plane,and it has open and programmable interfaces, and centralized control of optical network resources. With the expansion of network and emergency of new services, optical network resources need to be divided into several sub-regions, each sub-region has certain self-control capabilities and its own single domain controller (PNC). Each PNC is connected to multi-domain controller, which can achieve end-to-end control in global network,and it can achieve centralized scheduling and management among many manufacturers as well. Then the idea of hierarchical control of optical network is gradually developed. In the hierarchical control optical network architecture, the layers of controllers need to coordinate with each other to complete the centralized network control. In addition, the controller's northbound needs to support rapid business innovation, which requires flexibility and scalability of northbound interface. Therefore, the open programmability of the interface in the hierarchical control optical network is of great significance to the development of SDON technology. In this paper, we will study the interface technology in hierarchical optical network.Based on the architecture of ACTN (Abstraction and Control of TE Networks), this paper designs a scheme about comparison between two protocols on programmable interfaces, this paper also conduct an experiment to demonstrate the performance of SDON with protocols. At the same time, this paper also studies the northbound interface in SDON architecture. Based on the technology of intent framework and global network view, this paper also proposed northbound interfaces abstraction model. It can provide complete application to the north layer, then the scheme is designed to validate the feasibility of the model.The main work and innovation of this paper are as follows:Firstly, based on the SDON network scenario, a typical hierarchical control optical network architecture-ACTN architecture is proposed, and the controller and the interfaces between the controllers are studied.Secondly, based on ACTN architecture, two experimental schemes are proposed to solve the problem of the performance of the southbound interface and the interface between controllers under this hierarchical optical network architecture. For the interfaces in ACTN, the topology convergence function are completed with the binary protocol and the text protocol respectively. Experimental results show that the binary-based PCEP protocol can achieve better performance than the text-based Restconf protocol in terms of the first convergence time of the topology update.Thirdly, aiming at solving the different standard of SDON northbound interface and not meeting the diversified demands of APP application in optical network. The paper focuses on the northbound open interface of ACTN architecture, and proposes a northbound interface abstraction model,which can provide complete northbound APP. The simulation results show that APP applications, including Topology application, Service Request application, SSE (Service Scheduling Expert) application, BOD(Bandwidth of Demand) application and VON (Virtual Optical Network)application in SDON network can be supported by this northbound interface abstraction model.