Aiming at the problem that the processing ability of software-defined network single controller can’t meet the requirement of scalability and that the current distributed multi-controller platform can’t change the service according to the actual situation, this paper puts forward the design of service abstraction layer at the control level, and tests the feasibility of the abstract service layer in the application of controllers for the operation of the bottom layer or the interaction between applications. Try. The traditional network architecture is distributed, and each network device has relatively independent operating system and control level. The exchange of information and data between devices through distributed network protocols leads to more and more tedious and complex network management and configuration. Through existing networks, it is becoming increasingly difficult for managers to innovate and upgrade and deploy new network structures. Therefore, a new architecture is needed, which can classify and control data dynamics, and realize forwarding and control. Software-Defined Networking (SDN), as a new network architecture, has attracted wide attention. Aiming at the problems of software definition network, scalability, performance evaluation and some related test methods, this paper proposes a control platform architecture model for the problems of insufficient processing ability of a single controller and the inability of current distributed solutions to change the service architecture according to the actual situation. The existing architecture is analyzed and summarized. Based on the model, the service abstract architecture controller is designed, and the function and performance of the controller are tested. SoftwareDefined Networking obtains global network information by controlling and forwarding the separated, open north-south interface and centralized control plane, and dynamically allocating and optimizing network resources according to the needs of the business. This measure greatly improves the flexibility of network control, makes it possible to manage, programmable and dynamically change the network, thus realizing the flexible control of network traffic, and provides a good platform for innovation of core network and application. The traditional Internet architecture is distributed, and each network device has relatively independent operating system and control level.
Information and data are exchanged between devices and devices through distributed network protocols. Its structure has several shortcomings: complex network devices. Configuration is difficult. Network features are tied to the underlying operating system, making it difficult to add new features.
OpenFlow is the main network platform for software definition. The method of separating control logic from forwarding devices makes the data plane have the ability to add and upgrade flexible devices. A typical approach of multi-controller SDN network is to divide the network into several control regions, each controlled by one controller. The existing multi-controller architectures can be divided into two categories: horizontal multi-controller architecture and hierarchical multi-controller architecture. Distributed deployment of multiple controllers is one of the important means to solve the performance, scalability and reliability problems of SDN networks. However, the existence of multiple controllers also faces other new challenges. The most critical problem is how to choose the number of controllers and the location of controllers. Current research work mainly considers the placement of controllers from several aspects: the placement of controllers based on transmission delay, reliability and other indicators. SDN manages and controls the network in a logically centralized way. In order to solve the problem of failure in centralized control environment, deploying multiple controllers in the network is an important means to solve the problem of the reliability of SDN control plane. Faults in SDN control plane can be divided into controller faults and node or link faults of transmission control flow. In order to overcome the faults of the controller, the reliability of the SDN control plane is improved mainly by the passive or active replication technology of the controller. In order to overcome the failures of nodes or links in transmission control flow, the reliability of SDN control plane is mainly improved by path protection or path recovery. Multi-controller platform involves architecture design, controller placement and other issues. In view of these problems, this paper combines the existing research classification, through analysis and summary, can deeply understand the problems of multi-controller platform, and propose solutions, which lays a theoretical foundation for the design of abstract service layer. In order to solve the problems of limited processing capacity of centralized control platform and high cost of collecting global view information, this paper uses multi-controller to meet the demand. Controllers should be transparent to applications, that is, applications are written in the same way regardless of how services change. That is to say, when the underlying services change, the original application does not need any modification. To achieve this, thermostatic element the underlying protocol must be changed more carefully and the application must be relatively transparent. Service abstraction layer can be used to achieve this. Service abstraction layer can dynamically link controller applications with southbound protocols to provide basic network services, such as using similar topology management module to realize the functions of topology construction and device discovery. The service provided by the abstraction layer is constructed by the controller based on the function provided by the application or network device. The abstraction layer of the request service for the application maps to the corresponding controller plug-in, and chooses the appropriate southward protocol to communicate with the given network device. Service abstraction layer in the process design between services and plug-ins for example: when a plug-in supporting OpenFlow protocol receives an ARP request packet, it needs to dispatch this packet to the ARP processing program. The protocol plug-in will call the data package output service interface and transfer the data package to the service abstraction layer. The ARP handler registers the data to the listening packet service interface. In the last step, the data received by the service abstraction layer will be transferred to the corresponding application of the ARP handler. The application can now process this packet.
Through the above analysis combined with the current situation of software definition network, the software definition network multi-controller platform is theoretically analyzed and designed to verify. Experimental verification of network topology under multi-control platform. The controller provides a physical network topology view with logic centralization for application. In order to directly manage network rules strategy for network application, the controller supports the change of forwarding rules for network devices. Like most controllers, the controller uses device connections discovered by LLDP messages to construct the network topology. The Topology View option provides a graphical view of the switch and host topologies. In the multi-controller topology of abstract service control, each manager stores and equipments corresponding to the controller, including the function and accessibility information of the device.
This information is stored by the controller and managed by the topology manager. Other components include ARP handler, host explorer, device manager, switch manager, etc. to assist the topology manager in generating network topology database. Experimental verification of service abstraction under multi-control platform. Configuration of experimental environment.
Start Mininet in a machine that has a Mininet environment installed, and configure multiple hosts and switches accordingly. Start a simple forwarding package application in the controller layer. It detects each host connected to the network through ARP packets, and installs rules for switches so that the packet can be transferred to each host smoothly. By dragging the device, the logical topology is formed and the configuration is saved. Experimental analysis. Because the controller is hosted in the server, after making the configuration similar to the above, the first thing is to connect the controller, through the state information of the controller response to understand the operation of the network, in which response 201 indicates the success of the operation.
In order to narrate intuitively and concisely, three switches are configured in the experiment. The south-facing protocols used in each switch are different. Get deleted host information (see Figure 3). The simulation results show that the abstract service layer can verify the feasibility of the underlying operation or interaction design between applications in controller application by acquiring topology information, configuring and acquiring user link information, acquiring and deleting host information and other experimental operations. It realizes multi-controller, multi-protocol support and application transparency. No matter how the service changes, the application is written in the same way. This paper uses the experimental platform to simulate and demonstrate the problems related to software defined network and multi-controller platform, and realizes the multi-controller platform of service abstraction architecture. The service abstraction layer can dynamically link the application of controller and the south-facing protocol to provide basic network services, such as using similar topology management module to complete the construction of topology and discovery device functions. Service abstraction layer and controller plug-in are independent and coupled, so that network protocols or applications can be upgraded flexibly.