Automation, informationization and mutual you, you */ dynamic smart grids need a smarter network. SDN Software Definition Network (SDN Software Definition Network) can help the rapid development of intelligent power/network. OpenDaylight is an open source controller framework for SDN. It is easier to open and innovate SDN in a collaborative way and model driven architecture. SDN controller framework OpenDaylight technology has been studied in depth. Smart grid is based on integrated high-speed two-way communication network, using a variety of high-tech and advanced equipment, can truly realize the security, efficiency, stability, environmental protection, economy of the grid, is the future development trend.
Smart grid needs automation, information and interaction. All this requires a more intelligent network. SDN software definition network can help the smart grid develop faster. OpenDaylight is an open source controller framework for SDN. It is easier to open and innovate SDN in a collaborative way and model driven architecture. In this paper, the OpenDaylight technology of SDN controller framework is deeply studied.
OpenDaylight shields the bottom layer, the network serves the application, builds a unified open SDN platform, the goal is to create a SDN network operating system. OpenDaylight includes the following core technologies. OSGI: A service-oriented architecture that treats applications as peer-to-peer collaboration and supports the installation, deletion and updating of services while the controller is running. MAVEN: Building tools can help us automate the building process, from cleaning, compiling, testing to generating reports, to packaging and deployment. SAL: The whole architecture introduces the business abstraction layer, which abstracts the service and isolates the calls from the upper layer to the north and the lower layer to the south. MD: Model Drive. Using YANG tools and business model driven to design interfaces and realize business functions, according to YANG files, YANG tools directly generate the framework of business management, mainly used for adapting North-South interface data, so that developers can really focus on specific business. South to API: Openflow, etc. The controller manages the bottom layer through the South-to-South API. Northbound API: REST API, the application layer manages the controller through the Northbound API. OSGI modularization defines the concept of OSGI module, and calls it a BUNDLE, which contains a metadata JAR file, in which the metadata MANIFEST.MF, composed of NAME_VALUE pairs, consists of classes and related resources, focuses on packaging and sharing code. Life cycle defines how OSGI can be dynamically installed and managed in the framework. Through the operation of life cycle, installation, update, uninstallation, dynamic management and improvement of applications do not require restarting applications.
The emphasis is on module management at execution time and access to the underlying OSGI framework. Service level to service, service registration, search and so on. Interface and implementation are separated. OSGI is a JAVA interface, and the components in the module interact and communicate with each other. Bundle’s abstract base class manages global and container-related services, and bundle itself is a big service. Container is a network domain in OpenDaylight. Container Manager manages containers, and OSGI manages bundles. Each module has multiple implementations, in which dependencies are managed through Dependency Manager.
Each component implements a Component, thermostatic element and each Component is a service, which describes the interfaces everywhere and dependencies. Dependency Manager manages dependencies with component. The main function of SAL is to abstract the service, no matter what protocol is used between the controller and the network device, to provide the unified service of the protocol. SAL is the core design of ODL.
It supports a variety of southward protocols and provides consistent services for modules and applications. The implementation of these services is the interface provided by the underlying plug-ins based on the functions of existing components and network devices. Specific requests are mapped to the corresponding plug-ins to complete the service. Data Packet Services provide services for data message processing. Topology Service provides update information of nodes and links for applications. Inventory service provides API queries for nodes such as nodes or node connections. Flow Programming Service is a stream programming service. Resource service provides resource services. The main function of MD-SAL is to promote pipelines between providers and users. It can provide pipes between providers and users in different containers. It will connect to a message bus and cluster opendaylight container for shared data storage. The consistency of South and North directions. Providers or consumers are registered in MD-SAL. Thus, a consumer can find the supplier he needs.
Providers can generate notifications, consumers can receive notifications and obtain data from providers. Plug-in SAL roles are consumers or producers, and the data in the SAL they define is removed or stored. Providers can store data in SAL, and a consumer can read data from SAL. MD-SAL provides request routing and infrastructure services to support services. But it does not provide services by itself, but is provided by plug-ins. YANG makes APIs between Components, plugins, northbound, etc. It makes this interface more abstract than the AD-SAL REST interface and conforms to the idea of model-driven. The Openflow message first arrives at Controller and sends it to a class that has registered to listen to Openflow messages for processing. Packet In message arrives, passes through the underlying plugin, passes through the SAL layer, invokes and implements the receiveDataPacket processing of IListenDataPacket. It mainly involves three modules: ARPHandler, HostTracker and simple Forwarding. ARPHandler is mainly responsible for arpRequest and arpReply. HostTracker is responsible for host information, updating host, and connection status. SimpleForwarding processes IP messages and installs the flow to each host. Controller sends the message to Discovery Service.
It implements Idata packetlisten. In the process of processing Openflow message in DataPacket muxdemux, it processes the link process Discovery Packet message and gives it to Topology service his Implements Idiscoverylistener, which implements idiscoverylistener. SDN opens up a road of network innovation, which transforms the original message forwarding process completely controlled by switch/router into the joint completion of OpenFlow switch and controller Controller, thus realizing the separation of data forwarding and routing control. Controller is the core of SDN. It can control the flow meter in OpenFlow switch by pre-defined interface operation, so as to achieve the purpose of intelligent control of data forwarding. SDN technology has broad prospects for building smart grid.