Research On Asynchronous Transmission And Bandwidth Allocation In Software Defined Networks

Under the rapid advancement of Internet technology,the data traffic undertaken on the Internet has grown exponentially in recent years.In order to meet the requirements of new services and new applications for the network,a large number of protocols have been added to the traditional network,making the network structure more and more bloated.Thus,it is more and more difficult to adapt to development of future.These challenges have all contributed to the emergence of the emergence of Software Defined(SDN).SDN is a new network paradigm that separates the control plane from the data plane.A centralized controller manages the network,making the network devices of the data plane transparent to the upper-layer network applications in the SDN network.In addition,the unified programming interface provided by the southbound protocol is used to implement flexible scheduling of network resources.The transition from an existing network to an SDN network is a trend.Broadband Services and the Internet of Things are two main kinds of business applications in carrier network today.In order to improve the utilization of resources and simplify management to network in carrier network,the thesis optimizes the network to support the two kinds of business applications,Broadband Services and the Internet of Things,with combination of the research field of SDN.1.For the IoT business,it is necessary to combine existing IoT network with softwaredefined network to enhance the efficiency of data transmission of the IoT network.In the IoT system,asynchronous data transmission in the mode of multiple points to single point(M2P)causes heavy load on the controller.For the problem,this thesis proposes one request scheme for software-defined network to update the forwarding rules for multiple data transmissions from the same event in batch with the first packet from the gateway.What's more,to discuss the conflict between data transmission of M2 P and potential sensing events and propose routing scheme with multiple sensing events.2.For Broadband Services,the operator provides different services for users according to users' subscription.The mode of service cannot provide customized services according to users' needs,such as providing users with dynamic allocation of bandwidth.It wastes valuable network resources and increases the burden on users.Ultimately it reduces the user experience.Based on the OpenDaylight controller,this thesis designs and implements the application for dynamic allocation of bandwidth to these problems in SDN network.The system automatically completes allocation of bandwidth to the users according to the request of bandwidth from the users.The main functional modules of the system are measurement module,topology module,route calculation module and bandwidth allocation module.3.In order to verify proposed various algorithms and mechanisms in large-scale SDN networks,this thesis designs a scalable multi-controller SDN testbed.It has six modules,consisting of data plane module,host module,control plane module,monitoring module,export module and analysis module.Introducing the function of every modular and concrete method of implementation and emphasizing the mechanism of multiple controllers and implementation of multiple controllers in the thesis.With the experience from the building of the SDN testbed,we design experiments to test and verify the process of asynchronous transmission and allocation of bandwidth in the software-defined network.