Software Defined Multimedia Multicast System And Transmission Strategy

In recent years,with the progress of network and multimedia technologies,multi-media applications,such as IPTV,video conferencing,VoD,Internet video surveillance and virtual reality,have become part of people's daily life,which is followed by the rapid growth of IP traffic in the network.The huge consumption of network resource may lead to network congestion and large transmission delay,which will finally reduce the quality of multimedia services,resulting in poor user experience.So it's neces-sary to seek new mechanisms,architectures and algorithms to optimize the multimedia transmission services.As the network carrying more and more services,current Inter-net becomes bloated and lacks the guarantee of QoS.Researchers are exploring the design of new network architectures.Software Defined Networking(SDN)has been fast emerging as a promising network technology for building next-generation services and networks,since it provides open interfaces to programmatically manage and control network behavior.It is a great significance to solve the challenges of multimedia trans-mission by researching on the multimedia transmission mechanisms,architectures and algorithms over SDN.In order to guarantee the quality of network multimedia services and optimize the utilization of network resources,this dissertation studies the multi-media multicast transmission control and optimization problem over SDN by using the advanced multimedia codec technology,network optimization theory,online network measurement and multicast.The main research work is summarized as follows:1)Design of software defined scalable video multicast architecture.Based on scal-able video codec and the open interfaces of controllable and programmable net-work provided by SDN,this dissertation focuses on how to design a multimedia multicast service system.Firstly,in order to enable the forwarding nodes in the network identifying the video content and realize the completely controllable mul-ticast,we design a management subsystem.We define the functional entities in the video service system,and design the modules in the functional entities.Sec-ondly,this dissertation presents a method of monitoring available bandwidth and network delay in SDN,which can support the quality of service for multimedia traffic.Thirdly,we propose a solution for inter-domain and multi-ISP service de-ployment that handles the scalability problem over large-scale networks.Finally,on the basis of the proposed architecture,we build a software defined scalable video multicast prototype,and conduct some experiments to evaluate the system.Experimental results show that the proposed architecture can realize the scalable video multicast transmission service over SDN,and can achieve the purpose of optimizing the utilization of network resources.2)Studies on adaptive multicast transmission strategy for scalable video over SDN.Policy module in the management server of the proposed software defined scal-able video multicast system can support customizing routing calculation,mul-ticast tree construction and video transmission control algorithms.Policy mod-ule can deploy different strategies according to different scenarios,applications and requirements.In this dissertation,we propose a bandwidth and delay con-strained multicast routing algorithm over SDN.According to the network topol-ogy and link state provided by SDN controller,a minimum cost video multicast tree with QoS constraints is constructed.Meanwhile,we propose an in-network adaptive scalable video transmission strategy based on equivalent bandwidth es-timation.In the process of video transmission,the system can detect the network link congestion according to the network state information,and select the number of transmitted video layers by the corresponding algorithm.Dynamically adjust-ing the number of scalable video layers can avoid link congestion to guarantee the user's viewing experience.We conduct the related experiments in the prototype.Experimental results show that the proposed strategy can effectively avoid link congestion and improve QoS of the video service.3)Research on video conferencing system based on layered multicast over SDN.In this dissertation,we deploy video conferencing services based on scalable video and network multicast technology over SDN.In MCU-based video conferencing systems,because the centralized MCU has a very high load,it probably becomes the bottleneck of the system and difficult to ensure high QoS.In P2P-based con-ferencing systems,the limited network uplink bandwidth resource of a conference member may also lead to service interruption.We design a centralized conference manager,which manages the conference without receiving and processing media data from conference members.It can obtain network topology,available band-width,path delay and other information through the interface provided by the network controller.The conference manager can establish a multicast tree with QoS constraints for SVC video streams,and use in-network adaptive scalable video transmission strategy to dynamically adjust the video stream transmitted in the network.Experimental results show that the proposed system can not only provide flexible and controllable multicast transmission for video conferencing,but also can reduce the consumption of network bandwidth and ensure the quality of video conferencing services.