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Frontiers of Information Technology & Electronic Engineering
ISSN 2095-9184 (print), ISSN 2095-9230 (online)
2016 Vol.17 No.7 P.672-681
A video conferencing system based on SDN-enabled SVC multicast
Abstract: Current typical video conferencing connection is bridged by a multipoint control unit (MCU), which may cause large delay and communication bottleneck for the whole system. With the development of network technology, a video conferencing system can be implemented based on software-defined networking (SDN), which makes the service controllable and improves the scalability and flexibility. Additionally, a video encoding method called scalable video coding (SVC) can also help. In this paper, we propose a video conferencing architecture based on SDN-enabled SVC multicasting, which discards the traditional Internet group management protocol (IGMP) and MCU. The system implements SVC multicast streaming to satisfy different device capabilities of various conference terminals. The SDN controller is responsible for dynamically managing and controlling the layers of a video stream when a conference member faces network congestion. Also, a conference manager is designed to facilitate the management of the conference members. Experimental results show that our system can not only provide a flexible and controllable video delivery, but also reduce the network usage while guaranteeing the quality of service (QoS) of video conferencing.
Key words: Software-defined networking (SDN), Multicast, Scalable video coding, Video conferencing system
创新点：我们设计了在软件定义网络中采用分层组播思想的视频会议系统。该系统摒弃了当前典型视频会议系统中的多点控制单元（MCU），采用全新的架构，从而可以根据异构的终端能力、网络的链路状态，对与会者进行差异服务，提高服务质量。
方法：本文目标是能够在节省带宽、降低时延和保证服务质量的前提下，构建一个稳定全新的视频会议系统。摒弃当前典型视频会议系统的MCU，提出了全新的服务架构（图2）。系统可分为四部分功能实体：会议管理服务器，SDN网络控制器，OpenFlow交换机和会议终端（图3）。采用模块化设计思想，在会议管理服务器中，集成了组管理、信息管理和接入控制等模块；在网络控制器中，集成了拓扑管理、QoS管理和路由管理等模块。各功能实体和模块相互协作，为参会者提供视频会议服务。我们搭建了一个试验床来测试系统：首先测试了网络带宽的使用量和服务时延（图6），之后测试了网络内部SVC视频层数自适应调节的性能（图7、8）。实验结果表明：相比于基于MCU的视频会议系统和SDN单层视频组播视频会议系统，本文提出的系统性能更优。
结论：采用基于SDN的SVC视频组播技术来构建视频会议系统。所构建的系统可以根据异构的终端能力、网络的链路状态，对与会者进行差异服务并实现网络内部的视频层数动态调节，从而避免网络拥塞，提高服务质量。
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Open peer comments: Debate/Discuss/Question/Opinion
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DOI:
10.1631/FITEE.1601087
CLC number:
TP393; TN919.8
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On-line Access:
2016-07-05
Received:
2016-03-14
Revision Accepted:
2016-06-19
Crosschecked:
2016-06-25