Live video streaming traffic and related applications have experienced significant growth in recent years. However, this has been accompanied by some challenging issues, especially in terms of resource utilization. Although IP multicasting can be recognized as an efficient mechanism to cope with these challenges, it suffers from many problems. Applying software-defined networking (SDN) and network function virtualization (NFV) technologies enable researchers to cope with IP multicasting issues in novel ways. In this article, by leveraging the SDN concept, we introduce OSCAR (Optimizing reSourCe utilizAtion in live video stReaming) as a new cost-aware video streaming approach to provide advanced video coding (AVC)-based live streaming services in the network. In this article, we use two types of virtualized network functions (VNFs): virtual reverse proxy (VRP) and virtual transcoder function (VTF). At the edge of the network, VRPs are responsible for collecting clients’ requests and sending them to an SDN controller. Then, by executing a mixed-integer linear program (MILP), the SDN controller determines a group of optimal multicast trees for streaming the requested videos from an appropriate origin server to the VRPs. Moreover, to elevate the efficiency of resource allocation and meet the given end-to-end latency threshold, OSCAR delivers only the highest requested quality from the origin server to an optimal group of VTFs over a multicast tree. The selected VTFs then transcode the received video segments and transmit them to the requesting VRPs in a multicast fashion. To mitigate the time complexity of the proposed MILP model, we present a simple and efficient heuristic algorithm that determines a near-optimal solution in polynomial time. Using the MiniNet emulator, we evaluate the performance of OSCAR in various scenarios. The results show that OSCAR surpasses other SVC- and AVC-based multicast and unicast approaches in terms of cost and resource utilization.

中文翻译：

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OSCAR：关于优化实时视频流中的资源利用

近年来，实时视频流流量和相关应用程序经历了显着增长。但是，这伴随着一些具有挑战性的问题，尤其是在资源利用方面。尽管IP多播可以被认为是应对这些挑战的有效机制，但它存在许多问题。应用软件定义的网络（SDN）和网络功能虚拟化（NFV）技术可使研究人员以新颖的方式应对IP多播问题。在本文中，通过利用SDN概念，我们引入OSCAR（优化实时视频流的资源利用）作为一种新的可感知成本的视频流方法，以在网络中提供基于高级视频编码（AVC）的实时流服务。在本文中，我们使用两种类型的虚拟化网络功能（VNF）：虚拟反向代理（VRP）和虚拟代码转换器功能（VTF）。在网络的边缘，VRP负责收集客户端的请求并将其发送到SDN控制器。然后，通过执行混合整数线性程序（MILP），SDN控制器确定一组最佳多播树，以将请求的视频从适当的原始服务器传输到VRP。而且，为了提高资源分配的效率并满足给定的端到端等待时间阈值，OSCAR仅通过组播树从源服务器向最佳VTF组传递最高请求的质量。然后，选定的VTF对接收的视频片段进行转码，然后以多播的方式将其传输到发出请求的VRP。为了减轻建议的MILP模型的时间复杂度，我们提出了一种简单有效的启发式算法，可以确定多项式时间内的近似最优解。使用MiniNet仿真器，我们可以评估OSCAR在各种情况下的性能。结果表明，在成本和资源利用率方面，OSCAR优于其他基于SVC和AVC的多播和单播方法。