An Extended SDN Architecture for Video-on-Demand Caching

Owing to the variety of ways to view the Internet and the changes in user behavior on the Internet, network traffic has been explosively growing in recent years. Users can watch high-quality videos on the Internet; it is a critical issue to reduce network traffic and increase the user's quality of experience (QoE). Therefore, there have been in-network caching services that cache the content that had been fetched by the user in a proxy server. Meanwhile, the software-defined network (SDN) has been developed to implement the network function through the virtualization function. Programmers can implement customized network functions using the SDN architecture. In this paper, we proposed an Extended SDN Cache service architecture (ESC). The ESC decomposes the function of inspecting incoming traffic, making cache decisions, and caching content to three network entities. This design can reduce the load of a single network entity. To reduce the load of the SDN controller, we utilize an extended OpenFlow switch named the DPI (deep packet inspection) switch, which can inspect the incoming traffic. The ESC designed a mechanism that can cache the different parts of a video in distinct cache nodes. The distributed content storage mechanism can increase the cache capability and the system's flexibility. We use the M/M/1 queuing model to analyze the average queuing delay time and compare the ESC queuing delay time with the C-flow and the OpenCache. The numerical analysis results show that the ESC queuing delay is shorter than the other two.