An Extended SDN-Based In-Network Caching Service for Video on Demand

The network traffic has been growing explosively in recent years after users can watch the high quality video from the Internet. It is an important issue to reduce network traffic and increase the user quality of experience (QoE). Therefore, there have been in-network caching schemes to cache the content fetched by users in proxy servers. Recently, software defined networking (SDN) was proposed to implement the network function by the virtualization function. Programmers can implement the customized network functions by the SDN architecture. This paper proposes an extended SDN-based caching service architecture, abbreviated as ESC. The ESC decomposes the function of inspecting incoming traffic, making cache decision, and storing cache content into three types of network entities: an extended OpenFlow (DPI-based) switch, a cache controller, and cache nodes. This design can lessen the load of single network entity. Moreover, the ESC can cache different parts of a video in distinct cache nodes. The distributed content storage mechanism can increase the cache capability and the system flexibility. In addition, we use 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 results in numerical analysis show that the ESC average queuing delay is shorter than the other two.