Scalability of closed-loop video delivery service

Scalability is a key issue of on-line video service. Different methods have been proposed for the closed-loop video service, such as batching and patching. However, scalability itself has not been formally defined and the condition for a scalable system is not well studied yet. This paper studies scalability and the condition for scalable systems. It is found that when the arrival rate is across the threshold Θ the system becomes scalable. This threshold value depends only on the number of videos, video length, and request distribution. We present an analysis for batching and patching. Comparison of batching, patching, and a new method, scheduled video delivery (SVD), is presented in this paper.