Conservative staircase data broadcasting protocol for video on demand

Using multiple channels to broadcast a popular video is common in near video on demand (NVOD) systems. There are various protocols that adopt this method. Among those protocols, the harmonic protocol and its derivative protocols have the best performance in reducing the viewer's waiting time under a given bandwidth. The staircase protocol is reported to have the lowest buffer requirement and disk I/O requirement to client end. However, two defects in staircase protocol that may cause video discontinuity at the client site are ignored. In this paper, we talked about these two defects and explained how they cause video discontinuity at the client site. Then, we presented the conservative staircase protocol. As its name implies, this protocol adopts a conservative bandwidth assignment to ensure the continuity of the video received. At last, we compared the performance of this protocol with that of the staircase protocol. The results showed that our protocol has a similar performance compared with the staircase protocol but with more practicability.