Local Optimal File Delivery Scheduling in a Hop by Hop File Delivery System on a One Link Model

Abstract

Many content distribution systems such as CDN and P2P file sharing have been developed. In these systems, file-type contents require downloads to be completed before they can be played and they have no value before the download finishes. Therefore, a user's satisfaction depends on the length of the service latency. That is, the length of time from when the user issued a request until the user received an entire file. Reducing the sum of that time is necessary for the whole delivery system to satisfy users and maintain dependability on system performance. We discuss a hop-by-hop file delivery system suitable for delivering file contents whereby the sum of service latency is reduced by using the request conditions. Moreover, we propose a file delivery scheduling algorithm for a one-link model given that the content request frequency is unknown. The algorithm is based on a local optimal strategy. We performed a characteristic analysis by computer simulation. The results showed that our algorithm performs at nearly the theoretical efficiency limit of the hop-by-hop system when the request frequency distribution of each content has a deviation.