A Novel Interval Caching Strategy for Video-on-Demand Systems

Abstract

In a Video-on-Demand (VOD) system, in order to guarantee smooth playback of a video stream, sufficient resources (such as I/O bandwidth, network bandwidth) have to be reserved in advance. Given limited resources, the number of simultaneous streams can be supported by a video server is restricted. Due to the mechanical nature, the I/O subsystem is generally the performance bottleneck of a VOD system, and there have been a number of caching algorithms to overcome the disk bandwidth limitation. In this paper, we propose a novel caching strategy, referred to as client-assisted interval caching (CIC) scheme, to balance the requirements of I/O bandwidth and cache capacity, in a cost-effective way. The CIC scheme tends to use the cache memory available in clients so as to dramatically reduce the demand on the I/O bandwidth of the server. Our objective is to maximize the number of requests that can be supported by the system and minimize the overall system cost. Experimental results show the superior of CIC scheme to the traditional Interval Caching (IC) scheme, with respect to request accepted ratio and average servicing cost per stream.

Design and implementation of video servers for VoD system

“…While interval-based algorithms are heavily used in the VoD system. IC, DISTANT, dynamic grouping (DG), GIC and GIS are the examples of interval-based schemes (Wujuan et al, 2006). The dynamic grouping buffer management scheme merges and decomposes in two groups with largest profit (Sheu et al, 1997).…”

“…Recently, various interval-based buffer management schemes have been proposed to take advantage of the sequential access pattern of video streams, e.g., interval caching (IC), greedy interval caching (GIC) and greedy-interval-strategy (GIS) (Dan and Sitaram, 1993;Wujuan et al, 2006;Neil et al, 1993;Boll et al, 2000). The interval-based buffer management scheme uses the temporal locality of the consecutive requests for the same video.…”

Optimizing Caching in a Patch Streaming Multimedia-on-Demand System

“…These techniques can be divided into two categories: interval-based [1, [9][10][11] caching and prefix and interval-based [4,10,12] caching.…”

“…Interval-based schemes: Interval-based caching schemes include interval caching (IC) [1], popularity-aware interval caching (PIC) [9], and client-assisted interval caching (CIC) [11]. All interval-based caching techniques are characterized by caching intervals between two consecutive requests on a single media object.…”

“…A number of caching techniques are proposed [1,4,[9][10][11][12], and some are optimized to work with a batch streaming system. These caching techniques are mostly used as a means of decreasing the start-up latency since batch streaming is characterized by large inherent latency.…”