Number Of Simultaneous Streams Research Articles

Data stream management system for video on demand hybrid storage server

Video on demand (VOD) server requires a large storage capacity and rapid video retrieval from this storage to quickly stream these videos to users. The hybrid storage system, which combines HDDs and SSD in the server, has become popular because of such requirements. The combination of both storage modes is relatively weak in terms of optimising fast access prior and in supporting the production of a high number of simultaneous streams. This paper presents an enhanced hybrid storage system (EHSS)-based VOD server to improve the performance of the VOD server. The design of the EHSS and its streaming management scheme produce high performance and satisfy the performance requirements of a VOD server in terms of I/O throughput and access latency. The experimental results show that the proposed work provides better performance than the VOD server-based FADM because it enhances the average response times for the various scales of intensive workload by 69.89%.

A client-assisted interval caching strategy for video-on-demand systems

In a Video-on-Demand (VoD) system, in order to guarantee smooth playback of a video stream, sufficient resources (such as disk I/O (Input/Output) bandwidth, network bandwidth) have to be reserved in advance. Thus, 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 to serve the first few blocks of streams 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. Simulations are carried out to study the performance of our proposed strategy under various conditions. The experimental results show the superior of CIC scheme to the tradition Interval Caching (IC) scheme, with respect to request accepted ratio and average servicing cost per stream.

Resource-Based Striping: An Efficient Striping Strategy for Video Servers Using Heterogeneous Disk-Subsystems

In building a large-scale video server, it is highly desirable to use heterogeneous disk-subsystems for the following reasons. First, existing disks may fail, especially in an environment with a large number of disks, enforcing the use of new disks. Second, for a scalable server, to cope with the increasing demand of customers, new disks may be needed to increase the server's storage capacity and throughput. With rapid advances in the performance of disks, the newly added disks generally have a higher data transfer rate and a larger storage capacity than the disks originally in the system. In this paper, we propose a novel striping scheme, termed as resource-based striping (RBS), for video servers built on heterogeneous disks. RBS combines the techniques of wide striping and narrow striping so that it can obtain the optimal stripe allocation and efficiently utilize both the I/O bandwidth and storage capacity of all disks. RBS is suitable for applications whose files are not updated frequently, such as course-on-demand and movie-on-demand. We examine the performance of RBS via simulation experiments. Our results show that RBS greatly outperforms the conventional striping schemes proposed for video servers with heterogeneous or homogeneous disks, in terms of the number of simultaneous streams supported and the number of files that can be stored.

Delivery of low rate isochronous streams over the digital video broadcasting/Digital Audio-Visual Council cable television protocol

This paper examines the capacity and performance characteristics of the digital video broadcasting (DVB)/Digital Audio-Visual Council (DAVIC) cable television protocol for the delivery of low rate isochronous streams for a cable population of up to 700 nodes. Streams (ranging from 8 to 128 kbps) suitable for timing critical services such as compressed/uncompressed voice (e.g., VoIP: G711 and G.7231), audio and low quality video, were considered in order to study the effects on channel capacity when using reservation and fixed access for the delivery of timing critical services. The analysis focuses on the,performance of the upstream channel, which is the limiting factor of community antenna television (CATV) networks and is critical in the delivery of services to individual subscribers on demand. Simulation results indicated that such streams, within the given protocol limitations, can be supported for a particular system population with trade-offs in terms of system throughput and channel utilization. Network capacity, in terms of the number of simultaneous streams supported and link utilization, is significantly affected by packet size. Analysis of the results indicated that for different streams, packet sizes and combined with header suppression, the benefits from the use of fixed access is essential for the support of timing critical services.

Delivery of low bit rate isochronous streams over the DOCSIS 1.0 cable television protocol

The Data Over Cable Systems Interface Specification (DOCSIS) 1.0 protocol enables the delivery of Internet Protocol (IP) traffic over cable TV networks with significantly higher data rates when compared to analogue modems and integrated services digital network (ISDN) links. The availability of greater bandwidth enables the delivery of high quality audio and video services. Such services require bounded delay characteristics. This paper evaluates the capacity and performance characteristics of the DOCSIS 1.0 protocol for the delivery of isochronous streams given the limited quality of service (QOS) features of the protocol and a modem population of up to 500 nodes. Stream rates of up to 64 Kbps with different packet size were considered, suitable for compressed audio, voice and low quality video. Packet concatenation for upstream traffic was also considered. Simulation results indicated that such streams, within the given protocol limitations, can be supported for a particular system population with tradeoffs in terms of system throughput and channel utilisation of up to 50%. The network capacity, in terms of the number of simultaneous streams supported and link utilisation, is significantly affected by packet size. Support for concatenation has limited advantages. Performance benefits from concatenation are more evident when delivering higher rate bitstreams.