Balance content allocation scheme for peer-service area CDN architecture for IPTV services

One of the main problems in IPTV technology is how to manage the huge amount of multimedia contents efficiently to meet the demands of users especially for Video on Demand (VoD) services.Content Distribution Networks (CDN) are used to solve this problem but the problem of load imbalance among servers still exists due to the dynamic changes in contents and user interests in an IPTV environment.In the VoD context, many content storage management architecture models are proposed: single point, hierarchal, distributed, and service peer area architectures.In the this paper we choose peer-service area architecture for CDN to study the load imbalance problem and try to handle it by modifying peer-service area architecture and proposing a balanced content allocation scheme that solves the load imbalance problem by replicating the contents based on their popularity.Experimental results show that this proposed allocation scheme can maintain the load balancing among servers and avoid over/under utilization of servers

ATOM : a distributed system for video retrieval via ATM networks

The convergence of high speed networks, powerful personal computer processors and improved storage technology has led to the development of video-on-demand services to the desktop that provide interactive controls and deliver Client-selected video information on a Client-specified schedule. This dissertation presents the design of a video-on-demand system for Asynchronous Transfer Mode (ATM) networks, incorporating an optimised topology for the nodes in the system and an architecture for Quality of Service (QoS). The system is called ATOM which stands for Asynchronous Transfer Mode Objects. Real-time video playback over a network consumes large bandwidth and requires strict bounds on delay and error in order to satisfy the visual and auditory needs of the user. Streamed video is a fundamentally different type of traffic to conventional IP (Internet Protocol) data since files are viewed in real-time, not downloaded and then viewed. This streaming data must arrive at the Client decoder when needed or it loses its interactive value. Characteristics of multimedia data are investigated including the use of compression to reduce the excessive bit rates and storage requirements of digital video. The suitability of MPEG-1 for video-on-demand is presented. Having considered the bandwidth, delay and error requirements of real-time video, the next step in designing the system is to evaluate current models of video-on-demand. The distributed nature of four such models is considered, focusing on how Clients discover Servers and locate videos. This evaluation eliminates a centralized approach in which Servers have no logical or physical connection to any other Servers in the network and also introduces the concept of a selection strategy to find alternative Servers when Servers are fully loaded. During this investigation, it becomes clear that another entity (called a Broker) could provide a central repository for Server information. Clients have logical access to all videos on every Server simply by connecting to a Broker. The ATOM Model for distributed video-on-demand is then presented by way of a diagram of the topology showing the interconnection of Servers, Brokers and Clients; a description of each node in the system; a list of the connectivity rules; a description of the protocol; a description of the Server selection strategy and the protocol if a Broker fails. A sample network is provided with an example of video selection and design issues are raised and solved including how nodes discover each other, a justification for using a mesh topology for the Broker connections, how Connection Admission Control (CAC) is achieved, how customer billing is achieved and how information security is maintained. A calculation of the number of Servers and Brokers required to service a particular number of Clients is presented. The advantages of ATOM are described. The underlying distributed connectivity is abstracted away from the Client. Redundant Server/Broker connections are eliminated and the total number of connections in the system are minimized by the rule stating that Clients and Servers may only connect to one Broker at a time. This reduces the total number of Switched Virtual Circuits (SVCs) which are a performance hindrance in ATM. ATOM can be easily scaled by adding more Servers which increases the total system capacity in terms of storage and bandwidth. In order to transport video satisfactorily, a guaranteed end-to-end Quality of Service architecture must be in place. The design methodology for such an architecture is investigated starting with a review of current QoS architectures in the literature which highlights important definitions including a flow, a service contract and flow management. A flow is a single media source which traverses resource modules between Server and Client. The concept of a flow is important because it enables the identification of the areas requiring consideration when designing a QoS architecture. It is shown that ATOM adheres to the principles motivating the design of a QoS architecture, namely the Integration, Separation and Transparency principles. The issue of mapping human requirements to network QoS parameters is investigated and the action of a QoS framework is introduced, including several possible causes of QoS degradation. The design of the ATOM Quality of Service Architecture (AQOSA) is then presented. AQOSA consists of 11 modules which interact to provide end-to-end QoS guarantees for each stream. Several important results arise from the design. It is shown that intelligent choice of stored videos in respect of peak bandwidth can improve overall system capacity. The concept of disk striping over a disk array is introduced and a Data Placement Strategy is designed which eliminates disk hot spots (i.e. Overuse of some disks whilst others lie idle.) A novel parameter (the B-P Ratio) is presented which can be used by the Server to predict future bursts from each video stream. The use of Traffic Shaping to decrease the load on the network from each stream is presented. Having investigated four algorithms for rewind and fast-forward in the literature, a rewind and fast-forward algorithm is presented. The method produces a significant decrease in bandwidth, and the resultant stream is very constant, reducing the chance that the stream will add to network congestion. The C++ classes of the Server, Broker and Client are described emphasizing the interaction between classes. The use of ATOM in the Virtual Private Network and the multimedia teaching laboratory is considered. Conclusions and recommendations for future work are presented. It is concluded that digital video applications require high bandwidth, low error, low delay networks; a video-on-demand system to support large Client volumes must be distributed, not centralized; control and operation (transport) must be separated; the number of ATM Switched Virtual Circuits (SVCs) must be minimized; the increased connections caused by the Broker mesh is justified by the distributed information gain; a Quality of Service solution must address end-to-end issues. It is recommended that a web front-end for Brokers be developed; the system be tested in a wide area A TM network; the Broker protocol be tested by forcing failure of a Broker and that a proprietary file format for disk striping be implemented

Performance analysis of server selection schemes for Video on Demand servers

Web Services have gained considerable attention over the last few years. This is due to increase in use of the Internet which results in increased web traffic. Web servers find applications in E-commerce and Video-on-Demand(VoD) systems which have resulted in speedy growth of the web traffic. Therefore the concept of load balancer aimed to distribute the tasks to different Web Servers to reduce response times was introduced. Each request was assigned a Web Server decided by the load balancer in such a way that tasks were uniformly distributed among the available servers. Server selection algorithms are aimed to meet the QoS for interactive VoD.This thesis attempts to analyze the performance of FCFS, Randomized, Genetic algorithms and Heuristics algorithms for selecting server to meet the VoD requirement . Performance of these algorithms have been simulated with parameters like makespan and average resource utilization for different server models. This thesis presents an efficient heuristic called Ga-max-min for distributing the load among different servers. Heuristics like min-min and max-min are also applied to heterogeneous server farms and the result is compared with the proposed heuristic for VoD Servers. Ga-max-min was found to provide lower makespan and higher resource utilization than the genetic algorithm.Extensive simulations have been carried out by the simulator designed using MATLAB R2010a

Effectiveness of Cloud Services for Scientific and VoD Applications

Cloud platforms have emerged as the primary data warehouse for a variety of applications, such as DropBox, iCloud, Google Music, etc. These applications allow users to store data in the cloud and access it from anywhere in the world. Commercial clouds are also well suited for providing high-end servers for rent to execute applications that require computation resources sporadically. Cloud users only pay for the time they actually use the hardware and the amount of data that is transmitted to and from the cloud, which has the potential to be more cost effective than purchasing, hosting, and maintaining dedicated hardware. In this dissertation, we look into the efficiency of the cloud Infrastructure-as-a-Service (IaaS) model for two real time high bandwidth applications: A scientific application of short-term weather forecasting and Video on Demand services. We show that, cloud services are efficient in both network and computation for real time scientific application of weather forecasting. We present a related list reordering approach, which reduces the network traffic of serving videos from VoD services and improve the efficiency of caches deployed to serve them. Also, we present transcoding policies to reduce the transcoding workload and present prediction models to maintain performance of providing ABR streaming of VoD services at the client with online transcoding in the cloud

A server-less architecture for building scalable, reliable, and cost-effective video-on-demand systems.

Leung Wai Tak.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.Includes bibliographical references (leaves 58-60).Abstracts in English and Chinese.Acknowledgement --- p.IAbstract --- p.II摘要 --- p.IIIChapter Chapter 1 --- Introduction --- p.1Chapter Chapter 2 --- Related Works --- p.5Chapter 2.1 --- Previous Works --- p.5Chapter 2.2 --- Contributions of this Study --- p.7Chapter Chapter 3 --- Architecture --- p.9Chapter 3.1 --- Data Placement Policy --- p.10Chapter 3.2 --- Retrieval and Transmission Scheduling --- p.13Chapter 3.3 --- Fault Tolerance --- p.20Chapter Chapter 4 --- Performance Modeling --- p.22Chapter 4.1 --- Storage Requirement --- p.22Chapter 4.2 --- Network Bandwidth Requirement --- p.23Chapter 4.3 --- Buffer Requirement --- p.24Chapter 4.4 --- System Response Time --- p.27Chapter Chapter 5 --- System Reliability --- p.29Chapter 5.1 --- System Failure Model --- p.29Chapter 5.2 --- Minimum System Repair Capability --- p.32Chapter 5.3 --- Redundancy Configuration --- p.35Chapter Chapter 6 --- System Dimensioning --- p.37Chapter 6.1 --- Storage Capacity --- p.38Chapter 6.2 --- Network Capacity --- p.38Chapter 6.3 --- Disk Access Bandwidth --- p.39Chapter 6.4 --- Buffer Requirement --- p.41Chapter 6.5 --- System Response Time --- p.43Chapter Chapter 7 --- Multiple Parity Groups --- p.45Chapter 7.1 --- System Failure Model --- p.47Chapter 7.2 --- Buffer Requirement --- p.47Chapter 7.3 --- System Response Time --- p.49Chapter 7.4 --- Redundancy Configuration --- p.49Chapter 7.5 --- Scalability --- p.51Chapter Chapter 8 --- Conclusions and Future Works --- p.53Appendix --- p.55Chapter A. --- Derivation of the Artificial Admission Delay --- p.55Chapter B. --- Derivation of the Receiver Buffer Requirement --- p.56Bibliography --- p.5

Bitocast: a hybrid BitTorrent and IP Multicast content distribution solution

Dissertação apresentada para obtenção do Grau de Mestre em Informática, pela Universidade Nova de Lisboa, Faculdade de Ciências e TecnologiaIn recent years we have observed an increased use of the Internet as a means for transmitting large content. There have been several technology attempts to attack this problem, including costly distribution networks and, more recently, peer to peer (P2P) protocols. Amongst these P2P protocols, BitTorrent has proven itself as an effective means for transmitting large content items and today enjoys great popularity. Numerous researchers have analyzed BitTorrent and proposed concepts and models to enhance its reliability, efficiency and fairness. Further, there are proposals to extend BitTorrent to support on-demand multimedia streaming. In this Dissertation we present Bitocast, a content distribution system that combines IP Multicast and BitTorrent protocols in order to achieve a more efficient usage of an Internet Service Provider’s network and reduce download time when serving large sets of contents to large audiences

Interactivity And User-heterogeneity In On Demand Broadcast Video

Video-On-Demand (VOD) has appeared as an important technology for many multimedia applications such as news on demand, digital libraries, home entertainment, and distance learning. In its simplest form, delivery of a video stream requires a dedicated channel for each video session. This scheme is very expensive and non-scalable. To preserve server bandwidth, many users can share a channel using multicast. Two types of multicast have been considered. In a non-periodic multicast setting, users make video requests to the server; and it serves them according to some scheduling policy. In a periodic broadcast environment, the server does not wait for service requests. It broadcasts a video cyclically, e.g., a new stream of the same video is started every t seconds. Although, this type of approach does not guarantee true VOD, the worst service latency experienced by any client is less than t seconds. A distinct advantage of this approach is that it can serve a very large community of users using minimal server bandwidth. In VOD System it is desirable to provide the user with the video-cassette-recorder-like (VCR) capabilities such as fast-forwarding a video or jumping to a specific frame. This issue in the broadcast framework is addressed, where each video and its interactive version are broadcast repeatedly on the network. Existing techniques rely on data prefetching as the mechanism to provide this functionality. This approach provides limited usability since the prefetching rate cannot keep up with typical fast-forward speeds. In the same environment, end users might have access to different bandwidth capabilities at different times. Current periodic broadcast schemes, do not take advantage of high-bandwidth capabilities, nor do they adapt to the low-bandwidth limitation of the receivers. A heterogeneous technique is presented that can adapt to a range of receiving bandwidth capability. Given a server bandwidth and a range of different client bandwidths, users employing the proposed technique will choose either to use their full reception bandwidth capability and therefore accessing the video at a very short time, or using part or enough reception bandwidth at the expense of a longer access latency

Recent Trends in Communication Networks

In recent years there has been many developments in communication technology. This has greatly enhanced the computing power of small handheld resource-constrained mobile devices. Different generations of communication technology have evolved. This had led to new research for communication of large volumes of data in different transmission media and the design of different communication protocols. Another direction of research concerns the secure and error-free communication between the sender and receiver despite the risk of the presence of an eavesdropper. For the communication requirement of a huge amount of multimedia streaming data, a lot of research has been carried out in the design of proper overlay networks. The book addresses new research techniques that have evolved to handle these challenges

Quality of Service based Retrieval Strategy for Distributed Video on Demand on Multiple Servers

The recent advances and development of inexpensive computers and high speed networking technology have enabled the Video on Demand (VoD) application to connect to shared-computing servers, replacing the traditional computing environments where each application was having its own dedicated computing hardware. The VoD application enables the viewer to select, from a list of video files, his favorite video file and watch its reproduction at will. Early video on demand applications were based on single video server where video streams are initiated from a single server, then with the increase in the number of the clients who became interested in VoD services, the focus became on Distributed VoD architectures (DVoD) where the context of distribution may be distributed system components, distributed streaming servers, distributed media content etc.The VoD server must handle several issues in order to be able to present a successful service. It has to receive the clients’ requests and analyze them, calculate the necessary resources for each request, and decide whether a request can be admitted or not. Once the request is admitted, the server must schedule the request, retrieve the required video data and send the video data in a timely manner so that the client does not suffer data starvation in his buffer during the video reproduction. So, the overall objective of a VoD service provider is to provide a better Quality of Service (QoS). Some issues related to QoS are-efficient use of bandwidth, providing better throughput etc.One of the important issues is to retrieve the video data from the servers in minimum time and to start the playback of the video at client side with a minimum waiting time. The overall time elapsed in retrieving the video data and starting the playback is known as access time. The thesis presents an efficient retrieval strategy for a distributed VoD environment where the basic objective is to minimize the access time by maintaining the presentation continuity at the client side. We have neglected some of the network parameters which may affect the access time, by assuming a high speed network between the servers and the client. The performance of the strategy has been analyzed and is compared with the referred PAR (Play After Retrieval) strategy. Further, the strategy is also analyzed under availability condition which is a more realistic approach

Design, analysis, and experiment on multiple servers technology for video-on-demand service in distributed networks

Master'sMASTER OF ENGINEERIN