Mukaddim Pathan

Content Delivery Networks

Content Delivery Networks enables the readers to understand the basics, to identify the underlying technology, to summarize their knowledge on concepts, ideas, principles and various paradigms which span on broad CDNs areas. Therefore, aspects of CDNs in terms of basics, design process, practice, techniques, performances, platforms, applications, and experimental results have been presented in a proper order. Fundamental methods, initiatives, significant research results, as well as references for further study have also been provided. Comparison of different design and development approaches are described at the appropriate places so that new researchers as well as advanced practitioners can use the CDNs evaluation as a research roadmap. All the contributions have been reviewed, edited, processed, and placed in the appropriate order to maintain consistency so that any reader irrespective of their level of knowledge and technological skills in CDNs would get the most out of it. The book is organized into three parts, namely, Part I: CDN Fundamentals; Part II: CDN Modeling and Performance; and Part III: Advanced CDN Platforms and Applications. The organization ensures the smooth flow of material as successive chapters build on prior ones.

BodyCloud: Integration of Cloud Computing and body sensor networks

Spatially distributed sensor nodes can be used to monitor systems and humans conditions in a wide range of application domains. A network of body sensors in a community of people generates large amounts of contextual data that requires a scalable approach for storage and processing. Cloud computing can provide a powerful, scalable storage and processing infrastructure to perform both online and offline analysis and mining of body sensor data streams. This paper presents BodyCloud, a system architecture based on Cloud Computing for the management and monitoring of body sensor data streams. It incorporates key concepts such as scalability and flexibility of resources, sensor heterogeneity, and the dynamic deployment and management of user and community applications.

A Taxonomy of CDNs

Content Delivery Networks (CDNs) [79, 97] have received considerable research attention in the recent past. A few studies have investigated CDNs to categorize and analyze them, and to explore the uniqueness, weaknesses, opportunities, and future directions in this field. Peng presents an overview of CDNs [75]. His work describes the critical issues involved in designing and implementing an effective CDN, and surveys the approaches proposed in literature to address these problems. Vakali et al. [95] present a survey of CDN architecture and popular CDN service providers. The survey is focused on understanding the CDN framework and its usefulness. They identify the characteristics and current practices in the content networking domain, and present an evolutionary pathway for CDNs, in order to exploit the current content networking trends. Dilley et al. [29] provide an insight into the overall system architecture of the leading CDN, Akamai [1]. They provide an overview of the existing content delivery approaches and describe Akamai’s network infrastructure and its operations in detail. They also point out the technical challenges that are to be faced while constructing a global CDN like Akamai. Saroiu et al. [84] examine content delivery from the point of view of four content delivery systems: Hypertext Transfer Protocol (HTTP) Web traffic, the Akamai CDN, Gnutella [8, 25], and KaZaa [62, 66] peer-to-peer file sharing systems. They also present significant implications for large organizations, service providers, network infrastructure providers, and general content delivery providers. Kung et al. [60] describe a taxonomy for content networks and introduce a new class of content networks that perform “semantic aggregation and content-sensitive placement” of content. They classify content networks based on their attributes in two dimensions: content aggregation and content placement. Sivasubramanian et al. [89] identify the issues

Content Delivery Networks: State of the Art, Insights, and Imperatives

Over the last decades, users have witnessed the growth and maturity of the Internet which has caused enormous growth in network traffic, driven by the rapid acceptance of broadband access, the increases in systems complexity, and the content richness. The over-evolving nature of the Internet brings new challenges in managing and delivering content to users, since for example, popular Web services often suffer congestion and bottlenecks due to the large demands posed on their services. Such a sudden spike in Web content requests (e.g. the one occurred during the 9/11 incident in USA) is often termed as flash crowds [14] or SlashDot [11] effects. It may cause heavy workload on particular Web server(s), and as a result a “hotspot” [14] can be generated. Coping with such unexpected demand causes significant strain on a Web server and eventually the Web servers are totally overwhelmed with the sudden increase in traffic, and the Web site holding the content becomes temporarily unavailable. A Content Delivery Network (CDN) [47, 51, 54, 61, 63] is a collaborative collection of network elements spanning the Internet, where content is replicated over several mirrored Web servers in order to perform transparent and effective delivery of content to the end users. Collaboration among distributed CDN components can occur over nodes in both homogeneous and heterogeneous environments. CDNs have evolved to overcome the inherent limitations of the Internet in terms of user perceived Quality of Service (QoS) when accessing Web content. They provide services that improve network performance by maximizing bandwidth, improving

Maximizing Utility for Content Delivery Clouds

A content delivery cloud, such as MetaCDN, is an integrated overlay that utilizes cloud computing to provide content delivery services to Internet end-users. While it ensures satisfactory user perceived performance, it also aims to improve the traffic activities in its world-wide distributed network and uplift the usefulness of its replicas. To realize this objective, in this paper, we measure the utility of content delivery via MetaCDN, capturing the system-specific perceived benefits. We use this utility measure to devise a request-redirection policy that ensures high performance content delivery. We also quantify a content providers benefits from using MetaCDN based on its user perceived performance. We conduct a proof-of-concept testbed experiment for MetaCDN to demonstrate the performance of our approach and reveal our observations on the MetaCDN utility and content providers benefits from using MetaCDN.

A two-stage approach for task and resource management in multimedia cloud environment

In recent years, multimedia cloud computing is becoming a promising technology that can effectively process multimedia services and provide quality of service (QoS) provisioning for multimedia applications from anywhere, at any time and on any device at lower costs. However, there are two major challenges exist in this emerging computing paradigm: one is task management, which maps multimedia tasks to virtual machines, and the other is resource management, which maps virtual machines (VMs) to physical servers. In this study, we aim at providing an efficient solution that jointly addresses these challenges. In particular, a queuing based approach for task management and a heuristic algorithm for resource management are proposed. By adopting allocation deadline in each VM request, both task manager and VM allocator receive better chances to optimize the cost while satisfying the constraints on the quality of multimedia service. Various simulations were conducted to validate the efficiency of the proposed task and resource management approaches. The results showed that the proposed solutions provided better performance as compared to the existing state-of-the-art approaches.

An economic replica placement mechanism for streaming content distribution in Hybrid CDN-P2P networks

Hybrid CDN-P2P networks blend Content Delivery Networks (CDN) and Peer-to-Peer (P2P) networks to overcome their shortcomings. Replica placement in these networks is still an open problem. Hierarchical structure of these networks makes it inefficient to use available replica placement strategies specialized to CDN or P2P network domains. In this work, we introduce a novel replication strategy which enables traditional CDNs to offer Hybrid CDN-P2P streaming content delivery services. The proposed solution relies on economic model of the Hybrid CDN and employs a dynamic mechanism to optimize the number and places of replicas for P2P service. In particular, processing and communication complexities of the proposed solution are studied and its performance is analyzed in a typical Hybrid CDN-P2P network in comparison to related strategies.

Architecture and performance models for QoS-driven effective peering of content delivery networks

The proprietary nature of existing Content Delivery Networks (CDNs) means they are closed and do not naturally cooperate. A CDN is expected to provide high performance Internet content delivery through global coverage, which might be an obstacle for new CDN providers, as well as affecting commercial viability of existing ones. Finding ways for distinct CDNs to coordinate and cooperate with other CDNs is necessary to achieve better overall service, as perceived by end-users, at lower cost. In this paper, we present an architecture to support peering arrangements between CDNs, based on a Virtual Organization (VO) model. Our approach promotes peering among providers, while upholding user perceived performance. This is achieved through proper policy management of negotiated Service Level Agreements (SLAs) between peers. We also present a Quality of Service (QoS)-driven performance modeling approach for peering CDNs in order to predict the user perceived performance. We show that peering between CDNs upholds user perceived performance by satisfying the target QoS. The methodology presented in this paper provides CDNs a way to dynamically distribute user requests to other peers according to different request-redirection policies. The model-based approach helps an overloaded CDN to return to a normal state by offloading excess requests to the peers. It also assists in making concrete QoS guarantee for a CDN provider. Our approach endeavors to achieve scalability and resource sharing among CDNs through effective peering in a user transparent manner, thus evolving past the current landscape where non-cooperative and distinct} CDNs exist.

Editorial: Integration of Cloud computing and body sensor networks

Wireless Sensor Networks (WSN) [1,2] are revolutionizing distributed sensing in awide range of application domains, ranging from home automation to processmonitoring, healthcare analysis, weather forecasting, military situation awareness, and traffic control. Sensor nodes in a WSN can generate a large amount of real-time, in-situ contextual data about a specificmonitored space, e.g. agricultural field, city quarter, building, room, humanbody. The capabilities of aWSNdo not only involve collection and forwarding of raw sensor readings, but also include in-node/in-network data processing (e.g. aggregation and merging) and, sometimes, innetwork complex elaboration, such as event detection, object tracking and classification based on even sophisticated distributed classification algorithms. A specific class ofWSN is Body Sensor Networks (BSN) that represents an emerging platform for many human-centered applications, spanning from medical to sports performance monitoring, gaming, and social networking. As a result of the advancements of ubiquitous and increasingly powerful wearable devices, to support thewide variety of application contexts, there exists a growing number of health monitoring systems with sophisticated capabilities. Moreover, there is enormous public interest in products that allow individuals, ranging from children to elders, to monitor and improve their own health and lifestyle. In a common healthcare scenario, assisted livings monitored by BSN are able to gather data streams to not only process in real-time but also store them into remotemedical data repositories. This implies a huge amount of data to be transmitted, stored and analyzed. In the coming years, BSN are likely to be exploited to allow for implicit social interaction among people, who can exchange private/public information through their worn BSN nodes when they come into contact. BSN of co-located people can be also exploited as a mobile sensor infrastructure to support other context-aware applications such as disaster, medical emergency and mass event management. In such context, management of a large number of disparate BSN as well as cooperative BSN to support various applications is a crucial issue to deal with. Moreover, the huge amount of data, that a BSN is able to deliver, demands a powerful, scalable storage and processing infrastructure to perform both online and offline analysis of BSN data streams. BSN, with their huge amount of gathered sensor data and their limited processing power, can be empowered by exploiting a Cloud computing infrastructure to realize an integrated platform that provides: (a) the ability to utilize heterogeneous sensors; (b) scalability of data storage; (c) scalability of processing power for different kinds of data analysis; (d) global access to the processing

An economic mechanism for request routing and resource allocation in hybrid CDN–P2P networks

Summary Hybrid content delivery networks (HCDN) benefit from the complementary advantages of P2P (Peer to Peer) networks and CDNs (Content Delivery Network). In order to extend a traditional CDN and enable it to offer hybrid content delivery service, we have modified a traditional domain name system-based request routing mechanism. The proposed scheme relies on an oligopolistic mechanism to balance the load on the edge servers and employs a truthful profit-maximizing auction to maximize the contribution of users in the P2P content delivery. In particular, economics of content delivery in HCDNs is studied, and it is shown that through our request routing mechanism, it is possible to deliver higher quality of service to majority of end-users, increase the net profit of the HCDN provider and decrease the content distribution cost at the same time. Copyright