http://emamispnu.persiangig.com/Projects/Cloud%20Computing/science_2.pdf

Review: A survey on security issues in service delivery models of cloud computing

Over the Internet today, computing and communications environments are significantly more complex and chaotic than classical distributed systems, lacking any centralized organization or hierarchical control. There has been much interest in emerging Peer-to-Peer (P2P) network overlays because they provide a good substrate for creating large-scale data sharing, content distribution, and application-level multicast applications. These P2P overlay networks attempt to provide a long list of features, such as: selection of nearby peers, redundant storage, efficient search/location of data items, data permanence or guarantees, hierarchical naming, trust and authentication, and anonymity. P2P networks potentially offer an efficient routing architecture that is self-organizing, massively scalable, and robust in the wide-area, combining fault tolerance, load balancing, and explicit notion of locality. In this article we present a survey and comparison of various Structured and Unstructured P2P overlay networks. We categorize the various schemes into these two groups in the design spectrum, and discuss the application-level network performance of each group.

/pdf/a-survey-and-comparison-of-peer-to-peer-overlay-network-cpcv2ij1hk.pdf

A survey and comparison of peer-to-peer overlay network schemes

http://rboutaba.cs.uwaterloo.ca/Papers/Journals/2010/Mosharaf10.pdf

A survey of network virtualization

Cloud computing providers have setup several data centers at different geographical locations over the Internet in order to optimally serve needs of their customers around the world However, existing systems do not support mechanisms and policies for dynamically coordinating load distribution among different Cloud-based data centers in order to determine optimal location for hosting application services to achieve reasonable QoS levels Further, the Cloud computing providers are unable to predict geographic distribution of users consuming their services, hence the load coordination must happen automatically, and distribution of services must change in response to changes in the load To counter this problem, we advocate creation of federated Cloud computing environment (InterCloud) that facilitates just-in-time, opportunistic, and scalable provisioning of application services, consistently achieving QoS targets under variable workload, resource and network conditions The overall goal is to create a computing environment that supports dynamic expansion or contraction of capabilities (VMs, services, storage, and database) for handling sudden variations in service demands.

This paper presents vision, challenges, and architectural elements of InterCloud for utility-oriented federation of Cloud computing environments The proposed InterCloud environment supports scaling of applications across multiple vendor clouds We have validated our approach by conducting a set of rigorous performance evaluation study using the CloudSim toolkit The results demonstrate that federated Cloud computing model has immense potential as it offers significant performance gains as regards to response time and cost saving under dynamic workload scenarios.

/pdf/intercloud-utility-oriented-federation-of-cloud-computing-3hscqfkz1e.pdf

InterCloud: utility-oriented federation of cloud computing environments for scaling of application services

Recent technology trends in the Web Services (WS) domain indicate that a solution eliminating the presumed complexity of the WS-* standards may be in sight: advocates of REpresentational State Transfer (REST) have come to believe that their ideas explaining why the World Wide Web works are just as applicable to solve enterprise application integration problems and to simplify the plumbing required to build service-oriented architectures. In this paper we objectify the WS-* vs. REST debate by giving a quantitative technical comparison based on architectural principles and decisions. We show that the two approaches differ in the number of architectural decisions that must be made and in the number of available alternatives. This discrepancy between freedom-from-choice and freedom-of-choice explains the complexity difference perceived. However, we also show that there are significant differences in the consequences of certain decisions in terms of resulting development and maintenance costs. Our comparison helps technical decision makers to assess the two integration styles and technologies more objectively and select the one that best fits their needs: REST is well suited for basic, ad hoc integration scenarios, WS-* is more flexible and addresses advanced quality of service requirements commonly occurring in enterprise computing.

/pdf/restful-web-services-vs-big-web-services-making-the-right-2tg7890x7z.pdf

Restful web services vs. "big"' web services: making the right architectural decision

Peer-to-Peer (P2P) networks enable users to directly share digital content (such as audio, video, and text files) as well as real-time data (such as telephony traffic) with other users without depending on a central server. Although originally popularized by unlicensed online music services such as Napster, P2P networking has recently emerged as a viable multimillion dollar business model for the distribution of academic and clinical information, telecommunications, and social networking. Written at an accessible level for any reader familiar with fundamental Internet protocols, Peer-to-Peer Networking and Applications explains the conceptual operations and architecture underlying basic P2P systems using well-known commercial systems as models. The book also delineates the latest research directions, thereby providing not only a sophisticated understanding of current systems, but also the means to improve upon these systems with innovations that will better performance, security, and flexibility. Peer-to-Peer Networking and Applications is thus both a valuable starting point and an important reference to those practioners employed by any of the 200 companies with approximately $400 million invested in this new and lucrative technology.



Uses well-known commercial P2P systems as models, thus demonstrating real-world applicability.

Discusses how current research trends in wireless networking, high-def content, DRM, etc. will intersect with P2P, allowing readers to account for future developments in their designs.

Provides online access to the Overlay Weaver P2P emulator, an open-source tool that supports a number of peer-to-peer applications with which readers can practice.

P2P Networking and Applications

Round trip times (RTTs) play an important role in Internet measurements. In this paper, we explore some of the ways in which routing policies impact RTTs. In particular, we investigate how routing policies for both intra- and inter-domain routing can naturally give rise to violations of the triangle inequality with respect to RTTs. Triangle Inequality Violations (TIVs) might be exploited by overlay routing if an end-to-end forwarding path can be stitched together with paths routed at layer 3. However, TIVs pose a problem for Internet Coordinate Systems that attempt to associate Internet hosts with points in Euclidean space so that RTTs between hosts are accurately captured by distances between their associated points. Three points having RTTs that violate the triangle inequality cannot be embedded into Euclidean space without some level of inaccuracy. We argue that TIVs should not be treated as measurement artifacts, but rather as natural features of the Internet's structure. In addition to explaining routing policies that give rise to TIVs, we present illustrating examples from the current Internet.

/pdf/internet-routing-policies-and-round-trip-times-1x5c3c29fx.pdf

Internet routing policies and round-trip-times

Internet coordinate systems embed Round-Trip-Times (RTTs) between Internet nodes into some geometric space so that unmeasured RTTs can be estimated using distance computation in that space. If accurate, such techniques would allow us to predict Internet RTTs without extensive measurements. The published techniques appear to work very well when accuracy is measured using metrics such as absolute relative error. Our main observation is that absolute relative error tells us very little about the quality of an embedding as experienced by a user. We define several new accuracy metrics that attempt to quantify various aspects of user-oriented quality. Evaluation of current Internet coordinate systems using our new metrics indicates that their quality is not as high as that suggested by the use of absolute relative error.

http://conferences.sigcomm.org/imc/2005/papers/imc05efiles/lua/lua.pdf

On the accuracy of embeddings for internet coordinate systems

Network coordinate (NC) systems provide a lightweight and scalable way for predicting the distances, i.e., round-trip latencies among Internet hosts. Most existing NC systems embed hosts into a low dimensional Euclidean space. Unfortunately, the persistent occurrence of Triangle Inequality Violation (TIV) on the Internet largely limits the distance prediction accuracy of those NC systems. Some alternative systems aim at handling the persistent TIV, however, they only achieve comparable prediction accuracy with Euclidean distance based NC systems. In this paper, we propose an NC system, so-called Phoenix, which is based on the matrix factorization model. Phoenix introduces a weight to each reference NC and trusts the NCs with higher weight values more than the others. The weight-based mechanism can substantially reduce the impact of the error propagation. Using the representative aggregate data sets and the newly measured dynamic data set collected from the Internet, our simulations show that Phoenix achieves significantly higher prediction accuracy than other NC systems. We also show that Phoenix quickly converges to steady state, performs well under host churn, handles the drift of the NCs successfully by using regularization, and is robust against measurement anomalies. Phoenix achieves a scalable yet accurate end-to-end distances monitoring. In addition, we study how well an NC system can characterize the TIV property on the Internet by introducing two new quantitative metrics, so-called RERPL and AERPL. We show that Phoenix is able to characterize TIV better than other existing NC systems.

Eng Keong Lua

Papers

A survey and comparison of peer-to-peer overlay network schemes

P2P Networking and Applications

Internet routing policies and round-trip-times

On the accuracy of embeddings for internet coordinate systems

Phoenix: A Weight-Based Network Coordinate System Using Matrix Factorization