A Study on the Cloud Computing Architecture, Service Models, Applications and Challenging Issues

A Study on the Cloud Computing Architecture, Service Models, Applications and Challenging Issues Rajbir Singh 1, Vivek Sharma 2 1, 2 Assistant Professor, Rayat Institute of Engineering and Information Technology Ropar, Punjab, India 1 ranaji.singh@gmail.com, 2 er.viveksharma22@gmail.com Abstract - Cloud computing has been seen as unitary of the technology that poses the nextgeneration computing revolution and rapidly becomes the hottest topic in the field of IT. This fast move towards Cloud computing has fuelled concerns on a fundamental point for the success of information systems, communication, virtualization, data availability and integrity, public auditing, scientific application, and information security. Therefore, cloud computing research has attracted tremendous interest in recent years. This paper presents an overview on the concept of Cloud Computing, its architecture, Service models, applications and challenging issues. Keywords - Cloud Computing, Service Models, Cloud server, Load Balancing I. INTRODUCTION The IT industry has always a momentum improve the technology, as from the 1946 the beginning of computer world and till now the evolution in technology can be seen. During the invention of mainframe system, researchers had assumed mainframes as the future of this IT and computing world because mainframes were able to perform different tasks and applications in less time. At present, we perform same tasks in lesser time and portable fashion using the cloud servers based desktop computers named as cloud computing system [1]. Cloud computing [2] brings a new network application mode by which people will not be constrained to physical resources, even they can use IT application and services on the cloud through internet. This evolution in IT world to Cloud Computing is shown by figure 1. Mean while there was rapid growth in technology and wireless networking system that forced the cloud services to be used. So, the electronic devices like Computers, tablets, smart phones and cloud resources are converting in cloud computing (CC) [3]. Cloud Computing presents a new platform for users that they can make use of IT services at anywhere using mobile internet through cloud. Started from the introductory part of IT world and Cloud Computing, the rest of the paper is presented as follows: Section II briefs the concept of cloud computing and its Architecture; Section III describes the service models of cloud computing; Section IV presents its application models; Section V describes some challenging issues that make users to reduce the use Cloud Computing; Section VI gives the conclusion. 40

Fig 1: Evolution of IT world from Mainframe system to Cloud computing. II. CLOUD COMPUTING Cloud computing [4] has become a significant and efficient research topic of IT and scientific area since 2007. Cloud computing is a cluster of servers and personal computers grouped together to provide various services including software services, hardware services and application services on the internet. In other words, we can say that cloud computing concentrates all the computing resources together, therefore people can use the various services anywhere anytime using the internet surf. Cloud computing provides the next generation of internet-based, highly scalable distributed computing systems in which computational resources are offered 'as a service'. Cloud computing is a construct that allows to access application resided at a location other than user s PC and offers its capabilities as a service [5]. Cloud services enable the users to access the IT resources anytime and from anywhere using multiple devices such as PCs, laptops and Smart phones etc. Availability of data in cloud allows the user to access the data at any time. Cloud computing paradigm provides scalable and virtualized resources. Virtualization is useful for resource sharing and optimum utilization of resources. Since, users are not maintaining the IT resources, hence they are free to concentrate on business rather than on IT, that is looked after by specialized and trained manpower of cloud provider. Cost saving, dynamic scalability and high availability are some of the most significant advantages of cloud computing.the cloud computing paradigm is builds on the foundations of distributed computing, grid computing, 41

networking, virtualization service orientation and market oriented computing. Cloud Computing can be defined by various form but the widely accepted definition, including by cloud security alliance [6] is given by NIST, that defines cloud computing as Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. This cloud model is composed of five essential characteristics, three service models, and four deployment models. The complete architecture of Cloud computing is given in thee figure 1 as below. Figure 1: Cloud Computing Architecture Even though cloud computing is the most discussed topic and facilitates the user in performing majority of the task, still there are some bottlenecks which retards the proliferation of cloud computing. Heavy Load on cloud is one of these bigger retardation and load balancing becomes the biggest issue for the cloud computing. For efficient load balancing there must be some parameters to evaluate the load balancing techniques to get better resource distribution for the user demands. Measurement parameters allow us to see whether the given technique is good enough to balance the load of the traffic on the server or not. These parameters include throughput, fault tolerance, response time, performance, scalability and resource utilization. III. CLOUD SERVICE MODEL Cloud computing is an emerged form of distributed computing having the property to disperse data and process that distributedly. So, we can solve a huge problem efficiently using cloud computing. Cloud computing is based on the basic Service delivery models which are explained as below: A. Cloud Service Delivering Model Cloud Service delivering models are the basic model by which the services are delivered through cloud [7] [8]. These models are IaaS (Infrastructure as a Service), PaaS (Platform as a Service), SaaS (Software as a Service) as explained below. Due to increasing services, a combined term XaaS is generally used to define X as a service means anything as a service. It includes the entire basic service model and also some secondary model like BaaS (Business as aservice), CaaS (Communication as a service), NaaS (Network as a sercice), MaaS (Monitering as a service) etc. Figure 2 represents the Cloud Service model. Three basic cloud service models and their management is shown by the fig 2: 42

Fig 2: Cloud Service Model The three most common service models of cloud computing are explained as below: 1). Software as a service (SaaS): Provides consumer the capability to use applications running on a cloud infrastructure mainly on the web browser to access software that offer as a service over the web. The consumer do not have control or figure out how to the underlying framework including system, servers, network, operating systems, storage, or even individual application capacities, with the conceivable exemption of constrained client particular application setup settings. Google Docs and Sales forces are prominent examples. 2). Platform as a Service (PaaS): Provides the capability to deploy onto the cloud infrastructure, consumer created applications, produced using set of programming languages and tools that are supported by the Paas provider. The consumer does not oversee or control the underlying cloud framework including network, servers, operating systems, or storage, yet has control over the sent applications and conceivably application facilitating environment arrangements. Much the same as the Saas model, clients do not have control or access to the underlying base being utilized to have their applications at the Paas level. Examples of PaaS are Google App Engine and Microsoft Azure are prominent examples that use the PaaS model of cloud computing. 3). Infrastructure as a service (IaaS): Provides the consumer with the capability to provision processing, storage, networks, and other fundamental computing resources from an IaaS provider, and allow the consumer to deploy and run any software, which can include operating systems, services and applications. The client has control over operating systems, storage, deployed applications and perhaps constrained control of select systems administration parts. Rather than the Paas model, the Iaas model is a low level of reflection that permits clients to the right of the entrance the underlying foundation through the utilization of virtual machines. Iaas gives clients more adaptability than Paas as it permits the client to convey any product stack on top of the operating system. Examples of IaaS are Amazon Web Services EC2 and S3 are 43

prominent examples that use the IaaS model of cloud computing. IV. APPLICATIONS A. Cloud Computing For E-Learning E-learning is a new trend in education that tries to make the best use of information technology (IT). Cloud computing is an attractive environment for students, faculty members and researchers. As an emerging IT, cloud computing can provide universities and research centers with powerful and cost-effective computational infrastructure. Students can connect to campus educational services through their personal mobile devices from anywhere. Faculty members can have efficient and flexible access to their course material in their class rooms. Researchers can find articles, models and run their experiments on the cloud faster than ever [9]. B. Cloud Computing for ERP Traditional Enterprise Resource Planning (ERP) systems have some limitations. As the business grows inside an organization, different software applications may be needed to manage information in many areas such as human resources, payroll, finance and administration. Obviously, purchasing, installing and maintaining such multiple types of software applications represent a challenge for business growing. Furthermore, traditional ERP systems are limited in terms of multiple user accessibility, performance and availability of resources. ERP cloud [10] refers to installing the ERP applications on the cloud infrastructure (e.g. servers in datacenters) so that they can be accessed by the organizations ubiquitously through a network connection. Therefore, with this technology, project managers do not need to worry about installing, upgrading and maintaining applications inside their organizations. In addition, ERP cloud provides organizations with cost-effective scalable resources, high availability of data and applications and multitenant accessibility. Organizations can reduce their capital expenses and achieve higher Return on Investment (ROI) and shorter payback period by leasing resources and services on the cloud rather than purchasing new equipments and software applications. This is important especially for small and medium scale business where budgets are limited. C. Cloud Computing For E-Government Cloud computing technology can significantly improve the way a government functions, the services it provides to its citizens and institutions and its cooperation with other governments. It can help address these challenges by providing elastic scalable, customized and highly available environment. It also relieves governments from the burden of upgrading, maintenance and licensing SW and allows them to focus on the core work. Scalable and cost effective data storage can also be provided and file replication and multiple installations in geographically separated locations can be used for data recover in case of disasters. Security approaches an techniques can be deployed on the Cloud to prevent malicious behaviour and protect data integrity and confidentiality V. CHALLENGING ISSUES A. Handling Uncertainties It has been demonstrated that one of the difficulties in provisioning cloud assets is uncertainty [11] [12]. Resource uncertainty emerges from a number of issues including client location, content type, noxious exercises, heterogeneity, and so forth. At times, multimedia content delivery application may confront with disappointment of resources or it 44

may experience the ill effects of absence of sufficient resources. Considering that bandwidth is one of the most important resources especially in multimedia applications, lack of bandwidth may lead to huge degradation in QoS. In multimedia Application the amount of required bandwidth is largely affected by three factors: 1) Media application bandwidth demand; 2) user s workload bandwidth demand; and 3) user s location and device type. These factors change rapidly and may result in bandwidth shortage at some points. B. Handling Workload An important benefit of hybrid architectures of cloud that has not been explored above, is their potential to handle peaks in workload. In particular, the local data-center could be provisioned with enough server ability to handle workloads while cloud assets could be invoked as required to manage peaks. The methodology could conceivably help in arranging formats that can manage dynamic workload varieties. One methodology is to utilize the model to focus the suitable configurations for a mixed bag of evaluated workloads, and build the final configuration on the expected probabilities of every workload. An alternate methodology is to utilize the model occasionally as workloads change over time, to figure out whether a change in placement is needed. More point by point examination of these issues can be conceded and an open opportunity to work on. C. Optimization of Virtual Network Topologies In virtualised data centers VMs regularly communicate between one another, making virtual system topologies. However, because of VM migrations or no streamlined allocation, the communicating VMs may wind up facilitated on logically distant physical nodes giving expensive information exchange between one another. If the communicating VMs are dispensed to the hosts in diverse racks or enclosures, the network communication may include network switches that consume critical amount of power. To take out this information exchange overhead and minimize power utilization, it is important to observe the communication between VMs and spot them on the same or nearly placed nodes. To give compelling reallocations, the power utilization models can be developed of the network devices and assessment the expense of information exchange relying upon the traffic volume. As relocations consume extra energy and they have a negative effect on the execution, before launching the relocation, the reallocation controller needs to guarantee that the expense of migration does not surpass the profit. VI. CONCLUSIONS In this paper, we have presented the concept of cloud computing, application, architecture and its service models. This paper discussed the emerging research issues that pursued the advance scientific features of cloud computing with layer wise classification of the cloud services, and highlighted the subsequent guidelines of research facing the both industry and academic community. This survey and future issues demonstrated that there are a few routes in which the cloud research group can gain from related groups. V. REFERENCES [1] Buyya, R., Yeo, C. S., Venugopal, S., Broberg, J., & Brandic, I. (2009). Cloud computing and emerging IT platforms: Vision, hype, and reality for delivering computing as the 5th utility. Future Generation computer systems, 25(6), 599-616. [2] Armbrust, M., Fox, A., Griffith, R., Joseph, A. D., Katz, R., Konwinski, A.,... & Zaharia, M. (2010). A view of cloud computing. Communications of the ACM,53(4), 50-58. [3] Buyya, R., Yeo, C. S., Venugopal, S., Broberg, J., & Brandic, I. (2009). Cloud computing and emerging IT 45

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