Review of Cloud Computing and future research

Review of Cloud Computing and future research Computer Science, IIS University, India Abstract: Cloud computing is also referred to as the evolutionary offspring of distributed computing, parallel computing, grid computing and utility computing and the outcome of the developments in virtualization, load balance and network storage. Building a virtual pool of computing resources by centralizing the computing resources by means of a network and provide the services like software, platform and infrastructure is the main idea behind the cloud computing. As an internet based supercomputing paradigm, the cloud computing permits the users to dynamically share a collection of software, data resources and hardware while they will only be charged based on their actual usage. Cloud computing offers a wide area for research in cloud security that is still under- evaluated by researchers. This paper gives brief review of cloud computing and future directions in it. Keywords: Service Delivery models, Private cloud, benefits, Public cloud, Hybrid Cloud, Infrastructure, Software, Platform as a service 1. Introduction According to Bisong, Syed and Rahman (2011) the cloud computing is in vogue pattern of computing that came out during the year 2006, where a pond of resources furnish a platform, infrastructure and software to numerous users by sharing the resources useable. The cloud computing is developing continuously and at that place also subsist various cloud providers. The leading cloud providers are Google, Yahoo, Amazon, Microsoft etc.. Bisong, Syed and Rahman (2011) state that, the association of a wide range of computing techniques like distributed computing, virtualization, load balancing etc is truly the cloud computing. Purpose of internet are facilitated by the private clouds; cloud services like server time, networks and processing power, deployment of software, virtual application, increases computation power, reliability of software applications, web applications, high maintenance, maximized utilization of server, larger storage, could be catered necessarily as needed by the clients without any requirement of human interaction, service of CC (Cloud Computing) supported for large and vigorous projects, cost-effective plan for usage, maintenance and enhancing, multi-users or multi-tenants are authorized in CC (Cloud Computing) and so on. Cloud Computing is characterized with viz elasticity, multitenacity, resource pooling, broad network access, on demand self- service, reliability, security, agility, Application etc. There are three types of cloud- Private cloud, Public cloud and hybrid cloud. Cloud Computing offers three service models on the basis of demand and pay as per use which are Infrastructure as a service(iaas), Platform as a service (Paas), Software as a service(saas). 380

2. Characteristics of cloud computing Discrete key features are displayed by the cloud computing. The National Institute of Standards and Technology has analysed five vital features of cloud computing and they are as follows: Rapid elasticity: cloud computing suggests flexible catering and dispensing of the capabilities. At times, to scale immediately inside and outside compatible, it is done accordingly. Resource pooling: in order to aid various end users in the multi- tenant model, the computing resources are merged and that get dynamically delegated according to the demand of the consumers. Broad network access: the end users are permitted to access the capabilities on the network from different platforms through standard mechanisms. On demand self-service: automatic and one-sided catering of computing capabilities viz network storage and server time provided to the end users without human interaction with every service provider. Measured service: the resources in the cloud computing are naturally improved and regulated by influencing the capability of taking into account according to the type of service, for example, processing, storage, active user accounts and bandwidth. The consumption of resources can be regulated, stated and supervised by offering clarity for the end user and the provider with reference to the used services. ISACA (n.d) has stated the sixth vital feature of cloud computing as the Multi Tenacity. The requirement for policy oriented seclusion, division, reinforcement, governance, billing or chargeback models and service levels are all guided by the multi tenacity feature. Smith and Mitchell D (2013), have reported the other key features displayed by cloud computing and they are as follows. Agility: The cloud computing enhances the performance of the end users to provide the resources of technological base. Application Programming Interface: The cloud computing grants access to software which allows the machines to interact with the cloud applications just like how a traditional user interface promotes the interaction between computers and users. REST (Representational State Transfer) based APIs (Application Program Interface) are typically used by the cloud computing systems. Cost: According to Bruneo, Distefano, Longo, Puliafito and Scarpa (2013), the capital expenditure is converted in to operational expenditure by the cloud computing which benefit the cost reductions. Location and Device Independence: The users in the cloud computing are permitted to access systems with the aid of a web browser regardless of the device they use (mobile phone/ personal computer) and their location. Maintenance: The software applications on cloud computing are simple to manage as they do not need to be installed on each and every computer and the cloud computing also grants access from different places. Security: As the data is centralized, the cloud computing bids an enhanced security. The resources are also concentrated for security. 381

Reliability: King and Rachael (2008) stated that authenticity is assured by the cloud computing and it enhances with the use of various repetitive sites making the well-planned cloud computing best adapted for disaster recovery and business continuity. In addition to these features, accomplishment and output acquired from cloud computing is also productive as the users from multiple locations are allowed to work on the same data simultaneously. 3. Types of cloud computing There are three types of clouds in the Cloud Computing world and they are Public clouds, Private clouds and Hybrid clouds. 3.1 Public Clouds: Figure 1: Public clouds Source: Metzler, Jim, Taylor and Steve (2010) The sequence of computing services ready to use and delivered over a public internet which is accessible for the usage of public is called a public cloud. According to Metzler, Jim, Taylor and Steve (2010), the service applications offered on the public clouds can be software like the Gmail from Google or Salesforce.com; can be platforms for development of the software as a service like the Azure from Microsoft or a service of Infrastructures from various vendors. The services offered on the cloud like the resources, storage and applications may be free or a pay as per usage model. The public cloud computing offers benefits like high scalability; reduced costs; automatic upgradation and backup of data and applications; the capital investments get converted to operating expenses and in turn upgrades the cash flow and universal approachability. It is stated in The Economist (2009) that, the public clouds and private clouds have not much difference in their architecture. Only the security aspect may differ considerably for the services that are provided by the provider to the public and when a non-trusted network effects the communication. As the public 382

cloud applications mostly run on a basis of multi- tenants, it is not the best choice for every small business (Baburajan and Rajani (2011). 3.2 Private Clouds: Figure 2: Private cloud types Source: Metzler, Jim, Taylor and Steve (2010) The cloud infrastructure created solely for a single organization or a business is called as the Private cloud. The private clouds host infrastructures, development environments and applications while addressing the concerns of control and data security which are encountered in the public cloud environment. Mao, Ming and Humphrey (2012) state that, private clouds are of two types and they are On Premises Private Cloud or Internal Cloud and Externally Hosted Virtual Private Cloud. The internal cloud is possessed by the data centre of the organization while a third party service provider hosts the external cloud who creates an exclusive cloud and manages the implementing and securing the cloud infrastructure. The cream provided by a private cloud is that, it is expandable, virtualized and provides elastic frameworks. According to DynaSis, (n.d), companies create and control a private cloud to pool network, storage, virtual resources, hardware and web for more dynamic, cost effective employment of resources. 3.3 Hybrid Clouds: A configuration or consolidation of more than two private or public clouds which are distinct entities but constrained together to offer the advantages of multiple deployment models is called a Hybrid Cloud. According to The NIST Definition of Cloud Computing (n.d), the capability of a cloud to combine allocation, committed or managed services with cloud resources is meant as the Hybrid cloud. 383

8Figure 3: Hybrid clouds Source: Metzler, Jim, Taylor and Steve (2010) The hybrid cloud permits the continuation of the capability or the scope of a cloud service by unification, tailored or aggregate with other cloud services. Metzler, Jim, Taylor and Steve, (2010) call a hybrid cloud as the leading brand. The utility of a public cloud and the ease of a private cloud are united in a hybrid cloud. Characteristics Public Clouds Private Clouds Hybrid Clouds Elasticity Very High Limited Very High Efficiency Authenticity Cost Good, but depends on the security measures of the service provider Medium; depends on Internet connectivity and service provider availability. Very good; pay as you go model and no need for on premise storage infrastructure. Most secure, as all storage is on- premise High, as all equipment is on premise. Good, but requires on premise resource, such as data centre space, electricity and cooling. Table 2: Comparison Table of Clouds Very secure; integration options add an additional layer of security Medium to high, as cached is kept on premise, but also depends on connectivity and service provider availability. Improved, since it allows moving some storage resources to pay as you go model. 384

4. Cloud Computing Service Delivery Models: Cloud computing has three leading models for service delivery such as Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS) and Infrastructure-as-a-Service (IaaS). The other service models included are NaaS (Network as a service) and CaaS (Communication as a service). 4.1 Infrastructure-as-a-Service: Balachandra, Ramakrishna and Rakshit (2009) stated that IaaS is an individual tenant layer in the tenant where the merchant of cloud computing (CC) had provided resources which could be shared with contracted end users on the base of pay-per-usage. Such things largely scale down the requirement for prominent elementary capital investment in computer hardware like networking devices, servers and processor power etc.. Moreover IaaS permits dissent degrees of operational and financial tractability not accepted with apposition services or internal data centres since computing resources could be comprised or liberated cost-efficiently and instantly than collocation service or internal data centre. Constituents of IaaS comprise of storage, virtual machines, load balancers, firewalls and more. With IaaS, users can immediately access the software service which is present in the lowest-level stack i.e. to the management control panel of load balancer or firewall and to the OS (operating system) on virtual machines. Amazon web services are the best example for the IaaS providers (Subashini and Kavitha, 2010). 4.2 Platform-as-a-Service: PaaS is a packet of software and development tools present on the servers of the provider. PaaS exists one layer upon the infrastructure as a service on the stack and selects everything up to operating system, middleware and so on. PaaS promotes an interrelated set of developer conditions in which a developer is able to develop their applications without any disruptions. PaaS assist developers with a service which grants an eventual management for life cycle of software development, beginning from planning, designing, building, implementing, testing and maintenance. According to Grobauer, Walloschek and Stocker (2010) cloud layer of PaaS behaves as such IaaS but PaaS provides an additional plane of continued performance. Users using services of PaaS move even more amount from investment of capital to operational cost but have to acknowledge the extra constraints posed by extra layers in the function. PaaS, on the backend accordingly provides and ranks the needed constituents of infrastructure based on requirements of software applications. One of the popular providers of PaaS was Google App Engine (Kresimir and Zeljko, 2010 and Chen and Chen, 2011). 4.3 Software-as-a-Service: SaaS is a representative for dispersion of software in which applications would be introduced by provider of service or vendor and received by clients through the network specifically over the internet. It grants available online solutions for software. Subashini and Kavitha (2010) stated that the software provider has eventual software application authority. Examples of applications of SaaS enclose project-management systems, online mail, social media platforms and customer relationship management. The major difference between PaaS and SaaS is that SaaS gives online software 385

applications which are developed or devised immediately whereas PaaS provides a platform for establishing the application. 5. Discussion on Cloud Computing: Though Cloud Computing invites a vast area for research viz. resource sharing, load balancing and security aspects for datacentres from the side of cloud providers. Certain Security threats in cloud computing are analysed and then stated as the notorious nine by the CSA(Cloud Service Alliance) as Data Breaches, Data Loss, Account or Service traffic high jacking, Insecure Interfaces and APIs, Denial of Service, Malicious Insiders, Abuse of Cloud Services, Insufficient due diligence, Shared Technology Vulnerabilities. There are great opportunities for researchers to work on Cloud Security Threats as very less work is accomplished in this area called cloud security. 6. Conclusion: This review paper broadly discusses about the key features of cloud computing and the main service delivery models offered by cloud computing in today s world of internet. The paper also describes the types of cloud available to the consumers on the basis of pay as per use. After referring to literature review about cloud computing, some threats and issues were analysed on which very few people have worked upon. Thus, this review paper on cloud computing concludes that cloud computing offers a vast area for researchers, to study and solve security issues and threats of cloud in future. References: 1. Bisong A, Syed and Rahman M (2011). An overview of the security concerns in Enterprise cloud computing, International Journal of Network Security & Its Applications (IJNSA), Vol.3, No.1, 2. Foster I, Zhao Y, Raicu I and Lu S, (2008). Cloud Computing and Grid Computing 360- Degree Compared, In: Grid Computing Environments Workshop, GCE '08, p. 10, 1. 3. Seth M S, Mishra R (2011). Comparative Analysis of Encryption Algorithms for Data Communication, International Journal of Computer Science and Technology, Vol. 2, Issue 2. 4. Sinduja.R and Sumathi.G (2013), Ensuring Cloud Security Using Hybrid Encryption Scheme and Disaster Recovery Mechanism, International Journal of Computer Trends and Technology, vol 4, issue 6, pp:1797-1803. 5. V. Sarathy, P. Narayan, and R. Mikkilineni (2010), Next generation Cloud Computing Architecture, 2nd International IEEE Workshop On collaboration & Cloud Computing. 6. Z. Wang (2011), Security and Privacy Issues Within Cloud Computing, IEEE Int. conference on computational and information sciences, Chengdu, China. 7. Ramgovind S, Eloff MM and Smith E (2010). The Management of Security in Cloud Computing, Information Security for South Africa (ISSA), Sandton, Johannesburg, 2-4. 8. Metzler, Jim, Taylor and Steve. (2010). Network World: "Cloud computing: Reality vs. fiction," Retrieved on September 30, 2014 from http://www.networkworld.com/newsletters/frame/2010/082310wan1.html 386

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