Article Preview
Top1. Introduction
Cloud computing is a virtual pool of resources delivers a computing services like servers, storage, databases, networking, software, analytics and intelligence via internet which offers a faster innovation and flexible usage of resources. It provides IT services as on-demand and pay per use which is accessible from anywhere, anytime and by authorized users only. Create new apps and services, store backup and recovery, test and build applications, analyze data, deliver software on demand, stream audio and video, embed intelligence are examples of what today cloud service providers (CSPs) are providing (Harba, 2017). It’s also provides benefits of cost, speed, global scale, productivity, performance and security. There are four types of cloud deployment models namely public, private, hybrid and community (Bamiah & Brohi, 2011). Public clouds are owned and operated by third party CSPs which provide their resources like servers and storage via internet. Microsoft Azzure is an example of a public cloud. Private cloud is used exclusively by single organization which can be located on the organization on site data Centre. Amazon NC and Rackspace are the example of private cloud. Hybrid clouds are the combination of both public and private clouds which bound together to provide a common interface between them due to which it provides your business a greater flexibility, more deployment option and helps to optimize your existing infrastructure. Azure stack is an example of hybrid cloud. In community cloud, infrastructure is shared among several companies work on the same platform, having similar needs and concerns (security, compliance, performance etc.). Community cloud has been designed for various organizations such as working on joint projects or research, professional communication, geographic community etc. They all provide five type of services which are given as under (Kaplan et al., 2017):
- •
Infrastructure as a Service (IaaS)
- •
Software as a Service (SaaS)
- •
Platform as a Service (PaaS)
- •
Network as a Service (NaaS)
- •
Identity as a Service (IDaaS)
IaaS delivers cloud computing infrastructure including things such as servers, network and storage. Some common examples are Google Cloud Platform, Microsoft Azure and Digital Ocean (Odun-Ayo et al., 2018). SaaS utilizes internet hence provides us flexibility to access software online like google apps. NaaS provides an access to the network infrastructure directly. It also uses virtualization network infrastructure to provide better service to the user as Amazon and Rackspace and IDaaS is a cloud-based authentication which is operated by a third-party user. IDaaS companies provide identity management to enterprise who subscribed that like google and Facebook. Figure 1 provides a pictorial representation of the cloud models.
Figure 1. Types of cloud with their services
Data storage service is one of the most widely consumed cloud service. In today’s scenario media technology is carrying a rapid rise towards the intelligent cloud system. This is also another place where data get generated at a very high speed (Psannis et al., 2019). Users have greatly benefited from cloud storage since they can store huge volume of data without upgrading their devices and access them at any time and from any place. However, cloud data storage offered by CSPs still incurs some problems so because of that different type of security has been required in cloud storage due to data sensitivity (Kartit et al., 2015).
The important aspect of cloud computing is its precise implementation for maintaining Quality of Service (QoS) of its availability and performance of resources. Many researchers have applied the idea of queuing theory to develop cloud computing system (Guo et al., 2014; Gupta & Arora, 2018) in their study. Figure 2 provides better illustration of semantic procedure followed by queuing system, ‘n’ number of requests queued and further selected for a service when scheduled by the scheduler.