ABSTRACT
Contents 14.1 Introduction ................................................................................................................... 364 14.2 Background .................................................................................................................... 364 14.3 QoS Ontology ................................................................................................................ 365
14.3.1 QoS Ontology Basic Layer .................................................................................. 366 14.3.2 QoS Ontology Support Layer ............................................................................. 366
14.4 QoS Aspects for Cloud Computing................................................................................ 367 14.4.1 Performance ........................................................................................................ 367
14.4.1.1 Response Time and Latency ................................................................. 367 14.4.1.2 roughput .......................................................................................... 368
14.4.2 Transparency ...................................................................................................... 369 14.4.3 Information Assurance ....................................................................................... 371 14.4.4 Security Risks ..................................................................................................... 371 14.4.5 Trustworthiness .................................................................................................. 374 14.4.6 SaaS Readiness .................................................................................................... 376
14.5 QoS Models for Cloud Platforms ................................................................................... 378 14.5.1 QoS Models for SaaS .......................................................................................... 378 14.5.2 QoS Models for PaaS and IaaS ........................................................................... 381
14.6 Selection Approaches in Clouds ..................................................................................... 382 14.6.1 QoS Levels’ Formalization .................................................................................. 383 14.6.2 Cost-Benefit Analysis ......................................................................................... 384 14.6.3 Cost Calculation ................................................................................................. 385
14.1 Introduction Cloud computing has gained considerable attention in the past few years as one of the important paradigms in distributed computing and Internet technologies, where hardware and software are delivered as a service on demand through the Internet, following a simple pay-as-you-go financial model. e source of the cloud power is its ability to stand at different levels of service: (1) infrastucture-as-a-service (IaaS), where the cloud enables access to hardware resources, such as servers and storage devices; (2) platform-as-a-service (PaaS), where the cloud allows the access to software resources, such as operating systems and software development environments; and (3) software-as-a-service (SaaS), where classical software applications running on local computers are instead provided remotely by the cloud. Such service-oriented diversity makes the cloud a very promising technology, and it becomes crucial to understand and explore its methodologies as well as its quality of service (QoS) management criteria.
