Quality of Service (QoS) in Service Oriented Architecture (SOA) Research Paper

Quality of Service (QoS) in Service Oriented Architecture (SOA) Applications - Research Paper Example The current levels of available reliability and performance will be assessed for their application to real life business applications. Keywords – Quality of Service, Service Oriented Architecture, QoS, SOA, reliability, performance, mathematical model I. Introduction Service oriented architecture (SOA) environments have gained popularity in recent years given their inherent flexibility and reusability. The typical SOA is structured around methods that promote software creation as interoperable services [1]. The various services used to construct a SOA are well-defined business functions. These business functions are construed as various software building blocks that can be used repeatedly to promote decreased development time and debugging effort [2]. Currently the SOA model is finding great appeal for web application development as well as grid computing [3]. The current speed of SOA architecture development indicates that SOA applications will dominate the future avenues of development. II. Quality of Service (QoS) and Service Oriented Architecture (SOA) The most important method of describing a SOA’s characteristics in general is the quality of service (QoS) it offers [4]. The current development of the QoS concept sees divergence and some commonality depending on the various fields that employ SOAs. Most web based application SOAs require real time transfer rates such as for fiscal information transfer or multimedia applications. In contrast, other areas such as mobile grid computing see SOA QoS as a set of non-functional outputs that guarantee reliability [5]. The existing disparity between QoS definitions for SOA implementations in networking, web applications and grid computing mean that QoS needs to be defined in a more comprehensive yet unambiguous fashion. Most previous definitions of QoS promote the idea that only the best possible service levels can be classified as QoS [6]. However, more modern definitions of QoS contend that any leve l of services that meet user requirements can be classified as QoS for that particular application [7]. QoS can also be compared to Service Level Agreements (SLAs) where the user and the service provider agree upon acceptable levels of performance parameters such as functionality, costs etc. QoS for SOAs can be classified in the form of â€Å"request, specification, provision and negotiation† of some particular network features [7]. A typical SOA application may require QoS for the latency, the error rate, bandwidth, availability as well as the network security [8]. However, these characteristics alone should not be seen as describing the entire umbrella for QoS for SOAs. Instead, these characteristics form some of the characteristics of QoS for SOAs. Moreover, the QoS agreements would tend to vary from application to application in SOA depending on user requirements, functional expectations and non-functional expectations of the user [9]. For example, users accessing multime dia content through SOA applications would emphasize more on bandwidth than users dealing with defense applications through SOA who would emphasize more on reliability and security [10]. The classification method provided above for QoS in SOA applications is limited in scope. The QoS may be broken down into smaller metrics for further QoS classification. For example, jitter in network connection could be treated through consecutive difference in jitter or through the average jitter. The results from these metrics would tend to differ