Quality of Service Attributes in Web Services

As Web Services development grew rapidly since 2002, the need for Quality of Services (QoS) has become a significant factor for building a trustworthy service application. There have been many proposals and frameworks which adds QoS to Web Services. However, few technologies have survived the race and forced their way to standardization. This paper will explore some of what has been done in Web Services QoS in the last decade. Some of the questions answered in this paper are: Where exactly do we stand now in supporting QoS attributes representing non-functional requirements for Web Services? What technologies as well as QoS attributes have proven themselves to be worthy for standardization? Three main models and two main technologies will be discussed, i.e., Web Services Publishing & Discovery, Web Services Description & Handling, and the combination of both. These models are combined with two technologies: Universal Description Discovery and Integration (UDDI) and WS-Policy. This paper will show that many approaches introducing non-functional characteristics to Web Services have mainly considered security, reliable messaging, transaction, accounting, availability and response time as major quality characteristics for Web Services. This paper will conclude that policies has found popularity and acceptance among industry vendors.