2. Target Based: Supports URL based prioritisation so that for example when a user 

starts to purchase a produce it receives higher priority  

The previous section has presented a brief synopsis of how QoS is implemented on a number 

of levels. It is worth mentioning that architectures have been developed that attempt to 

enable end to end QoS for applications that have highly constrained requirements, in 

particular multimedia applications[10] [11]. Although these architectures provide a means to 

provision QoS from the network up to the application on an end to end basis, they are not 

specifically targeted at the most common application delivery framework for the foreseeable 

future, which is Web based delivery of applications.  

Finally, there is one final type of QoS that has not been discussed at all. This is Quality of 

Service as perceived by the end user and is of particular relevance in the context of web 

delivered applications. End user QoS encompasses the failure or success of all other forms of 

QoS from server to client in the service delivery chain. 

2.3 Current Approaches to Service Management 

A number of current approaches to service management will be discussed next. They offer 

some insight into current methods of managing services and determining service availability. 

These examples are not specifically Web based services but highlight the concepts and 

issues involved. 

One approach to service management is to manage services as a single unit, not just as 

individual components. For instants, an Internet Service Provider (ISP) might provide an e 

mail service on one of its servers to its customers. For this service to operate within specified 

parameters, all of the components within that host on must be operating. 

Research suggests that services should be modeled as a tree structure [5]. For example an E 

mail service would have the following structure.