A Web service can be selected based on the supported quality metrics. Is it highly
available? Does it answer a client??™s requests in an acceptable time? Furthermore, quality
metrics will serve as the basis for adaptation of QoS. During process execution, the QoS
needs to be monitored and checked against predefined and expected values, and when deviations
are identified, dynamic adaptation mechanisms may be triggered.
Table 1. Differentiated classes of services
N/A: not applicable
A Scalable QoS-Aware Web Serv ces Management Arch tecture (QoSMA)
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QoS.Management......
Overview....
Since network architectures (protocols) and the distributed applications deployed on those
networks are continuously evolving, a configurable, realizable, manageable and maintainable
QoS support is needed.
QoS management in distributed systems is among the hot topics that have received a great
deal of interest in recent years. Many architectures have been proposed to manage the QoS
for distributed applications (Benerjea, Ferrari, Mah, Oran, Verma, & Zhang, 1996; Braden,
Clark, & Shenker, 1994; Aurrecoechea, Campell & Hauw, 1998; Campbell, Coulson, &
Hutchison, 1994; Fischer, Hafid, Bochmann, & de Meer, 1997).
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