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A Framework for the Smart Dynamic Selection of Web Services Access Points

A Framework for the Smart Dynamic Selection of Web Services Access Points. Marco Bianchi bianchi@di.univaq.it. Giorgio Gambosi gambosi@mat.uniroma2.it. Carlo Gaibisso gaibisso@iasi.rm.cnr.it. Flavio Lombardi lombardi@di.uniroma1.it. Workshop on QoS in Geographically Distributed Systems.

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A Framework for the Smart Dynamic Selection of Web Services Access Points

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  1. A Framework for the Smart DynamicSelection of Web Services Access Points Marco Bianchibianchi@di.univaq.it Giorgio Gambosigambosi@mat.uniroma2.it Carlo Gaibissogaibisso@iasi.rm.cnr.it Flavio Lombardilombardi@di.uniroma1.it Workshop onQoS in Geographically Distributed Systems 10 June, 2004Rome

  2. Goal of this presentation To show a “in progress” research activity in the context of Web Service Technologies. The focus of this activity is on the discovery of the “best” available Web Service Instance “Best effort” approach ¹ QoS guaranteed approach

  3. ServiceDescription ServiceRegistry Publish Find Service ServiceRequestor ServiceProvider Bind ServiceDescription StaticBind DynamicBind Web Service Architecture Model Reference: Web Services Conceptual Architecture (WSCA 1.0) – IBM – 2001

  4. ServiceRequestor ServiceRegistry How the research communityis trying to fill this gap? Using a declarative approach. ServiceInstance1 ServiceInstancen Service all implementing the same interface (i.e. tModel) A model for a simple scenario 2 How can the Service Requestor choose the most “comfortable” Service Instance? 1 What happens in the Service Registry when a Service Instance goes down? Current discovery standards (i.e. UDDI) don’t provide any non-operational information about the run-time behavior of Service Instances! Nothing. Current discovery standards (i.e. UDDI) could contain obsolete reference to Services Instances! … Service Provider1 Service Providern

  5. Monitoring in order to discover “best” Web Services Discovery Monitoring Monitoring in order to“certificate” the declaredQoS Integration ofQoS declarationsin the discoveryprocess QoS Monitoring in order tomaintain the declaredQoS Web Services Technologies Relationships

  6. Discovery Monitoring • Service Requestors: • do not intend to deal with of QoS aspects • Service Providers: • are not interested in building up a SW/HW required infrastructure • are interested in avoiding providing services of “bad” quality QoS When ?

  7. UDDI/WSClient EnhancedUDDI Registry 3 1 2 Web ServiceInstance 1 Web ServiceInstance n CV1 CVn Main goal of the framework Enhanced UDDIRegistry still exposea standard UDDI Interface! … Web Server 1 Web Server n

  8. Roadmap First phase: a basic scenario • One Service Registry • Small set of Web Service Instances Second phase: more complex (and realistic) scenario • Several Service Registry • Large set of Web Services Instances • Authentication/Security • UDDI API extension … …

  9. Enhanced UDDIRegistry Web ServiceInstance 1 Web ServiceInstance n … Enhanced UDDI Monitoring Agent 1 Enhanced UDDI Monitoring Agent n Vi-1=(x1,..xm) Vi+1=(x1,..xm) … Basic Scenario: introducing monitoring Agent … Web Server 1 Web Server n Vi =(x1,..xm)

  10. Enhanced UDDI Registry Architecture UDDI Registry Points of AccessEvaluator StatisticsArchive UDDIClient RequestCatcher UDDI ExtensionManager AgentManager Enhanced UDDI Registry Enhanced UDDI Monitor Agent 1 Enhanced UDDI Monitor Agentn …

  11. UDDI/WSClient Enhanced UDDIRegistry UDDIRegistry Basic Scenario: Discovery Operation • In order to fully exploit the advantages derived by the ordered list is it necessary to modify existing clients?No, if clients adopt the Invocation Pattern suggested by UDDI Technical Committee. “Give me addresses associated to this tModel” Unordered list of addresses “Give me addresses associated to this tModel” Ordered list of addresses

  12. Enhanced UDDIRegistry 1 3 monitored 2 usual 4 Web ServiceInstance i 5 Enhanced UDDI Monitor Agent i Basic Scenario: Publishing Operation Web Server ServiceAdministrator

  13. Prototype implementation details Enhanced UDDI Monitoring Agent Handlers for the AXIS Soap Engine Monitored parameters: Availability Time of Completation Throughtput Enhanced UDDI Registry JUDDI: an opensource Java implementation of the UDDI Specification

  14. Concluding remarks • Presentation of a framework for the association of a dynamic convenience value to Web Service Instances implementing a “best effort” approach • More details in:M. Bianchi, C.Gaibisso, G.Gambosi, F. Lombardi“A Framework for the Smart Dynamic Selection of Web Service Access Points” Submitted to International Conference (ECOWS04)

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