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WSOL & WSOI - Web Service Offerings Language and Infrastructure. Vladimir Tosic, Bernard Pagurek, Kruti Patel, Babak Esfandiari , Wei Ma Network Management & Artificial Intelligence Lab Department of Systems & Computer Engineering Carleton University, Ottawa, Canada [email protected] - PowerPoint PPT Presentation
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WSOL & WSOI - Web Service Offerings Language and
Infrastructure
Vladimir Tosic, Bernard Pagurek, Kruti Patel, Babak Esfandiari, Wei Ma
Network Management & Artificial Intelligence Lab Department of Systems & Computer
EngineeringCarleton University, Ottawa, Canada
[email protected]://www.sce.carleton.ca/~vladimir/
WSOLpublications.html
Outline
=> Introduction: definition of terminology, problem statement
Web Service Offerings Language (WSOL)
Web Service Offerings Infrastructure (WSOI)
Conclusions and future work
Definition of Terminology
Web Service (WS) - software application Identified by URIs Using XML messaging (SOAP), description
(WSDL), and discovery (UDDI) Web Service composition
(orchestration, choreography, flow, network)
Consumer(Requester)
WS
Provider(Supplier)
WS
AnotherWS
Problem Statement
WSDL does not formally describe important management information classes of service, SLAs, constraints, prices,
penalties, management parties, policies, … => Our solution: WSOL
How to implement management of WSOL-enabled Web Service and their compositions
=> Our solution: WSOI
=> WSOL
Introduction
=> Web Service Offerings Language (WSOL): language constructs, WSDL and WSOL, support for management applications, comparisons with related work
Web Service Offerings Infrastructure (WSOI) Conclusions and future work
WSOL Language Constructs
Service Offering (SO) - class of service constraints (functional, QoS, access rights)
expressions (Boolean, arithmetic, …)
statements (prices/penalties, management responsibility)
reusability constructs (extension, constraint groups, inclusion, instantiation of constraint group templates, …)
Service Offerings Dynamic Relationships (SODRs) - can change during run-time
WSDL and WSOL: Example
buyStock Web Service
buyStockPortType buySingleStockOperation buySingleStockRequest symbol quantity buySingleStockResponse totalStockBuyingCost … buyStockBindingbuyStockPort
buyStock.wsdl ServiceOffering1
accounting party: provider Constraint1: preCondition domain: buyStockOperation quantity > 0 Constraint2: QoSConstraint domain: buyStockOperation ResponseTime < 0.5 s Price: 0.5 $ServiceOffering2 …
buyStock.wsol
Applications of WSOL
Web Service Management (WSM) Measurement and calculation of QoS metrics,
evaluation of constraints, accounting and billing, control of the behavior of the Web Service
WS Composition Management (WSCM) Which WS co-operate in a composition What contracts are used => dynamic
manipulation of WSOL service offerings Dynamic selection and negotiation of
Web Services and classes of service
WSOL Support for WSM
Service offerings - a lightweight alternative to SLAs, contracts, profiles
Constraints and statements - policies QoS constraints - performance mgmt.Price/penalty statements - accounting mg. Functional constraints - fault managementManagement responsibility statements -
configuration management (part.)Access rights - security management (part.)
WSOL Support for WSCM
Service offerings dynamic relationships (SODRs) for switching, deactivation, and reactivation
of service offerings
Reusability constructs (static relationships between service offerings) mainly for creation of service offerings
WSOL - Some Related Work
Differentiated services (e.g., in telecom) Formal specification of various constraints Specification and management of
custom-made SLAs for Web Services: WSLA (Web Service Level Agreement) - IBM WSML (… Management ...) - HP SLAng - University College London
WS-Policy - IBM/Microsoft/BEA/SAP DAML-S - the Semantic Web community
Distinctive Characteristics of WSOL
Classes of service (service offerings) Various types of constraint Management statements Broad set of reusability constructs SO dynamic relationships (SODRS)Management third parties, accounting
parties Relative simplicity Features with lower run-time overhead Support for WSM and WSCM
=> WSOI
IntroductionWeb Service Offerings Language (WSOL)
=> Web Service Offerings Infrastructure (WSOI): support for monitoring of Web Services, mechanisms for manipulation of service offerings
and WSOI support for these mechanisms, comparisons with related work
Conclusions and future work
WSOI Support for WSMWSM - monitoring of WSOL service offerings:
Measurement and calculation of QoS metrics Evaluation of constraints Accounting
Modules for WSM: Based on open-source Apache Axis SOAP engine WSOI-specific handlers and chains Timer module Data structures Modules for SO Management (SOM) port types
WSOI-specific Handlers and Chains: Example
req.
res.
op. call
WSOI (Extends Axis SOAP Engine)
Pr
…SH
SH
SOI
SOO…
WSOIChain
RTB
RTS
AI
AO QCE
WSCM - Dynamic Manipulation of WSOL SOs
Switching between service offerings Provider- or consumer-initiated
Deactivation and reactivation of SOs With accommodation of affected consumers
Deletion of deactivated SOs Creation of new SOs (same WSDL files)
Provider decides when it is possible and allowed
Deactivation, reactivation, deletion, and creation of SODRs
Benefits of Manipulation of Service Offerings
Comparison methodology: Analytical studies and experiments with WSOI
=> Simpler, faster, and incurs less overhead than re-negotiation of SLAs and switching or re-composition of Web Services
Provides additional flexibility Enhances robustness of WS compositions Not a complete replacement for alternatives Can be their lightweight complement
WSOI Support for WSCM
Implementation of algorithms and protocols for the manipulation of SOs
Modules for WSCM (not based on Axis): SOMgmtDecisions module - operations
with decisions about applying manipulation of SOs
Modules for SO Management (SOM) port types
Data structures (same as for WSM)
SOM Port Types
SessionMgmt
SONotification
SOComparisons
SOM-Prov
SODRMgmt
SOM-Cons
SOM-AccP
SOSecurity
SOM-MgmtPSOInfo
Monitoring of SOs: Manipulation of SOs:
WSOI - Comparison with Related Work
Related work: Management infrastructure for WSLA Management infrastructure for WSML A number of WSM papers and products (often
based on JMX or gateways/hubs/proxies) Several WSCM papers and products Management of Grid Computing
The main distinctive characteristic of WSOI: Monitoring and dynamic manipulation of
classes of service for Web Services
=> Conclusions and Future Work
Introduction Web Service Offerings Language
(WSOL) Web Service Offerings Infrastructure
(WSOI)
=> Conclusions and future work
Conclusions
WSOL and WSOI support WSM and WSCMWSOL support for management
applications: classes of service (service offerings), various types of constraint and statement, relationships between classes of service, …
WSOI support for management applications: WSOI-specific handlers and chains for Axis, algorithms and protocols for manipulation of
WSOL service offerings, modules, data structures, SOM port types, …
Current and Future WorkFull prototype implementation of the Web
Service Offerings Infrastructure (WSOI) Further experiments with the manipulation
of service offerings and alternatives Minor improvements of WSOL Full implementation of a prototype WSOL
compiler Integration of WSOL with UDDI …