1. 1 Introduction to Web Services Quality Model And Collaboration Issues for EERP 2007.12.12 Sojung Kim WSQM TC National Information society Agency

2. 2 A table of contents Critical Issue in SOA WSQM WS-Quality Factor Next Step EERP & WSQM

3. 3 Service Quality Issues have gained attention in SOA paradigm –SOA Governance : stakeholders’ role and responsibility –Different Service Life Cycle and a variety of stakeholders Service Acquirer/Developer/Consumer, Quality Information Provider, Quality/Assuror/Authenticator/Manager –Role of service registry and responsibility for guaranteed service What EERP wants –To build freestanding value networks in SOA –Deal with traditional but critical issues – Quality of Services effectively WSQM provides –From well known system information quality to business value quality Critical Issues in SOA

4. 4 Overview –To prepares a quality model in the context of contracting for Web services between associates conceptually, in order to secure Web services at a specific level of service quality Scope –To specify an overall model of quality of Web services in WSQM TC, It will include specified quality factors, associate roles, and activities WSQM TC

5. 5 WSQM TC : Background & Needs Requirements for definition of Service Quality according to Web Service proliferation Motivation for activating quality activity of Web service associates To help to make consensus between Web Service associates ex) negotiation/contracts

6. 6 WSQM A model for configuring Web service quality or differentiating service level It consists of 3 components: Quality Factor, Quality Associate, and Quality Activity. Quality Factor: fundamental components that recognize Web services quality as the target for control. Quality Associates: roles or tasks of the organizations or persons related with Web services. Quality Activity: various actions performed by associates

7. 7 7 Service stakeholder Service Developer Development Quality Contract Service Provider Service Consumer Management Quality Contract Service Development Service Operation & Management Quality Manager Service Broker Service user Example of Quality Activity Development Quality Contract: between Stakeholder and Developer Delivery time, Interoperability, Usability, Security Management Quality Contract: between Provider and Quality Manager Manageability, Composability Service Quality Contract WSQM : Quality Activities

8. 8 WS-Quality Model v1.0 WS-Quality Factor v1.0 WS-Quality Description Language v1.0 WS-Quality Use Case v1.0 WS-Quality Test Guideline v1.0 WS-Quality Specifications Family WS-Quality Model defines an abstract model in order to define Web Services quality WS-Quality Use Case provides a number of use cases as best practices that Web Services quality associates could be faced with in the process of developing Web Services WS-Quality Factors defines a list of non-functional properties of Web Services in which represents and valuates the quality of Web Services WS-Quality Description Language provides a basic description language in XML to describe of Web Services quality for exchange between Web Service quality associates WS-Quality Test Guideline provides a guideline and detailed mechanisms to test and measure the quality level of Web Services WSQM – 5 family specifications

9. 9 WS-QF (Web Service Quality Factor) Business Value Quality Group Business Value Quality Suitability Service Cost Effect Recognition level Service Measurement Quality Group Service Level Measurement Quality Performance Stability System Information Quality Group Interoperability Conformability Interoperability Business Processing Message Reliability Transaction Collaborability Manageability Introspection Control Notification Security Confidentiality Integrity Authentication Access Control Non-repudiation Non-repudiation Accessibility Audit trail Privacy Business Value Quality Group Business Value Quality Service Cost Recognition level Service Measurement Quality Group Service Level Measurement Quality Performance Stability System Information Quality Group Interoperability Suitability for Standards Conformability Interoperability Business ProcessingBusiness Process Quality Message Reliability Transaction Collaborability Collaboration Manageability Manageability Quality Management Information offerability Control Controlability Notification Security Security Quality Confidentiality Integrity Authentication Access Control Non-repudiation -Non-repudiation Accessibility Audit trail Audit Privacy Service SuitabilityService Aftereffect Recognition level Service Brand Value Privacy Sing-Sign-On

10. 10 WS-QF (Web Service Quality Factor) Business Value Quality Service Cost : a level of payment for value Service Suitability : Is a particular service suitable for business operation? Service Aftereffect : quantitatively or qualitatively expresses effect from a particular web service in business Service Brand Value : collection of reputation shaped by users Service Level Measurement Quality Performance : response time to a service request Stability : How stable web services provide services?

11. 11 Suitability for Standards Conformability : to evaluate if web services was built according to the standards Interoperability : how well service information can be exchanged and used? Business Process Quality Message Reliability : to exchange without any errors Transaction Process Ability : ability to process related tasks on process flow Business Process Collaboration Ability : How well is the collaboration scheme with Web Services suitable to business process WS-QF (Web Service Quality Factor)

12. 12 Manageability Quality Management information offerability Observability : feature to provide the management information Controlability : feature to change the inside information Security quality Confidentiality Integrity Authentication Access control Non-repudiation Availability Audit Privacy Sing-Sing on WS-QF (Web Service Quality Factor)

13. 13 Next Step Applying WSQM in multiple sets of government guidelines, recommendations, and standards Providing of quality information from WSQM test bed Collaboration between national Web Services Registry

14. 14 Consideration for Collaboration between EERP and WSQM

15. 15 A table of contents Core Technology of EERP Consideration 1: Service granularity Consideration 2: Weight for quality factor Consideration 3: How to get quality Info. Consideration 4: How to use quality info Consideration 5: Common Service Quality Consideration 6: Quality Chain

16. 16 Quality of Service: Framework - QoS description, evaluation, audition, mapping.. Dynamic Service Orchestration: Control - Resource optimization eXtensible Web Service Description: Representation - extension of WSDL with QoS and semantic expressions of ser vice functions Granularity of Service: Composition - Search the optimized unit of services Core Technology of EERP

17. 17 WSQM focuses on quality factors of simple type service. EERP varies service granularity flexibly. Considerations: Is WSQM proper model for various granularity of services? What part of WSQM or WSQDL should be changed for reflecting granularity? Consideration 1: service granularity Composite service Single or simple service

18. 18 Various quality factors for services. What is the major or minor factors for EERP selecting a service? Each business requires different level of weight of quality factor for selecting a service. Now, WSQDL has no information of weight for quality factor. Consideration 2: Weight for quality factor UDDI for quality info priorityfactorweight 1Security50 2Interop30 3Metric20 Service consumer 1 priorityfactorweight 1Metric40 2Interop40 3Security20 Service consumer 2 WSQDL 1 WSQDL 2 WSQDL 3 WSQDL n

19. 19 Getting time for quality information is different as quality factors. For completing WSQDL, it requires getting information carefully in each step and framework for collecting quality info. - Business related Info(cost, suitability,..): before running or after running - Operational related Info(measurement): while running - Technical related Info(Interop, security..): before running Consideration 3: How to get quality Info. Services for Biz Use the service Suitable for Biz purpose? Satisfy QoS in Tech? Is it possible Wrapping or alternative? Yes No No use No

20. 20 EERP Dynamic service orchestration requires real-time service search with quality info. For the purpose, we use UDDI which has quality classification and updates it with the help of service quality management system. Consideration 4: How to use quality info WS Quality Management System WS Quality Info WS Provider ① WS registration ② request new WS ③ provide WSDL of new WS ④ test with Agent ⑤ Store Quality Info connecting API ⑦ store the ref of WS Quality ⑥ provide WS Quality Info UDDI

21. 21 Each WS could be reclassified according to quality grade. Because there are various quality factors, we need quality context for describing quality values. EERP system can find services more rapidly if WS is categorized in quality context. Consideration 4: How to use quality info Quality Management System WSDL 1 Quality context 1 value Quality context 2 value Quality context 3 value WSDL 2 Quality context 1 value Quality context 2 value Quality context 3 value WSDL 3 Quality context 1 value Quality context 2 value Quality context 3 value WSQDL MetricEvalBiz ProcBiz Val InteropSecManage SecrecyNon-rep UDDI

22. 22 In EERP, Some services could be packed for common service. In this case, users have more interest in service quality of packing unit more than each unit service. If WSQDL support this type quality model, it makes quality system more simple. Consideration 5: Common Service Quality WSQDL 1WSQDL 2 Common Service Pack 1 PS 1 PS 2 PS 3 Common Service Pack 2

23. 23 The value of each quality factor is described in quality chain, in which each factor can refer the other factor. Quality factor is composed of measure factor, evaluation factor, biz process factor, and biz value factor. EERP can refer quality chain info for selecting a service Consideration 6: Quality Chain Target Web services Quality Factor Biz process factor Eval factor Biz value factor Measure factor PropertySub propertyFunctionPerformance Sub factor PropertyAppraisal Sub factorPropertyFunctionPerformance Metric

24. 24 If services are classified with business purpose and grouped in same quality context, we can find a service suitable for a situation. Single value or value bandwidth for an item on quality chain is possible. Consideration 6: Quality Chain eval/security/XML-enc keySize: 128 secAlgorithm: RSA encTime: 10ms-20ms S1 S2 S3 S4S5 Common value for quality factor Quality factor value in bandwidth Same purpose services

25. 25 Thank You!! SoJung Kim (ksjnu@nia.or.kr)