WSQDL (Web Service Quality Description Language)

1. WSQDL (Web Service Quality Description Language) 16th April, 2007 Youngkon Lee Korea Polytechnic University

2. A table of contents • What is WSQDL? • Background • Needs • What is WSQM? • What is WS Quality Factor? • WSQF – analysis • Concept of Quality Chain • Principle of Design • Complex type • Conclusion

3. What is WSQM TC? • Purpose: to establish Web services quality model and its necessary • specifications • Scope: quality factor, quality associates, and quality activity, quality • test guideline, quality description language for Web services • Members: Korea Government side (NIA, ETRI), Korea SI and IT • companies, DERI, etc Core Spec. WSQM WSQF WSQUC Subsidiary Spec. WSQDL WSTG

4. What is WSQDL? • XML schema for describing values of Web service quality factors with measuring/evaluation method, condition factors in specified and • normalized form by Web service associates. Specifying quality factor description Configuring quality factors Web services Web service Quality Model (WSQM) Web service Quality Description Language (WSQDL)

5. Background • Requirements for Web service quality according to Web service • proliferation • ex: needs in Korea e-Government project • Needs of specification for describing Web service quality model(WSQM) • Motivation for activating quality activity of Web service associates Quality Requirement Specification for WSQM Activating quality activity

6. Needs • Describing value of Web service quality factors in specified form • Automatic exchange of quality data • use of WSQDL objectively for quality activity ex) SLA • help to make consensus between Web service associates ex) • negotiation/contracts Making Consensus between Web service associates Objective Data for Quality activity Automatic exchange of quality data

7. What is WSQM (Web Service Quality Model)? • 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

8. What is WSQF (Web Service Quality Factor)? • WSQF refer to a group of • items for • representing • and valuing • the quality of Web services. • WSQF can be divided into 3 groups in the point of use by user.

9. WSQF - Analysis • Group possibly the quality factors by following criteria • functionality: function implemented, performance of function • Correspondence to user requirements • Evaluation time • Whether there is evaluation criteria or not ex) WS-I BP, BSP • Complexity: single criteria or multiple criteria Quality factor Evaluation factor Measurable factor No evaluation criteria Evaluation criteria • Availability • Accessability • Biz Value Single criteria Multiple criteria • Successability • service price • Response time • service suitability • Security • Biz Process • Throughput • service effect • Interoperability • service brand value • Management

10. WSQF – Business value factor • Value endowed by Web service user subjectively or objectively in the • viewpoint of business • Subjective sub-factors: evaluating the value of factors by survey or interview, ex) reputation, recognition • Objective sub-factors: evaluating them quantitatively, ex) price, • ROI, business effectiveness • Changed much by strategy, goal, core value, etc Quality Factor Sub Factor Property Evaluation Biz value service price price, penalty, compensation survey service suitability biz suitability, convenience user evaluation service effect biz effect, ROI index calculation service brand recognition, reputation survey, interview

11. WSQF – Security factor • Quality factor required for securing Web service system • Properties: confidentiality, certification, integrity, non-repudiation • Sub properties: message level or communication protocol level • Performance: security level, processing speed, interoperability,etc. Quality factor Property Function Performance Sub property Security confidentiality XML ENC message level confidentiality security level certification SAML, X.509 message level certification interoperability Integrity XML ENC DSIG message level integrity throughput non-repudiation XML DSIG message level non-repudiation throughput

12. WSQF – Interoperability factor • Quality for guaranteeing the technical consistency between Web • service system • Ratio or number of rules in WS-I BP, BSP satisfied by a Web service system • Consider severity (Must, Should, May) level of rule Quality Factor Property Function Evaluation Interoperability message conformity SOAP Handler WS-I satisfaction degree WSDL conformity WSDL I/F WS-I satisfaction degree UDDI conformity UDDI Registry WS-I satisfaction degree

13. WSQF – Measurement factor • Quality for representing technical performance of Web service • system • Consideration • What is the items measured? • How can we measure it? • How do we calculate measured value for result? Quality Factor SubFactor Function Performance measure factor Throughput # of trans/sec Response Time millisecond Accessability rate Successability rate Availability rate

14. WSQF – Business processing factor • Quality factor for applying Web service to real business area • Message reliability: transmission guarantee, duplicated message • removal, message ordering • Transaction processing: Atomic Transaction, Long-term Biz Activity • BP collaboration: Interoperability, Throughput, response time ,Error Handling, Recovery, compensability Quality Factor Sub Factor Property Function Performance biz processing reliable message AtMostOnce,… Retry, Ack throughput transaction processing ACID 2PC interoperability BP collaboration Compensable Context Mgmt security

15. WSQF – manageability factor • Quality factor representing how well Web service can manage other Web service or computing resources • Introspectability: manageable interface, # of metric inform, • rapidity, security • controllability: controllable interface, # of control items, rapidity, • security • Notifiability: notification interface, # of event type covered, • rapidity, security Quality Factor Property Function Performance • manageability • introspectability • Tracking,Logging • security • controllability • Resource Managing • response time • notifiability • Subscription • interoperability

16. Concept of Quality Chain • Configuration of dependency between Web service quality factors • Ex) The performance of security factor can be presented as • interoperability or metric value. • Biz value quality is evaluated on the basis of other technical • quality factors by users. Interoperability factor Manageability factor Security factor Biz value factor Biz processing factor Measurement factor : chain of dependency

17. Concept of Quality Chain • Security, manageability, interoperability can be grouped as evaluation • factor structured pattern. • The performance factor of biz process factor can be presented as • evaluation factor and measurement factor • Evaluation factor can be presented as itself recursively or measure factor Target Web services Measure factor Sub factor Metric Eval factor Property Sub property Function Performance Quality Factor Biz process factor Sub factor Property Function Performance Biz value factor Sub factor Property Appraisal

18. Principle of Design • Consistency of describing various factors • Convenience: Reference by global complex type and elements • Representation: recursive structure for representing quality chain • Conformity: representation of specification conformity • Flexibility for expanding coverage Consistency Convenience Representation Conformity flexibility

19. Complex type – Web service type • Complex type for representing Web service as a target evaluated • One service described in a WSDL is a minimum evaluation unit.

20. Complex type – Quality factor type • Composed of 4 major factors: Measurement factor, Biz value factor, • evaluation factor, Biz process factor • Each factor can be referenced in the other factors.

21. Complex type – Metric type • Global data type for representing measurement factor. • Composed of measuring method, condition variable, measuring function, metric value.

22. Complex type – Property type • Global data type for representing evaluation factor • Composed of sub property, function, and description • Function is composed of conformity, performance, and parameter • Performance has evaluation factor or measurement factor recursively

23. Complex type – Conformity type • Represents whether a function has conformity with a specification • Composed of specification, rule category conformity, and overall conformity

24. Complex Type - Appraisal Type • UserAppraisalType has WSUser and Appraisals. • WSUser describes information of user evaluating Web service • Appraisals have Appraisal as evaluation item • Appraisal is a type of evaluation degree type, which has item, value, unit, perfect score, description

25. Conclusion • WSQDL is a new specification for describing Web service quality • formally. • WSQDL probably activate business action between Web service • associates by enabling transmission of specified quality data • We have a plan to apply WSQDL to Web service test-bed in Korea • Government side for communicating quality information. • We have a plan to improve WSQDL to present OASIS standard and to expand it to cover SOA service level.

26. Thank You!! Youngkon Lee: yklee777@kpu.ac.kr