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

2. 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. 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 WSQDLWSTG WSQM WSQFWSQUC Core Spec. Subsidiary Spec.

4. 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. Configuring quality factors Specifying quality factor description Web services Web service Quality Model (WSQM) Web service Quality Description Language (WSQDL)

5. 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 Activating quality activity Specification for WSQM

6. 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 Automatic exchange of quality data Objective Data for Quality activity Making Consensus between Web service associates

7. 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. 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. 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 Measurable factor Evaluation factor Availability Accessability Successability Response time Throughput Evaluation criteria No evaluation criteria Security Interoperability Biz Process Management Biz Value service price service suitability service effect service brand value Single criteria Multiple criteria

10. 10 WSQF – Business value factor Quality Factor Sub FactorEvaluation service price service suitability service effect service brand Biz value Property price, penalty, compensation biz suitability, convenience biz effect, ROI recognition, reputation survey user evaluation index calculation survey, interview 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

11. 11 Quality factor Property confidentiality certification Integrity non-repudiation Security Function XML ENC SAML, X.509 XML ENC DSIG XML DSIG Performance security level interoperability throughput Sub property message level confidentiality message level certification message level integrity message level non-repudiation 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. WSQF – Security factor

12. 12 Quality Factor PropertyFunctionEvaluation message conformity WSDL conformity UDDI conformity Interoperability SOAP Handler WSDL I/F UDDI Registry WS-I satisfaction degree 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 WSQF – Interoperability factor WS-I satisfaction degree WS-I satisfaction degree

13. 13 Quality Factor SubFactorFunctionPerformance Throughput Response Time Accessability measure factor # of trans/sec millisecond rate Successability Availability rate 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? WSQF – Measurement factor

14. 14 Quality Factor Sub FactorPropertyFunction reliable message transaction processing BP collaboration biz processing AtMostOnce,… ACID Compensable Retry, Ack 2PC Context Mgmt Performance throughput interoperability security 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 WSQF – Business processing factor

15. 15 Quality Factor PropertyFunctionPerformance introspectability controllability notifiability manageability Tracking,Logging Resource Managing Subscription security response time interoperability 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 WSQF – manageability factor

16. 16 Concept of Quality Chain : chain of dependency Interoperability factor Biz processing factor Measurement factor Manageability factor Security factor Biz value factor 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.

17. 17 Target Web services Quality Factor Biz process factor Eval factor Biz value factor Measure factor PropertySub propertyFunctionPerformance Sub factor PropertyAppraisal Sub factorPropertyFunctionPerformance Metric 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 Concept of Quality Chain

18. 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 ConsistencyRepresentationConvenience Conformityflexibility

19. 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. 20 Composed of 4 major factors: Measurement factor, Biz value factor, evaluation factor, Biz process factor Each factor can be referenced in the other factors. Complex type – Quality factor type

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

22. 22 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 Complex type – Property type

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

24. 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. 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. 26 Thank You!! Youngkon Lee: yklee777@kpu.ac.kr