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WSQDL(Web Service Quality Description Language)

16th April, 2007

Youngkon LeeKorea Polytechnic University

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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

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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

WSQDL WSTG

WSQM

WSQF WSQUC

Core Spec.

Subsidiary Spec.

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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 serviceQuality Model

(WSQM)

Web serviceQuality DescriptionLanguage (WSQDL)

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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

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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

Automaticexchange ofquality data

ObjectiveData forQualityactivity

MakingConsensus

between Web service

associates

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What is WSQM (Web Service Quality Model)?

A model for configuring Web service quality or differentiating servicelevel It consists of 3 components: Quality Factor, Quality Associate, andQuality Activity.

Quality Factor: fundamental components that recognize Webservices 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

Quality AssociatesQuality Associates Quality FactorsQuality Factors

Quality ActivitiesQuality Activities

Perform Use

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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.

Business ValueQuality Group

Business Value QualityBusiness Value Quality

SuitabilitySuitability EffectEffect Recognition levelRecognition level

Service MeasurementQuality Group Service Level Measurement QualityService Level Measurement Quality

PerformancePerformance StabilityStability

System InformationQuality Group

InteroperabilityInteroperability

ConformabilityConformability InteroperabilityInteroperability

Business ProcessingBusiness Processing

Message ReliabilityMessage Reliability TransactionTransaction CollaborabilityCollaborability

ManageabilityManageability

IntrospectionIntrospection ControlControl NotificationNotification

SecuritySecurity

ConfidentialityConfidentiality IntegrityIntegrity AuthenticationAuthentication

Access ControlAccess Control Non- repudiationNon- repudiation AccessibilityAccessibility

Audit trailAudit trail PrivacyPrivacy

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WSQF - Analysis

Group possibly the quality factors by following criteriafunctionality: function implemented, performance of functionCorrespondence to user requirementsEvaluation timeWhether there is evaluation criteria or not ex) WS-I BP, BSPComplexity: single criteria or multiple criteria

Quality factor

Measurablefactor

Evaluationfactor

• Availability

• Accessability

• Successability

• Response time

• Throughput

Evaluationcriteria

No evaluationcriteria

• Security

• Interoperability

• Biz Process

• Management

• Biz Value

• service price

• service suitability

• service effect

• service brand value

Single criteria

Multiple criteria

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WSQF – Business value factor

Quality Factor

Sub Factor Evaluation

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

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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

throughput

Sub property

message level confidentialitymessage level certificationmessage levelintegritymessage 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

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Quality Factor

Property Function Evaluation

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 Webservice systemRatio or number of rules in WS-I BP, BSP satisfied by a Web service systemConsider severity (Must, Should, May) level of rule

WSQF – Interoperability factor

WS-I satisfaction degree

WS-I satisfaction degree

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Quality Factor

SubFactor Function Performance

Throughput

Response Time

Accessability

measure factor

# of trans/sec

millisecond

rate

Successability

Availability

rate

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

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Quality Factor

Sub Factor Property Function

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

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Quality Factor

Property Function Performance

• 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, securitycontrollability: controllable interface, # of control items, rapidity,securityNotifiability: notification interface, # of event type covered,rapidity, security

WSQF – manageability factor

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Concept of Quality Chain

: chain of dependency

Interoperabilityfactor

Biz processingfactor

Measurementfactor

ManageabilityfactorSecurity

factor Biz valuefactor

Configuration of dependency between Web service quality factorsEx) The performance of security factor can be presented asinteroperability or metric value. Biz value quality is evaluated on the basis of other technicalquality factors by users.

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Target Web services

Quality Factor

Biz process factor

Eval factor

Biz value factor

Measure factor

Property Sub property Function Performance

Sub factor

Sub factor Property Appraisal

Sub factor Property Function Performance

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

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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 RepresentationConvenience

Conformity flexibility

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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.

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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

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Global data type for representing measurement factor.

Composed of measuring method, condition variable, measuring

function, metric value.

Complex type – Metric type

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Global data type for representing evaluation factor Composed of sub property, function, and descriptionFunction is composed of conformity, performance, and parameterPerformance has evaluation factor or measurement factor recursively

Complex type – Property type

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Represents whether a function has conformity with a specification

Composed of specification, rule category conformity, and overall conformity

Complex type – Conformity type

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Complex Type - Appraisal Type

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

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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 t

o expand it to cover SOA service level.

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Thank You!!

Youngkon Lee: yklee777@kpu.ac.kr