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Introduction to Web Services Quality ModelAnd

Collaboration Issues for EERP

2007.12.12

Sojung KimWSQM TC

National Information society Agency

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A table of contents

Critical Issue in SOA

WSQM

WS-Quality Factor

Next Step

EERP & WSQM

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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

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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

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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

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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

Quality AssociatesQuality Associates Quality FactorsQuality Factors

Quality ActivitiesQuality Activities

Perform Use

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Service stakeholder

ServiceDeveloper

Development Quality Contract

ServiceProvider

ServiceConsumer

Management QualityContract

ServiceServiceDevelopmentDevelopment

ServiceServiceOperation &Operation &ManagementManagement

Quality Manager

Service Broker

Service userService user

Example of Quality Activity • Development Quality Contract:

between Stakeholder and DeveloperDelivery time, Interoperability, Usability, Security

• Management Quality Contract: between Provider and Quality ManagerManageability, Composability

Service QualityContract

WSQM : Quality Activities

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WS-Quality Model v1.0

WS-Quality Factor v1.0WS-Quality

Description Language v1.0

WS-Quality Use Case v1.0WS-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

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WS-QF (Web Service Quality Factor)

Business ValueQuality Group

Business Value QualityBusiness Value Quality

SuitabilityService Cost 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

Business ValueQuality Group

Business Value QualityBusiness Value Quality

Service Cost Recognition level

Service MeasurementQuality Group Service Level Measurement QualityService Level Measurement Quality

PerformancePerformance StabilityStability

System InformationQuality Group

InteroperabilitySuitability for Standards

ConformabilityConformability InteroperabilityInteroperability

Business ProcessingBusiness Process Quality

Message ReliabilityMessage Reliability TransactionTransaction CollaborabilityCollaboration

ManageabilityManageability Quality

Management Informationofferability ControlControlability NotificationNotification

SecuritySecurity Quality

ConfidentialityConfidentiality IntegrityIntegrity AuthenticationAuthentication

Access ControlAccess Control Non -repudiation-Non-repudiation AccessibilityAccessibility

Audit trailAudit PrivacyPrivacy

Service Suitability Service Aftereffect Recognition levelService Brand Value

PrivacySing-Sign-On

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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?

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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)

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Manageability QualityManagement information offerability Observability : feature to provide the management informationControlability : feature to change the inside information

Security qualityConfidentialityIntegrityAuthenticationAccess controlNon-repudiationAvailabilityAuditPrivacySing-Sing on

WS-QF (Web Service Quality Factor)

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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

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Consideration for Collaboration between EERP and WSQM

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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

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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

service functions

Granularity of Service: Composition- Search the optimized unit of services

Core Technology of EERP

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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

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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

priority factor weight

1 Security 50

2 Interop 30

3 Metric 20

Service consumer 1

priority factor weight

1 Metric 40

2 Interop 40

3 Security 20

Service consumer 2

WSQDL 1

WSQDL 2

WSQDL 3

WSQDL n

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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 runn

ing

- 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 inTech?

Is it possibleWrapping or alternative?

Yes Yes

No

No use

No

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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 QualityManagement

System

WS QualityInfo

WS Provider

① WS registration

② request new WS

③ provide WSDL of new WS

WS

④ test with Agent

⑤ Store Quality Info

connecting API

⑦ store the ref of WS Quality

⑥ provide WS Quality Info

UDDI

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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

Metric Eval Biz Proc Biz Val

Interop Sec Manage

Secrecy Non-rep

UDDI

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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 1 WSQDL 2

Common Service Pack 1

PS 1

PS 2

PS 3

Common Service Pack 2

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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

Property Sub property Function Performance

Sub factor

Sub factor Property Appraisal

Sub factor Property Function Performance

Metric

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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 S4 S5

Common value for quality factor

Quality factor value in bandwidth

Same purposeservices

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Thank You!!

SoJung Kim (ksjnu@nia.or.kr)