WSQDL

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

Core Spec.
WSQM
WSQF
WSQUC
Subsidiary Spec.
WSQDL
WSTG
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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.

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

Making consensus between Web service associates
Objective data for quality activity
Automatic exchange of quality data
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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

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What is WSQF (Web Service Quality Factor)?

• WSQF refer to a group of items that uses for
  representing and valuing the quality of Web
  services.
• WSQF can be divided into 3 groups in the point of
  use by user.

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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

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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
Evaluation
Property
service price
Biz value
price, penalty, compensation
survey
service suitability
biz suitability, convenience
user evaluation
service effect
biz effect, ROI
index calculation
service brand
recognition, reputation
survey, interview
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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
confidentiality
Security
XML ENC
security level
message level confidentiality
certification
SAML, X.509
interoperability
message level certification
Integrity
XML ENC DSIG
throughput
message level integrity
non-repudiation
XML DSIG
throughput
message level non-repudiation
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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
message conformity
Interoperability
SOAP Handler
WS-I satisfaction degree
WSDL conformity
WSDL I/F
WS-I satisfaction degree
UDDI conformity
UDDI Registry
WS-I satisfaction degree
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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
Throughput
measure factor

of trans/sec
Response Time

millisecond
Accessability

rate
Successability

rate
Availability

rate
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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
reliable message
biz processing
AtMostOnce,
Retry, Ack
throughput
transaction processing
ACID
2PC
interoperability
BP collaboration
Compensable
Context Mgmt
security
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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

• introspectability

• manageability

• Tracking,Logging

• security

• controllability

• Resource Managing

• response time

• notifiability

• Subscription

• interoperability

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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
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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
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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
Representation
Convenience
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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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.

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Complex type Metric type

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

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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

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Complex type Conformity type

• Represents whether a function has conformity with
  a specification
• Composed of specification, rule category
  conformity, and overall conformity

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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 item
• Appraisal 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 to expand it to cover SOA service
  level.

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Thank You!! Youngkon Lee yklee777_at_kpu.ac.kr