Adding Quality of Service to UDDI for Dynamic

Composition

Topics

1.Introduction

2.Basis of UDDI

3.Implementation1.Mapping QoS to tModels in UDDI

2.Publish API with QoS

3.Inquiry API with QoS

4.Performance Analysis

5.Conclusion

Introduction

• Many web services are available now and the need for combining service has increased.

• Dynamic Composition have been developed to combine the best web services automatically.

• Universal Description, Discovery and Integration (UDDI) as web service registry for DC.

• Quality of Service (QoS) information has been used for high-accuracy DC.

Problem and Proposal

• UDDI has no function to deal with QoS by itself.

• QoS information must be stored as data different from that of UDDI.

• We propose a approach to add QoS information to UDDI and provide QoS-based service discovery.

Basis of UDDI

• Web service registry.• Four entity types:

– BusinessEntity: a service provider.– BusinessService: a service.– BindingTemplate: a instance of a service.– TModel: a value set for a entity.

• API deals with web service– Publish API: register web service.– Inquiry API: search web service.

Data Structure of UDDI

Implementation

Architecture of UDDI with QoS

Mapping QoS to tModel

• A QoS information is consist of three tModels– name (ex, "Response Time")– value (ex, "10")– unit (ex, "seconds")

• A set of tModels is called KeyedReferenceGroup

• Several KeyedReferenceGroups belong to a BindingTemplate.

Mapping QoS to tModel

A example of bindingTemplate with QoS

Publish API with QoS

• Convert QoS information into tModels and KeyedReferenceGroups, and store it in UDDI.

• It is an ideal that the system automatically evaluates the QoS.

Inquiry API with QoS

• Inquires to UDDI and checks whether a web service satisfies constraints

• QoS constraints are given tModels in KeyedReferencGroups.

• A QoS constraint consists of five tModels.– Name, Value, Unit – Comparison operator (ex <, >, = )– Aggregation operator (ex Σ,max)

Overview of Inquiry API with QoS

Performance Analysis

• Analyzed by measuring how much the response time increases – when the registered service increases.– when the constraint become more complex.

• Case 1: no QoS constraint• Case 2: two QoS constraint• Case 3: four QoS constraint

Performance Analysis

Conclusion

• Providing QoS supported UDDI is achieved using tModels and extension of UDDI.

• The performance improving will be necessary.– QoS representation in UDDI.– Query algorithm.