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Web ServicesWeb ServicesPartha GoswamiPartha Goswami

04IT601504IT6015

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OverviewOverview

What is Web ServiceWhat is Web Service

Motivation for web ServicesMotivation for web Services

Web Services ArchitectureWeb Services Architecture

Future Vision and ChallengesFuture Vision and Challenges

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PO Service

Credit Service

Purchase Order

Credit

Check

ReserveInventory

Credit

Response

InventoryResponse

InvoiceConsolidate

Results

Example: Web based purchase

What Is Web Services

Web services are self contained, self describing, modular applications that can be published, located, and invoked across the web. Web services perform functions, which can be anything from simple requests to complicated business processes". ---- According to IBM ---- According to IBM Figure Taken from Oracle Figure Taken from Oracle Session id: 40024

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Service Description

Ser

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Ser

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Publish

Directory Service S

earc

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Use

Ser

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In

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Virtual TravelAgency

B2B

B2B

B2B

Features Of Web Services

Migration Of Existing web Application

Standards are the Base

Communicate using messages

Robust , Effective, Flexible Security

Services Description

Web Service Discovery

Figure Taken from Intelligent agent course 2003/2004 by Dr. Omar Belakhdar

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Benefits of Web Service?

Create a single, comprehensive, flexible Web platformCreate a single, comprehensive, flexible Web platform

Utilization existing InfrastructureUtilization existing Infrastructure

Web services gives users the option of choosing a particular Web services gives users the option of choosing a particular hardware and software platform without being concerned about hardware and software platform without being concerned about the integration cost.the integration cost.

Content management systems to store information in a repository Content management systems to store information in a repository where it is easily accessible for reusewhere it is easily accessible for reuse

Traditional security mechanisms have given way to "entitlement Traditional security mechanisms have given way to "entitlement programsprograms""

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Web Services Meet Business Web Services Meet Business ProcessesProcesses

Web Service 1

Web Service 2

Web Service 3

Web Service 4

Web Service 5

Web Service n

Sales

Logistics

Support

Finance

HR

Partners Support

Network

Network

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How widespread they are today?How widespread they are today?

““IDC reportIDC report, nearly 50% of enterprises interviewed will have implemented Web , nearly 50% of enterprises interviewed will have implemented Web services by 2006. IDC estimates that 5% of all U.S. enterprises had completed Web services by 2006. IDC estimates that 5% of all U.S. enterprises had completed Web Services initiatives by the end of 2002, and it projects that 80% will have some kind Services initiatives by the end of 2002, and it projects that 80% will have some kind of Web services project underway by 2008”of Web services project underway by 2008”

““Gartner expects Web services will dominate the deployment of new application Gartner expects Web services will dominate the deployment of new application solutions for Fortune 500 companies by 2004”solutions for Fortune 500 companies by 2004”

““Approximately 79% of companies surveyed in the summer of 2002 planned to Approximately 79% of companies surveyed in the summer of 2002 planned to implement a Web services project in 2003, according to the Software & Information implement a Web services project in 2003, according to the Software & Information Industry Association (SIIA) and Systinet Corp.,” Industry Association (SIIA) and Systinet Corp.,”

““To To notnot explore investing in some type of Web services initiative at this point would explore investing in some type of Web services initiative at this point would be a mistake. There's a distinct need today for application interoperability, which is be a mistake. There's a distinct need today for application interoperability, which is the goal of Web services."the goal of Web services."says Laurie A. Seymour, a program manager at research firm IDC. says Laurie A. Seymour, a program manager at research firm IDC.

Web services "are becoming extremely important, extremely fast," says Whit Web services "are becoming extremely important, extremely fast," says Whit Andrews, an analyst in research firm Gartner's Internet platform and Web services Andrews, an analyst in research firm Gartner's Internet platform and Web services group. group.

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Web Services ArchitectureWeb Services Architecture

Architecture can be described in terms ofArchitecture can be described in terms of

• What goes “on the wire”: What goes “on the wire”: Formats and protocolsFormats and protocols.- .- XML, SOAP, and WS-AddressingXML, SOAP, and WS-Addressing

• What describes what goes on the wire:What describes what goes on the wire:Description languages.- MDescription languages.- Machine-readable metadataachine-readable metadata

• What allows us to find these descriptions:What allows us to find these descriptions:Discovery of services- Discovery of services- Web service discoveryWeb service discovery

• What protocols to use to transportWhat protocols to use to transport

• Specification for enumeration of service resourcesSpecification for enumeration of service resources

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In Web services, a message is an XML document information item as In Web services, a message is an XML document information item as defined by the defined by the XML Information XML Information

The Information items generally maps to the various features in an XML document, such as elements, attributes, namespaces, and comments …. ….

There are eleven types of information items in an XML document.There are eleven types of information items in an XML document.

It allows opaque binary data to be interleaved with traditional text-based It allows opaque binary data to be interleaved with traditional text-based markup. The W3C XML-binary Optimized Packaging (or XOP) format.markup. The W3C XML-binary Optimized Packaging (or XOP) format.

SOAP Message Transmission Optimization Method, or MTOM, then specifies SOAP Message Transmission Optimization Method, or MTOM, then specifies

how to bind this format to SOAP how to bind this format to SOAP

XOP and MTOM are the preferred approach for mixing raw binary with text-XOP and MTOM are the preferred approach for mixing raw binary with text-based XMLbased XML

XML-XML-eXtensible Markup LanguageeXtensible Markup Language

.

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SOAP- SOAP- SSimple imple OObject bject AAccess ccess PProtocolrotocol

SOAP provides a simple and lightweight mechanism for SOAP provides a simple and lightweight mechanism for exchanging structured and typed information between peers in a exchanging structured and typed information between peers in a decentralized, distributed environment using XMLdecentralized, distributed environment using XML

Contains three elements: <Envelope>, <Header>, and <Body>.Contains three elements: <Envelope>, <Header>, and <Body>.

SOAP Node, SOAP Node, original senderoriginal sender , , ultimate receiverultimate receiver, , intermediaryintermediary, , message message pathpath. .

Message Exchange Patterns: Broadcast transportsMessage Exchange Patterns: Broadcast transports , Push Model, , Push Model, Pull ModelPull Model

Transport IndependenceTransport Independence: : using HTTPusing HTTP , , SOAP-over-UDPSOAP-over-UDP

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MetadataMetadata Metadata enables interoperability.Metadata enables interoperability.

Describe the message interchange formats the service can supportDescribe the message interchange formats the service can support

Web Service Description Language, or WSDL, was the first widely Web Service Description Language, or WSDL, was the first widely

adopted mechanism for describing the basic characteristics of a Web adopted mechanism for describing the basic characteristics of a Web service.service.

WSDL may define where the service is available and what WSDL may define where the service is available and what communications protocol is used to talk to the service.communications protocol is used to talk to the service.

WS-Policy introduces a simple and extensible grammar for expressing WS-Policy introduces a simple and extensible grammar for expressing policypolicy

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DiscoveryDiscovery Two most common approaches to finding information in a computer Two most common approaches to finding information in a computer

system: system: looking in a well-known locationlooking in a well-known location, or , or broadcasting a broadcasting a request to all available listeners.request to all available listeners.

The Universal Description, Discovery, and Integration protocol, or The Universal Description, Discovery, and Integration protocol, or UDDIUDDI,, specifies a protocol for querying and updating a common specifies a protocol for querying and updating a common directory of Web service information. directory of Web service information.

UDDI directory approach can be used when Web service information UDDI directory approach can be used when Web service information is stored in well-known locations. is stored in well-known locations.

Microsoft, IBM and SAP host the UDDI Business Registry.Microsoft, IBM and SAP host the UDDI Business Registry.

Directory entry has three primary parts – the Directory entry has three primary parts – the service providerservice provider, , Web Web services offeredservices offered, and , and bindings to the implementationsbindings to the implementations. .

Dynamically discovered Web services explicitly announce their Dynamically discovered Web services explicitly announce their arrival and departure from the network. arrival and departure from the network.

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Agreement CoordinationAgreement Coordination and and

Enumeration Enumeration

When multiple Web services complete a joint unit of work or When multiple Web services complete a joint unit of work or operate under a common behavior, there must be common operate under a common behavior, there must be common agreement on what protocols to use. This minimum amount of agreement on what protocols to use. This minimum amount of coordination among Web services is unavoidable.coordination among Web services is unavoidable.

The specifications that define this functionality are The specifications that define this functionality are WS-ReliableMessagingWS-ReliableMessaging, , Reliable Messaging WS-Coordination, WS-Reliable Messaging WS-Coordination, WS-

AtomicTransaction and WS-BusinessActivity.AtomicTransaction and WS-BusinessActivity.

Enumeration, in particular, is achieved though establishing Enumeration, in particular, is achieved though establishing a session between the data source and the requestor. a session between the data source and the requestor. Successive messages within the session transport the Successive messages within the session transport the collection of elements being retrievedcollection of elements being retrieved..

They are based on They are based on WS-Enumeration, WS-Transfer, and WS-Eventing.WS-Enumeration, WS-Transfer, and WS-Eventing.

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Security ChallengesSecurity Challenges Previously Security professionals tend to focus narrowly on Previously Security professionals tend to focus narrowly on

protecting assetsprotecting assets

Modern security systems that intelligently manage and store user Modern security systems that intelligently manage and store user information and cross-reference it with enterprise access rulesinformation and cross-reference it with enterprise access rules

Presently Security professionals help to rapidly launch new Presently Security professionals help to rapidly launch new business activities while protecting assetsbusiness activities while protecting assets

To maximize the reach of Web services, end-to-end security must To maximize the reach of Web services, end-to-end security must be provided when intermediaries are not trusted by the be provided when intermediaries are not trusted by the communicating endpoints.communicating endpoints.

Even though the security requirements for Web services are Even though the security requirements for Web services are complex, no new security mechanisms were invented to satisfy complex, no new security mechanisms were invented to satisfy the needs of SOAP-based messagingthe needs of SOAP-based messaging

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High Availability Web Services Using ClusterHigh Availability Web Services Using Cluster Administrators of large Web sites are faced with managing the Administrators of large Web sites are faced with managing the

growth in a 24x7 environment.growth in a 24x7 environment.

Networking strategies and services, and Server clusteringNetworking strategies and services, and Server clustering

IP traffic destined for the virtual server is assigned to the server in IP traffic destined for the virtual server is assigned to the server in

the cluster that is best suited for that transactionthe cluster that is best suited for that transaction

Clustering of servers provides the following benefitsClustering of servers provides the following benefits:: Rapid response to unexpected growthRapid response to unexpected growth

Balanced multiple work-loadBalanced multiple work-load Continuous application availabilityContinuous application availabilityInvestment protectionInvestment protection

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Future Vision and ChallengesFuture Vision and Challenges

Technology vendors plan to develop, market, and lend online Technology vendors plan to develop, market, and lend online Web services to fulfill virtually any business function.Web services to fulfill virtually any business function.

Companies will be able to simply search a public directory of Companies will be able to simply search a public directory of applications and download those that fit their needs. applications and download those that fit their needs.

Right now we have only tools and standards which are still Right now we have only tools and standards which are still not matured, but it’s needless to say that its time to learn not matured, but it’s needless to say that its time to learn and practice some web services developmentand practice some web services development

Challenges:Challenges:

How will vendors provide end-to-end security? How will vendors provide end-to-end security?

Who is accountable when vendors fail to deliver promised Who is accountable when vendors fail to deliver promised services?services?

How will vendors guarantee availability and reliability?How will vendors guarantee availability and reliability? How will vendors handle pricing? How will vendors handle pricing?

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ReferencesReferences 1. 1. An Introduction to the Web Services Architecture and An Introduction to the Web Services Architecture and

Its Its Specifications by Specifications by Luis Felipe Cabrera, Christopher Kurt, Don BoxLuis Felipe Cabrera, Christopher Kurt, Don Box

2. 2. Oncoming wave with Web Services - by Oncoming wave with Web Services - by Benny AlexanderBenny Alexander

3. 3. High Availability Web Services by High Availability Web Services by Cisco SystemsCisco Systems

4. 4. Web Foundation Overview by Web Foundation Overview by Cisco SystemsCisco Systems

5. 5. The Web Services Promise by The Web Services Promise by Cisco SystemsCisco Systems

7. 7. Web Services Infrastructure by Web Services Infrastructure by Phil WainewrightPhil Wainewright