Web Services

1
Web Services
Jnan R. Dash Executive Consultant (former
executive at Oracle,IBM) San Jose,
California September, 2002
2
Structure

• Whats Web Service?
• Whats the motivation now?
• Current Status, whats missing?
• Business Implications
• Conclusions

3

• Whats Web Service?

4
Definition

• loosely coupled applications that can be exposed
  as services and easily consumed by other
  applications using Internet standard technologies
  (XML, SOAP, WSDL, UDDI)
• Middlewear of the Internet
• Dial-tone Data Tone App. Tone

5
So, whats web service?

• Applications which describe themselves
• What they do
• How to call/access them
• Where they are in Web-space
• Subroutines/objects waiting to be invoked
• Callable from across the Web, thru Firewalls
• Standard look from the outside..
• ..but could be anything under the surface (Cobol)
• Discoverable (search/find/bind) from
  web-directories
• Invoked by applications, not humans

6
Taxonomy

• WS Web Services
• XML Extensible Markup Language
• WSDL Web Services Description Language
• SOAP Simple Object Access Protocol
• UDDI Universal Description, Discovery, and
  Integration
• ebXML e-Business XML
• WSFL Web Services Flow Language (IBM)
• XLANG Process Descriptions in BizTalk
• RosettaNet XML for the high tech industry
• OASIS Organization for the Advancement of
  Structured Information Standards

7

• Motivation

8
A brief history
1990 1991 1992 1993 1994
1995 1996 1997
1999
DCE CORBA COM/
Service-based Component XML Web
DCOM Architecture models
Services (J2EE,ASP/JSP)
OSF OMG
Microsoft
Gartner Java Community Major
Microsoft Vendors
Primary Drivers
9
Motivation

• Significantly change the cost barriers to
  application integration over the Internet

Tightly-coupled systems using proprietary
interfaces
Web services deliver Interoperability at entirely
new level

10
Motivation

• Agnosticism
• Operating system urinary Olympics?
• programming language beauty contests?
• object model wars?
• XML messaging as a bridge
• High degree of abstraction between implementation
  and consumption of services

11
Analogy
12

• Current Status

13
WS Infrastructure goals

• Loosely coupled
• Ubiquitous communication
• The Internet
• Universal data format
• Understand self-describing, text-based messages
• Components
• Discovery (locate Web Services)
• Describe (how to use?)
• Invoke (standard wire format to communicate)

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Mechanisms
Locate web services, advertise capabilities
Discovery Mechanism
UDDI
Define how to use this service
Service Description Scheme
WSDL
Standard Wire Format
SOAP
To communicate
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Web Service - Components
Find / Discover
Client Application
Web ServicesDirectory
Invoke (SOAP)
(UDDI)
Publish (WSDL)
Web Service
XML Binding
Service Implementation
(J2EE, Other)
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The Protocols
Workflow Search/find Description Message Forma
t Transport
WSFL/XLANG
UDDI
WSDL
SOAP
XML
HTTP/SMTP/FTP etc.
Time
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Technical Challenges

• Transactional Functions via vendor-specific SOAP?
  
• OASIS trying for vendor-neutral model
• Security issues like non-repudiation and digital
  signature not addressed in SOAP
• Performance
• Network latency bottlenecks for synchronous
  access to WS
• Directly proportional to WS payload
• Message guarantee
• if SOAP does not reach its destination, what
  happens? QoS issues
• Schema incompatibility
• ontology of data interchange

18
Web Service Implementation
XML, SOAP, WSDL, and UDDI are interface
technologies allowing the exposure of Web Services
XML SOAP WSDL UDDI
Guaranteed delivery, transactional support,
security, and logging are infrastructure required
for Web implementation
Quality of Service
The actual Web Service implementation is based on
existing enterprise applications and business
processes.
Service Implementation Enterprise Integration
19

• Business Implications

20
Where will they be used?

• Inside the Corporate Firewall
• For light-weight EAI
• Through the Corporate Firewall
• For using an external service (e.g. Passport)
• For exposing data to Partners (eSCM)
• Light-weight B2B
• Over the Web
• Composite applications
• Workflow components

21
The verdict

• Web services are relatively low-risk
  technology that can be used to implement high
  risk business strategies.

22
We are steadily moving toward a scenario in which
many applications will become product and service
hybrids where locally installed product
functionality represents the legacy system and
most new functionality is implemented as Web
Service and sold via the vendors service
delivery hub. - Intelligent Enterprise, March 8,
2002
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Demand Chain Process
Send Invoice via Web
Send Invoice via Web
In ERP
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Supply Chain Process
Web Service
Web Service
Web Service
Find New Suppliers via Web
Convert to Suppliers
Manage Order Fulfillment
Send Purchase Order
Send payment via Web
In ERP
In ERP
25

• Conclusions

26
Overall Trends

• EAI inside-the-firewall first priority
• Trust requirements imply private UDDI registries
  for partner integration
• Many customers starting to deploy (e.g. WS
  wrapper around Cobol)
• Anxiety to set a WS roadmap and start execution
• ISVs endorsing WS for internal integration as
  well as hosting key services

27
Summary

• Web Services are as disruptive a movement as
  mainframe to PCs
• Multi-vendor initiative on standards
• Opens up all kinds of opportunities for everyone
• Incremental, non-intimidating, minimal technology
  play
• Customers are starting without waiting for vendors