Overview

Although deceptively simple, XML is turning the way we build and use software inside out. The Web revolutionized how users talk to applications. XML is revolutionizing how applications talk to other applications—or more broadly, how computers talk to other computers—by providing a universal data format that lets data be easily adapted or transformed:

• Web services allow applications to share data.
• Web services are discrete units of code; each handles a limited set of tasks.
• They are based on XML, the universal language of Internet data exchange, and can be called across platforms and operating systems, regardless of programming language.
• Microsoft® .NET is a set of Microsoft software technologies for connecting your world of information, people, systems, and devices through the use of Web services.

Web Services: A Universal Language

Web services let applications share data, and—more powerfully—invoke capabilities from other applications without regard to how those applications were built, what operating system or platform they run on, and what devices are used to access them. Although Web services remain independent of each other, they can loosely link themselves into a collaborating group that performs a particular task.

		Benefits of Web Services Open the door to new business opportunities by making it easy to connect with partners. Deliver dramatically more personal, integrated experiences to users via the new breed of smart devices—including PCs. Save time and money by cutting development time. Increase revenue streams by easily making your own Web services available to others.

An Example: How Web Services Connect Applications

Say you have a stand-alone inventory system. If you don't connect it to anything else, it's not as valuable as it could be. The system can track inventory, but not much more. Inventory information may have to be entered separately in the accounting and customer relationship management systems. The inventory system may be unable to automatically place orders to suppliers. The benefits of such an inventory system are diminished by high overhead costs.

However, if you connect your inventory system to your accounting system with XML, it gets more interesting. Now, whenever you buy or sell something, the implications for your inventory and your cash flow can be tracked in one step. If you go further, and connect your warehouse management system, customer ordering system, supplier ordering systems, and your shipping company with XML, suddenly that inventory management system is worth a lot. You can do end-to-end management of your business while dealing with each transaction only once, instead of once for every system it affects. A lot less work and a lot less opportunity for errors.

These connections can be made easily using Web services. Web services allow the applications to share information via the Internet, regardless of the operating system or back-end software that the application is using.

Web Services Use Industry-Standard Protocols

Web services also make it possible for developers to choose between building all pieces of their applications, or consuming (using) Web services created by others. This means that an individual company doesn't have to supply every piece for a complete solution. The ability to expose (announce and offer) your own Web services creates new revenue streams for your company.

Web services are invoked over the Internet by means of industry-standard protocols including SOAP; XML; and Universal Description, Discovery, and Integration (UDDI). They are defined through public standards organizations such as the World Wide Web Consortium (W3C).

SOAP is an XML-based messaging technology standardized by the W3C, which specifies all the necessary rules for locating Web services, integrating them into applications, and communicating between them. UDDI is a public registry, offered at no cost, where one can publish and inquire about Web services.

Security and Web Services

A key benefit of the emerging Web services architecture is the ability to deliver integrated, interoperable solutions. Helping to protect the integrity, confidentiality, and security of Web services through the application of a comprehensive security model is critical.