Building dynamic application networks with Web Services

摘要

Looking at the state of the industry today, it is clear that we are in the early stages of Web Services development. Companies are still evaluating what the technology and considering how to apply it to their business. But over the past year, we seem to have reached an inflection point of companies building real systems based on Web Services. Partly this reflects an acceptance that the basic Web Services technologies - XML Schema [1][2], SOAP [3], WSDL [4] - have matured to the point where they can be used for mission critical applications. But it also reflects a growing understanding that Web Services enable a large class of systems that were previously very difficult to build. These systems are characterized by several critical properties:1. Rapid rates of change. The time is long past when companies could afford a year-long-effort to build out a new application. Businesses move at a faster pace today then ever before, and they are increasingly under pressure to do more work with fewer resources. This places a premium on the ability to build applications by quickly composing pre-existing services. The result is that systems are being connected in ways that were never imagined during development. This is reuse in the large - not just small services, but entire applications being linked together to solve a complex business function.2. Significant availability and scalability requirements. Many of these systems are "bet-your-business" types of applications. They have heavy scalability and availability requirements. Often then need to connect multiple partners and service hundreds of thousands of updates in a day, without ever suffering an interruption in service.3. Heterogeneous development tools and software platforms. Each of these applications typically involves components built using a wildly diverse set of tools, operating systems, and software platforms. Partly this is a result of building systems out of existing components - many of these components are locked into certainenvironments, and there are no resources to rewrite or migrate to a single homogenous platform. But it is also recognition that different problems are best solved by different toolsets. Some problems are best solved by writing code on an application server, others are best suited for scripting, and still others are solved by customizing an existing enterprise application. Heterogeneity is not going away. It is only increasing.4. Multiple domains of administrative control. An aspect of heterogeneity that is often overlooked is distributed ownership. As businesses merge, acquire, and partner with other companies, there is an increasing need to build applications that span organizational boundaries.These characteristics present a unique set of challenges to the way we think about developing, describing, connecting, and configuring applications. The challenges require us to develop new ways of looking at what it takes to build an application, and what makes up a network.In this session, we examine the nature of this next generation of application, and discuss the way in which Web Services are evolving to meet their needs. The session focuses on the development techniques that allow services to be easily and dynamically composed into rich applications, and considers the capabilities required of the underlying network fabric. The session concludes with an in-depth look at some of the critical Web Services specifications actively under development by industry leaders.