News Desk

The widespread adoption of distributed computing has been prognosticated for many years. Finally, a critical mass has been created of both enabling and demand trends that will ultimately realize the promised wave of distributed computing applications. This wave of distributed computing will have a profound impact on businesses and government agencies in many ways - and one area that will be particularly affected is wide-area networks (WAN).

SOA-Enabling Trends
Web services-based service-oriented architecture (SOA) is an evolved form of distributed computing that can trace its roots to earlier architectures such as CORBA and JINI. However, XML (the key protocol for Web services) has a level of sophistication and widespread acceptance that CORBA and JINI never achieved. Also, there's the ubiquitous nature of Web services tools, APIs, IDEs, and SOAP stack implementations. They're everywhere.

All major operating system vendors are on board and have, or soon will have, major releases that implement Web service entry points and tools. A major milestone for SOA adoption will be when Microsoft finally releases Vista (formerly known as Longhorn). Vista has been called the Web services release for Windows. It's now in its beta 1 stage (what Microsoft has previously called release candidate 2). Before long we should see the market-dominating operating system join Linux, Solaris, and HP-UX in enabling SOA-based applications.

Middleware vendors have been busy publishing their most popular applications services in Web services registries. For example, Oracle recently claimed that they have published over 400 services in their "Fusion Service Registry" - their name for a Web services registry. Oracle and other middleware vendors are devoting millions of people-hours to publishing more. These published services will be the building blocks for countless end-user applications, so they need to be rock solid. Middleware vendors are being particularly careful about testing, interface protections, metadata, etc.

Among major software vendors, SOA is the biggest initiative. These initiatives include:

• Oracle's Fusion Strategy
• Microsoft's Windows Server System
• IBM's WebSphere Software Platform
• BEA's WebLogic Platform
• SAP's NetWeaver
• Sun's Sun Java System
• Novell's exteNd Enterprise Suit

Operating system and middleware vendors have not just been quietly implementing Web service entry points and tools for their next major release. They have been actively training software developers throughout the world to use SOA. For many years now, software vendor developer conferences have had significant portions dedicated to SOA. Also, there are now what seems like libraries of books devoted to SOA, XML, and Web services.

Perhaps most important is the software development culture. There is an ongoing battle for the hearts and minds of software developers, and vendors are competing based on who has the best SOA tools. This is creating a culture within the software profession that dictates that anything other than SOA-based applications is passé.

SOA Demand Trends
SOA is not just a "build it and they will come" story. There are overwhelming-demand side reasons for increasing interest in SOA-based applications. Here are some of the major-demand side reasons, listed in order of priority:

1. Business Agility: Almost all business managers contend that business agility is directly proportional to business profitability. SOA enhances business agility by hastening the ability to respond with new and updated applications as business conditions change. This faster time to market for new business processes translates into a major competitive advantage. It's no wonder then that business managers - much more than IT managers - are driving today's deployments of SOA-based applications.
2. Information Access: Previously, businesses had to engage large system integrators such as Accenture, EDS, SAIC, and Lockheed to write gateway programs to get access to valuable information within legacy systems. These expensive gateway programs handcuffed many organizations. Every time a change (configuration, software revision, etc.) to either side of the gateway occurs, the system integrator needs to be reengaged to update, retune, and debug the gateway. (Typically, only the original system integrator has sufficient knowledge to update the gateway, so gateway programs are an endless drain on IT budgets and a job for life for the system integrator.) Through standard interfaces, SOA promises to minimize, if not eliminate, these resource-sucking gateway programs. (Insurance companies with valuable data locked up within old COBOL and FORTRAN applications are ideal candidates for exploiting SOA interoperability.)
3. Lower Development Costs: Software development is more economical with Web services. SOA standardizes what has been an informal practice within the software profession of reusable code. With standardization, developers have dramatically better access to proven software and can focus on their value-add rather than on rewriting what has previously been solved. Furthermore, the proliferation of Web services tools by operating system and middleware vendors greatly simplifies integration of published Web services.

SOA Adoption
It's valuable to see where SOA is receiving considerable market traction. Examples abound within many industries, including government, financial services, and healthcare:

• Government: Fratricide can account for almost 20 percent of all US military casualties (e.g., an Air Force ordinance dropping on US Army infantry). Anything that reduces fratricide has the highest military priority. Many within the Department of Defense (DoD) are convinced that SOA will lead to better interoperability and information sharing among disparate Army, Navy, Marine Corps, Air Force, and Coast Guard systems. SOA can better enable their vision of "Net-centric warfare." Thus as it was with the Internet, the DoD is one of the earliest adopters of SOA technology.
• Financial Services: Many financial institutions believe the key to success is finding more profitable customers faster. Because SOA promises more rapid application development and better interoperability between heterogeneous systems, many financial firms are embracing SOA technology.
• Healthcare: Hospital administrators believe that better patient care can be given with improved information sharing among healthcare professionals. Also, the likelihood of error and their exposure to malpractice claims can be reduced. (Remember: avoiding only a handful of malpractice lawsuits can more than justify the cost of IT investments.)

A 2005 Kubernan survey indicates that almost 90 percent of enterprises will employ Web services within the next year - almost two thirds significantly (see Table 1).

SOA Impact on WANs
SOA governs how internal and external systems interact. As these systems are developed, they are published as Web services that can be used by others. SOA defines how Web services communicate with each other. This communication can involve either simple data passing or two or more services coordinating an activity. Web services can be combined to create new applications and even more Web services (see Figure 1). As Web services proliferate within organizations, they will have four major networking effects:

• Site-to-site traffic volume will grow exponentially. Today, applications are normally executed within a single physical location. When Web services are used, code is executed at the location of the particular Web service. Since new applications will be created from some original code and a collection of Web services, code execution will be distributed - typically among multiple sites. Another element to the traffic growth is the employment of the XML protocol for inter-Web services communications. XML is a particularly verbose protocol that can take two to 10 times as many bits to send the same information as a more frugal protocol. As a consequence, a cottage industry of XML accelerator products has arisen (e.g., vendors such as Cambridge, MA-based Data Power).
• Low latency will be an increasingly critical network characteristic. Applications based on Web services depend more on machine-to-machine communications, and machine-to-machine interactions are always the most time-sensitive traffic on networks. Applications today mostly execute on a single server; interprocess communications are handled by the server's system bus. When processing is distributed with Web services, interprocess communications are carried over the network. That's a lot of time-sensitive traffic now traveling over the WAN. With SOA, network performance will directly affect the end user's experience.
• Less predictable traffic patterns. Web services can be combined in often unpredictable and complex ways. The possible combinations are endless. Network flexibility will be an increasingly important characteristic.
• High priority packet identification will become increasingly difficult. It will be almost impossible to ascertain when a particular Web service is being used as part of a mission-critical business process. For example, imagine an arbitrage program trading on the minor fluctuations of crop futures at various exchanges - one of the most time-sensitive applications among financial firms. It's not unreasonable to imagine a crop futures arbitrage program referring to a weather service. Most network administrators would never label communications to and from a weather program to be high priority. Yet, there's a scenario with SOA where that low-priority weather service could be in the critical path of a high-priority arbitrage program.