Over the years, Service Oriented Architecture (SOA) has increasingly become a “hot button” among CIOs and IT professionals inside the Department of Defense. But what is SOA and how is it helping the DOD . . . ?
SOA emphasizes the flexible composition of distinct business functions—or services—into a complete business process. In its most recent and successful manifestation, SOAs have been developed around standards for web services. These build on widely used protocols and formats, such as HTTP (used for serving web pages) and XML (used for web content and increasingly for electronic office documents). Because these standards are not coupled to a particular hardware platform, operating system, or programming language, the business processes built using such services are insulated from the underlying implementation of any particular service.
When individual web services are developed to conform to standards such as the World Wide Web Consortium’s (W3C) Web Services Description Language (WSDL), Simple Object Access Protocol (SOAP), and XML Schema, they can be assembled into larger processes using a common tool. Such tools are available for most platforms and are integrated into many general-purpose application servers.
The WSDL document plays a vital role in the orchestration of services. This document is a machine-readable description of the interface provided by a particular service. It allows an SOA tool to understand what inputs are required by a service, what outputs it will provide, and how to communicate with the service. The tool can then generate any code necessary for the designer’s preferred software development environment to make use of that service. Without a common descriptive format like WSDL, system designers would be confronted with a bewildering array of different implementation technologies, communications protocols, and message formats.
Message formats are described using an XML schema. As with WSDL documents, XML schema documents are machine-readable documents that can be processed by a tool to generate the software necessary to convert the platform-neutral messages into the form most natural for the target platform.
By using a common messaging protocol (SOAP), web services are invoked over a variety of transports, including HTTP/S and email. As with other layers in the web service stack, SOAP provides a common language so that tools can automatically interpret the contents of a message.
Underpinning all of this functionality is the World Wide Web. Universal connectivity and widespread support for the HTTP protocol greatly simplifies the deployment of web services. Rather than learning and supporting an entirely new protocol, system administrators and network engineers can leverage their understanding of HTTP to support new services that run on top of it.
Over the years, one of the biggest problems faced by the DOD is the myriad of computer systems and their inability to speak with one another. Each Military Service had it own stove-piped systems and each worked independently. Even before the DOD Net Centric Data Strategy was published in May 2003, DOD policies existed supporting the use of SOA technologies. DOD believes that the continued application of SOA technologies will facilitate communication between the Military Services, industry partners, and international allies.
For more information on SOA and its application within DOD, check out the following: