SOA designers should look to Net

The term “going forward” has become quite the catch phrase in today’s strategy-oriented jargon. Gartner analyst Nick Gall suggests it’s time to take a step back and more closely examine a technology platform that’s 30 years old.

Often fixated on building what’s perceived as the modern, designer IT system known as service-oriented architecture (SOA), enterprise architects should be paying more attention to the Internet, says Gall.

The Internet remains vibrant after 30 years as a platform for innovation because fundamentally it’s narrow at the waist, he says.

At the core of the Internet is a small number of uniform operations known as REST (Representational State Transfer). SOA architectures should adopt similar hourglass figures based on what Gall calls IFaPs (identifiers, formats and protocols).

SOA is typically pushed as an emerging platform that can revolutionize the way technology serves up business processes. Gall asserts it’s been around for decades and the Internet, as the archetypal gold standard, holds many lessons for today’s enterprise architect.

“The Internet is, and always has been, a service-oriented architecture,” says Gall, a vice-president with Stamford, Conn.-based Gartner Inc. “SOA is just a new label for some very old concepts.”

Enterprise architects need to think differently about how they’re approaching SOA and Web-oriented architectures. He urges architects to think more in terms of a global network. It’s less about Web Services and more about the Web.

Gall notes that enterprise application software architectures have failed over the past 35 years to keep IT systems soft, or flexible enough to match agile changes within business.

While software architecture systems decay from soft to hard with a half-life of five years, he adds, the Internetwork architecture continues to enable change. “The Internet is a remarkably soft architecture and it’s still supporting rapid innovation. It’s 30 years old now and still disrupting technology.”

Key to the Internet’s ability to evolve has been its interoperability, adds Gall. The architectural design behind the Internet means it can deliver decentralized innovation, or non-proprietary applications like file transfer and sharing, e-mail and instant messaging, voice over IP and videoconferencing.

As an example, Gall points to e-mail, which looks almost nothing like it did 20 years ago. “But it’s just extensions to the original Simple Mail Transfer Protocol (SMTP),” he says. Similarly, when writing application code in stacks that are more reusable, Gall recommends using the Internet and Web spanning layer concepts as a guide.

He says most SOA initiatives are point-to-point engineering exercises that rely too heavily on Web Services specifications. They’re not general architectures for reuse.

Most architects are assuming that the X in XML is automagic, says Gall, and that XML types and elements are automatically reusable.

The extensible content model has to be more open-ended, says Gall. “Get away from the notion of building something for a particular purpose…Use metadata to extend applications for customized use.”

Modular designs should extend outwards from the middle, as opposed to a top-down approach, he says. To illustrate this, Gall uses an hourglass model where simple identifiers, formats and protocols (IFaPs) extend outward from a narrow waist.

Examples of IFaPs used by the Internet are the URL identifier, HTML or MIME format and HTTP protocol. Similarly, e-mail uses the @address identifier, RFC 2822 format and SMTP protocol.

He says these three specifications — identifiers, formats and protocols — define the entire architecture of the Web, and making sure they’re extensible means they can change over time.

The secret to the Web’s dramatic ability to evolve, with its forwards and backwards interoperability, is its narrow waist, says Gall. “If an architecture can really crack the interoperability code,” he says, “then it can crack the evolvability code.”

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