Myths And Realities of Web Services
After all, the idea behind Web services, such as reusing code so applications don't have to repeat basic tasks when they speak to each other, is re-making the Web as a more dynamic global communications network. Want to add mapping features to your site? Maybe the ability to add a few "pushpins"? Welcome to the data-exposing world of Web services and the protocols they're built upon.
Just beware of the upside and downside of some protocols behind Web services, experts say.
"The good news about Web services is that we have open standards behind them," said James Metzler, vice president with IT consulting firm Ashton, Metzler & Associates. This means applications can communicate over any type of platform without proprietary systems getting in the way. "The bad news is that we don't have all we need yet," he added.
Some of the messaging protocols for Web services need to be refined, networking experts said during the Interop trade show and conference here.
Take the XML messaging standard for piping information across networks between applications. They can be quite the network hogs.
"Web services are real, but we've also learned that they're not perfect," said Peter Haggar, senior technical staff member in IBM's emerging technologies group.
Not that he's slamming XML messaging. XML messages help applications act on what's in the message body and content.
That helps servers prioritize the types of Web services requests traversing a network and decide which type of security policies should be applied to the messages.
XML-based messages also help networks segregate purchase orders from plain old queries and then find the least-busy server to act on those requests.
But all that messaging can become verbose. Because text-based XML messages take longer to process, the payloads in those messages can incur extra processing costs in the network. That can become an inhibitor to the adoption of Web services and SOAs.
"There are many applications that don't use XML today because it's too large and processes too slowly," Haggar added. He said that's why standards bodies are mulling a switch to a binary XML format in order to reduce the processing size of text-based XML messages.
That's not a panacea, either.
"It's not as simple as creating some other format," Haggar said. "XML works because it works. With binary XML, you may end up introducing interoperability issues," which are anathema to the open standards that drive Web services adoption.
Haggar said IBM is working with industry partners and a committee within standards body W3C to address the chatty XML problem.
Then there are issues with the SOAP messaging format, a lightweight XML-based messaging protocol for carrying messages about Web services across a network.
Turns out that envelope system is not as lightweight as everyone thought.