In-Depth

Can CORBA & Web services live together?

Web services, once hyped as the replacement for corba, is now being repositioned as a technology that can coexist with CORBA. It is not just the smaller players who are saying this: Microsoft, the main driver behind Web services, has now taken this stance. Still, a few die-hards insist Web services is the next technology wave.

However, the move toward coexistence has been boosted by the Object Management Group (OMG), which owns the CORBA specification. The OMG is planning additions to CORBA that would see CORBA and Web services come under the umbrella of the organization's Model Driven Architecture (MDA).

Why the shift in thinking? First, Web services vendors are recognizing that corporations have invested so much in legacy systems, including CORBA, that they do not want to throw them away. Second, Web services lacks fundamental, robust functionalities such as authentication, security and access control. This renders them unfit for prime-time, mission-critical applications, especially outside the corporate firewall.

The result: Microsoft and other vendors in both the CORBA and Web services markets agree that Web services will be used as a front end to legacy systems. Many observers say Web services will leverage CORBA's robust security features.

Web services believers
Robert Wegener, national director, solutions, at the Chicago offices of technology consultants RCG Information Technology, is among those who believe Web services will replace CORBA.

''I see CORBA just dropping off. Why would you use the proprietary stuff when you have all the open-source Web services?,'' said Wegener, who has extensive experience in various process, development, QA and testing methodologies. He believes the migration of the installed base over to Web services is ''a natural progression, especially for people who are already doing distributed processing. This will be a no-brainer.''

Wegener said Web services will get a boost because large vendors such as PeopleSoft and Oracle are adding Web services to their products; in addition, SAP has exposed ''about 500 Web services'' in MY SAP for its supply chain. Further, larger companies will push Web services to suppliers because ''they can offload processing power to other people,'' Wegener explained. He predicted that some of the larger companies -- ''the Wal-Marts, Sears, General Motors'' -- will be doing this ''within one year.''

Unlike the push to do business with suppliers over EDI -- which failed because it required heavy investment in equipment and services -- this push with Web services will succeed because ''the technology is in place -- most people have an application server so they won't need to make an infrastructure change,'' Wegener explained, ''and those people who don't have the infrastructure can get cheap solutions out there.''

For example, brokers will spring up who own UDDI directories for Web services and will let people use their Web services for a fee, Wegener said. Smaller companies will be able to use the services of such brokers relatively inexpensively, he added.

Another believer is Anne Thomas Manes, chief technology officer at Cambridge, Mass.-based Systinet Corp., which builds Web services infrastructure such as SOAP and UDDI servers. ''I would not qualify CORBA as dead, but it has definitely been hospitalized,'' she said. CORBA ''has always been a niche player; it has never been a pervasive technology because it is very hard to use. Java and J2EE are much more easy to use than CORBA,'' she added.

The advantage of Web services is faster time to market, Manes said. For example, one Systinet customer making network devices is ''very concerned with processing speed'' because it processes large amounts of traffic going over the network. That customer is considering a Web services router device to handle the traffic. The alternative is to build the device with CORBA or a proprietary protocol.

Using CORBA would require ''maybe six engineers who understand the stuff -- which means they're very, very expensive -- and they'd have to work for nine months, and it would cost X dollars to accomplish that. Or they could take much more junior programmers who understand Web services, have them build it on SOAP in two months, and give them a much bigger piece of hardware to run on,'' Manes said. The cost to build in Web services would be the same, ''but they'll get it out to market that much sooner. There's still a tradeoff, but hardware is so powerful that it's a good tradeoff,'' she said.

Manes agrees that CORBA is more robust than Web services, but ''that's only because we haven't developed the additional services -- transactions, security, a naming service -- that normally operate around the CORBA broker in the Web services world,'' she said. She expects these to be created ''within the next couple of years.''

Yes, we can all get along
The trouble is that there are other gaps in Web services technology. ''There's a whole bunch of standards missing,'' said Eric Blankenburg, engineering director at system integrator Avanade Inc., Seattle. ''Security, transactions ... How do I compose more than one service that is not a logical unit of work? Can I not call these services linearly?''

The solution is a queuing mechanism, but developing the solution has fragmented the Web services community. ''Microsoft has SOAPR, SOAP Reliable, but IBM is using HTTPR, which is HTTP Reliable,'' Blankenburg said. To call services in a non-linear fashion, Microsoft offers XLanguage, while IBM has Web Services Flow Language, he said.

The result: ''You can do some rudimentary things with Web services, but that's about all right now,'' Blankenburg said. ''I'm a big fan of Web services, but to think that somehow this technology is immediately going to replace IIOP, RMI, or COM and DCOM is a stretch.''

CORBA is not going away anytime soon, if only because the telecommunication and aircraft industries have a huge installed base of CORBA technology.

''AT&T manages its entire network infrastructure on our stuff,'' said John Rymer, vice president of product marketing at Iona, a leader in the CORBA field with headquarters in Dublin, Ireland. ÒBoeing runs its entire aircraft manufacturing operation -- 70,000 users, 7,000 servers, huge throughput, multiple plants and sites -- on a CORBA-based architecture, which is our stuff.''

Tony Goodhew, product manager for .NET Framework at Microsoft Corp., Redmond, Wash., agrees that Web services will coexist with CORBA because of corporations' huge existing investments in technology. ''Not throwing away existing investments makes a lot of sense,'' he said. ''The CORBA guys are right in that they're going to be around for a long time.''

The strongest argument for coexistence is that Web services do not mean anything by themselves. ''Web services, as currently formulated, are nothing more than client/server with XML protocol,'' said Hugh Grant, chief technical officer, Cape Clear Software, Campbell, Calif., which offers CapeConnect, a product for integrating Web services with existing systems such as J2EE and CORBA. ''Web services applications are solving exactly the same problem as client/server, but not adding business value; whereas if you leverage CORBA or some other back-end technology with Web services, there's a business win there,'' he said.

The lipstick on the bulldog
Web services solve the main problem with CORBA: The front end. ''The Achilles' heel of CORBA development was always that you'd end up with good servers but getting access to them is a problem,'' said Cape Clear's Grant, who was previously chief architect at Iona. This is because ''CORBA is a more technical thing to program and so there weren't enough front-end developers,'' he said.

Currently, Web services are being used as the best way to Web-enable access to CORBA systems to link them behind the corporate firewall. At AT&T, for example, Web services have been defined as the standard for all inter-domain registration going forward, Iona's Rymer said. AT&T has asked Iona to ''provide Web service front ends to their applications,'' Rymer said. The payoff: Better integration between the various back-end systems -- such as billing, customer management, call and marketing systems -- and the front end, leading to greater efficiency and, ultimately, a stronger bottom line.

Sridhar Iyengar, distinguished engineer, application and integration middleware at IBM in Irvine, Calif., described Web services as ''the lipstick on the bulldog.'' The bulldog is ''in back running on a mainframe or a Unix server, doing core transactions; it's reliable, secure and never fails,'' Iyengar said. The lipstick is the front end. When a new lipstick comes along, ''you write some code to generate a wrapper and now you're Web-enabled or Web services-enabled,'' he said.

The key thing about Web services, Iyengar said, is that the base standard of interoperability has been agreed upon ''by everybody,'' which means there is no differentiation and the playing field gets leveled for certain types of simple interoperability, for example, among a user's various devices. ''Today, when my secretary sets up a meeting, I have to synch my Palm and my laptop,'' Iyengar said. ''And different calendars on PCs have different proprietary standards. But if we use Web services, synching between Palm and laptop will be as easy as synching between the Palm and the mainframe. The tough thing in Web services will be agreeing upon what the schema are.''

There will be a guarantee for interoperability between CORBA and Web services because the OMG plans to create a standard way of mapping between CORBA's Interface Definition Language (IDL) and the Web Services Definition Language (WSDL), which is XML-based, Iyengar said. The OMG already has one request for proposals (RFP) out on mapping IDL to WSDL, as well as another on mapping WSDL to IDL. The first ''will let you invoke a CORBA object as a Web service; the second will let you invoke a Web service to a CORBA object,'' Iyengar said.

The OMG's MDA is ideal for running Web services because ''Web services is the integration of multiple middleware performing a function that gets exposed as Web services'' and an MDA development tool ''can generate invocations in any middleware,'' said Jon Siegel, the OMG's vice president of technology transfer. ''If you have two different platforms with different applications written in MDA, you just bring them into an MDA tool, draw a line between them, and get the tool to generate a cross-platform invocation.''

Modifications to CORBA will make it more suitable for transactions over the Internet. While CORBA has a tightly coupled architecture that is not suitable for conducting B2B transactions over the Internet, Siegel said this problem has been solved with a ''very nice'' asynchronous messaging definition, consisting of asynch invocation interfaces, that was added in CORBA 2.4 (the current version of CORBA is 2.6). This interface ''goes through the firewall, goes to Port 80 and looks like HTTP, and everyone says they need it,'' Siegel said. At the time of his interview for this story, Siegel said a firewall specification would soon be added.

Mapping to new technologies with MDA will be easy ''because the basic requirement hasn't changed in 20 years -- you make a request for something and it comes back,'' IBM's Iyengar said. ''At the end of the day, customers will be able to use existing Web services with CORBA objects.''

Like COBOL, CORBA is here to stay. And newer technologies will have to cope with the legacy systems.

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