In late summer, seven financial services giants -- Credit Suisse First Boston, Deutsche Bank, J.P. Morgan Chase , Lehman Brothers, Merrill Lynch, Morgan Stanley and UBS Warburg -- began efforts to leverage their collective clout to encourage standards for instant messaging in the banking industry, particularly with regard to interoperability.

Several vendors, meanwhile, have pulled back from SIMPLE at least in part because of its lack of more robust features. Microsoft, expected to include SIP support in its Greenwich server, is believed to have pushed back the ship date for the product -- which handles voice over IP, application sharing, and instant messaging -- due in part to concerns about the robustness of SIMPLE security and other features.

AOL Time Warner's IM leader America Online said it had initially explored ways to integrate SIP into its long-expected enterprise IM offering. But when that product debuted last week, it lacked SIMPLE compatibility -- due to what the company said was a lack of necessary features in the protocol, and the excessive cost of an implementation.

E-mail and messaging giant Gordano said last week that it had no immediate plans to support SIP interoperability in its new IM product -- citing a lack of demand from its clients, and shortcomings in the current SIMPLE specifications. Even IBM, which became one of SIMPLE's largest users early last month, when it launched a SIP-compliant version of its Lotus SameTime enterprise IM product, has conceded that SIMPLE functions remain primitive compared to its proprietary messaging protocol.

To its credit, SIP already has big-name support in the world of telephony and wireless messaging. The Third Generation Partnership Project, Europe's alliance of mobile telecommunications standards bodies, is signaling its support for SIP in the next version of its wireless network specifications. And a host of vendors -- including Nortel, Mitel, Siemens , Sun Microsystems, Ericsson , and Alcatel-- are already marketing telephony, wireless and networking products that incorporate SIP.

But its application remains controversial in instant messaging -- a fact that SIMPLE's authors are hoping to soon change.

"We've got the core mechanics in place," Sparks said. "It's in use. What the group is picking up on now is just fine-tuning -- honing-in on this session-messaging concept and looking at advanced management features."

Christopher Saunders is managing editor of Instant Messaging Planet.