Plan to limit Net data transfers

NEW YORK--Seeking to squeeze extra bandwidth out of an increasingly congested Internet, Marimba and a host of big-name industry partners are proposing a new protocol for distributing data across the Net, but Microsoft isn't likely to put its considerable weight behind the idea.

Lining up behind the start-up Marimba are Netscape Communications, Novell, Sun Microsystems, and the @Home Network. The companies want to standardize a way to send software and other content over the Internet without duplicating information already held by a client.

For example, when downloading a series of news articles from a Web page or channel, a server and client that use the proposed protocol, called the Distribution and Replication Protocol (DRP), would know to download only the articles posted since the last download. By limiting the amount of data exchange, the DRP--an enhancement to the existing HTTP(Hypertext Transfer Protocol)--is intended to ease Net congestion and improve data transfer reliability.

The absence of Microsoft from the list of supporters was somewhat surprising, given that the company teamed with Marimba two weeks ago to submit a related standard to the World Wide Web Consortium (W3C) standards-setting organization.

Redmond executives cited two main reasons for not supporting the protocol submission. First, DRP is a subset of a larger standards effort already under way in a different standards-setting organization, according to Microsoft program manager for Internet architecture Thomas Reardon. Second, the company takes exception to the "replication" in the DRP name.

"We think of the word 'replication' to describe something richer than just caching files," Reardon said. "It's a difficult problem and won't be solved with a toy solution."

The other standard, which Microsoft sees as a superset of DRP, is called Web Distribution of Authoring and Versioning (WebDAV) and addresses the problem of synchronizing files split into different versions with multiple authors, he noted.

"DRP bites off a small part of WebDAV," Reardon said. But DRP addresses issues that WebDAV does not, namely cutting down use of bandwidth, he added.

A FAQ list on Marimba's home page says the two proposals are "functionally complementary."

Dave Cope, Marimba's vice president of marketing, stressed that his company's own implementation of DRP is already in use in the Castanet software: "You don't need WebDAV to use DRP today."

As DRP goes through the standards process, anyone, including Microsoft, is able to make changes to it and create their own implementation, Cope said.

Despite Marimba's joint announcement with Microsoft on August 14, one Internet analyst sees the company as a focus of opposition to Microsoft in the standards battles. "Marimba is becoming a pivot point of opposition to Microsoft," said John Robb, principal of high-tech consultancy Gomez Advisors.

"[Content distribution] is so technical but so fundamental to the entire Internet, I'm fairly certain that Microsoft doesn't want to lose control of this mechanism," he added

Marimba's proposed DRP uses a technological sleight of hand, popular in the database software industry, of broadcasting only the files that have changed since the last update, instead of entire programs. It does this by letting the client cache an index of available files on a server. When the client reestablishes a connection with that server, it compares its index to that of the server. If the indices don't match up, the client can download the differences--an updated piece of software, for example, or a newly posted video clip.

The protocol has also been endorsed by other software makers, including Fujitsu, PeopleSoft, Sybase, Symantec, and Toshiba.

Marimba CEO Kim Polese said this morning that Microsoft representatives were "still reviewing the proposal," but Reardon's comments this afternoon make it clear that Microsoft isn't ready to endorse DRP outside the WebDAV standard.

Polese stressed the participation and backing of a sizable chunk of the software industry as proof enough that the protocol will survive, despite Microsoft's absence. "This is an open protocol; this is not just about Marimba."

If the protocol is adopted by the W3C as an Internet standard, software makers have promised to rush DRP-equipped products to market. "As soon as it happens, it will be in products," said Danny Shader, vice president of industry and developer relations at Netscape.