A group led by Marimba Inc has submitted a wire-level data distribution protocol to the World Wide Web Consortium, W3C, based on the ADP Application Distribution Protocol used in its Castanet Internet software distribution system. The DRP Distribution and Replication Protocol is an extension to the HTTP protocol that enables distribution of any type of software, data or web content using a differential engine that sends only portions of a web page, program or files that have changed since the last update. Marimba was joined in its effort by co-authors and submitters Novell Inc, Sun Microsystems Inc, Netscape Communications Corp and @Home Network Inc, and the submission has been recognized by the W3C. Microsoft Corp was approached around ten days ago to support the effort but has not replied, although Marimba said it thought Redmond would support it in time. Netscape says it will incorporate DRP into its Communicator client and SuiteSpot server products once it has been approved by the W3C. DRP will be discussed first at a W3C working group in Boston in two weeks’ time. It will go forward to a vote of those among the 204-strong W3C membership who are interested in the specification. Marimba says that as DRP is almost the same as its ADP, it will support it almost immediately. DRP uses an encryption algorithm based on RSA Data Security Inc’s MD-5 CheckSum, to ‘fingerprint’ software when it is downloaded. The DRP client checks the latest fingerprint against what it finds at the source and updates with the latest software. The fingerprint is also used in DRP’s multi-layer caching, so that the remote client does not have to trawl through everything in the cache trying to find what it needs – the protocol locates what is new and needs to be downloaded. This is especially useful when the software is being sent over very long distances and the updates can then be stored closer to the remote client. Another advantage of DRP, says Marimba, is its ability to cope with varying levels of differentiation, so it send just the most up to date software or information, or the previous day’s or the previous two weeks’ if necessary.
Geared towards HTTP
Marimba says it will continue to make its money by adding services such as security, management, transaction and more advanced updating technologies in Castanet, despite giving away part of what is a patent-pending technology. Marimba says DRP is complimentary to other recent internet standards efforts. Microsoft’s Channel Definition format and Netscape similar Meta Content Framework (CI No 3,183) describe the HTML content; Marimba and Microsoft’s Open Software Description (CI No 3,226) describe software components and now DRP provides a way of distributing those components. All have been submitted to the W3C. News that Marimba offering up part of its patent-pending protocol for royalty-free licensing is not good for companies such as Novadigm Inc, which has a patented software differentiation engine also, but was not available for comment. Marimba sees its chief competition as distribution technologies used by IBM Corp subsidiary Tivoli Systems Inc or Microsoft’s SMS server. The reason W3C likes DRP so much, Marimba claims, is that DRP is geared entirely towards HTTP. Other conventional software distribution protocols are focused entirely on the PC market. Marimba says the 80% of SMS intellectual property is tied up in its Windows-based dynamic link library functions while 80% of DRP is devoted to HTTP.
Unworkable
Furthermore, the parties believe putting distribution and replication techniques together with one message-to-many-client ‘multicasting’ technology will be a natural progression. However while Marimba’s plan is to offer replication using multicasting techniques in future, co-founder and chief technology officer Arthur van Hoff says multicasting is currently largely unworkable. Messages have to be re-broadcast due to machines that aren’t listening or are down – defeating the very object of multicasting. In addition, many router and hub networking infrastructure products don’t support multicasting (nor do most internet service providers), as Marimba learnt after it bought in a load of kit to try and create its own multicast network internally. He says the company’s efforts have been redirected (if not entirely communicated) away from the conventional push technology market where the PointCasts and BackWebs struggle to make million dollar deals, towards new and more lucrative software distribution paradigms.
