Akamai Technologies Inc is trying to have rival Digital Island Inc forced to turn off its flagship content delivery service, in the latest twist to the patent wrangle between the two firms, Kevin Murphy writes.

"Akamai today filed a motion for entry of an injunction in the ongoing patent dispute against Digital Island," said an Akamai spokesperson. "This is as a result of a Boston jury's finding of Digital Island's infringement of the Leighton-Lewin patent."

In December, a jury found DI's Footprint CDN infringes the parts of US patent 6,108,703, the so-called "Leighton-Lewin patent", which cover a "two-level DNS" method used by both Akamai and DI to route web traffic to edge-of-network caches.

The two-level DNS claims basically cover the practice of rewriting the URLs of embedded objects in web pages so that the original URL is pre-pended by a CDN hostname. DI's general counsel Howard Lasky told ComputerWire that less than a dozen of its customers have implemented DI in the "legacy" way covered by the patent.

"I'm going to have these customers rewriting in the more modern fashion tomorrow," Lasky said. He said that if an injunction is issued, by the time it becomes effective, no DI customers will be infringing the Akamai patent. The only possible setback for DI, he said, would be if an awkward customer decided they didn't want to rewrite their URLs.

The Akamai spokesperson said the requested injunction would be "broad-based", and would cover Footprint 2.0. DI's Lasky claims any injunction would only cover the specific claims of Leighton-Lewin DI was found to infringe. He additionally claims that other parts of the patent are far more important.

The same Boston jury that found DI infringed the first five claims of '703 also decided that three, arguably more important, '703 claims should be invalidated.

Their reasoning was that a DI patent on Footprint "anticipated" the three Akamai claims, which cover CDN methodologies far more fundamental than the way a URL is rewritten.

The Akamai spokesperson said: "We believe that finding was made in error, and we will appeal if the court does not agree with us." The three claims in question cover broad notions such as changing a URL to point to a cache chosen based on current internet conditions - the key behind every CDN.

Lasky said that DI intends to have the US Patent and Trademark Office transfer these three claims to its Footprint patent, based on the jury's decision. He said that if DI, now a Cable & Wireless Plc subsidiary, manages to get hold of these claims "I believe I would be able to enjoin everyone I know of in the CDN space," he said.

Lasky anticipates that the USPTO action should be complete in five to 12 months from now, though the overworked, understaffed organization is always difficult to predict. Whatever happens, it seems the two leading CDN players in the business will be arguing over their intellectualproperty for some time to come.

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