Patent Details Emerge In Level 3’s Suit Against Limelight Networks

While I have not yet seen any detailed documentation or records filed with the court regarding Level 3’s patent infringement suit against Limelight Networks, with trial slated to start on October 14th, I have been able to confirm that the Level 3 patents at the heart of the suit are 7054935, 6654807 and 6473405.

Patents 807 and 935 talk to the same abstract, which is "Resource requests made by clients of origin servers in a network are
intercepted by reflector mechanisms and selectively reflected to other
servers called repeaters. The reflectors select a best repeater from a
set of possible repeaters and redirect the client to the selected best
repeater. The client then makes the request of the selected best
repeater. The resource is possibly rewritten to replace at least some
of the resource identifiers contained therein with modified resource
identifiers designating the repeater instead of the origin server

Patent 405 talks to the same idea of routing traffic to the best source through a selection process. While the abstract of patent 405 is similar to patents 807 and 935, patent 405 has a more detailed abstract that talks to measuring traffic on the network and states "…. is
based on real-time measurement of costs associated with the alternative
paths, in response to a user request for transmission of message data
to a destination on the network. Cost metrics include delay,
throughput, jitter, loss, and security

Reading through the filings, I notice that patents 807 and 935 specifically talk to HTTP delivery, so one has to wonder if any of Limelight’s traffic that is not delivered via HTTP, for instance streaming video via RTSP or RTMP, would fall under violation of the patents. It could be a similar case to the Akamai patent suit where only a portion of Limelight’s business falls under the technical description of the patents in question.

All three of the patents were filed in 2001 or 2002 which makes them fall under the Digital Island/Cable & Wireless time frame. However, it is interesting to note that the 807 and 935 patents list employees from the Sandpiper days as the inventors, who are now employed at Level 3.

I don’t have enough of the details from Level 3 or Limelight, or access to all of the data to make any guess on whether or not Limelight is or is not in violation and whether or not Level 3’s patents will hold up in court. And at the slow rate that patent infringement cases move, I don’t expect we’ll hear any real information one way or another from this case for at least a year or more.

Many of the content delivery related patents that are going to court these days sound awfully broad and it’s getting harder and harder to decipher exactly what these patents mean, what type of content they cover and what type of data transmission they are referencing. While there have been many content delivery networks over the past ten years that have sued one another, none of the suits have yet to have a major impact on any one vendor. That could change years from now when the content delivery market truly grows and as more companies, like Level 3, make intellectual property a big part of their strategy.

Note: As my bio states, while I have worked as an expert on various patent suits pertaining to IP based video, I am not working on any case involving Akamai, Limelight or Level 3. And while I have been asked by firms in the past to work on some CDN related cases, I have never worked on any lawsuit involving any content delivery network.