Rackspace US Inc v. PersonalWeb Technologies LLC

1. Case Identification

• Case #: IPR2014-00059
• Patent #: 6,415,280
• Filed: October 10, 2013
• Petitioner(s): Rackspace US, Inc. and Rackspace Hosting, Inc.
• Patent Owner(s): PersonalWeb Technologies, LLC and Level 3 Communications, LLC
• Challenged Claims: 10, 15, 16, 18, 25, 31, 32, 33, 36, and 38

2. Patent Overview

• Title: Identifying and Requesting Data in Network Using Identifiers Which Are Based on Contents of Data
• Brief Description: The ’280 patent discloses systems and methods for managing data files in a computer network by generating a substantially unique, content-based identifier for each file (termed a "True Name"). This identifier, derived from the file's data content itself, allows for location-independent access and retrieval, contrasting with prior art systems that relied on context-dependent pathnames.

3. Grounds for Unpatentability

Ground 1: Anticipation Over Woodhill - Claims 10, 15, 16, 18, 25, 36, and 38 are anticipated under 35 U.S.C. § 102(e) over Woodhill.

• Prior Art Relied Upon: Woodhill (Patent 5,649,196).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Woodhill disclosed every element of the challenged claims. Woodhill described a distributed storage management system that uses content-based identifiers, called "Binary Object Identifiers," to uniquely identify data objects for backup and retrieval across a network. These identifiers, like the ’280 patent's "True Names," are calculated from the contents of the data (using CRC and hash values) so that duplicate objects can be recognized regardless of their location. Woodhill’s system operated on a network of computers that could act as both clients (requesting files) and servers (providing files), satisfying the "network of servers" limitation. For dependent claims, Woodhill’s "File Prioritization" routine, which managed network resources based on availability and limited transmission capacity, was argued to teach resolving requests based on a measure of the servers (claims 15-16).

Ground 2: Obviousness Over Woodhill in view of Langer - Claims 10, 15, 16, 18, 25, 31, 32, 33, 36, and 38 are obvious over Woodhill in view of Langer under 35 U.S.C. § 103.

• Prior Art Relied Upon: Woodhill (Patent 5,649,196) and Langer (a 1991 Usenet newsgroup post).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Woodhill taught the broad method of using a content-based hash to create a unique identifier. Langer, which addressed the same problem of uniquely identifying files across different systems, explicitly suggested using a specific, well-known cryptographic hash function—MD5—to generate a unique identifier based on the entire file contents. While Woodhill described its own hash algorithm, Langer provided the specific MD5 hash required by claim 31.
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) seeking to implement Woodhill’s system would have been motivated to use a robust and standardized hashing algorithm to ensure a low probability of collision, which Woodhill identified as a critical goal. Langer provided a known technique (MD5 hashing) to improve a similar system (Woodhill's) in a predictable way. The combination was presented as a simple substitution of one known element (Langer's MD5 hash) for another (Woodhill's generic hash) to achieve a predictable and improved result.
  • Expectation of Success: A POSITA would have had a high expectation of success because using cryptographic hashes like MD5 to generate unique file identifiers was a well-understood and established technique for the exact purpose described in both Woodhill and Langer.

4. Key Claim Construction Positions

• "a network of servers" (claims 10, 18, 25, 31): Petitioner argued this term should be construed as "a network of processors acting as servers, at least part of the time." This construction was based on the ’280 patent’s specification and prosecution history, which described a peer-to-peer system where processors dynamically change roles between client and server, rather than a network of dedicated servers. This broader interpretation was critical to mapping the prior art, which disclosed similar peer-to-peer network architectures.
• "a network comprising a plurality of processors, some ... being servers and some ... being clients" (preamble, claims 36, 38): Consistent with the argument above, Petitioner contended this preamble term, which the PTAB previously found to have patentable weight, should be interpreted similarly to allow for a single processor to satisfy both client and server roles depending on the needs of the system.

5. Arguments Regarding Discretionary Denial

• Petitioner acknowledged that the PTAB had previously instituted a trial (IPR2013-00082) on claims 36 and 38 of the ’280 patent. However, Petitioner argued for institution in the present case because this petition challenged a broader set of claims (10, 15, 16, 18, 25, 31, 32, and 33) that were not subject to the previously instituted trial. Further, it presented new grounds and evidence against all challenged claims, justifying a complete review.

6. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 10, 15, 16, 18, 25, 31, 32, 33, 36, and 38 of the ’280 patent as unpatentable.