PTAB

IPR2015-00549

Dell Inc v. Elec & Telecomm'N Research INST

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1. Case Identification

2. Patent Overview

  • Title: APPARATUS FOR REDUNDANT INTERCONNECTION BETWEEN MULTIPLE HOSTS AND RAID
  • Brief Description: The ’346 patent relates to a fault-tolerant system that provides redundant interconnections between multiple host computers and a Redundant Array of Independent Disks (RAID) storage system. The disclosed architecture features two RAID controllers, each equipped with two network interface controllers (NICs), which are connected to the hosts via two separate hub or switch devices to ensure high availability.

3. Grounds for Unpatentability

Ground 1: Obviousness over Mylex and Hathorn - Claims 1-9 are obvious over Mylex in view of Hathorn.

  • Prior Art Relied Upon: Mylex (a 1998 Mylex Corporation white paper titled “Storage Area Networks: Unclogging LANs and Improving Data Accessibility”) and Hathorn (Patent 5,574,950).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Mylex discloses nearly every element of the challenged claims, including a fault-tolerant architecture with multiple hosts, dual RAID controllers (each with multiple ports/NICs), and redundant connections through hubs or switches in a Storage Area Network (SAN). The primary element Mylex does not explicitly teach is the exchange of information directly between the NICs of different controllers. Instead, Mylex discloses a dedicated "heartbeat" communication path between the main controllers for exchanging fault tolerance information. Hathorn was cited to remedy this difference, as it teaches that dedicated communication paths are expensive and discloses modifying NICs to communicate with each other over the existing, shared switch network. Petitioner asserted that combining Mylex's architecture with Hathorn's more efficient inter-controller communication method renders the claimed invention obvious.
    • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would combine these references for both technical and commercial reasons. Technically, a POSITA would seek to replace Mylex's expensive dedicated heartbeat path with Hathorn's more elegant and cost-effective solution of leveraging the existing network for inter-controller communication. This represents a simple substitution of one known communication method for another to achieve a predictable improvement in cost and efficiency. Furthermore, Petitioner noted that IBM (assignee of Hathorn) acquired Mylex in 1999, providing a strong business motivation for engineers to combine the companies' respective storage technologies.
    • Expectation of Success: A POSITA would have a high expectation of success, as the combination merely involved applying a known communication technique from Hathorn to a known fault-tolerant system architecture from Mylex. The result—a redundant RAID system with inter-controller communication over the main network—was predictable.

Ground 2: Obviousness over Deitz/Mylex in view of Griffith/DeKoning - Claims 1-9 are obvious over Deitz or Mylex in view of Griffith or DeKoning.

  • Prior Art Relied Upon: Deitz (Patent 6,578,158), Mylex (white paper), Griffith (Patent 6,401,170), and DeKoning (Patent 6,073,218).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that both Deitz and Mylex disclose redundant RAID systems that meet most of the claim limitations, including dual controllers with active and inactive (failover) ports connected to hosts via hubs. However, similar to the argument in Ground 1, both Deitz and Mylex accomplish inter-controller communication via a direct, dedicated "heartbeat" path. Petitioner presented Griffith and DeKoning as references that teach alternative, known methods for achieving the same function. Specifically, Griffith teaches exchanging fault tolerance information between controllers by using the existing switch network, while DeKoning teaches using several communication mediums, including the existing host-side communication bus.
    • Motivation to Combine: A POSITA, starting with the systems of Deitz or Mylex, would be motivated to improve upon them by incorporating the more integrated communication methods taught by Griffith or DeKoning. Replacing a dedicated hardware path with a method that utilizes existing network infrastructure is a well-known engineering principle for reducing cost, complexity, and potential points of failure. As all four references are in the same field of endeavor and address the same problem of fault tolerance, a POSITA would have naturally looked to the solutions in Griffith and DeKoning to improve the designs of Deitz or Mylex.
    • Expectation of Success: Success would be expected because the modification involved implementing known communication protocols (from Griffith or DeKoning) over existing network paths in the RAID systems of Deitz or Mylex. This would predictably enable the required inter-controller communication for failover monitoring and coordination without altering the fundamental operation of the RAID system.

4. Key Claim Construction Positions

  • "connection unit": Petitioner proposed this term be construed as "a hub or switch." This construction was central to the argument, as the prior art references explicitly describe using standard hubs and switches to build the network connecting the hosts and RAID controllers.
  • "network interface controller," "network controlling unit," and "network interface controlling unit": Petitioner argued these related terms should be construed broadly as "the part of a RAID controller that allows the RAID controller to communicate with the 'connection units'." This interpretation allows the various ports disclosed in the prior art references to satisfy the limitations for these claimed units.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-9 of the ’346 patent as unpatentable.