PTAB

IPR2015-00777

NetApp Inc v. Crossroads Systems Inc

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Storage Router and Method for Providing Virtual Local Storage
  • Brief Description: The ’035 patent describes a storage router that provides host computing devices with virtual local storage on remote storage devices. The router uses a supervisor unit to map host devices to specific subsets of storage space, implement access controls, and allow access using native low-level block protocols like Fibre Channel Protocol, making remote storage appear local to the host.

3. Grounds for Unpatentability

Ground 1: Claims 1-14 are obvious over the CRD-5500 references in view of Smith

  • Prior Art Relied Upon: CRD-5500 SCSI RAID Controller User’s Manual (“CRD-5500 Manual”), CRD-5500 SCSI RAID Controller Data Sheet (“CRD-5500 Sheet”), and Smith (a Hewlett-Packard Journal article, Oct. 1996).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the CRD-5500 Manual and Sheet disclose a modular RAID controller that performs the functions of the claimed "storage router." This controller routes data between hosts and storage, provides virtual storage by mapping host LUNs to RAID redundancy groups, includes a data buffer, and has I/O slots for host and storage interface modules. The "Host LUN Mapping" feature disclosed in the CRD-5500 Manual was asserted to teach the claimed mapping and access control limitations by allowing an administrator to make specific storage groups visible to certain hosts while hiding them from others.
    • Motivation to Combine: The CRD-5500 Sheet explicitly stated that the controller’s architecture was "designed to support tomorrow’s high speed serial interfaces, such as Fibrechannel." Smith described the "Tachyon" chip, an off-the-shelf Fibre Channel-to-SCSI protocol bridge. Petitioner contended a person of ordinary skill in the art (POSITA) would combine Smith's Tachyon chip with the CRD-5500 controller to implement the expressly suggested Fibre Channel capability, thereby gaining the known benefits of high bandwidth and extended connection distances.
    • Expectation of Success: A POSITA would have had a high expectation of success, as the combination involved integrating a commercially available chip (Tachyon) into a modular controller (CRD-5500) to enable a feature explicitly contemplated by the controller’s manufacturer.

Ground 2: Claims 1-4 and 7-14 are obvious over Kikuchi in view of Bergsten

  • Prior Art Relied Upon: Kikuchi (Patent 6,219,771) and Bergsten (Patent 6,073,209).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Kikuchi disclosed a control device connecting Fibre Channel (FC) hosts to SCSI storage, which functions as a basic storage router. Kikuchi’s device performed access control by checking a host address against a registration unit and mapped hosts to specific storage partitions. Bergsten was argued to disclose a more advanced storage controller with a sophisticated two-stage virtual mapping scheme (host logical address to internal logical address, then to a physical address), enabling transparent relocation of physical storage.
    • Motivation to Combine: A POSITA would combine Bergsten's advanced virtualization and flexible FC-to-SCSI bridging architecture with Kikuchi's system to create a more capable and hardware-independent storage network. This combination would improve the rudimentary mapping in Kikuchi, enhance storage management flexibility, and increase the number of accessible storage devices, goals that Bergsten identified as desirable in the art.
    • Expectation of Success: The petition argued that the architectures of Kikuchi and Bergsten were compatible, and the proposed modifications to enhance Kikuchi's correlation chart with Bergsten's virtual mapping functionality would have been a routine task for a skilled storage engineer.

Ground 3: Claims 3, 7-10, and 13 are obvious over Bergsten in view of Hirai

  • Prior Art Relied Upon: Bergsten (Patent 6,073,209) and Hirai (JP Application # Hei 5[1993]-181609).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground used Bergsten as the primary reference for its disclosure of a virtualized storage controller network. Petitioner argued that while Bergsten mentioned access controls (e.g., write-protecting data blocks), it lacked specific implementation details. Hirai was asserted to cure this deficiency by disclosing a detailed, granular access control system for shared storage. Hirai taught using a partition control table to assign specific rights (read, write, create, delete) to different hosts on a per-partition basis.
    • Motivation to Combine: A POSITA would be motivated to integrate Hirai's robust, mapping-based access control system into Bergsten's storage controller network to provide more granular and secure access in a multi-host environment. This would directly enhance Bergsten’s more generalized security features, providing a significant improvement necessary for managing shared data with varying access privileges.
    • Expectation of Success: Petitioner contended that applying the access control logic from Hirai's tables to the logical addresses in Bergsten’s mapping tree would have been a predictable and straightforward implementation for a POSITA.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge for claims 5 and 6 based on the combination of Kikuchi, Bergsten, and Smith. This ground used Smith to provide specific teachings for the internal architecture of the controller modules (e.g., protocol units, FIFOs, DMA interfaces) within the broader framework established by Kikuchi and Bergsten.

4. Key Claim Construction Positions

  • "Native low-level block protocol" (NLLBP): Petitioner argued that, under the broadest reasonable interpretation, this term encompasses protocols like SCSI and Fibre Channel Protocol (FCP). The key characteristic of an NLLBP, as described in the ’035 patent, is that it enables the direct exchange of block-level storage commands and data without the translation overhead of higher-level network protocols and file systems typically required by general-purpose network servers. This construction was central to asserting that the prior art systems, which used FCP and encapsulated SCSI, met the claim limitations.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued against discretionary denial under 35 U.S.C. §325(d) by addressing a prior related proceeding, IPR2014-01197. Petitioner explained that the Board declined to institute the prior IPR not on the merits of the prior art, but due to a procedural defect where the petition improperly incorporated arguments by reference to an expert declaration. Petitioner asserted that the present petition corrected this flaw by fully articulating all arguments and evidence within the four corners of the document, and therefore requested the Board provide a full consideration on the merits.

6. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-14 of Patent 6,425,035 as unpatentable.