PTAB

IPR2015-00776

NetApp Inc v. Crossroads Systems Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Storage Router for Providing Virtual Local Storage on Remote Devices
  • Brief Description: The ’041 patent describes a storage router that provides host devices access to remote storage devices over a serial transport medium. The router uses a mapping system to make the remote storage appear as local storage to the hosts and manages access using native low-level block protocols.

3. Grounds for Unpatentability

Ground 1: Obviousness over CRD-5500 References and Smith - Claims 1-53 are obvious over the CRD-5500 User Manual and Data Sheet in view of Smith.

  • Prior Art Relied Upon: CRD-5500 User Manual (a 1996 manual for a SCSI RAID controller), CRD-5500 Data Sheet (a 1996 data sheet for the controller), and Smith (an October 1996 journal article describing the "Tachyon" Fibre Channel protocol chip).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the CRD-5500 RAID controller is a "storage router" that provides "virtual local storage" through its "Host LUN Mapping" feature. This feature constitutes the claimed map, which associates host devices with specific storage regions (redundancy groups) on remote SCSI drives and controls access. Smith discloses the Tachyon chip, which provides the necessary Fibre Channel-to-SCSI bridging functionality. Incorporating the Tachyon chip into the CRD-5500's modular I/O slots would create the claimed "first controller operable to interface with a first transport medium" (Fibre Channel). The system would receive commands in a first protocol (FCP) and forward them in a second (SCSI).
    • Motivation to Combine: Petitioner asserted that the CRD-5500 Data Sheet explicitly suggests its architecture was designed to support high-speed serial interfaces like Fibre Channel. A person of ordinary skill in the art (POSITA) would have been motivated to combine the CRD-5500 controller with the Tachyon chip described in Smith to enhance connectivity, increase bandwidth, and extend the distance between hosts and storage, which were well-known benefits of Fibre Channel.
    • Expectation of Success: The combination was a straightforward integration of a controller designed for high-speed interfaces with a chip specifically made for bridging those interfaces (Fibre Channel) to the controller's native protocol (SCSI).

Ground 2: Obviousness over Kikuchi and Bergsten - Claims 1-53 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 contended that Kikuchi discloses a control device (a storage router) that connects multiple host devices via Fibre Channel to a single SCSI storage device. Kikuchi uses a correlation chart to map different partitions of the storage device to different hosts, thereby providing a form of virtual storage and access control. Bergsten teaches a more advanced storage controller that virtualizes remote storage subsystems, making them appear completely transparent to hosts by mapping virtual addresses to physical locations. The combination of Kikuchi's access control framework with Bergsten's superior virtualization and Fibre Channel-to-SCSI emulation drivers discloses all limitations of the challenged claims.
    • Motivation to Combine: A POSITA would have been motivated to enhance Kikuchi's basic system with the advanced virtualization taught by Bergsten. This would improve the system by making it independent of specific hardware configurations and increasing the number and range of storage devices accessible to hosts, a stated goal in Bergsten.
    • Expectation of Success: The architectures were compatible, as both deal with bridging Fibre Channel host networks to SCSI storage arrays. Incorporating Bergsten’s emulation drivers and virtual mapping functionality into Kikuchi's controller would have been a predictable modification.

Ground 3: Obviousness over Bergsten and Hirai - Claims 1-53 are obvious over Bergsten in view of Hirai.

  • Prior Art Relied Upon: Bergsten (Patent 6,073,209) and Hirai (JP Application Publication No. Hei 5[1993]-181609).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Bergsten provides the primary storage router system, teaching virtualization, Fibre Channel-to-SCSI bridging, and mapping of host addresses to logical and physical storage locations. While Bergsten mentions write-protection, it lacks detail on implementation. Hirai remedies this by disclosing a detailed, table-based access control system ("partition control table") that assigns specific access rights (read, write, create, delete) on a per-host, per-partition basis.
    • Motivation to Combine: A POSITA would combine these references to improve the access control capabilities of the Bergsten system. Incorporating Hirai's mapping-based, granular access controls would allow an administrator to implement sophisticated permissions (e.g., read-only for some users, full access for others), a clear advantage for networked storage. This combination would predictably enhance Bergsten's goal of transparently managing multiple back-up copies.
    • Expectation of Success: Integrating a table-based access control scheme like Hirai's into Bergsten's mapping architecture would be a straightforward design choice for a POSITA seeking to implement robust access controls.

4. Key Claim Construction Positions

  • "Native low-level block protocol" (NLLBP): Petitioner argued for a construction based on the specification and reexamination history of a related patent. This construction includes protocols like SCSI and Fibre Channel Protocol (FCP) that enable information exchange without the overhead of high-level protocols and file systems typically required by network servers. The construction explicitly excludes protocols like TCP/IP that require translation by a network server to generate low-level requests. This distinction is central to Petitioner's argument that the prior art combinations operate as claimed.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that denial under 35 U.S.C. §325(d) would be inappropriate. A previous petition on the same patent (IPR2014-01177) was denied institution not on the merits of the prior art, but on a procedural failing: the petition improperly attempted to incorporate by reference arguments and citations from a supporting expert declaration. Petitioner asserted that the present petition corrects this defect by presenting all prior art evidence and arguments fully within the petition itself, warranting a full consideration on the merits.

6. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-53 of the ’041 patent as unpatentable.