Invalidity dossier
US 5528584
Added 9/23/2026, 4:24:09 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 5,528,584 A
Title: High performance path allocation system and method with fairness insurance mechanism for a fiber optic switch.
Assignee/Inventor data (from supplied record): Original assignee Hewlett Packard Co.; later recorded assignees include McData Corporation and Brocade Communications Systems LLC. Inventors: Robert H. Grant, Bent Stoevhase, Robin Purohit, Gregory T. Sullivan, David Book.
Dates: Priority/filing 1994-10-27; granted and published 1996-06-18. Status listed as expired (anticipated expiration 2014-10-27).
Purpose: To overcome deficiencies in prior fiber optic switches (notably the ANCOR switch, characterized in the text as inflexible, providing primarily circuit switching for class 1 transfers and very limited frame switching for class 2) by providing a flexible, high-performance path allocation system and method accommodating both class 1 circuit switching and class 2 frame switching per the Fibre Channel industry standard. A stated object is "insurance so that transfer requests will ultimately be accommodated by the switch without reliance on probabilities of port availability."
Plain-language scope (per the supplied excerpt): A fiber optic switch has multiple ports, each with port intelligence (transmitter and receiver). A memory interface system temporarily stores incoming class 2 data frames from source ports and provides bypass paths for class 1 transfers. A switch module includes control, main, and intermix distribution networks selectively interconnecting memory interface systems. A sentry detects new frames and solicits path data (source port, memory address, destination port). A scheduler maintains a per-port destination queue, places path data in the appropriate queue, and retrieves it in a defined order, serviced according to glue logic that checks whether each port's transmitter is busy or available. An arbitrator controls transfers through the switch module.
Not established by this excerpt: The full claim set and exact claim language; detailed operation of the fairness insurance mechanism; drawing contents; the "ANCOR" reference's full citation; the omitted remainder of the description; and any legal conclusions on validity, scope, or ownership status.
Generated 10/1/2026, 9:50:54 PM
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Litigation summary
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Proceedings on file (0)
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PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.