Invalidity dossier
US 5592472
Added 9/23/2026, 5:50:31 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 5,592,472 A
Title: "High performance path allocation system and method for a fiber optic switch for a fiber optic network"
Assignee/Inventor: Original assignee Hewlett-Packard Co.; inventors Robert Grant, Bent Stoevhase, Robin Purohit, Gregory T. Sullivan, and David Book. (Google Patents lists a current assignee of Brocade Communications Systems LLC, but per the operating rules this overview does not analyze ownership transfers.)
Key dates: Priority/filing date 1994-10-27; publication/grant date 1997-01-07. Status listed as "Expired – Lifetime," with anticipated expiration 2014-10-27. Foreign counterparts noted: CA 2155040, EP 0709984, JP 08256168.
Purpose: The invention generally relates to data communications and fiber optic networks, and more particularly to a path allocation system and method for allocating data paths between fiber optic channels through a fiber optic switch, while providing high performance and flexibility and minimizing hardware requirements. A stated object is to accommodate both efficient circuit switching (class 1 transfers) and frame switching (class 2 transfers) per the Fibre Channel industry standard, overcoming deficiencies noted in the prior-art ANCOR switch (IBM).
Plain-language scope (from the excerpt): Ports correspond to fiber optic channels; each port has a port intelligence mechanism with a transmitter and receiver. A memory interface system temporarily stores incoming new frames from source ports for class 2 transfers and provides bypass paths for class 1 transfers. A switch module includes a control distribution network (CDN), main distribution network (MDN), and intermix distribution network (IDN) to selectively interconnect data paths. A sentry detects new frames and solicits path data (source port indicator, memory address, destination port indicator). A scheduler maintains a destination queue per port, places path data accordingly, and services queues in an order defined by glue logic. An arbitrator controls transfers via the MDN or IDN.
Source: https://patents.google.com/patent/US5592472/en
What the excerpt does not establish: The excerpt is partial and omits the claims and much description. It does not establish claim scope, embodiment details beyond those summarized, the full reference list, or file-history specifics. No litigation, validity, or prior-art conclusions are drawn.
Generated 10/1/2026, 9:43:15 PM
Cases on file (0)
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Litigation summary
Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.
Proceedings on file (0)
All PTAB activity →AIA trial proceedings (IPR / PGR / CBM) filed at the USPTO Patent Trial and Appeal Board against this patent. Sourced from the USPTO Open Data Portal and refreshed every six hours; each proceeding number deep-links to the PTAB E2E docket.
No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
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
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
Earlier patents, publications, and products that may anticipate or render the claims unpatentable.
Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.