Invalidity dossier
US 5751971
Internet protocol (IP) work group routing
Current assignee: Enterasys Networks Inc
Added 9/23/2026, 7:27:21 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview: US5751971A
Title: Internet Protocol (IP) Work Group Routing
Patent number: US5751971A
Application number: US08/501,324
Inventors: Kurt A. Dobbins; David L. Cullerot; Stephen H. Negus; William T. Haggerty
Original assignee: Cabletron Systems Inc.
Current assignee (as listed): Enterasys Networks Inc.
Priority/filing date: 1995-07-12
Grant/publication date: 1998-05-12
Anticipated expiration: 2015-07-12
Legal status: Expired – Lifetime
Purpose and plain-language scope. The patent concerns routing Internet Protocol (IP) traffic organized into "work groups." According to the source, the disclosed approach involves monitoring and forwarding behavior in which a host's address is associated with a work group, and forwarding decisions are made at an interface based on that association. The classification scheme places the invention in data switching networks (H04L12/00, H04L12/28) and LAN interconnection (H04L12/46), including LAN interconnection over a bridge-based or backbone network (H04L12/462/4625), as well as address mapping and allocation (H04L61/00, H04L61/09, H04L61/25) including address allocation for group or multicast communication (H04L61/5069). It is further classified under network security for separating internal from external traffic (H04L63/02, H04L63/0227) with filtering by address, protocol, port, or service (H04L63/0236), and under TCP/IP or UDP/IP stack implementation (H04L69/16, H04L69/161). The prior-art keywords listed are: host, address, work group, forwarding, interface.
What the excerpt does not establish. The supplied text is a bibliographic/classification excerpt; it omits the abstract, full description, and claims (each listed only as a presence count, e.g., 7 claims, 45 description mentions). Therefore this overview cannot state the precise claim language, the exact mechanisms disclosed, specific embodiments, or the technical problem solved. It also does not establish inventorship disputes, validity, enforceability, or the effect of the recorded reassignments and security interests (Cabletron → Enterasys, plus later security agreements and releases); the source expressly notes that legal status and assignee listings are assumptions, not legal conclusions.
Source: https://patents.google.com/patent/[US5751971](/patent/US5751971)/en
Generated 10/1/2026, 9:42:03 PM
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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