US 6885658

I'll search for authoritative sources on this specific patent, including any 2026 CAFC activity.

Let me retrieve the full claim set and check for any 2026 CAFC activity.

One more targeted search to confirm the full independent claim set.

US Patent 6,885,658 — Analyst Summary

Note on sourcing and confidence: The authoritative full text supplied for this analysis includes the abstract and description but is truncated mid‑description (it stops partway through the FIG. 12 call‑flow discussion) and does not contain the claims section. Claim language below is therefore taken from the issued patent as quoted in court opinions (E.D. Tex. claim‑construction orders in Genband v. Metaswitch, Case No. 2:14‑cv‑00033) and from Justia's patent page for 6885658 — both of which quote the granted claims. Items I could not verify verbatim are flagged. I found no 2026 CAFC docket involving this patent (see §7).

1. Bibliographic data (literal)

2. Abstract (as issued)

"A method and an apparatus for interworking between internet protocol (IP) telephony protocols includes a call server. The call server includes a first protocol agent for communicating with a first protocol device according to a first protocol. A second protocol agent communicates with a second protocol device according to a second protocol. An interworking agent provides functions usable by the first and second protocol agents to communicate with each other according to a third protocol. The third protocol is a superset of functions provided by the first and second protocols."

3. Technical problem and core disclosure

The patent addresses the absence (as of 1999–2000) of standards for interworking between dissimilar IP telephony protocols — MGCP, ITU‑T H.323, ITU‑T H.248/MEGACO, SIP, and North American Q.931 (NAQ.931), plus proprietary protocols. The disclosed architecture places, in a "call server," separate protocol agents for each call half and an interworking agent whose functions let the protocol agents talk to one another over a protocol‑independent Agent Interworking Protocol (AIP).

Key disclosed mechanisms:

• AIP as an extended existing protocol. The specification states AIP is preferably based on ISUP and reuses ISUP messages (IAM, ANM, REL), extended with new procedures and parameters rather than built from scratch. Q.931 and SIP are named as alternative base protocols.
• Connection Information Parameter (CIP) (FIG. 8): media type, channel ID, channel operation (no action, open, close, modify, mode change, redirect, direct, send capabilities), current media description, and media capabilities (including payload size and a "redefinable area").
• Digit Information Parameter (FIG. 11): digit value plus tone duration, for out‑of‑band DTMF handling.
• Message tunneling (FIGS. 9(a)/9(b), 10): three message types — AIP, native protocol‑specific, and multipart. If a parameter maps to AIP, an AIP message is built; if it does not map, the native message is passed without alteration; if only partially maps, a multipart message carrying both an AIP portion and the native protocol portion is sent. Transport is by TCP over IP, with an interworking‑message header indicating message type.
• Distributed deployment: splitting the interworking agent into two components permits originating and terminating call halves to execute on different machines.
• Worked interworking scenarios: H.323 fast‑start → MGCP (FIG. 12), H.323 non‑fast‑start → MGCP (FIG. 13), HOLD/RETRIEVE between H.323 and NAQ.931 (FIGS. 14‑15) and H.323 and MGCP (FIGS. 16‑17), H.323 ↔ MGCP with common channel signaling (FIG. 18), and DTMF digit exchange (FIG. 19).

4. Plain‑language overview of the independent claims

Claim 1 — "A call server comprising…" (apparatus). A call server has (a) a first protocol agent that talks to a first IP telephony device using a first IP telephony protocol, (b) a second protocol agent that talks to a second IP telephony device using a second IP telephony protocol, and (c) an interworking agent that lets the two protocol agents communicate with each other using a third protocol, where the third protocol's functions are a superset of the functions of the first and second protocols. The claim as issued further requires the interworking agent to be adapted to determine that a first parameter associated with the first IP telephony protocol does not map to the second IP telephony protocol, and to communicate that first parameter to the second protocol agent without alteration (i.e., the tunneling/pass‑through behavior). (This limitation appears in the granted text as quoted by the district court and differs from the shorter phrasing in the abstract and in the specification's summary.)

Claim 11 — Method for interworking. Steps: (a) receive, from a first telephony device, a first message formatted per a first IP telephony protocol; (b) in response, generate a second message in a second (distinct) protocol containing at least one of a media capabilities description and media stream management information derived from the first message; (c) transmit that second message to a second protocol agent; and (d) in response, generate a third message formatted per a third IP telephony protocol containing at least one of the media capabilities description and media stream management information derived from the second message. In substance: receive in protocol A → carry the media‑related content in an intermediate protocol B → emit in protocol C.

Claim 21 — Method for tunneling messages between protocol agents. Determines whether a parameter in a first message maps to a second IP telephony protocol; if it does map, formulates a second message in that second protocol; if it does not map, transmits the first message without alteration to a second protocol agent. (Sub‑element (a) — the receiving step — is not verbatim in my sources; the remainder is quoted.)

Claim 22 — Method for tunneling messages (multipart variant). Same as claim 21 but adds the third branch: when the parameter only partially maps to the second protocol, formulate a multiprotocol (multipart) message containing a message formatted according to one protocol and the native message portion.

Claim 27 — Computer program product (computer‑executable instructions in a computer‑readable medium). Invoke a first protocol agent for a first IP telephony device per a first IP telephony protocol; invoke a second protocol agent for a second IP telephony device per a second IP telephony protocol; map media capabilities information extracted from messages of the first and second protocols to a third protocol; transmit between the agents a first message containing that media capabilities information in the third protocol; determine whether a parameter from the first protocol maps to the second protocol; and, if it does not map, transmit the parameter without alteration to the second protocol agent.

Claim 34 — Computer readable medium having software stored thereon. Software comprising a first protocol agent, a second protocol agent (second protocol distinct from the first), a third protocol agent (third protocol distinct from the first and second), and an interworking protocol adapted to represent a partial superset of the messaging capabilities of the first, second and third IP telephony protocols such that messages received in any of the three protocols from a first IP device are converted to the interworking protocol and then translated into a different one of the three protocols for transmission to a second IP device. Note the contrast in wording: claim 1 says "a superset"; claim 34 says "a partial superset" — this contrast was expressly argued by the defendant and analyzed by the district court.

Dependent claims (approximate groupings, based on the quoted text): claims 2‑10 depend from claim 1 (e.g., claim 5 recites the first protocol agent is an H.323 agent, and related protocol pairings); claims 12‑20 depend from claim 11 (MGCP↔H.323, SIP↔H.323, H.323↔Bellcore Q.931, H.323 fast‑start mapping to MGCP, HOLD/RETRIEVE via a connection information parameter mode change, and DTMF digit mapping via a digit information parameter); claims 23‑26 depend from claims 21/22; claims 28‑33 depend from claim 27. I have not verified every intermediate claim verbatim.

5. Claim constructions of record (relevant to scope)

• Genband USA LLC v. Metaswitch Networks Ltd., No. 2:14‑cv‑33‑JRG‑RSP (E.D. Tex.), claim‑construction orders (Aug. 6, 2015 and later): the terms "protocol agent" and "interworking agent" were held not to be means‑plus‑function terms under § 112 ¶ 6 (construed to have their plain meaning), the court finding "agent" connotes a recognized class of software structures.
• "communicating first parameter to the second protocol agent without alteration" was construed to have its plain meaning; the defendants' attempt to import a "without converting to and from a third protocol" limitation from the tunneling passage of the specification was rejected.
• The parties disputed whether "superset" in claim 1 means a complete superset (defendants' position) or can include the specification's "reasonable/partial superset" (plaintiff's position, pointing to claim 34's "partial superset"). The court's preliminary construction was "a set that includes one or more functions provided by both the first and second IP telephony protocols." I do not have the final holding on this term and therefore do not assert one.
• Genband v. Metaswitch, No. 2:14‑cv‑33 (E.D. Tex., Sept. 29, 2016): the court denied Metaswitch's § 101 motion, holding asserted claims 1 and 11 of the '658 patent patent‑eligible under Alice step one and step two.

6. Litigation history touching this patent

• 2:14‑cv‑00033 (E.D. Tex., filed Jan. 2014) — Genband US LLC v. Metaswitch Networks Ltd. et al.; the '658 patent was one of the asserted patents. January 2016 jury verdict of infringement with $8,168,400 in damages across the asserted patents.
• CAFC No. 2017‑1148 — Genband US LLC v. Metaswitch Networks Corp. (Fed. Cir. July 10, 2017): the Federal Circuit vacated and remanded the district court's denial of Genband's permanent injunction, finding the district court may have applied an unduly strict "drive demand"/causal‑nexus standard.
• 2:18‑cv‑00155 (E.D. Tex., filed April/May 2018) — Sonus Networks, Inc. v. Metaswitch Networks Ltd et al.; listed for this patent in the Stanford NPE Litigation Database. Per Google Patents' litigation links, this family also produced CAFC No. 2018‑1869.
• PTAB — US 6,885,658 itself was not the challenged patent in any IPR I located. Rather, its disclosure was used against others: it is Exhibit 1076 in IPR2024‑01282 (Cisco Systems, Inc., petitioner), and the '658 patent's teachings (cited as "Ress") were relied on by a petitioner in IPR2019‑01233 concerning U.S. Patent 7,773,588 B2, where the Board found Ress suggested various limitations.

7. 2026 CAFC docket check — result and uncertainty

I searched for CAFC 2026 dockets and PTAB/USPTO activity naming patent 6885658 and found nothing dated 2026. This is consistent with the patent's anticipated expiration on February 18, 2020 (Google Patents legal status: Expired – Lifetime), which leaves no live infringement exposure to appeal. The most recent activity I can substantiate is the 2017‑1148 and 2018‑1869 appeals and the 2024 Cisco IPR exhibit.

Explicit uncertainty: I could not query the CAFC PACER docket system or the USPTO PatentCenter/PTAB APIs directly through the tools available here; my check relied on web search results. It is possible but not evidenced that a 2026 filing, sealing, or docket‑only entry exists. Also note that search hits for "658" frequently refer to unrelated patents (e.g., U.S. 8,862,978, U.S. 8,856,638, and a different authentication‑related "'658 patent"), which I excluded; only references matching 6,885,658 / US 6,885,658 B1 were used.

I'll research the litigation history for US patent 6885658 using the sources indicated.

Let me gather more details on the separate Sonus v. Metaswitch case and the Federal Circuit appeals.

Litigation Involving U.S. Patent No. 6,885,658

Patent: U.S. 6,885,658 B1 — "Method and apparatus for interworking between internet protocol (IP) telephony protocols" (Nortel Networks; now Ribbon Communications Operating Company, Inc., f/k/a GenBand US LLC). Filed Feb. 18, 2000; issued Apr. 26, 2005; expired Feb. 18, 2020.

Based on the Google Patents litigation data for this patent plus independent court records, there are two district-court cases and two Federal Circuit appeals known to involve the '658 patent, all part of the Genband/Sonus/Ribbon v. Metaswitch dispute. Details below. (Note: the related case 2:14-cv-744, Metaswitch v. Genband, concerned the '640 patent, not the '658 patent, and is excluded.)

1. Genband US LLC v. Metaswitch Networks Ltd. and Metaswitch Networks Corp.

Sources: Google Patents litigation data; CourtListener opinion "Genband US LLC v. Metaswitch Networks Ltd." (E.D. Tex. findings of fact/conclusions of law, listing '658 Patent claims 1 and 11 as asserted and infringed); TelecomTV/Genband press release (Jan. 2016); Ribbon Communications 10-K (2019).

2. Sonus Networks, Inc. v. Metaswitch Networks Ltd. et al.

Sources: Google Patents litigation data (lists 2:18-cv-00155); Stanford NPE Litigation Database (lists this case as the sole asserted case for patent 6885658); Dockets.Justia and Unified Patents docket for 2:18-cv-00155 (motion to dismiss, stay pending appeal, joint notice of settlement, agreed dismissal with prejudice); Ribbon Communications 10-K (2019).

Federal Circuit Appeals (from the cases above)

• Genband US LLC v. Metaswitch Networks Corp., No. 2017-1148 (Fed. Cir.) — Appeal of the district court's denial of a permanent injunction. Decided July 10, 2017, 861 F.3d 1378: the Federal Circuit vacated and remanded, holding the district court may have applied an unduly strict "causal nexus / drive demand" standard for irreparable harm. (Panel: Taranto, author.)
• Metaswitch Networks Ltd. v. Genband US LLC, No. 2018-1869 (Fed. Cir.) — Metaswitch's appeal of the March 22, 2018 final judgment (notice of appeal filed Apr. 19, 2018; brief filed July 6, 2018; oral argument set for Mar. 8, 2019). This appeal was stayed/settled in connection with the settlement of the related 2:18-cv-00155 case.

Notes, Caveats, and Related Non-'658 Matters

• Inter partes reviews: The Genband–Metaswitch dispute also spawned PTAB proceedings (e.g., IPR2015-01456/01457 concerning Metaswitch's '640 patent), but I found no IPR directly challenging the '658 patent. If an IPR on the '658 patent exists, I could not confirm it from the available sources.
• Related but distinct actions (do not involve the '658 patent, noted to avoid confusion): the Texas state-court trade-secret case (Genband/Sonus v. Metaswitch, Dallas County, filed Mar. 28, 2017); Metaswitch's S.D.N.Y. antitrust suit against Ribbon (filed Nov. 9, 2018, No. 1:18-cv-10815); and Metaswitch v. Genband, 2:14-cv-744 (the '640 patent).
• Caveat on precision: The core facts above (parties, courts, case numbers, the '658 claims 1 and 11 infrngement finding, the $8,168,400 verdict, and the two appeal numbers) are well corroborated. Some specific dates for procedural milestones and the exact terms/timing of the settlement and dismissal in 2:18-cv-00155 are taken from secondary sources (dockets, 10-K) and should be verified against PACER before being relied on for any filing.
• Per the Google Patents record, the patent is Expired – Lifetime (anticipated expiration Feb. 18, 2020), and the listed current owner is Ribbon Communications Operating Company, Inc. (f/k/a GenBand US LLC).

Summary: The only known litigation asserting U.S. 6,885,658 is the Genband/Ribbon-versus-Metaswitch series — principally Genband US LLC v. Metaswitch Networks Ltd. et al., 2:14-cv-00033 (E.D. Tex.) (won by the patent owner at trial) and Sonus Networks, Inc. v. Metaswitch Networks Ltd. et al., 2:18-cv-00155 (E.D. Tex.) (settled/dismissed with prejudice), with Federal Circuit appeals 17-1148 and 18-1869.

I'll start by verifying the canonical list from the ODP block and searching for any PTAB proceedings on this patent.

Let me search more specifically for PTAB filings against the '658 patent and any related appeals.

Let me run a few more targeted searches to make sure I'm not missing any PTAB or reexam filings.

PTAB Proceedings — U.S. Patent No. 6,885,658

Prepared 2026-09-28. Canonical source: USPTO Open Data Portal structured "PTAB proceedings on file" block supplied with this assignment. Supplementary searching performed against public PTAB/CAFC materials, Docket Alarm, CourtListener, and district-court records.

Proceedings overview

There are zero AIA trial proceedings on file for U.S. Patent No. 6,885,658 — no IPR, no PGR, no CBM. The ODP structured block returns no AIA trials, and my independent searching surfaced no IPR/PGR/CBM docket naming the '658 patent (the IPRs in the Genband/Metaswitch dispute — e.g., IPR2015-01456 and IPR2015-01457 — were directed at Metaswitch's U.S. Patent No. 8,687,640, with Genband as petitioner, not at the '658 patent). Consequently there is no claim-level PTAB outcome to report: no claim of the '658 patent has been canceled, confirmed, or even addressed in a Final Written Decision, and no § 315(e)(2) estoppel has been created by any petitioner.

Defensive posture: the patent is neither PTAB-hardened nor PTAB-wounded — it is PTAB-virgin, but litigated-hardened. Claims 1 and 11 have already been through a jury (found infringed and not invalid, 2016-01-15), a Rule 50 JMOL motion (denied), a § 101 bench-trial challenge (rejected), and a Federal Circuit appeal. And critically, the patent expired 2020-02-18. A defendant today is not facing a live-injunction patent; it is facing, at most, a backward-looking damages claim for pre-expiration conduct within the § 286 six-year window, on claims that have survived every challenge actually brought.

Individual proceedings

None. There is no {PROCEEDING_NUMBER} — {Petitioner} v. {Patent Owner} entry to populate, and I will not manufacture one.

For completeness, the following related-but-different matters are sometimes confused with PTAB activity on the '658 patent, and are not AIA trials:

Sources: CAFC 17-1148 opinion; CourtListener 861 F.3d 1378; Docket Alarm IPR2015-01457 FWD (the '640 patent, not the '658); Stanford NPE Litigation Database — 6885658.

Strategic summary

Claim status: everything UNTESTED at the PTAB, and the two independent claims that matter are district-court-SUSTAINED. The '658 patent has two independent claims, claim 1 (call server apparatus) and claim 11 (interworking method), and both were asserted at trial and adjudged infringed and not invalid. No dependent claim was canceled or confirmed in any PTAB forum because no PTAB forum ever examined this patent. If you are being asserted against on claim 1 or claim 11, you cannot point to a certificate canceling those claims — that defense is simply not available. Conversely, the patent is not "hardened": the jury verdict does not bind the PTAB, and the jury's validity finding has no preclusive effect on an Article III invalidity challenge litigated with new art.

Estoppel landscape: empty. § 315(e)(2) estoppel attaches only to petitioners, RPIs, and privies in a proceeding that was instituted and reached an FWD. Since no IPR/PGR/CBM was ever instituted on the '658 patent, there is no IPR estoppel bar against any defendant, including parties connected to Metaswitch. That cuts both ways: the full universe of § 102/§ 103 prior art — including art that Metaswitch raised in the district court, and art it did not — remains available to a new defendant in district court and in a fresh IPR petition. The one hard constraint is statutory, not estoppel-based: § 315(b)'s one-year bar runs from service of a complaint alleging infringement on your client. If your client has already been served, the IPR clock is running and may already have run.

Pattern signals. There is no serial-petitioner pattern on this patent and no defensive-aggregator (Unified Patents, RPX, etc.) IPR in the chain. The most striking signal is the negative one: this patent carried an eight-figure verdict against a well-resourced competitor and still attracted no IPR petition. Plausible explanations include § 315(b) timing, the fact that the 2014–2016 litigation window predates the maturation of discretionary-denial practice, and the reality that the '658 patent is a narrow interworking-mechanism claim that is hard to invalidate cleanly but also hard to assert broadly. A sophisticated defendant should also note the expiration date: the patent expired 2020-02-18 (Google Patents legal-status entry "Anticipated expiration"), so no ongoing royalty or injunction exposure exists.

Recommended next steps

1. Do not expect a PTAB silver bullet. There is no FWD to cite and no canceled claim to hang a defense on. Any defense must be built in district court or in a new IPR petition you file yourself.
2. If your client has been served with a complaint asserting the '658 patent, calendar the § 315(b) one-year date immediately — that is the single most consequential deadline. If the window is open, a fresh IPR petition on claims 1 and 11 is procedurally available and faces no § 325(d) problem (nothing was ever presented to the Office on this patent) and no § 315(e) estoppel.
3. Press the expiration/solvency angle. With the patent expired as of 2020-02-18, the only exposure is damages for pre-expiration infringement subject to the 35 U.S.C. § 286 six-year lookback — and the accompanying laches/notice equities that Metaswitch litigated (and lost) in Genband. Confirm the applicability of the current § 286 framework to the pre-complaint period.
4. Read the claim-construction record. The E.D. Tex. construction of "a superset of functions provided by the first and second IP telephony protocols," "protocol," "communicating first parameter to the second protocol agent without alteration," and "adapted to determine that a first parameter … does not map to the second IP telephony protocol" drives both infringement and any invalidity theory. The Genband claim-construction order is public at Justia/Casetext.
5. Cite the JMOL denial if you need the operative validity posture. The court's order (E.D. Tex. 2:14-cv-00033, "GENBAND US LLC v. Metaswitch," available at business.cch.com) addresses the '658 patent's claim 1 "without alteration" limitation and claim 11 "media capabilities description" limitation directly and is the most useful single document for understanding what the patent owner must prove.

Confidence note: I am highly confident there is no AIA trial proceeding on the '658 patent and that the IPR2015-01456/01457 proceedings belong to the '640 patent with Genband as petitioner. I have not been able to verify the subject matter of CAFC Appeal No. 2018-1869, and I have not verified whether any ex parte reexamination was ever requested on this patent — the canonical ODP block covers AIA trials, not reexaminations, so a reexam file, if any, would not appear there. If that distinction matters to your analysis, it should be checked directly in Patent Center.

Sources for specific opinions cited: CAFC 17-1148 (Genband v. Metaswitch), 861 F.3d 1378. Patent record: US6885658B1 on Google Patents.

I'll research this patent's ownership chain, litigation history, and asserter status, then reconcile with the assignment events already present in the patent record you provided.

I have the litigation and chain-of-title context. Let me pin down the exact reel/frame listing and the later litigation/assignee details.

Ownership reconstruction — US 6,885,658 B1

Data provenance note (read first): I could not pull live records from USPTO Assignment Center in this session. The reel/frame citations below come from (a) the patent's own legal-events feed (the authoritative text supplied), and (b) a Rule 3.73B chain-of-title statement that GENBAND US LLC filed with the USPTO in 2010 (retrieved via the Internet Archive copy of application 09/735,427's file). Where the legal-events feed gives a date but no reel/frame, I say so rather than inventing one. Correspondent-of-record data was not obtainable from the sources I could reach — see signal 3.

Inventors

All four are listed on the face of the patent (75) as inventors. Applicant was Nortel Networks Corporation; the application was filed 2000-02-18, claiming benefit of provisional 60/137,867 filed 1999-06-07.

Unusual pattern — but not the "mass departure" kind. The original assignment executed at filing (reel 010578/0564) named only Ress, Li and Ingram. Utas was inadvertently omitted and had to be picked up by a second assignment recorded as reel 010839/0783 (dated 2000-05-15 per the legal-events feed), with the cover-sheet error explicitly recited in the record. This is a clean-up defect, not evidence of a fire-sale precursor. There is no evidence in the record of any inventor departing Nortel; I found no data supporting that inference and will not assert it.

Original assignee

Nortel Networks Limited (originally Nortel Networks Corporation at filing; renamed 2000-08-30 — reel/FRAME not stated in feed).

• Primary line of business: Tier-1 telecom network equipment — optical systems, carrier switching, and the Carrier VoIP and Application Solutions (CVAS) line (softswitches and media gateways). Court findings state Nortel "held a leading position in optical systems and the Internet and communications field" in 2000.
• Did they ship a product embodying the claims? The '658 patent is an internal call-server / media-gateway-controller architecture patent (protocol interworking between MGCP and H.323 via an "agent interworking protocol"). It maps to the CVAS softswitch/media-gateway product line, which was a real shipping business — not a paper asset.
• Current status: DISSOLVED via bankruptcy. Nortel filed Chapter 11 / CCAA in January 2009 (Bankr. D. Del. case 09-10138), sold its business units, and by end-2011 was split into regional wind-down entities. At the time of the 2015 discovery dispute Nortel had "no remaining employees" and one facility.

Assignment timeline

Dates are as given in the legal-events feed (which does not separately label execution vs. recording date). Reel/frame shown only where I have affirmative evidence.

• 2000-02-18 / recorded 2000-02-18 (order-of-record) — Reel 010578/0564

  • Conveyance: Assignment
  • Assignor: David P. Ress, Xuewen Li, Denise J. Ingram
  • Assignee: Nortel Networks Corporation
  • Correspondent: not available (see signal 3)
  • Context: Inventor-to-employer assignment of the original application; omits Utas.

• 2000-05-15 / recorded ~2000 — Reel 010839/0783

  • Conveyance: Assignment (corrective) — "CORRECTION OF ASSIGNOR GREGORY ROBERT UTAS INADVERTANTLY NOT FILED WITH RECORDATION COVER SHEET ON REEL 010578 FRAME 0564"
  • Assignor: Gregory Robert Utas, Denise J. Ingram, Xuewen Li, David P. Ress
  • Assignee: Nortel Networks Corporation
  • Correspondent: not available
  • Context: Internal cleanup — perfects the chain so all four inventors are of record.

• 2000-08-30 — Reel/frame not stated in feed

  • Conveyance: Change of Name
  • Assignor: Nortel Networks Corporation
  • Assignee: Nortel Networks Limited
  • Correspondent: not available
  • Context: Internal reorg / corporate name change only — no change in beneficial ownership. This is why the 2005-issued patent names Nortel Networks Limited.

• 2010-06-02 — Reel 024468/0507

  • Conveyance: Change of Name
  • Assignor: GENBAND Inc.
  • Assignee: GENBAND US LLC
  • Correspondent: not available
  • Context: Name/entity conversion of the acquirer, not an asset transfer.

• 2010-06-18 — Reel/frame not stated in feed

  • Conveyance: Security Agreement (Patent Security Agreement)
  • Assignor: GENBAND US LLC
  • Assignee: One Equity Partners III, L.P., as Collateral Agent
  • Correspondent: not available
  • Context: Securitization — the private-equity sponsor taking a lien on the acquired portfolio, not a transfer of title.

• 2010-08-25 — Reel 024879/0519 (later corrected 2012-03-30)

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: Nortel Networks Corporation (corrected to add Nortel Networks Limited)
  • Assignee: GENBAND US LLC
  • Correspondent: not available
  • Context: Bankruptcy fire-sale conveyance — this is the actual transfer of the '658 patent out of the Nortel Chapter 11 estate as part of the CVAS business unit sale (Stalking Horse Agreement, Dec 2009; acquisition closed 2010-05-28).

• 2010-11-09 — Reel/frame not stated in feed

  • Conveyance: Security Agreement
  • Assignor: GENBAND US LLC
  • Assignee: Comerica Bank
  • Correspondent: not available
  • Context: Securitization — working-capital lender lien.

• 2012-03-30 — Reel/frame not stated (corrects 024879/0519)

  • Conveyance: Corrective Assignment — "CORRECTIVE ASSIGNMENT TO CORRECT THE CONVEYING PARTY DATA, PREVIOUSLY RECORDED ON REEL 024879 FRAME 0519"
  • Assignor: Nortel Networks Corporation, Nortel Networks Limited
  • Assignee: GENBAND US LLC
  • Correspondent: not available
  • Context: Clean-up of the 2010 bankruptcy conveyance — adds the correct Nortel conveying entity. This is the conveyance Genband relied on for standing in the 2014 suit.

• 2014-01-10 — Reel/frame not stated in feed

  • Conveyance: Release by Secured Party
  • Assignor: One Equity Partners III, L.P., as Collateral Agent
  • Assignee: GENBAND US LLC
  • Correspondent: not available
  • Context: Lien release — clears the One Equity security interest.

• 2016-07-06 — Reel 039269/0234 (per the 2017-01-03 corrective entry)

  • Conveyance: Patent Security Agreement
  • Assignor: GENBAND US LLC
  • Assignee: Silicon Valley Bank, as Administrative Agent
  • Correspondent: not available
  • Context: Securitization — refinancing lien.

• 2016-07-07 — Reel/frame not stated in feed

  • Conveyance: Release and Reassignment of Patents
  • Assignor: Comerica Bank, as Agent
  • Assignee: GENBAND US LLC
  • Correspondent: not available
  • Context: Lien release.

• 2017-01-03 — corrects Reel 039269/0234

  • Conveyance: Corrective Assignment — corrects patent number 6,381,239 previously recorded at 039269/0234
  • Assignor: GENBAND US LLC
  • Assignee: Silicon Valley Bank, as Administrative Agent
  • Correspondent: not available
  • Context: Administrative correction only.

• 2017-12-29 — Reel/frame not stated in feed

  • Conveyance: Termination and Release of Patent Security Agreement
  • Assignor: Silicon Valley Bank, as Administrative Agent
  • Assignee: GENBAND US LLC
  • Correspondent: not available
  • Context: Lien release tied to the Sonus/GENBAND combination into Ribbon.

• 2018-01-02 — Reel/frame not stated in feed

  • Conveyance: Security Interest
  • Assignor: GENBAND US LLC, SONUS NETWORKS, INC.
  • Assignee: Silicon Valley Bank, as Administrative Agent
  • Correspondent: not available
  • Context: Securitization — single credit facility now covering both merged entity families (this entry is the record-level proof that Genband and Sonus are one consolidated obligor group).

• 2020-03-03 — Reel/frame not stated in feed

  • Conveyance: Security Interest
  • Assignor: RIBBON COMMUNICATIONS OPERATING COMPANY, INC.
  • Assignee: Citizens Bank, N.A., as Administrative Agent
  • Correspondent: not available
  • Context: Securitization — assignee of record has now been renamed to the Ribbon entity.

• 2021-12-06 — Reel 044978/0801 (terminated)

  • Conveyance: Termination and Release of Patent Security Agreement
  • Assignor: Silicon Valley Bank, as Administrative Agent
  • Assignee: Ribbon Communications Operating Company, Inc. (f/k/a GENBAND US LLC and Sonus Networks, Inc.)
  • Correspondent: not available
  • Context: Lien release.

• 2024-06-24 — Reel/frame not stated in feed

  • Conveyance: Release by Secured Party
  • Assignor: Citizens Bank, N.A.
  • Assignee: Ribbon Communications Operating Company, Inc.
  • Correspondent: not available
  • Context: Final lien release. No assignment of title has ever left the Nortel→Genband→Ribbon corporate line.

Current assignee of record: Ribbon Communications Operating Company, Inc. (f/k/a GENBAND US LLC and Sonus Networks, Inc.).

Timeline diagram

timeline
    title Ownership of US 6885658
    2000 : Inventors assign to Nortel Networks Corp
         : Corrective assignment adds G R Utas
         : Nortel Corp renamed Nortel Networks Ltd
    2009 : Nortel files Chapter 11
    2010 : Genband buys Nortel CVAS assets
         : Assignment recorded to Genband US LLC
         : Genband Inc renamed Genband US LLC
         : One Equity takes security interest
         : Comerica takes security interest
    2012 : Corrective assignment recorded
    2014 : Genband sues Metaswitch
    2016 : Silicon Valley Bank takes security interest
         : Comerica release recorded
    2017 : Genband and Sonus combine as Ribbon
         : SVB security interest terminated
    2018 : Second E D Texas case filed
    2020 : Patent reaches anticipated expiration
    2024 : Citizens Bank release recorded

NPE / troll-pattern signals

1. Shell-entity transfer — NOT PRESENT.
Every title-holding assignee in the chain is an operating entity: Nortel Networks Corporation/Limited (reel 010578/0564; 010839/0783; 024879/0519), then GENBAND US LLC (reel 024468/0507; 024879/0519), then Ribbon Communications Operating Company, Inc. The non-operating names in the record are secured lenders, not owners — One Equity Partners III, Comerica Bank, Silicon Valley Bank, Citizens Bank (2010-06-18; 2010-11-09; 2016-07-06; 2018-01-02; 2020-03-03). No "IP/Holdings/Licensing/Ventures" suffix appears, and no single-purpose Delaware or Texas LLC was created to hold the patent.

2. Known asserter in the chain — NOT PRESENT.
Checked against the standard NPE list (Acacia, Marathon, IV, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Spangenberg entities): no match. The litigant here, Genband US LLC, is a product company — the E.D. Tex. docket itself is classified "Patent Owner: Operating Company (W)" (case 2:14-cv-00033). Its owned products (G-series media gateways, Call Feature Server, softswitches) were the subject of practicing-products expert reports in the case, i.e. Genband was proving its own gear embodies the claims.

3. Repeat correspondent across the chain — UNCLEAR (data not available; not a finding).
The legal-events feed supplied for this patent omits the correspondent/recording-attorney field entirely, and the supplementary Rule 3.73B chain-of-title statement likewise lists only assignor/assignee/reel-frame. I could not retrieve recording cover sheets. I will not name a correspondent I have not seen. To close this signal, pull the cover sheets for reels 010578/0564, 010839/0783, 024468/0507, 024879/0519, 039269/0234 and 044978/0801 from Assignment Center.

4. Cascading transfers — NOT PRESENT.
There are 17 recorded events, but only four involve a change of ownership: inventor→Nortel (2000), Nortel Corporation→Limited name change (2000-08-30), GENBAND Inc.→GENBAND US LLC name change (2010-06-02), and Nortel→GENBAND US LLC (2010-08-25, reel 024879/0519). The rest are security interests, releases and corrections. Critically, the 2010 ownership events cluster around a single bankruptcy sale, not a chain of unrelated LLCs; the consecutive 2010-06-02 / 2010-06-18 / 2010-08-25 / 2010-11-09 entries are one acquisition plus its financing, not a layering scheme.

5. Pre-litigation transfer — NOT PRESENT.
Genband acquired the '658 patent in the CVAS closing of 2010-05-28; the first infringement complaint was filed 2014-01-21 in E.D. Tex. (2:14-cv-00033). That gap is ≈3.7 years, far outside the 6-month window. The E.D. Tex. court expressly found Genband "first obtained rights to enforce" the patent in May 2010, "approximately four years before the filing of this lawsuit." The 2012-03-30 corrective assignment (fixing the 024879/0519 conveying party) is also ~22 months pre-suit and plainly remedial.

6. Bankruptcy fire-sale — PRESENT (this is the defining event).
Nortel filed Chapter 11 in January 2009 (Bankr. D. Del. 09-10138; parallel CCAA/UK filings). In December 2009 Genband executed a "Stalking Horse Agreement" to buy substantially all assets of Nortel's CVAS business — expressly including the '658 patent (trial finding FF49, citing DX-240, DX-314) — closing 2010-05-28. The estate was then wound down with all remaining assets sold (Avaya, Ciena, Ericsson, Genband, Hitachi, Kapsch, Radware, Rockstar). The recorded conveyance at reel 024879/0519 (corrected 2012-03-30) is that bankruptcy sale.

7. Privateering — NOT PRESENT.
Privateering requires an operating company to hand a patent to a separate NPE that asserts on its behalf. Here the operating company itself sued a direct competitor (Metaswitch) for its own product-line patents — Genband sold SBCs/softswitches/media gateways in the same market. There is no intermediate asserting NPE. (Metaswitch's Nov. 2018 SDNY antitrust complaint attacking Genband's own prior suit as anticompetitive is a two-way competitor dispute, not evidence of privateering.)

8. Defensive aggregator — NOT PRESENT.
The chain terminates at Ribbon Communications Operating Company, Inc., an operating company — not at RPX, AST, LOT, Unified Patents or OIN. Note however that the patent reached its anticipated expiration on 2020-02-18, so from a defensive standpoint the asset is inert regardless of the 2018 case (2:18-cv-00155) and Fed. Cir. appeals 17-1148 / 18-1869 that remain in the litigation record.

Verdict

Operating-company assertion.

The chain never leaves the corporate line Nortel → GENBAND → Ribbon; the only transfers of title are the 2000 inventor assignments (reels 010578/0564 and 010839/0783), the 2000 name change, and the 2010-08-25 bankruptcy conveyance recorded at reel 024879/0519 (corrected 2012-03-30) out of Nortel's Chapter 11 case 09-10138. Every other entry — One Equity (2010-06-18), Comerica (2010-11-09), Silicon Valley Bank (2016-07-06; 039269/0234; 2018-01-02), Citizens Bank (2020-03-03) — is a security interest or a release by a secured lender, not an NPE transfer. The single "fire-sale" flag (signal 6) is real but benign: the patent was bought as part of an operating business unit and asserted ~4 years later by the buyer against a competitor whose products Genband itself competes with, which the E.D. Tex. docket classifies as an operating-company patent owner.

Verify: https://assignmentcenter.uspto.gov/ (search patent 6,885,658; also assignee GENBAND US LLC and RIBBON COMMUNICATIONS OPERATING COMPANY, INC.). Cover sheets for the reel/frame entries above are the only way to populate the missing correspondent column.

I'll research US patent 6885658 and its cited prior art references.

I have the cited references list. Let me get the exact claims of US6885658 and details on each cited reference.

Prior Art Analysis — US Patent No. 6,885,658 B1

1. Patent Identification (literal reading)

⚠️ Disambiguation warning (I am following the strict rule of literal interpretation): Several search results blend this patent with a different patent, U.S. 6,683,858 ("Ex Parte Reexamination of U.S. Patent No. 6,683,858," referencing Pearce, Oran, Hoshi, Salama). 6,683,858 ≠ 6,885,658. They are different numbers (digit transposition). The reexamination/grounds-of-rejection material about Pearce/Oran/Hoshi/Salama belongs to the '858 patent, not to this '658 patent, and I have not merged it into the analysis below.

2. Source of the Reference List

The cited references below are drawn from the "References Cited" block printed on the face of US 6,885,658 (USPTO front page), confirmed by the PTAB exhibit reproducing the same front page: https://www.docketalarm.com/cases/PTAB/IPR2024-01282/Cisco_Systems_Inc/08-13-2024-Petitioner/Exhibit-1076-Ex1076___US6885658_Ress/

Important limitation: The patent front page and the PTAB exhibit list the references without the examiner's per-claim annotations. Unlike a PCT/EPO search report (which carries an "X/Y/A" category and a "Relevant to claim No." column), the US front page here does not state which claims each reference was applied against. Therefore, my §102 anticipatory mapping below is analysis, not a quoted examiner finding, and I flag confidence levels accordingly.

3. U.S. Patent Documents Cited

(a) US 5,915,008 A — Dulman

• Full citation: U.S. Patent 5,915,008, "System and method for changing advanced intelligent network services from customer premises equipment," Scott Dulman.
• Dates: Filed Oct. 4, 1995; issued Jun. 22, 1999. (Google Patents: https://patents.google.com/patent/US5915008)
• Brief description: Concerned with Advanced Intelligent Networks (AIN) — letting CPE/subscribers modify AIN service profile data (ISCP/SCP databases, TCAP queries, DTMF input). It is not about IP telephony protocol interworking.
• §102 analysis: Qualifies as prior art under §102(a)/(b) (issued before the June 7, 1999 priority date). Subject-matter overlap with the asserted claims is weak. It does not disclose a "call server" with first/second protocol agents and an interworking agent communicating via a superset third protocol. Best characterized as general telecom background; I would not assert it anticipates Claims 1–22. Low confidence that it was applied against any specific claim.

(b) US 6,201,805 B1 — Strathmeyer

• Full citation: U.S. Patent 6,201,805 B1, Carl R. Strathmeyer (class 370/356).
• Dates: Issued Mar. 2001. I was unable to retrieve a verified filing date for this reference within the available tools — treat the filing date as unconfirmed.
• Brief description: Relates to internet-telephony / gateway architecture (residential internet telephony sector), per its classification and the co-cited Huitema IEEE Network paper.
• §102 analysis: If its filing date precedes June 7, 1999, it could be prior art under §102(e). It is potentially relevant to the "call server" / gateway-architecture concepts of Claim 1 and the interworking method of Claim 11, but I lack the verified dates/text to assert anticipation. Low-to-moderate confidence.

(c) US 6,275,574 B1 — Oran

• Full citation: U.S. Patent 6,275,574 B1, David R. Oran (class 379/201.01).
• Dates: Issued Aug. 2001. Filing date not verified within available tools.
• Brief citation/description: Oran is a prolific IETF author; the '574 patent is in the call-control/telephony-services space.
• §102 analysis: Potentially available as §102(e) prior art only if its filing predates the priority date; unverified. Possible relevance to call-control-agent concepts (Claim 1 / Claim 11), but I cannot responsibly assert anticipation. Low confidence. Note: an "Oran" reference also appears in the separate '858 reexam art — do not conflate.

(d) US 6,339,594 B1 — Civanlar et al.

• Full citation: U.S. Patent 6,339,594 B1, M. Reha Civanlar et al. (class 370/352 — combined circuit/packet switching).
• Dates: Issued Jan. 2002. Filing date not verified within available tools.
• Brief description: Internet-telephony gateway / gateway-control subject matter (AT&T-origin work in IP telephony).
• §102 analysis: If its filing predates June 7, 1999, it is potentially §102(e) art bearing on media stream / gateway-control aspects of Claims 1, 11 (media capabilities / media stream management). Unverified filing date; moderate-low confidence.

(e) US 6,490,275 B1 — Sengodan

• Full citation: U.S. Patent 6,490,275 B1, Senthil Sengodan.
• Dates: Issued Dec. 2002. Filing date not verified within available tools.
• Brief description: IP telephony / VoIP signaling-area art (Nokia-origin).
• §102 analysis: Potentially §102(e) art if filed before the priority date. Could bear on protocol-mapping / call-establishment claims (Claims 11, 12, 15), but unverified and low confidence.

(f) US 6,584,093 B1 — Salama et al.

• Full citation: U.S. Patent 6,584,093 B1, H. F. Salama et al. (class 370/351).
• Dates: Issued Jun. 24, 2003; per related litigation briefing, Salama's application was filed January 1999 (before both the June 7, 1999 priority date and Feb. 18, 2000 filing).
• Brief description: Routing of internet-telephony calls across PSTN/IP networks; leverages H.323 and SIP signaling and describes SIP/H.323 gateways converting between protocols (per the court briefing at https://storage.courtlistener.com/recap/gov.uscourts.txwd.[1141573](/patent/1141573)/gov.uscourts.txwd.1141573.45.6.pdf).
• §102 analysis: This is the most substantively relevant U.S. patent reference in the list because its subject matter (protocol conversion between SIP and H.323 in a gateway) overlaps the core of the '658 disclosure. With a Jan. 1999 filing date it is available as §102(e) prior art. It is potentially relevant to Claim 1 (interworking between two protocol agents via a protocol-independent mechanism) and Claim 11 (convert a first-protocol message into a second-protocol message and then a third-protocol message), and to the SIP/H.323 conversions of Claims 12–15. Moderate confidence — but note Salama discloses a gateway conversion, whereas the '658 claims recite a call server with separate protocol agents and an interworking agent; a §102 showing would still need to map those structural elements.

No foreign patent documents are listed on the '658 front page (unlike, e.g., the AT&T '009 patent's front page, which lists EP 1143683 and WO 00/33550).

4. Non-Patent Literature Cited ("Other Publications")

(g) Huitema, C. et al., "An Architecture for Residential Internet Telephony Service"

• Citation: IEEE Network, May/Jun. 1999, pp. 50–56, XP-000870631.
• Date: May/June 1999 (before the June 7, 1999 priority date).
• Description: Residential VoIP architecture; introduces the MGC/MG/media-control model.
• §102 analysis: §102(a)/(b) art. Potentially relevant to Claim 1 (call server / agent architecture) and the media-control aspects of Claim 11. But it is a printed publication describing an architecture — a §102 anticipation showing requires the reference to disclose every claimed element; an architecture paper likely does not expressly disclose the "third protocol that is a superset" limitation. More useful for §103. Moderate confidence, mixed §102/§103.

(h) Hamdi, M. et al., "Voice Service Interworking for PSTN and IP Networks"

• Citation: IEEE Communications Magazine, May 1999, pp. 104–111, XP-000830888.
• Date: May 1999 (before the priority date).
• Description: Interworking of voice services between PSTN and IP networks — i.e., directly on-point to the "interworking" problem.
• §102 analysis: The most on-point NPL reference for the interworking concept. Potentially relevant to Claim 1 and Claims 11–15 (protocol interworking between different telephony environments). Moderate confidence.

(i) Anquetil, L-P. et al., "Media Gateway Control Protocol and Voice Over IP Gateways"

• Citation: Electrical Communication (Alcatel), Brussels, Apr. 1, 1999, pp. 151–157.
• Date: Apr. 1, 1999 (before the priority date).
• Description: MGCP and VoIP gateway operation.
• §102 analysis: §102(b) art. Potentially relevant to the MGCP-side claims specifically — Claims 12 (MGCP↔H.323), 15, 16 (MGCP mapping / fast start). Moderate confidence.

(j) Handley et al., "SIP: Session Initiation Protocol," RFC 2543

• Citation: IETF Network Working Group RFC 2543, pp. 1–111 (Mar. 1999).
• Date: March 1999 (before the priority date).
• Description: The SIP standard, including SDP-in-INVITE capability negotiation.
• §102 analysis: §102(b) art. Potentially relevant to the SIP-specific claims (Claim 13: SIP→H.323) and to the "media capabilities description" limitation of Claim 11. As a protocol-spec standard, standing alone it does not disclose a call server with two protocol agents and an interworking agent. Moderate confidence for dependent claims only.

(k) Arango et al., "Media Gateway Control Protocol (MGCP)"

• Citation: IETF Internet Draft <draft-huitema-megaco-mgcp-v0r1-05.txt>, pp. 1–119 (Feb. 21, 1999). (Note: the front page renders this draft name slightly garbled in the OCR; the referenced MGCP draft is the Huitema/Arango MEGACO draft.)
• Date: Feb. 21, 1999 (before the priority date).
• Description: The MGCP specification (CRCX/MDCX/NOTIFY semantics).
• §102 analysis: §102(b) art. Supports the MGCP-signaling aspects of Claims 12, 15, 16 and the MGCP messages recited in the specification. Moderate confidence for MGCP-dependent claims.

(l) Huitema et al., "Media Gateway Control Protocol (MGCP) Call Flows"

• Citation: IETF Internet Draft <draft-huitema-megaco-flows-01>, pp. 1–125 (Jan. 20, 1999).
• Date: Jan. 20, 1999 (before the priority date).
• Description: MGCP call-flow examples.
• §102 analysis: §102(b) art; supports the MGCP call-flow-dependent subject matter. Low-to-moderate confidence for specific claims.

(m) ITU Recommendation H.323

• Citation: International Telecommunication Union, ITU-T Recommendation H.323, Packet-Based Multimedia Communications Systems (Oct. 1997 version cited on the front page; the specification's body also cites the Feb. 1998 version).
• Date: 1997/1998 (before the priority date).
• Description: H.323 packet-based multimedia conferencing; gateways, gatekeepers, fast start, H.245.
• §102 analysis: §102(b) art. Potentially relevant to the H.323-side claims (Claims 5, 12–16; and the fast-start mapping of Claim 16). Again, standing alone it does not disclose the call-server interworking architecture. Moderate confidence for dependent claims.

(n) International Search Report (PCT/IB00/00854)

• Citation: International Search Report for corresponding PCT application No. PCT/IB00/00854, mailed Mar. 6, 2001.
• Note: This is a procedural document (the search report for the '658 family PCT), not substantive prior art; it appears in the "Other Publications" block because it was filed in the case.

5. Summary Table — §102 Relevance (my analysis; not an examiner finding)

6. Required Caveats (so you can rely on this)

1. Per-claim annotations are not available from the sources consulted. The US front page and PTAB exhibit list the references but do not classify them (X/Y/A) or map them to claim numbers. Any §102 anticipation assertion above is my subject-matter analysis, not a quoted USPTO determination.
2. Filing dates for several U.S. references are unverified (Strathmeyer '805, Oran '574, Civanlar '594, Sengodan '275) because my tool access was exhausted before I could confirm them. For post-1999-issued patents, availability as prior art under §102(e) depends entirely on their filing dates relative to June 7, 1999; I could not confirm those dates and will not fabricate them.
3. Do not conflate US 6,885,658 with US 6,683,858. The reexamination art (Pearce, Oran, Hoshi, Salama) surfaced in search results belongs to the other patent number.
4. If you need an authoritative, claim-mapped anticipation chart, the correct next step is to pull (a) the USPTO file wrapper / Image File Wrapper for the '658 patent to see which references were applied against which claims during prosecution, and (b) the IPR2024-01282 petition (Cisco Systems) papers, which contain the modern claim-mapped invalidity grounds. I can pursue those if you want a fully sourced 102/103 chart.

Key sources: Google Patents US6885658 (https://patents.google.com/patent/US6885658); PTAB Ex.1076 front page (https://www.docketalarm.com/cases/PTAB/IPR2024-01282/Cisco_Systems_Inc/08-13-2024-Petitioner/Exhibit-1076-Ex1076___US6885658_Ress/); Justia claims (https://patents.justia.com/patent/6885658); Dulman US5915008 (https://patents.google.com/patent/US5915008); Salama briefing (https://storage.courtlistener.com/recap/gov.uscourts.txwd.1141573/gov.uscourts.txwd.1141573.45.6.pdf).

I'll research the prior art landscape for this patent, since the "Prior Art" section wasn't included in the material provided to me. Let me gather what's available.

Important: I found a potential contradiction with the previously-generated PTAB section (which asserted zero AIA proceedings on the '658 patent). Let me investigate, and also pull the actual claims and the cited prior-art references.

Let me pin down the claims, the Cisco IPR exhibit, and whether any reexamination touches the '658 patent.

Obviousness Analysis — U.S. Patent No. 6,885,658 (Ress et al.), 35 U.S.C. § 103

Prepared: 2026-04-26 · Patent: US 6,885,658 B1 · Appl. No. 09/506,945 · Filed 2000-02-18 · Provisional 60/137,867 (1999-06-07) · Issued 2005-04-26 · Assignee of record Ribbon Communications Operating Company, Inc. (f/k/a GenBand US LLC) · Expired 2020-02-18.

⚠️ Threshold disclosure about my inputs. My assignment says to "use the results from the Prior Art section of this page." No such section was included in the material supplied to me — the fetched Google Patents text I received was truncated before the "References Cited" block and before the claims. I therefore reconstructed the cited-art list directly from the patent's own front page (the USPTO PDF at patentimages.storage.googleapis.com) and the WO/EP family record. If a curated prior-art list was intended, re-run this analysis against that list; my reconstruction is faithful to the patent's face but may not be identical to the list you meant.

1. Legal framework and critical date

Pre-AIA § 103 governs (application filed 2000-02-18, never subject to AIA first-inventor-to-file). The earliest effective date asserted on the face is 1999-06-07 (provisional 60/137,867); Google Patents carries "Prior art date 1999-06-07." The application itself was filed 2000-02-18.

Two consequences matter, and both cut against a challenger:

• Art published before 1999-06-07 is available as § 102(a)/(b)/§ 102(e) art.
• Art published between 1999-06-07 and 2000-02-18 is available only as § 102(a)/102(e) art, and only if the claims do not get provisional benefit. Several references in the family search report — Dalgiç, "Comparison of H.323 and SIP for IP Telephony Signaling," SPIE, Sept. 1999; ITU-T H.323, Sept. 1999 edition; Korpi et al., "Supplementary Services in the H.323 IP Telephony Network," IEEE Commun. Mag., July 1999 (WO2001078418A1 record) — post-date the 1999-06-07 priority date and cannot be § 103 art against these claims unless the priority claim fails. A petitioner who reflexively uses the family search report will build on sand. Likewise H.248/MEGACO is not prior art: the specification itself describes H.248 as the contemporaneous MEGACO/ITU effort, and H.248 v1 post-dates the priority date. It is not a § 103 reference.

POSITA: a person with a B.S. in EE/CS (or equivalent) and ~2–3 years of experience in packet-based telephony and signaling-protocol design, familiar as of June 1999 with MGCP, H.323 (H.225/H.245), SIP/RFC 2543, SDP, and ISUP/Q.931.

2. The claims at issue

Claim 1 (verbatim from the E.D. Tex. claim-construction order, cases.justia.com 2:14-cv-00033 Dkt. 135):

1. A call server comprising:
   (a) a fi[r]st protocol agent for communicating with a first internet protocol (IP) telephony device according to a first IP telephony protocol;
   (b) a second protocol agent for communicating with a second IP telephony device according to a second IP telephony protocol; and
   (c) an interworking agent for providing functions usable by the first and second protocol agents to communicate with each other according to a third protocol, the functions provided by the third protocol being a superset of functions provided by the first and second IP telephony protocols, said interworking agent further adapted to determine that a first parameter associated with the first IP telephony protocol does not map to the second IP telephony protocol and communicating first parameter to the second protocol agent without alteration.

Claim 11 is the method counterpart (34 total claims; "20 Drawing Sheets"). I could not retrieve claim 11 verbatim in this session. Publicly available records (same construction order; the E.D. Tex. JMOL order) indicate it is the method analog of claim 1 and includes a limitation directed to a "media capabilities description." The mapping below is stated at that level and must be confirmed against the issued claim text before filing anything.

Construction is essentially all "plain meaning": "protocol" = a set of rules, procedures…; "interworking agent" is not means-plus-function (plain meaning); "communicating first parameter to the second protocol agent without alteration" = plain meaning; "adapted to determine that a first parameter… does not map to the second IP telephony protocol" = construed as "…does not [map to / have a match in] the second IP telephony protocol" (plain meaning). A § 103 case therefore does not get help from a narrow construction — but it also isn't defeated by one.

3. The prior-art universe

3(a) References cited on the face of the '658 patent

Front-page list confirmed at the USPTO PDF: US6885658.pdf. EP 0 966 145 A2 (Nortel, "Gateway for IP telephony") also appears in the family record.

Critical point: the '658 specification itself incorporates MGCP v0.1 (Feb. 21, 1999), H.323 (Feb. 1998), and RFC 2543 (Mar. 1999) by reference. Those incorporations are effectively the applicant conceding the content of the three protocols that supply almost every element of claim 1.

3(b) The one reference whose mapping I can document in detail: Salama (US 6,584,093)

Salama is quoted extensively in a public reexamination/invalidity record I located (storage.courtlistener.com/recap/gov.uscourts.txwd.1141573/…45.6.pdf). Per that document, Salama discloses:

• routing a voice call "over multiple hops, with some of these hops being in the data network while others are in the voice network" (Salama 1:18–23);
• a "mechanism for selecting the best path towards the destination address… a PSTN phone, an IP phone, or any other voice terminal" (9:1–4);
• that H.323 is "a standard architecture for multimedia conferencing… designed by the ITU-T" (2:9–13) and that SIP is a known "signaling protocol for establishing connections between endpoints" (5:45–48);
• a "SIP/H.323 gateway 1326" that "can convert SIP protocol calls received from gateway 1116 over IP network 1130 into H.323 protocol calls… and converts H.323 calls received over intranet 1320 into SIP" (6:37–43), with FIGS. 10 and 13 (both admitted prior art in Salama) showing SIP→SIP (multi-proxy) and PSTN→SIP/PSTN gateway→IP→SIP/H.323 gateway→H.323 terminal; and
• the need "to keep track of which signaling protocol should be used on a particular segment of the IP networks" (6:43–46).

The reexamination record for U.S. 6,683,858 relied on "Pearce, Oran, Hoshi, and Salama" as Ground VIII — two of those (Oran US 6,275,574 and Salama US 6,584,093) are cited on the face of the '658. Note the number literally: 6,683,858 ≠ 6,885,658 — that is a different patent and the two should not be conflated (see § 7).

4. Element-by-element mapping of claim 1

Claim 11's method steps are the mirror image of (a)–(c) plus the documented "media capabilities description" step, and are met by the same references: MGCP's LocalConnectionOptions/SDP and H.323's fastStart/H.245 TCS are exactly the "media capabilities description" and "capabilities exchange at either time" that the '658's AIP normalizes (spec, "Capabilities Exchange Between H.323 Devices" / "Between MGCP and SIP Devices").

5. Proposed § 103 grounds

Ground 1 — MGCP (Arango draft, 1999-02-21) + MGCP Call Flows (1999-01-20) + H.323 (Oct. 1997/Feb. 1998) + RFC 2543 (Mar. 1999) + Anquetil (Apr. 1999).
MGCP supplies the call server (call agent), the first protocol agent, the connection parameter/mode semantics, and the media-management operations. H.323 supplies the second protocol agent, the gatekeeper/gateway architecture, fastStart capability exchange, and the H.245 channel open/close operations plus H.245 tunnelling. RFC 2543 and Anquetil supply SIP-side and gateway-side interworking and multipart/opaque-body handling. Motivation: the standards bodies themselves (IETF MEGACO, ITU) were actively reconciling MGCP/H.323/SIP in this exact window, and a carrier-class MGC had to serve both MGCP media gateways and H.323 gateways to be commercially useful. Reasonable expectation of success: PSTN↔IP gateways already performed the analogous translation (Hamdi; Anquetil).

Ground 2 — Oran (US 6,275,574) + Salama (US 6,584,093) + MGCP draft + H.323.
This is the ground the Office has seen before in sibling form (the "Pearce, Oran, Hoshi, Salama" Ground VIII in the 6,683,858 reexamination file). Salama supplies explicit, admitted-prior-art SIP↔H.323 conversion at a gateway and the per-segment protocol-tracking function (the "interworking agent" function). Oran supplies distributed telephony call control. MGCP supplies the call-agent architecture; H.323 supplies channel semantics. Motivation: Salama itself states the problem ("keep track of which signaling protocol should be used on a particular segment") and motivates a central, protocol-aware coordinating entity.

Ground 3 — Huitema, "An Architecture for Residential Internet Telephony Service" (IEEE Network, May/Jun. 1999) + Hamdi (IEEE Commun. Mag., May 1999) + Anquetil + RFC 2543.
Huitema (a co-author of MGCP itself) sets out the MGC/MG/signaling-gateway decomposition; Hamdi sets out voice-service interworking between PSTN and IP; Anquetil sets out MGCP-controlled VoIP gateways. Together they establish the architecture of a central controller mediating multiple IP telephony protocols.

Ground 4 (if claim 11 or the tunnelling limitation needs a dedicated reference) — Ground 1 or 2 + RFC 2543 (multipart MIME body forwarding) + H.323 (H.245 tunnelling within H.225 call signaling), alternatively Q.931 unrecognized-information-element procedures.
Each of these teaches, in a packet-telephony signaling context, that a node which cannot map/interpret a parameter passes it through essentially unaltered. That is the "without alteration" limitation.

Why a POSITA would have combined (KSR v. Teleflex)

1. Same field, same problem, same art. All references are in IP telephony signaling; all address connecting heterogeneous telephony protocols.
2. Finite, identified, predictable solutions. The '658 itself enumerates the universe: MGCP, H.323, H.248/MEGACO, SIP, "proprietary protocols." Combining two of a handful of known protocols through a known gateway/mediator is a predictable use of known elements.
3. Explicit design-choice motivation in the patent's own words. The specification states: "Rather than designing an entirely new protocol for use as the agent interworking protocol, it is more desirable to select an existing protocol that comes close to meeting the superset definition described above and extending that protocol. Existing protocols that could be used as the base protocol… include Q.931, ISUP, and SIP." (9:6-16 context). That is a written admission that (i) the problem admitted a finite set of known solutions and (ii) extending a known protocol was "more desirable" than designing new — the classic KSR fact pattern.
4. The "superset" limitation is result-oriented. "[A] reasonable superset of the messaging capabilities of all protocols to be supported" is a statement of intended coverage, and the patent concedes the superset need not be complete because unmappable content is tunnelled — so the "superset" requirement imposes no structural limit beyond what a mapping layer inherently does.
5. Written admission of the problem. Spec: "standards for interworking equipment that communicates using one protocol with equipment that communicates using another protocol are immature, nonexistent, or focus only on a specific type of application. Accordingly, there exists a long-felt need…" A statement of a recognized need, in the same breath as the enumerated known protocols, is powerful motivation evidence (though see § 6).

6. What the patent owner will say, and the counter-evidence already on the record

• Jury verdict of "not invalid" (2016-01-15) and denial of JMOL in Genband US LLC v. Metaswitch, 2:14-cv-00033. That verdict is not preclusive against a different defendant or against art not tried, but it is a real headwind: it means a prior-art combination was presented and rejected by a jury on claims 1 and 11.
• No PTAB cancellation exists on this patent — there is no FWD to cite. The challenger must build the record from scratch.
• Secondary considerations. The owner can point to the patent's own "long-felt need" statement, to rapid industry adoption of MGC/gatekeeper interworking, and to the eight-figure verdict. Under KSR, a long-felt need satisfied by a predictable combination of known elements is weak — but a § 103 challenger must still rebut it with a POSITA declaration tying each reference to each limitation, especially the "superset" and "without alteration" limitations.
• Best defense theory: narrower, alternative grounds are unlikely to succeed because the claims were construed broadly (all plain meaning). The better theory is a clean, well-documented two-reference combination (MGCP + H.323) with Salama as the interworking teaching, supported by the patent's own admissions — plus, if the "superset" limitation becomes the battleground, evidence that a mapping layer must necessarily span the union of the protocols it interworks.

7. ⚠️ Contradictions with the previously-generated sections (flagged per instructions)

I am required to flag contradictions rather than paper over them. Three items in the prior "PTAB challenges" section do not survive checking:

1. "There are zero AIA trial proceedings on file for U.S. Patent No. 6,885,658… no IPR petition naming the '658 patent." — Contradicted. The '658 patent is of record as Exhibit 1076 in IPR2024-01282, Cisco Systems, Inc., filed 2024-08-13 (Docket Alarm exhibit page). Important nuance: the '658 appears to be submitted as prior art/background, not as the challenged patent (the same exhibit list includes US 2003/0093563 (Young)), so this is not proof of an IPR against the '658. But the prior section's absolute statements — "no PTAB forum ever examined this patent," "no IPR petition naming the '658 patent" — are overbroad and should be corrected. I could not verify in this session which patent IPR2024-01282 actually challenges.
2. "the patent is PTAB-virgin." — Partially contradicted. In the Final Written Decision in IPR2019-01233 concerning U.S. 7,773,588, the Board relied on Ress (the '658 patent) as prior art for a "detecting" limitation, analysing FIGS. 9(a)/9(b), FIG. 5, and the CIP, and held: "we are persuaded by Petitioner's showing that Ress suggests limitation [b]… in order to perform AIP mapping and protocol conversion, the protocol must be detected" (FWD, IPR2019-01233). So the Board has examined the '658's disclosure — as art, not as a challenged patent. For § 103 purposes this is affirmatively useful: the Board credited the '658's FIGS. 9(a)/9(b) as teaching the "determine whether a mapping is available" step that the '658 now claims.
3. Ex parte reexamination. The prior section stated it could not verify whether any reexamination was requested. I found a public record captioned "Ex Parte Reexamination of U.S. Patent No. 6,683,858" (Ground VIII: Pearce, Oran, Hoshi, Salama) in Texas Western District case txwd.1141573. Read the number literally: 6,683,858, which is a different patent from 6,885,658. I flag it because (a) the digits are transposition-prone and (b) the ground uses Oran and Salama, both cited on the '658's face — but I cannot represent this as a reexamination of the '658, and it may well be a scrivener's error in the source document. Verify in Patent Center.

8. Confidence and open items

High confidence: the cited-art list on the '658's face; the 1999-06-07 priority date and 2000-02-18 filing date; claim 1's verbatim text and the plain-meaning constructions; that MGCP v0.1, RFC 2543, Anquetil, Huitema, Hamdi and H.323 (1997/98) all pre-date the priority date and are § 103-available; that H.248, the Sept. 1999 H.323, Dalgiç (Sept. 1999) and Korpi (July 1999) are not prior art; that the '658 is now being used as prior art by Cisco (2024) and was so used by the Board in IPR2019-01233.

Not verified (do not rely on without checking): the full disclosure of Dulman '008, Strathmeyer '805, Oran '574, Civanlar '594, Sengodan '275 — I have only their front-page data and CPC classes; a petition needs their specifications read against each limitation. Verbatim claim 11 and claims 2–34. The subject patent of IPR2024-01282. Whether the "6,683,858" caption is a typo. And, most importantly, the contents of whatever "Prior Art section" this task intended me to use — my § 3 is a reconstruction, not that list.

Bottom line: claims 1 and 11 are, on paper, vulnerable to a well-built § 103 case — principally MGCP + H.323 (+ Salama, + RFC 2543, + Anquetil/Hamdi/Huitema) — because the claim elements are the prior art's architecture, the prior art's connection/mode semantics, and the prior art's tunnelling/multipart pass-through technique, and because the specification contains express admissions that extending a known protocol to carry a "reasonable superset" was the desirable design choice. The obstacles are procedural and evidentiary (a live jury verdict of no invalidity, no PTAB FWD to lean on, and the need for a rigorous POSITA mapping of the "superset" and "without alteration" limitations), not doctrinal.