US 6633564

I'll search for authoritative information on this patent.

Let me check for any litigation or PTAB activity specifically involving this patent number.

US Patent 6,633,564 — Analyst Summary

Bibliographic data (authoritative bibliographic — from the patent record)

Chain of title (from Google Patents reassignment records): Nortel Networks Corporation (1999‑09‑22) → Nortel Networks Limited (name change, 2000‑08‑30) → Rockstar Bidco, LP (2011‑10‑28) → Apple Inc. (2012‑07‑26). Google Patents lists the current assignee as Apple Inc.; the patent itself, as issued, names Nortel Networks Limited.
Sources: https://patents.google.com/patent/US6633564/en ; https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/[5705037](/patent/5705037)/FID2793/OG/html/1275-2/us06633564-20031014.html

Abstract (as printed)

"This invention provides a communication network with a method and apparatus for interrupting the transmission of an existing stream of data to insert interrupting packets which may have a higher priority than the existing data stream. The interrupting packets are inserted in the data stream by making use of unused pointer values in common transmission schemes known as the Data Over Cable Service Interchange Specification (DOCSIS) or the Asynchronous Transfer Mode (ATM) adaptation layer 2 (AAL2) format of the International Telecommunications Union (ITU) recommendation I363.2. Advantageously, the scheduling of packets is significantly simplified and the packet jitter is better controlled which results in a significant improvement in transmission performance."

Plain-language overview of the claims

The claim set contains 42 claims. Based on the claim text retrieved, there appear to be three independent claims — 1, 8, and 36 — with the rest depending from them (chains 2–7; 9–20; 21–35; 37–42). I have verbatim text for claim 1 and claim 36 and partial text for the claim‑8 chain; I could not retrieve the exact opening words of claim 8, so my characterization of it below is an inference from dependent claims 15/16/20 and should be treated as such.

Claim 1 — Independent method claim (core of the patent). A method of interrupting a packet already being transmitted so a higher‑priority "interrupting packet" can be sent, in a system where packets travel as consecutive physical‑layer blocks that normally cannot be interrupted. The method: (a) transmit one or more physical‑layer blocks of the existing packet; (b) before finishing the existing packet, transmit at least one physical‑layer block for the interrupting packet; (c) indicate the interrupting packet's presence by putting a value (or combination of values) into existing block fields — i.e., fields that already have a different defined purpose — in a way that is outside their defined purpose (reusing "invalid"/unused field values as an interrupt flag); and (d) resume transmission of the existing packet. (Verbatim from the Official Gazette text: "…denoting the presence of the interrupting packet in the physical layer block for the interrupting packet by using a value or combination of values in one or more existing fields located therein in a manner such that these fields are not used for the defined purposes; and resuming transmission of the existing packet.")

Claim 8 — second independent method claim (inferred). Directed to the same general concept but phrased around denoting a "new packet" as the interrupting packet, and encompassing the DOCSIS/MPEG pointer‑field mechanism. Dependent claims 16–20 specify: a pointer field is used; it sits in the block payload; its normally defined purpose is to point to a predetermined range in the payload; and the interrupting packet is flagged by setting the pointer field outside that range — specifically to 255 (claim 15 and claim 20).

Claim 36 — Independent apparatus claim ("scheduler"). A scheduler for interrupting an existing packet in transmission, coupled to receive packets requiring transmission, comprising: means for transmitting physical‑layer blocks of the existing packet; means for transmitting at least one physical‑layer block for the interrupting packet before the existing packet's transmission completes; means for denoting the interrupting packet's presence by using a value/combination of values in existing fields in a manner not used for their defined purposes; and means for resuming the existing packet's transmission — wherein the scheduler is operable to decide, for each packet received, whether to treat it as an interrupting packet or to wait until an existing packet completes. Dependent claims 37–42 add queue structure: the scheduler draws from multiple queues each associated with a transmission priority, and the determination of whether to interrupt is made on that priority basis.

Notable dependent‑claim coverage (illustrative, not exhaustive): recursion/nested interruptions (claim 29, "recursively repeated for nested interruptions"); a second interrupting packet (claims 30–35) flagged by a continuation field set to a non‑zero value (which may encode the number of interrupting packets remaining) and set to zero to signal resumption of the interrupted packet; and the ATM AAL2 (ITU I.363.2) analogue, where the presence of an interrupting packet is flagged via the OSF set outside its defined range — specifically to 63 (claims 21–28).

USPTO / CAFC docket check (2026)

I searched for litigation and Federal Circuit activity specifically tied to 6,633,564 and found no 2026 CAFC docket, IPR, or district‑court matter naming this patent. That is consistent with the record: the patent's anticipated expiration was 2019‑09‑22 and its status is "Expired – Lifetime," so it cannot be asserted for post‑expiration infringement. I found no authoritative evidence of any 2026 proceeding involving this patent number, and I will not assert one exists.

Identifiers that must NOT be confused with this patent (flagged per the literal‑interpretation rule)

• OSTI ID 6633564 — a U.S. DOE Office of Scientific and Technical Information record, not a patent number; it corresponds to US 4,432,134 (Rockwell International), a Josephson tunnel junction fabrication process. https://www.osti.gov/biblio/6633564
• A Brazilian municipal employee roster also contains the bare sequence "6633564" — unrelated data. http://previni.novaiguacu.rj.gov.br/images/documentos/censo/inativos_recadastrados2019.pdf
• A 2013 Rockstar/Nortel assertion campaign against Google/Android OEMs concerned seven other Nortel patents; I found no indication that 6,633,564 was among them.

Other observations (with sources)

• The patent is cited as prior art in later filings, e.g. CN 1894900 B ("Method, apparatus and system for multiplexing protocol data units") and EP 2783490 B1 (French‑language claims retrievable at patentimages). It is functioning in the art as a reference, not as an asserted patent.
• Third‑party valuation sites list an "approx value" of ~$59.6M for this patent (patentleaderboard.com). This is an estimate by a private analytics site, not an official or authoritative figure, and should not be relied on.
• Verbatim claim 1 and the bibliographic face data come from the Official Gazette mirror (Indiana University virtual disk library), and the Google Patents full text reproduces the specification. Note the specification contains typographical artifacts ("psec" where "μsec" is meant) — reproduced as printed.

Uncertainty statement: I have high confidence in the bibliographic data, the abstract, claim 1, and claim 36. My statements about claim 8's independence and exact wording are inferred from dependent claims 15, 16, and 20 and are not confirmed against a primary source in this session. If claim‑8 precision matters (e.g., for a validity or infringement analysis), the issued patent's printed claim column should be consulted directly.

I'll search for litigation involving US patent 6633564 across patent litigation databases.

Let me run more targeted searches on litigation databases and the Rockstar/Nortel portfolio.

Let me search more specifically for this patent number in litigation contexts and check litigation databases.

Summary Answer

Based on my searches, I could not find any litigation that asserts U.S. Patent No. 6,633,564 specifically. I want to be explicit rather than pad this out: I did not locate a single complaint, counterclaim, case number, or docket in which 6,633,564 is identified as a patent‑in‑suit. I also could not directly query the specific databases you named (Unified Patents litigation caselist, PACER, CAFC dockets), because the tool available to me returned only general web results; I hit my search-step limit before I could exhaustively verify via those portals. So treat the "no known litigation" conclusion below as a reasoned finding from the searches I could run, not as a certified clearance.

Patent identified (for the record)

• Patent: US 6,633,564 B1 — "Method and apparatus for inserting packets into a data stream"
• Inventors: David G. Steer; Paul M. Row
• Application: 09/401,856; Filed: 1999‑09‑22; Granted: 2003‑10‑14
• Original assignee: Nortel Networks Ltd.
• Chain of title (per Google Patents): Nortel Networks Corp. → Nortel Networks Ltd. → Rockstar Bidco, LP (2011‑10‑28) → Apple Inc. (2012‑07‑26, current assignee)
• Status: Expired – Lifetime; anticipated expiration 2019‑09‑22

This is a DOCSIS/MPEG and ATM AAL2 (ITU I.363.2) patent about interrupting an existing packet's physical-layer block stream to insert higher-priority packets using previously-unused values in the MPEG pointer field / the AAL2 offset field (OSF). That profile matters, because the most plausible venues for an assertion would be the Nortel-portfolio campaigns (Rockstar / Constellation / Bockstar / Spherix, and cable-operator DOCSIS suits) — and those are exactly the campaigns I examined.

Litigation check: what I found (and why it is NOT this patent)

My searches surfaced a large volume of "’356" and "6633564"-looking hits, but none of them are US 6,633,564. I want to flag the near-misses so they aren't mistaken for results:

Every Rockstar-family patent list I located — the seven patents in the Android/Google campaign, the 29-patent Cisco counterclaim list, and the DOCSIS/cable-operator assertion sets — omits 6,633,564. Notably, none of the cable/DOCSIS-focused Rockstar or Constellation/Bockstar pleadings I retrieved named it, even though it is a DOCSIS-relevant Nortel patent that the consortium inherited.

Conclusion

• Known litigation involving US 6,633,564: none found in the searches I was able to run. No plaintiff, defendant, jurisdiction, case number, filing date, or outcome can be reported, because no case was identified.
• The patent was swept into the Rockstar Bidco → Apple ownership chain (2011–2012), and its prosecution-era owner (Nortel) was a DOCSIS/MPEG standard participant — so an assertion is plausible in principle, but I found no evidence that it was ever asserted. The patent's term ran out in 2019, which further reduces the likelihood of a live suit.

Confidence and caveats (per your rules):

• Medium confidence in "no known litigation," based on targeted web searches. I could not directly query PACER, the CAFC docket, Unified Patents' caselist, RPX Insight, or Docket Alarm, and I reached my search-step limit. Those sources are the authoritative check for a negative assertion.
• If you need this verified to a litigation-grade standard, the definitive steps are: (1) run the patent number through RPX Insight / Unified Patents / Docket Alarm litigation tabs; (2) pull the USPTO Patent Assignment and PatentCenter records for 6,633,564 to see whether any assignment or license names an asserting party; (3) query PACER for the patent number as a party-searchable term and check the CAFC docket for any appeal citing it. I can help interpret those records if you pull them.
• I did not auto-correct or normalize any identifier; I interpreted each number literally, and I flag that many "’356"/"’633" hits in search results are entirely different patents.

If you'd like, I can next dig specifically into whether Constellation, Bockstar, or Spherix ever charted 6,633,564 (they took large DOCSIS-adjacent tranches of the Rockstar portfolio), which is the most likely place it would surface if it was ever asserted.

I'll start by checking the structured block's default (no PTAB activity) against web search, since the prompt instructs me to flag anything the ODP ingest may have missed.

The second result is significant — a Docket Alarm hit for IPR2021-00984 (Juniper Networks) using US6633564 as an exhibit. I need to determine whether '564 was the challenged patent or merely prior art. Let me dig.

IPR2021-00984 turns out to be on US 6,876,669 (Juniper v. Correct Transmission), with '564 used only as prior art (Ex. 1008) — not a proceeding on '564. Let me search directly for any proceeding challenging '564.

Proceedings overview

Total AIA trial proceedings on US 6,633,564: 0. The canonical structured block (USPTO ODP) reports no AIA trial proceedings, and my independent web screening surfaced no IPR, PGR, or CBM naming '564 as the challenged patent — so the defensive posture is not "survived two IPRs and hardened," but rather "no AIA trial has ever been filed against this patent; the invalidity record is a blank slate built entirely in district court and prosecution, and the patent expired on 2019-09-22."

Because there are zero proceedings, the per-proceeding template below has no entries to populate. Rather than fabricate dockets, I set out (a) the near-miss hits that look like '564 proceedings but are not, and (b) the strategic picture. I flag one search result expressly because it superficially resembles a '564 proceeding and a careless analyst could mis-cite it.

⚠️ Near-miss that is NOT a '564 proceeding — do not cite as one

IPR2021-00984 — Juniper Networks, Inc. v. Correct Transmission, LLC

• Type: Inter Partes Review
• Patent actually challenged: US 6,876,669 B2 — not '564. Source: Unified Patents PTAB portal, https://portal.unifiedpatents.com/ptab/case/IPR2021-00984 ("PATENT NUMBER 6876669").
• Filed: 2021-05-19 | Status: Not instituted — merits (institution denied 2021-11-19)
• Panel: Bryan F. Moore, John R. Kenny, Stephen E. Belisle. Decision text via vLex: https://case-law.vlex.com/vid/juniper-networks-inc-v-893284883
• Why '564 appears: US 6,633,564 (Steer) was submitted by the Petitioner as Exhibit 1008 — prior art against the '669 patent. Patent Owner also filed "(Steer) A-16" invalidity contentions as Ex. 2010. So in this proceeding '564 is a sword, not a defendant-facing shield.
• Defensive value for a '564 defendant: None directly. It confirms only that '564 is technically material as prior art in the packetization space — which cuts against '564's validity arguments, not for them.

Other screened candidates (all negative)

Caveat on completeness: I was stopped by a tool step-limit before exhausting every query. ODP returns zero, and my screening found zero, but I cannot represent that a very recently filed petition (e.g., within the ODP ingest lag window) does not exist. Given the 2019 expiration, a fresh filing is commercially implausible.

Strategic summary

Claim status: all 36 claims are UNTESTED in any AIA forum. No claim of '564 has been canceled or sustained by the PTAB, because no trial ever reached a Final Written Decision. Claims 1–36 are presumptively valid under § 282 and carry no PTAB-created narrowing. Note the practical effect of expiration on 2019-09-22: the patent is now "Expired – Lifetime," so there is no injunction exposure and no ongoing royalty — a defendant's exposure is limited to past damages for pre-expiration conduct, further bounded by the six-year lookback of 35 U.S.C. § 286. That is the single most important fact for anyone facing a demand letter today.

Estoppel landscape: clean, but empty. Because no IPR/PGR/CBM was ever instituted against '564, there is no § 315(e)(2) estoppel of any kind — no petitioner (and no privy) is barred from raising any § 102/§ 103 ground, and the full universe of prior art is available to a defendant. The flip side: § 311 limits IPR to § 102/§ 103 grounds only, and PGR (the only AIA vehicle that could reach § 101 eligibility or § 112) is unavailable on a 1999 filing. So an AIA-based strategy on this patent is structurally narrow — eligibility and written-description attacks must be litigated in district court. Also note the § 315(b) one-year bar: any defendant served and now outside one year of service cannot file an IPR at all.

Pattern signals: none. No serial petitioner, no PTAB appeal by the patent owner (necessarily — there is no FWD to appeal; no CAFC docket exists for this patent), and no Unified Patents or other defensive aggregator involvement found. The ownership chain is:

Nortel Networks Ltd (original) → 2000-08-30 Nortel Networks Limited (name change) → 2011-10-28 Rockstar Bidco, LP → 2012-07-26 Apple Inc. (current assignee).

The Rockstar/Constellation campaign (Constellation Technologies LLC v. Time Warner Cable et al., E.D. Tex. 2013) asserted other Nortel patents against cable operators — 5,583,862; 5,761,197; 5,850,397; 6,128,649; 6,130,893; 6,321,253; 6,845,389; 6,901,048; 7,154,879; 7,486,615; 8,134,917; 8,464,299 — and ultimately settled (Cisco at $188M, per Law360 2014-11-20; https://www.law360.com/cases/52a8f583381e1b3158000001/articles). '564 was not among the patents named in that letter, though Constellation expressly warned the named patents were "examples" of a far larger portfolio.

Where '564 has actually shown up: as an offensive prior-art reference — Exhibit 1008 in IPR2021-00984, and cited during prosecution of US-family/foreign counterparts of Qualcomm's CN 1894900 B. That is a meaningful background signal: '564's own disclosure has been used to invalidate a later packet-fragmentation patent, which suggests a defendant may want to mine the same 1990s packet-interrupt/priority art for use against '564.

Recommended next steps

1. Do not build a defense around an IPR on this patent. There is no AIA proceeding to piggyback on, no estoppel to exploit, and — critically — expired-patent IPRs are unattractive: the patent owner cannot meaningfully amend, and past damages are the only stake. If a demand letter cites '564, the leverage is expiration plus prior art, not the PTAB.

2. If you were served within the last 12 months, an IPR remains theoretically available (§ 311 does not bar expired patents; the Board has instituted on expired patents to settle past-damages exposure). But weigh it against the low remaining stake and the § 286 six-year lookback. If you are outside the § 315(b) window, an IPR is time-barred.

3. The absence of PTAB activity is itself a signal. Well-asserted, valuable patents invariably attract IPRs; '564 never did. Combined with the 2019-09-22 expiration and Apple's passive ownership (no litigation campaign on '564 found), the realistic picture is a dormant, expired patent — high-pressure demand letters citing it should be scrutinized for whether the demands are even temporally supportable.

4. Preserve § 101 / § 112 arguments for district court. They cannot be raised in an IPR, and PGR is unavailable. Any invalidity defense deck should lead with district-court-only grounds plus § 102/§ 103 art.

5. Verify before relying. Re-run the ODP PTAB API and the Unified Patents portal against "6633564" immediately before any filing or board presentation; my screening confirmed zero but was not exhaustively complete, and ODP has an ingest lag. Useful links: https://patents.google.com/patent/US6633564/en ; https://portal.unifiedpatents.com/ptab/case/IPR2021-00984 (the near-miss); full claim set at https://www.freepatentsonline.com/6633564.html.

I'll research the assignment records and cross-references for US 6633564.

Let me dig into the specific assignment record details and any litigation history.

Let me try to pin down the exact reel/frame records for this patent.

Ownership & Assignment Reconstruction — US 6,633,564

Source note / limitation up front: Google Patents' legal-events view gives me the event chain, dates and parties (reproduced authoritatively in the patent text supplied above), and I corroborated the Rockstar-era links against litigation and IPR filings. What I could not retrieve in this session is the USPTO Assignment Center reel/frame and correspondent-of-record fields for this specific patent. I have therefore left reel/frame blank where unverified rather than reconstructing it from sibling patents. Verify at USPTO Assignment Center / Assignment Search by searching 6633564.

Inventors

Both inventors assigned their rights to Nortel Networks Corporation on the filing date itself (1999-09-22), which is normal for a large corporate filer and indicates no personal retention of rights.

Pattern observations:

• Nothing in the record indicates an early inventor departure. Inventor-departure data is not exposed by patent assignment records, and I found no employment or departure evidence for either inventor tied to this filing. Not determinable — I will not infer a fire-sale precursor here.
• Two inventors, one filing, clean corporate assignment — no co-owner, no government-interest (no NSF/DARPA/DOE statement on the face of the patent), no third-party funding rights. This matters for title: there is no third-party consent needed for a downstream transfer.

Original assignee

Entity named on the issued patent: Nortel Networks Limited (the assignee of record on the filing-date assignment was its predecessor name, Nortel Networks Corporation, which changed its name to Nortel Networks Limited — recorded 2000-08-30).

• Primary line of business: Nortel was a global telecommunications and enterprise-networking equipment vendor — carrier switching/routing, optical, wireless (CDMA/LTE), and cable access networking. It was a longstanding CableLabs participant and a supplier of DOCSIS cable-access equipment, which is directly relevant to this patent's subject matter (DOCSIS/MPEG physical-layer block packing and PUSI/pointer-field signalling). Note, however, that a party in the Nortel estate litigation alleged that "Nortel and/or its affiliates and predecessors joined the CableLabs DOCSIS patent pool" (Bankr. D. Del. No. 09-10138, D.I. 14559) — that is an allegation in a pleading, not a verified fact, but if true it could carry licensing commitments touching DOCSIS-related Nortel patents.
• Did they ship a product embodying the claims? Nortel shipped DOCSIS cable modem termination system (CMTS) equipment, and the scheduler technique claimed here is the kind of firmware-level packetisation behaviour such a product would implement. Likely, but not documented in the sources I reviewed — I will not state it as established. The patent's own background notes Nortel-engineered R&D "directed toward products and areas of technology that our competitors were working in," per a former Nortel patent manager quoted by Wired.
• Current status: Dissolved / wound down. Nortel filed for Chapter 11 on 2009-01-14 in the U.S. Bankruptcy Court for the District of Delaware (Case No. 09-10138-KG), with parallel Canadian CCAA proceedings. Its assets were liquidated; the patent portfolio sale was the largest single realization (~$8B raised in total asset sales). This is one of the canonical patent bankruptcy fire-sales.

Assignment timeline

Two post-issuance assignments are documented. Reel/frame values for US 6,633,564 specifically could not be verified in this session; where I give a reel/frame below, it is from a different Nortel patent sold in the same transaction and is labelled as corroborative only — do not read it as this patent's record.

1. 1999-09-22 (executed) / recorded 1999-09-22 — Reel/Frame: not verified

• Conveyance: Assignment (of inventors' rights)
• Assignor: Paul M. Row; David G. Steer
• Assignee: Nortel Networks Corporation
• Correspondent: not retrieved
• Context: Standard employment-contract assignment of invention to the operating-company employer, executed on the filing date.

2. 2000-08-30 (executed) / recorded 2000-08-30 — Reel/Frame: not verified

• Conveyance: Change of Name
• Assignor: Nortel Networks Corporation
• Assignee: Nortel Networks Limited
• Correspondent: not retrieved
• Context: Internal corporate reorganisation only — no transfer of beneficial ownership; the same Nortel group entity continued to hold title. This is the name under which the patent issued.

3. Issue date 2003-10-14 — US 6,633,564 B1 granted to Nortel Networks Limited. (Not an assignment; included for chain continuity.)

4. Executed/effective 2011-07-29 (per the underlying Asset Sale Agreement); recorded 2011-10-28 — Reel/Frame: not verified for this patent (sibling Nortel assets in the same transaction were recorded at, e.g., 027143/0717 and 027164/0356 on 2011-10-28 — corroborative only)

• Conveyance: Assignment (bankruptcy sale)
• Assignor: Nortel Networks Limited
• Assignee: Rockstar Bidco, LP
• Correspondent: not retrieved. For context only, Nortel's estate was represented in the sale by Cleary Gottlieb Steen & Hamilton LLP (quoted by Reuters as sale counsel) — but I have no correspondent-of-record confirmation, so I am not attributing the recording to them.
• Context: Bankruptcy fire-sale. The June 30, 2011 Asset Sale Agreement between Nortel Networks Limited and Rockstar Bidco, LP et al. transferred ~6,000 patents/applications for $4.5B; approved by the U.S. and Canadian courts on 2011-07-11 (Reuters). Rockstar Bidco LP was the six-company consortium vehicle — Apple, Microsoft, Research In Motion, Ericsson, Sony, EMC.

5. Executed 2012 (recorded) 2012-07-26 — Reel/Frame: not verified for this patent (the corresponding Rockstar Bidco LP outbound recording for a sibling Nortel asset was 028558/0928 — corroborative only)

• Conveyance: Assignment
• Assignor: Rockstar Bidco, LP
• Assignee: Apple Inc.
• Correspondent: not retrieved
• Context: Consortium distribution, not a transfer to an asserter. Rockstar Bidco LP assigned directly to its limited partners a minority of the Nortel assets, and assigned the remainder to Rockstar Consortium US LP. Apple received 568 Nortel U.S. grants; Microsoft 182; BlackBerry 127; Ericsson 9 (Chipworks data via Lexology, Dec 2014). US 6,633,564 falls in the Apple tranche.

No further recorded assignment appears after 2012-07-26 in the legal-events record. The chain terminates at Apple Inc. Legal status: Expired – Lifetime, anticipated expiration 2019-09-22 (20-year term from the 1999-09-22 filing).

Timeline diagram

timeline
    title Ownership of US 6633564
    1999 : Filed by Nortel Networks Corporation
         : Steer and Row assign rights to Nortel
    2000 : Name change to Nortel Networks Limited
    2003 : Patent US 6633564 B1 granted
    2009 : Nortel files Chapter 11 in Delaware
    2011 : Portfolio sold to Rockstar Bidco LP
         : Recorded 28 Oct 2011
    2012 : Apple Inc receives the patent
    2013 : Rockstar sues Google and Android makers
    2019 : Patent term expires

NPE / troll-pattern signals

1. Shell-entity transfer — PRESENT (at the intermediate link), with an important qualification.
The patent moved from operating-company Nortel Networks Limited to Rockstar Bidco, LP (recorded 2011-10-28), a single-purpose acquisition vehicle formed by six operating companies for the sole purpose of buying and holding/enforcing patents. It had no products and no operating business. Qualification: this is not the classic Delaware-registered-agent shell of the Acacia/IV type — Rockstar Bidco LP's owners are publicly known (Apple, Microsoft, RIM/BlackBerry, Ericsson, Sony, EMC) and the patent then moved out of the vehicle to an operating company (Apple, 2012-07-26) rather than staying in a licensing-only entity.

2. Known asserter in the chain — PRESENT.
Rockstar Bidco, LP / the Rockstar Consortium entities are a well-documented patent-assertion/licensing operation: a 32-person outfit that reverse-engineered products and sought licensing from "as many as 100 potential licensees," and in October 2013 sued Google, Samsung, HTC, ZTE, LG, Pantech, Asustek and Huawei in the Eastern District of Texas. Two important limiting facts: (a) Rockstar is an operating-company-owned privateer, not an independent troll; and (b) US 6,633,564 was not among the seven patents Rockstar asserted against those defendants (those were the search/advertising patents plus US 5,838,551), nor among the Constellation Technologies patents asserted in Texas ('649, '389, '048, '879, '917, '299). So the asserter is in the chain, but this patent is not documented as having been asserted by it.

3. Repeat correspondent across the chain — UNKNOWN / NOT VERIFIED.
I could not retrieve the correspondent-of-record (attorney/firm) for the 1999, 2000, 2011 or 2012 recordings from the sources available. I am not making a finding here, because the single most useful NPE tell is exactly the field I couldn't read. The correct next step is a reel/frame pull from Assignment Center for all four links and a cross-check of the 2011 and 2012 correspondents — if the same attorney or firm filed both the Nortel→Rockstar Bidco and Rockstar Bidco→Apple recordings, that is worth flagging; if they differ (likely, since the first was filed by bankruptcy-estate counsel and the second by Rockstar's counsel), the signal is negative.

4. Cascading transfers — NOT PRESENT (in the classic form).
There are only two post-issuance transfers, ~9 months apart (2011-10-28 and 2012-07-26), through a single intermediate non-practicing LP, and the second hop lands on an operating company, not another LLC. This does not match "multiple consecutive assignments through chained LLCs."

5. Pre-litigation transfer — NOT PRESENT for this patent.
Rockstar's assertion wave was filed 2013-10-31; the Rockstar Bidco acquisition was effective 2011-07-29 (~27 months prior) and the Apple assignment 2012-07-26 (~15 months prior). Neither is within 6 months of a suit, and no suit naming US 6,633,564 is documented.

6. Bankruptcy fire-sale — PRESENT (strong).
Nortel filed Chapter 11 on 2009-01-14 (Bankr. D. Del. No. 09-10138-KG). Its ~6,000-asset patent portfolio was auctioned and sold to Rockstar Bidco, LP for $4.5B; the Asset Sale Agreement is dated 2011-06-30, court approval 2011-07-11, effective date 2011-07-29, assignment recorded 2011-10-28. This is a textbook fire-sale of a bankrupt operating company's crown-jewel IP.

7. Privateering — PRESENT (strong).
Apple, Microsoft, RIM/BlackBerry, Ericsson, Sony and EMC — six operating companies, three of them direct Android competitors — bought Nortel's portfolio through a non-practicing consortium vehicle rather than bidding individually. The American Antitrust Institute flagged exactly this concern to the DOJ (AAI letter); Apple contributed $2.6B of the $4.5B, and Google's counsel successfully litigated Apple's control over Rockstar's litigation decisions. The patents were then enforced against Google/Android OEMs. That is privateering by definition — with Apple here as a principal, not a mere licensee.

8. Defensive aggregator (anti-NPE) — NOT PRESENT.
The chain does not terminate at RPX, AST, LOT, Unified or OIN. Note the near-miss: RPX did buy the remnants of Rockstar on 2014-12-23 for $900M — but that purchase covered only the ~2,000 undistributed Rockstar assets. US 6,633,564 had already been distributed to Apple in 2012 and was not part of the RPX transaction. There is also no evidence the patent was contributed to OIN or LOT. This patent was not neutralised by a defensive aggregator.

Verdict

NPE — moderate confidence.

The chain carries three genuinely strong NPE-pattern markers, but they attach to the intermediate link rather than the terminal owner: a bankruptcy fire-sale (Nortel Chapter 11, Case No. 09-10138-KG; Asset Sale Agreement 2011-06-30, effective 2011-07-29, recorded 2011-10-28) into a single-purpose non-practicing consortium vehicle, Rockstar Bidco, LP, which is a documented privateer (Apple $2.6B of the $4.5B; AAI antitrust complaint; Rockstar's Oct 2013 suits against Google and Android OEMs). The reason this is moderate rather than high confidence is the terminal link: the assignment recorded 2012-07-26 moves the patent out of the licensing vehicle and into Apple Inc., an operating company — and I found no evidence that US 6,633,564 itself was ever asserted (it is absent from the Rockstar Texas/California asserted sets and from the Constellation Technologies set). It also expires 2019-09-22, so it is no longer assertable. Equally, "operating-company assertion" does not fit, since Apple neither sues on this patent nor demonstrably ships an embodying DOCSIS product. The one piece of evidence that could move this call is the correspondent-of-record field, which I could not retrieve — pull all four links at the USPTO Assignment Center (patent 6633564) and record reel/frame and correspondent for each before relying on this verdict.

I'll research US patent 6633564 and its cited prior art references.

Let me find the front-page citation data for this patent specifically.

Analyst Report: US 6,633,564 B1

Important limitation up front

I must be explicit about a sourcing failure per my operating rules. My searches against the Google Patents full text (the authoritative text supplied in the prompt), Google Patents, and general web sources did not return the front‑page "References Cited" / U.S. Patent Documents list for US 6,633,564. The full text fetched from patents.google.com for this patent (reproduced in the prompt) contains the description, claims, abstract, and classification data, but omits the front‑page citation tables (examiner‑cited references and applicant‑cited references). The searches I ran returned the patent's own disclosure text and third‑party documents (unrelated search reports), not the §56 citation list for this patent.

Because of that, I cannot provide a verified, itemized list of each examiner‑cited reference with its claim‑level anticipation mapping. Fabricating citations, dates, or §102 claim mappings would violate the "do not fabricate" rule. Below I give (1) verified bibliographic facts about the patent, (2) the substantive prior‑art landscape that is verifiable from the patent's own text, and (3) exactly what still needs to be retrieved and from where.

1. Verified bibliography (from the patent text and the Official Gazette record)

Source: Official Gazette record (Indiana University Virtual Disk Library, us06633564‑20031014) and the Google Patents bibliographic record in the prompt.

Independent claim 1 (from the OG record) recites: transmitting physical-layer blocks for an existing packet; before completing transmission of the existing packet, transmitting at least one physical-layer block for an interrupting packet; denoting the presence of the interrupting packet by using a value or combination of values in one or more existing fields in a manner such that these fields are not used for their defined purposes; and resuming transmission of the existing packet.

2. Prior-art/background art that IS verifiable from the patent's own text

These are references the specification expressly discusses as the pre‑existing art the invention builds on or departs from. They are standards documents rather than patent citations, so they are relevant to §102/§103 as printed publications, subject to their pre‑1999‑09‑22 publication dates:

1. ATSC A/53 Digital data/television standard — cited in the "Background Art" as the scheme grouping user data into 188‑byte blocks at 10.7 Msym/s, with 1–9 blocks per packet (76–684 µs). Relevance: establishes the physical-layer block framing and the jitter problem the invention addresses; potentially relevant to claims generally (block-based transmission), not to the novel "unused field value" limitation.

2. DOCSIS (Data Over Cable Service Interchange Specification) — the specification the invention's preferred embodiment uses, including the PUSI bit and the one‑byte Pointer Field. Relevance: the patent states the pointer field accommodates 0–255 while the MPEG block payload is only 184 (or 183) bytes, "which leaves the pointer field values from 184 to 255 unused." This is the crux of claim 1's "not used for the defined purposes" limitation.

3. MPEG physical-layer block format / RS(188,204) Reed‑Solomon FEC — 4‑byte MPEG header, 16‑byte RS‑FEC, PUSI bit, optional pointer field.

4. ATM AAL2, ITU recommendation I363.2 (spelled "I363.2" in the patent) — the OSF (offset field), 6 bits, values 0–63, with 48–63 unused per the standard (value 47 = no new packet). Relevance: the second embodiment's counterpart to the MPEG pointer field.

5. Implicit background: ITU‑T / ISO 8802 (IEEE 802) data packet framing used in FIG. 2 (DA, SA, Type/Length, user data, CRC).

Caveat on item 4: the patent writes "I363.2" and "I.363.2" — I am reporting the identifier literally as it appears; the standard's official designation may differ, but I am not auto-correcting it under the operating rules.

3. Claim-by-claim anticipation analysis (what the record supports)

With only the specification's self‑identified background art, none of the above references appears to anticipate the independent claims, for a specific reason grounded in the text:

• The ATSC A/53, MPEG, and DOCSIS references teach consecutive, uninterruptible block transmission and the conventional meaning of PUSI/Pointer Field (pointer values 0–183/184 for locating packet starts).
• The patent itself states the conventional limitation: "the transmission of any packet must be completed before any other packet can be sent," and that once a long packet starts, "it will delay the transmission of all other packets until all of its physical layer blocks have been transmitted."
• Claim 1's distinguishing limitation — flagging an interrupting packet by reusing unused values of an existing field in a manner inconsistent with its defined purpose — is precisely what the patent presents as new over these standards (pointer field 184–255; OSF 48–63).

So, on the material available, these references go to the state of the art / motivation, i.e., §103 background, not §102 anticipation of claims 1–42. I cannot responsibly assign them to specific claims as anticipatory references without the actual examiner citation list and the references' full texts.

4. Forward-citation data found (not prior art)

For completeness, these documents were found citing US 6,633,564 — they are downstream citations and therefore not prior art to '564:

• US 8,483,105 B2 ("High speed media access control") cites US 6,633,564 B1.
• KR 10‑1855443 B1 cites US 6,633,564 B1.

5. What is required to complete the requested table, and where to get it

To produce the citation‑by‑citation §102 analysis you asked for, retrieve the PTO‑892 / "References Cited" front page for US 6,633,564. Recommended authoritative sources (none of which returned the list in my searches):

1. USPTO PatentCenter / Public PAIR for application 09/401,856 — "References Cited" and the examiner's Notice of References Cited (PTO‑892). URL: https://patentcenter.uspto.gov (search application 09/401,856).
2. USPTO Full‑Text (patft) and the patent's granted front page PDF — the front page lists "(56) References Cited."
3. Espacenet / Global Dossier — for the corresponding search‑report "A/B documents."
4. Google Patents "Citations" tabs ("Patent Citations" and "Non‑Patent Citations") for US6633564B1 — https://patents.google.com/patent/US6633564B1/en — the tabbed data did not load in my retrievals but is the fastest route to the list.

If you can supply the PTO‑892 list or the front‑page "(56) References Cited" table, I will immediately produce the requested deliverable: for each reference — full citation, publication/filing date, brief description, and the specific claim(s) it potentially anticipates under 35 U.S.C. §102 (with the element‑by‑element mapping to claim 1's four limitations and the dependent claims' added features).

Summary

• Patent identified and verified literally as US 6,633,564 B1 (Steer & Row, Nortel Networks, filed 1999‑09‑22, granted 2003‑10‑14, 42 claims). I did not find or use any "similar number" as a substitute.
• I could not retrieve the official cited‑references list for this patent; therefore I am not asserting specific §102 anticipatory references, to avoid fabrication.
• Verified background art from the patent's own text: ATSC A/53, DOCSIS, MPEG/RS(188,204), and ATM AAL2 ITU I363.2 — these support the state of the art and the §103 motivation but, as described in the patent, do not appear to anticipate claim 1's "unused existing‑field value" limitation.
• Action needed: obtain the PTO‑892 / "(56) References Cited" front-page list to complete the requested reference‑by‑reference anticipation table.

Obviousness Analysis — U.S. Patent 6,633,564 B1

"Method and apparatus for inserting packets into a data stream"
Steer & Row; Appl. No. 09/401,856, filed 1999‑09‑22; granted 2003‑10‑14 (42 claims); original assignee Nortel Networks Ltd.; now Apple Inc. (via Rockstar Bidco, LP); status "Expired – Lifetime" (anticipated expiration 2019‑09‑22).
Source: https://patents.google.com/patent/[US6633564B1](/patent/US6633564B1)/en

0. A necessary caveat about the record on this page

The Google Patents page for US 6,633,564, as rendered here, contains a "Prior art keywords" entry (packet; interrupting; physical layer; block; packets) and a "Prior art date" (1999‑09‑22), plus a forward‑citation list ("Cited By (58)" per Google Patents; 59 per the secondary index at https://scispace.com/papers/method-and-apparatus-for-inserting-packets-into-a-data-565697umcy). It does not, in the text available to me, include a searchable "References Cited" (front‑page U.S. patent document) list, and my searches did not surface one. So:

• I am not able to reproduce the examiner's cited references verbatim; anything presented below as the primary prior art is drawn from (a) the page's own prior‑art keywords, and (b) the admitted prior art in the specification's Background Art section, which is itself citable against the claims as an admission.
• The "Cited By" list is not prior art for this patent. Its members (e.g., US 2002/0041595 A1 "System and method for suspending and resuming transmission of information without creating significant additional overhead"; US 2002/0131425 A1 "Packet fragmentation with nested interruptions"; US 2003/0058887 A1 "Method and apparatus for interleaving DOCSIS data with an MPEG video stream") post‑date the 1999‑09‑22 filing and are cited as forward citations. They are at most evidence of the state of the art/field, not § 102 pre‑AIA art, unless a specific member carries an earlier § 102(e) effective date that I could not verify here. I flag this explicitly rather than asserting dates I did not confirm.

Because the application was filed 22 Sep 1999, the pre‑AIA version of 35 U.S.C. §§ 102/103 governs (AIA first‑inventor‑to‑file provisions apply to applications filed on/after 16 Mar 2013).

1. The claim to be tested

Independent claim 1 (verbatim from the Official Gazette text, https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/[5705037](/patent/5705037)/FID2793/OG/html/1275-5/us06633564-20031014.html):

"1. A method to interrupt an existing packet in transmission for transmitting an interrupting packet in a communication system where packets are each transmitted in the form of physical layer blocks, the physical layer blocks of each packet containing fields for previously defined purposes and being designed to be consecutively transmitted without interruption, the method comprising:
transmitting one or more physical layer blocks for the existing packet;
before completing the transmission of the existing packet, transmitting at least one physical layer block for the interrupting packet;
denoting the presence of the interrupting packet … by using a value or combination of values in one or more existing fields located therein in a manner such that these fields are not used for the defined purposes; and
resuming transmission of the existing packet."

I was not able to retrieve the full text of claims 2–42 from the page text supplied; from the specification and the description at https://patents.google.com/patent/US6633564B1/en, the dependents add (i) the DOCSIS/MPEG specifics — PUSI bit + pointer field set to a reserved value (184–255), (ii) the continuation field, (iii) the AAL2/OSF variant (reserved values 48–63), (iv) recursive, multi‑level interruption, and (v) scheduler/apparatus implementations. My claim‑by‑claim treatment of those is therefore an inference from the disclosure, not a verified quotation.

Two scope observations that matter for § 103:

• Claim 1 is field‑agnostic. It does not require the field to be an "unused/invalid" code per se — only that the value be used "in a manner such that these fields are not used for the defined purposes." That is a broad repurposing-of-existing-signalling limitation.
• Claim 1 is format‑agnostic — it does not even require MPEG, DOCSIS or AAL2. The specification states the invention "is not restricted to the DOCSIS packets formatted with the MPEG protocol or the ITU ATM AAL2 I.363.2 format."

2. Prior art available for combination

A. Admitted/documented background art (all pre‑1999):

1. MPEG‑2 Transport Stream, ISO/IEC 13818‑1 / ITU‑T H.222.0 — 188‑byte transport packets; the header's PUSI bit and the one‑byte pointer_field, whose values 0–183 locate a new packet start and whose values 184–255 are left unused (the specification admits this at "The maximum payload size in the MPEG block is 183 bytes, which leaves the pointer field values from 184 to 255 unused").
2. DOCSIS (Data‑Over‑Cable Service Interface Specifications, RF Interface Specification, CableLabs/MCNS, 1997–1999) — specifies the 188‑byte MPEG block size and the carriage of variable‑length DOCSIS/ISO8802 MAC frames in MPEG blocks using PUSI/pointer_field, with RS(188,204) FEC.
3. ATSC A/53 — cited in the Background as the source of the 188‑byte / 10.7 Mbaud numbers and of the 76–684 μs delay/jitter figures.
4. ITU‑T Recommendation I.363.2 (ATM AAL Type 2) — 47‑byte CPS payload, 6‑bit OSF in the 1‑octet STF (with the 1‑bit sequence number and parity), used values 0–47, values 48–63 unused (admitted in the specification).

B. Preemption/preempt‑resume art appearing in the page's own citation network (to be verified for exact numbers/dates):

• "System and method for low overhead multiplexing of real-time and non-real-time data," David C. Oliver, dated 10 June 1998 (per the Scispace citation listing, above) — low‑latency multiplexing of real‑time over non‑real‑time traffic within a common frame with minimal efficiency loss.
• "Method of determining whether to use preempt/resume or alternate protocol for data transmission" — selecting a preempt‑and‑resume protocol.
• "Method and apparatus for graceful preemption on a digital communications link" — saving/restoring link‑controller status so a preempted user resumes from the point of interruption without data retransmission.

I did not independently verify the patent numbers or exact publication dates of these three; they are cited here by title as they appear in the citation index, and would need to be papered with the actual front pages before being relied on.

3. Ground 1 — MPEG‑2 TS/DOCSIS + preempt‑resume art ⇒ claims 1–28

Motivation (KSR, 550 U.S. 398 (2007); MPEP § 2143 rationales A, B, F, G):

1. Backward compatibility / no new signalling bits. A POSITA could not add new header bits to standardized 188‑byte or 47‑byte blocks without breaking standardized FEC and legacy decoders. The only available degree of freedom is the reserved code space already defined in the standard's own field. Rationale A (simple substitution of a known code for a known purpose — both codes delimit a packet start).
2. The problem was expressly recognized and the solution was in the art's own toolbox. The Background itself frames the problem (76→684 μs jitter for speech/video, TCP/IP low‑priority bulk data, wasted headroom if the scheduler reserves bandwidth). Oliver (1998) and the preemption family show the art already accepted preemption of in‑progress transmission as the answer to exactly that jitter problem. Rationale B (known technique improving similar devices in the same way).
3. The improvement is merely the recognizable, predictable relocation of the interruption point from "packet boundary" to "physical‑layer‑block boundary" (76 μs), which is the smallest granularity the standard permits. Rationale G (design choice/obvious to try a finite number of identified, predictable solutions).
4. No unexpected results. The patent asserts only the expected consequences — reduced jitter, less idle bandwidth, simpler scheduling — which are the very results the preemption art sought.

Expected § 103 outcome: Claim 1 would very likely be held obvious over MPEG‑2 TS/DOCSIS in view of a preempt‑resume reference, with the AAL2 OSF teaching (Ground 2) as an alternative or cumulative primary reference. The narrow, non‑inventive character of the difference — using a reserved pointer value instead of a new bit — is the classic "unused code" substitution.

4. Ground 2 — ITU‑T I.363.2 (AAL2) + preempt‑resume art ⇒ the AAL2 claims

Identical structure, different field: the 6‑bit OSF has 16 spare values (48–63) in a 47‑byte payload (the specification says this, and it is inherent in the standard). A POSITA working in ATM/CBR‑to‑VBR adaptation with the same jitter problem (real‑time CBR/AAL1‑like traffic delayed behind long AAL2/AAL5 cells) would apply the same preemption approach to the same kind of spare code space. That the two grounds are so symmetrical that the specification describes them in one breath (FIG. 5–8 for MPEG, FIG. 9 for AAL2, "in the same general manner") is itself strong evidence that the AAL2 variant was a routine extension, not an inventive leap — and the specification's own statement that it may be applied to "other transmission schemes" is an admission of the generality of the idea.

5. Ground 3 — the dependent claims (continuation field, count‑encoding, recursion)

• "Continuation field" dependents (a byte after the interrupting packet: zero ⇒ resume interrupted packet; non‑zero ⇒ another interrupting packet / count). The specification itself offers the design alternative of putting the count into the unused pointer values (256 − N), which is the most straightforward use of the same spare code space, and the two variants are described as equivalent trade‑offs. Under MPEP § 2143 rationale A (substitution of one known element for another to obtain its anticipated advantage), and given that preemption schemes inherently must signal "resumption," these dependents add little.
• "Number of following interrupting packets" dependents: counting/priority‑stack approaches are routine programming of a scheduler once the preemption concept is adopted; a continuation byte that decrements is a design choice.
• Recursive multi‑level interruption dependents (FIGS. 11A–11D; "interrupt level" counter, "current Q" pointer): this is the strongest non‑obviousness position. A preemption reference may show one level of preemption; a challenge must show, or make it obvious to derive, nested preemption with explicit level accounting and unwind back to the interrupted packet. Supporting cases (e.g., priority‑queue/nested‑interrupt schedulers in ATM and in OS interrupt handling) must be assembled; absent such a secondary reference, these dependents may survive. Note however the claim‑level breadth of claim 1: because the broad claim does not require recursion, invalidating the dependents does not improve the independent claims' position much.
• Apparatus/system claims: a scheduler and buffers for block assembly (FIG. 10) are conventional; the double‑buffer current/next block arrangement is standard hardware practice.

6. Where a challenge is weakest / what I cannot verify here

1. I could not retrieve the actual front‑page "References Cited" list for US 6,633,564 from the page or via search. A complete invalidity position requires the real cited art, the file history, and the claim text of claims 2–42, none of which I could confirm here.
2. Forward citations must not be miscited as prior art. Several superficially on‑point documents in the Google Patents "Cited By" list (Delvaux's suspend/resume overhead, Shalom's "nested interruptions," Broadcom's DOCSIS header hardware) are 2001–2003 publications and are not § 102 art against a 1999‑09‑22 filing. Any petition that cites them without an earlier § 102(e) effective date is defective.
3. The three preemption references I listed by title need date/number verification. I have not confirmed their publication dates from primary sources in this session; treat that portion of the position as provisional.
4. Claim construction risk: "physical layer block," "fields for previously defined purposes," and "value or combination of values" are functional/broad terms that, if construed narrowly (e.g., as limited to invalid values of a start‑of‑packet pointer field specifically, and to DOCSIS/MPEG), narrow the prior‑art coverage; if construed broadly, the claim becomes easier to invalidate. Note also the odd 1999 reference to ITU rec. "I363.2" for AAL2 — the specification consistently writes "I363.2"/"I.363.2," and I have not auto‑corrected it.
5. Secondary considerations: I found no evidence of record of unexpected results, commercial success, licensing (beyond the Nortel→Rockstar→Apple asset sale, which is not nexus‑bearing for the invention), or industry praise. Absent a nexus, the objective indicia prong of Graham v. John Deere cuts against patentee.

7. Bottom line

• Strongest § 103 ground: MPEG‑2 TS / ISO‑IEC 13818‑1 (PUSI + pointer_field with unused values 184–255) and/or DOCSIS RFI in view of a preempt‑resume/preemption reference (e.g., Oliver 1998; graceful‑preemption; preempt‑vs‑alternate‑protocol selection) ⇒ claims 1 and the format‑specific dependents obvious.
• Second ground: ITU‑T I.363.2 (OSF unused values 48–63) + the same preemption art ⇒ AAL2 dependents obvious.
• Weakest ground: the recursive multi‑level interruption and scheduler‑state dependents, which require a secondary reference on nested/priority‑stacked preemption.
• Caveats: my analysis rests on the prior art identified on the page (keywords, admitted background art, and the citation network) because I could not retrieve the examiner's cited‑reference list; the forward‑citation list is not prior art; and I flag rather than auto‑correct the document's "I363.2" notation and the "76 psec"/"μsec" typography in the fetched text.