US 9686183

I'll search for authoritative information on this patent, including recent litigation dockets.

Now let me get the actual claim text and litigation details.

Let me get the granted patent's exact claim set from Justia and FreePatentsOnline.

US 9,686,183 — Identification and Summary

Important scoping note first: I searched for the literal identifier 9686183 only. All results below relate to that number; no near-miss numbers are included. I also flag one date discrepancy: your prompt states "Current Date: April 26, 2026," while the authoritative document I was given is stamped 2026-09-30. I have not tried to reconcile those.

1. Bibliographic data (verified, low uncertainty)

Source: https://patents.google.com/patent/US9686183/en

One inventor-name artifact worth noting: an assignment record reflects a corrective assignment changing the recorded name "KAHN, SHABBIR" to "KHAN, SHABBIR." The correct spelling per the corrective record is Khan.

2. Abstract (verbatim)

"A digital object may be routed via a network. Routing of a digital object may be based in part on a requested service, and/or on an ability of an intermediate node to provide the requested service, and/or on a willingness of the intermediate node to provide the requested service."

3. Independent claims — overview

Grounding caveat (important): The full patent text supplied to me was truncated before the claims section, and my searches returned the claim text of the pre-grant publication US 2007/0291773 A1 (which bore 64 claims) rather than a verbatim copy of the granted patent's claim set. I could not authoritatively confirm the granted claim count or the exact granted claim language in this session. Treat the following as the published-application independent claims, which are probative of scope but may differ from the issued claims. Google Patents does not expose a claim count for '183 in the material I retrieved.

From the published application (source: https://patents.justia.com/patent/20070291773), the independent claims appear to be claims 1 (method), 33 (apparatus), 41 (apparatus), and 49 (article of manufacture):

• Claim 1 — Method. Receives a digital object to be forwarded on a network, where the digital object includes at least one requested service; adds a payload to the digital object; adds the at least one requested service to the digital object; and forwards the digital object according to the at least one requested service. Plain language: a router/intermediary accepts a file that carries its own delivery requirements, attaches the payload and the requirements, and routes based on those requirements rather than on a destination IP address alone.

• Claim 4 (dependent on claim 1, cited because it captures a core concept). Further includes determining whether there is a change in the availability of one or more nodes to provide the requested service. Plain language: the routing decision is re-evaluated when node capability changes over time.

• Claim 33 — Apparatus. An apparatus whose computing platform is adapted to store requested-service information separately from the digital object and to transmit that service information on the network separately from the digital object. Plain language: the "digital transmission form" (DTF) — delivery metadata — can travel as its own object, on its own path, decoupled from the payload it describes.

• Claim 41 — Apparatus. An apparatus comprising a computing platform, the computing platform being adapted to: [perform the routing operations of the method] — i.e., a hardware/system counterpart to claim 1.

• Claim 49 — Article of manufacture. A storage medium with instructions that, when executed by a computing platform, cause routing of a digital object by receiving a digital object to be forwarded on a network, the digital object including at least one requested service [and routing per the requested service]. Dependent claim 50 adds arranging a routing table based at least in part on the availability of one or more nodes to provide the at least one requested service; dependent claim 55 adds separate storage/transmission of the requested-service information.

Conceptual thrust of all independents (spec-grounded): the specification frames the invention as departing from TCP/IP, where "data packets are routed automatically by intermediary nodes to a destination IP address without regard to the available services a given node may provide and/or without regard to compensation based on the services provided." The claimed advance is route selection driven by a requested service (QoS, timing, priority, price/billing) matched against an intermediary's capability and willingness to provide it, with routing tables dynamically updated as node conditions change (FIGS. 4, 5, 10).

4. Litigation posture — Delaware 2026; no CAFC matter found

The Google Patents record flags "Family has litigation" and lists two Delaware District Court matters:

• Darts/Unified entry: 1:26-cv-00397 and 1:26-cv-00392 (Delaware District Court), https://portal.unifiedpatents.com/litigation/Delaware%20District%20Court/case/1%3A26-cv-00397

PACER Monitor corroborates 1:26-cv-00397: The Travelers Indemnity Company v. Intellectual Ventures I LLC et al, Delaware District Court, assigned to Judge Gregory B. Williams (case numbers associated in the assignment order: 1:26-cv-00392-UNA, 1:26-cv-00397-UNA, 1:26-cv-00417-UNA). Named defendants include Callahan Cellular LLC, Cufer Asset Ltd. LLC, Gula Consulting LLC, Intellectual Ventures I LLC, Intellectual Ventures II LLC, OL Security LLC, Tamiras Per Pte. Ltd., LLC, and Zarbaña Digital Fund LLC. The docket describes a COMPLAINT for Declaratory Judgment and Non-Infringement with Jury Demand, with Zarbaña served on 4/9/2026 (answer deadline shown as 4/30/2026) and a stipulated extension to 6/29/2026 for certain defendants.
Source: https://cdn.pacermonitor.com/public/case/64022259/The_Travelers_Indemnity_Company_v_Intellectual_Ventures_I_LLC_et_al

Plain-language read: this is a declaratory-judgment action brought by Travelers (an insurer) against Zarbaña and related IV-family entities — i.e., Zarbaña appears as a defendant, not as a plaintiff asserting '183. I could not confirm from the retrieved materials that US 9,686,183 is one of the patents specifically put at issue in either case, nor could I confirm the substance of 1:26-cv-00392.

CAFC: I found no 2026 Federal Circuit docket or appeal naming US 9,686,183 or the 2026 Delaware cases. I cannot rule out a docket that is not indexed in the sources I searched.

5. Explicit uncertainties

1. Granted claim text/count for US 9,686,183 is not authoritatively confirmed here. The claim overview above is from the 2007 pre-grant publication (64 claims), not the issued patent. The specification was also truncated at the "storage medium" definitional passage, so I could not read the issued claims from the supplied text.
2. Date inconsistency between your stated current date (April 26, 2026) and the document's 2026-09-30 stamp is unresolved.
3. Which patents are at issue in the Travelers declaratory-judgment actions is unconfirmed.
4. The "Family has litigation" and "Adjusted expiration 2036-03-06" entries are Google Patents annotations; that page itself disclaims that legal-status and priority statements are assumptions, not legal conclusions.

If you need the verbatim issued claims, the authoritative source is the USPTO PatentCenter / patentimages PDF for US 9,686,183 — I was unable to pull that document body in this session and will not reconstruct claim language from memory.

I'll research litigation involving US 9686183 across patent litigation sources.

Let me search more specifically for the Delaware cases and the patent owner.

I've found key cases. Let me verify the '183 patent's role and search for any additional litigation.

Litigation involving US Patent 9,686,183

Short answer: Yes — US 9,686,183 ("Digital object routing based on a service request," currently assigned to Zarbana Digital Fund LLC) is identified on its Google Patents record as a patent whose "family has litigation," with two District of Delaware cases flagged. Both are recent (2026) declaratory-judgment actions brought by insurers against Intellectual Ventures entities — not offensive infringement suits in which Zarbana asserts the '183 patent. I found no Federal Circuit appeals and no earlier asserted cases for this specific patent.

Case list

Sources: Google Patents record for US9686183B2 (which links Unified Patents litigation entries for Delaware District Court cases 1:26-cv-00397 and 1:26-cv-00392); PacerMonitor dockets for 1:26-cv-00392 and 1:26-cv-00397; Insurance Business Mag reporting on the Hartford action.

The '183 patent's role in these cases

• The Hartford action (1:26-cv-00392) is a 16-count declaratory-judgment suit seeking declarations of non-infringement and invalidity of eight IV patents. The complaint states that "Zarbaña Digital Fund LLC is the assignee of the '183 Patent," so US 9,686,183 is one of the DJ patents at issue. (Verified from the Hartford complaint docket text and the IV/Zarbana corporate disclosure statements filed in D. Del.)
• The accused products/technologies are open-source and third-party enterprise software (e.g., Docker, Kubernetes, Apache Spark, Apache Airflow, MongoDB, Elasticsearch), and the record indicates IV has pursued similar campaigns against other insurers (Nationwide, Liberty Mutual, GEICO) and companies such as JPMorgan, American Airlines, Southwest Airlines, BNY Mellon, Home Depot, and Deere & Company. The same patents appear across several of those matters.
• Both cases are defensive postures by insurers against a licensing/enforcement campaign by Intellectual Ventures, under which Zarbana Digital Fund LLC holds the '183 patent.

Important caveats and non-matches

• Do not confuse with unrelated cases bearing similar numbers. Case 1:26-cv-00397 (W.D.N.Y.) is a personal-injury/removal matter ("v. 786 Delaware, LLC"), and 1:26-cv-00392 (N.D. Ill.) is a copyright matter ("Shenzhen Peishi Advertising Media Co. v. Envoylei"). Neither involves US 9,686,183 and neither is one of the Delaware patent cases above.
• Possible additional related case (unverified): Robinhood Markets, Inc. v. Intellectual Ventures I LLC et al., 1:26-cv-00774 (D. Del.) is a declaratory-judgment action naming Zarbana Digital Fund LLC as a defendant, with Zarbana served 7/1/2026. I could not confirm that US 9,686,183 specifically is one of the patents asserted in that action, and it was not listed among the '183 family litigation links on the patent record. Treat as a lead to verify, not a confirmed '183 case.
• The Google Patents record also references a "first worldwide family litigation" entry via Darts-IP (family 38123611), which I could not open within my search limits.
• I found no IPR/PGR proceedings and no CAFC appeals specific to this patent number in the sources searched.

Reliability note

My confirmation rests on docket text and the patent's own litigation linkage. A definitive check would require running the exact patent number in Lex Machina, Docket Navigator, or PACER/Unified Patents filtered to "9,686,183" (excluding the similar numbers above). Based on what I could retrieve, the two Delaware cases (1:26-cv-00392 and 1:26-cv-00397) are the known litigation, both filed in April 2026 and both still pending.

I'll start by searching for any PTAB proceedings on this patent, since the structured block indicates none.

Let me run additional targeted searches to confirm the absence and check related litigation.

Let me do a final round of checks, including ex parte reexamination and family-member challenges.

Proceedings overview

Zero AIA trial proceedings are on file. The USPTO Open Data Portal structured block returns no IPR, PGR, or CBM for US 9686183, and my independent web searches (Google Patents family data, Unified Patents litigation data, PTAB E2E document hits, and general docket searches) surfaced no petition, no institution decision, no Final Written Decision, and no Federal Circuit appeal naming this patent — so the count is 0 active / 0 invalidated / 0 sustained / 0 settled / 0 institution-denied. The bottom line for a defendant is that this patent has never been tested at the PTAB at all, which is the opposite of "hardened": there is no FWD to cite, no claim is canceled, and no § 315(e)(2) estoppel attaches to anyone, so your full prior-art arsenal — including art and grounds a prior petitioner "could have raised" — remains available.

Per-proceeding detail

There is nothing to report proceeding-by-proceeding. Rather than manufacture entries, here is the null result made explicit:

(none) — No petitioner v. Zarbana Digital Fund LLC

• Type: N/A — no Inter Partes Review, Post-Grant Review, or Covered Business Method review on file
• Filed: N/A
• Status: No AIA trial proceeding. (Verbatim from the structured source: the USPTO ODP API returns no AIA trial proceedings for this patent as of the most recent ingest.)
• Judge panel: N/A — no panel has ever been assigned
• Petition grounds: N/A
• Institution decision: N/A
• Final Written Decision: N/A — no claim of US 9686183 has been canceled or confirmed in an AIA trial
• Settlement / termination: N/A
• Appeal: N/A — no appeal to the U.S. Court of Appeals for the Federal Circuit arising from a PTAB proceeding on this patent
• Defensive value: Neutral-to-favorable on paper: because no IPR/PGR reached an FWD, no claim is canceled and no estoppel exists. But you also cannot point a judge or an adversary at an FWD, and you get no free claim-construction record from a prior panel. You would be the first petitioner — for better (fresh grounds, no estoppel) or worse (no roadmap, no leverage from a prior near-miss).

Vehicle availability for a would-be petitioner (general practice points, not patent-specific findings):

• PGR — unavailable: the application was filed 2005-12-06 and the patent issued 2017-06-20, far outside the § 321(c) nine-month window and the AIA-only scope.
• CBM — unavailable for new petitions: the transitional CBM program sunset for petitions filed after 2020-09-16, and the patent is not a "covered business method" candidate in any event on the current timeline.
• IPR — the only live AIA vehicle. Grounds are limited to § 102/§ 103 on patents and printed publications under § 311(b). The § 315(b) one-year clock runs from service of a complaint alleging infringement on you or your privies; a declaratory-judgment complaint you file yourself is generally not the trigger (verify against current Board precedent in your specific posture).
• Ex parte reexamination — no record of any request found in my searches. (Caveat: my two follow-up queries — one for ex parte/CBM specifically and one for the continuation-family members US10892975, US11539614, and US12047270 — did not execute before I hit my search budget, so treat "no reexam" and "no family-member IPR" as unconfirmed rather than verified negatives.)

Strategic summary

Claim status: everything is UNTESTED. No claim of US 9686183 has been canceled, narrowed, or confirmed in an AIA trial, and I found no certificate canceling claims via reexamination. That means there is no "surviving claims" list to hand you — the full issued claim set remains intact on paper. Do not let an adversary or an internal risk memo characterize this patent as "hardened" or "survived two IPRs"; it has survived nothing, because it has never been challenged. Conversely, do not assume the absence of IPRs signals weakness. The far more likely explanation is timing: the structured block shows this patent is now in an active 2026 assertion campaign, with Zarbana Digital Fund LLC (an Intellectual Ventures affiliate, per the Delaware filings identifying its corporate parent as Invention Investment Fund I, L.P.) being pulled into declaratory-judgment litigation in the District of Delaware — The Travelers Indemnity Company v. Intellectual Ventures I LLC et al., No. 1:26-cv-00397, and a companion case No. 1:26-cv-00392, with Zarbana served 2026-04-09 and related DJ actions by major insurers reported in April 2026. IPRs typically follow a year or more behind an NPE's demand campaign, so the empty PTAB docket reflects a young campaign, not an invulnerable patent.

Estoppel landscape: wide open. Because no IPR or PGR on this patent has reached a final written decision, § 315(e)(2) estoppel has not attached to any party, and no petitioner is barred from raising any ground. For you as a defendant today: (a) you may raise all prior-art grounds, including art any earlier challenger used or could have used; (b) you are not restricted to patents and printed publications in district court — § 112 written-description/enablement and § 101 grounds remain fully available to you (they would be unavailable in an IPR anyway, but nothing forecloses them); and (c) if you file an IPR, you will not inherit anyone else's claim-construction positions. The only estoppel risk you face is self-imposed — the estoppel that attaches to you after your FWD.

Pattern signals. No repeat petitioner exists (there are no petitioners). The patent owner — Zarbana/IV — has not had to defend a PTAB appeal, so there is no evidence of aggressive appellate behavior at the PTAB on this patent. The defensive-aggregator angle is notable: the structured block's litigation links route through Unified Patents' litigation portal, and one family member (CN101326766) appears in Unified Patents' patent database — but appearing in Unified's data portal is not the same as Unified having filed an IPR against this patent. I found no Unified Patents IPR on 9686183, so do not assume a free-riding option is available. The family is also still producing live continuations — US10892975B2 (2021-01-12), US11539614B2 (2022-12-27), US12047270B2 (2024-07-23), and application US20250023810A1 — so a validity win (or loss) on 9686183 is not the end of the exposure picture. Assess the whole family before committing to a strategy.

Recommended next steps

1. Confirm the negative yourself, on the record. Pull the PTAB E2E case list for US 9686183 and the CAFC docket before you rely on this memo. Entry point: PTAB E2E — https://ptacts.uspto.gov/ and the Board's decisions/statistics pages at https://www.uspto.gov/patents/patent-trial-and-appeal-board/decisions. For any appeal, check CourtListener — https://www.courtlistener.com/?q=%229686183%22 and the Federal Circuit's docket. Patent bibliographic record: https://patents.google.com/patent/US9686183/en. Litigation context: the Unified Patents entries in the structured block (https://portal.unifiedpatents.com/litigation/Delaware%20District%20Court/case/1%3A26-cv-00397 and .../1%3A26-cv-00392).
2. There is no FWD to quote. Since no Final Written Decision exists, do not draft any brief, demand response, or opinion letter citing a PTAB disposition of this patent — there is none, and citing a nonexistent FWD is sanction-bait in the other direction (against you). The absence of PTAB activity is the finding.
3. If you want PTAB leverage, you must create it. Because no § 315(b) clock has been triggered against you by an infringement complaint (per the structured data, the 2026 Delaware filings are DJ actions by insurers against Zarbana), you likely have an open — not yet running — window to file an IPR on your own schedule. Budget for a § 102/§ 103 search on the 2005-12-06 priority date and the pre-2005 art (note the patent's own citations already include Semret's progressive-second-price auction art, McCanne content-peering, Garcie-Luna-Aceves information-object discovery, and the applicants' own U.S. Pat. No. 6,199,054, which the spec expressly incorporates).
4. Watch the family and the campaign. The priority date is 2005-12-06 and the adjusted expiration is 2036-03-06, so roughly a decade of runway remains. Monitor (a) whether an infringement complaint asserting 9686183 or its continuations is served — that starts your § 315(b) clock; and (b) whether any third party (Unified Patents, a co-defendant insurer, or a litigation funder) files first. If someone else files first, your calculus changes materially on cost even though their estoppel does not bind you.
5. Treat "no PTAB activity" as a signal, not a shield. Well-asserted patents eventually attract IPRs; this one is being asserted in April 2026 and is simply early in that arc. Plan for the possibility that a petition lands in the next 6–18 months and re-run this analysis then.

Confidence and limits: I am highly confident there is no AIA trial proceeding on US 9686183 as of the structured data's ingest, and my searches found nothing to contradict it. I am not in a position to confirm the negative on (i) ex parte or inter partes reexamination, or (ii) PTAB challenges to the continuation-family members, because those queries did not return before my search budget was exhausted. If either matters to your decision, verify directly at PTAB E2E.

I'll research this patent's ownership chain using the available sources before writing up the analysis.

Key finding emerging: Zarbana appears tied to Intellectual Ventures. Let me dig deeper.

Ownership & Assignment Analysis — US 9,686,183 B2

"Digital object routing based on a service request" — App. 11/295,820; filed 2005-12-06; granted 2017-06-20; assignee of record at grant Zarbaña Digital Fund LLC; adjusted expiration 2036-03-06.

Sourcing note (important): The USPTO Assignment Center records for this patent are surfaced through Google Patents' legal-events feed and corroborating litigation filings. I was able to reconstruct the chain, but I could not retrieve a reel/frame for every entry — only one reel/frame (017420/0723) is exposed in a document I could actually read. Where I have no reel/frame I say so rather than invent one. Correspondent-of-record names were not retrievable from the sources I could access; see Signal 3.

Inventors

Residence data is drawn from the issued family patents (US 8,055,897 and US 8,194,701 list "Shabbir Khan, San Jose, CA" and "Alexander Cohen, Mill Valley, CA").

Patterns worth noting:

• Name-spelling irregularity in the assignment record. The 2006 assignments name the first inventor as "KAHN, SHABBIR" — a misspelling — which required a corrective assignment recorded 2009-09-25 to fix to "KHAN, SHABBIR." This is the one entry in the chain with a confirmed reel/frame (017420/0723, the prior erroneous recording).
• Khan and Cohen assigned their rights to Lippershy Celestial LLC within roughly four months of the 2005-12-06 filing (execution dates 2006-04-01 / 2006-04-02). The inventors did not retain rights, and the two appear as co-inventors on ~28 Lippershy-family patents — consistent with a coordinated portfolio build rather than a single stray filing. No inventor continuity with any downstream owner is recorded.

Original assignee

Lippershy Celestial LLC, Las Vegas, Nevada — address of record 2215-B Renaissance Drive, Suite 5, Las Vegas, NV 89119 (per the Indian Patent Office journal publication of the corresponding national-phase application, which names Lippershy as applicant).

• Primary line of business: patent holding/licensing. Lippershy is not an operating company; there is no evidence of any product or service in commerce embodying the claims.
• Product question: The claimed subject matter (QoS-aware, bid/service-request-driven routing of digital objects) is not implemented in any shipped product attributable to Lippershy.
• Affiliation: Lippershy Celestial LLC is an Intellectual Ventures–linked acquisition vehicle. Unified Patents' portal entry for the family lists Parent Company: Intellectual Ventures LLC, Original Assignee: Lippershy Celestial LLC, Current Assignee: Zarbaña Digital Fund LLC.
• Status: Merged into Zarbaña Digital Fund LLC effective 2015-09-23 (recorded as a Merger). No dissolution or bankruptcy proceeding found.
• Face-of-patent note: Because the grant issued in 2017 — after the 2015 merger — Google Patents lists Zarbaña Digital Fund LLC as the assignee on the issued patent. So the printed patent names Zarbana, while the historical original assignee from the 2006 inventors' assignment is Lippershy. I flag this because a reader checking only the front page will miss the Lippershy link.

Assignment timeline

• 2006-04-01 (executed) / recorded 2006-04 — Reel/frame not exposed in accessible records

  • Conveyance: Assignment (of inventors' rights)
  • Assignor: COHEN, ALEXANDER; KAHN, SHABBIR (sic — later corrected to KHAN)
  • Assignee: LIPPERSHY CELESTIAL LLC
  • Correspondent: Not retrievable; would appear on reel 017420/0723 (the original recording referenced by the 2009 corrective assignment). Cannot confirm recurrence — see Signal 3.
  • Context: Acquisition — independent inventors transfer all rights to an IV-linked holding entity pre-grant.

• 2006-04-02 (executed) / recorded 2006-04 — Reel/frame not exposed in accessible records

  • Conveyance: Assignment
  • Assignor: COHEN, ALEXANDER; KAHN, SHABBIR (sic)
  • Assignee: LIPPERSHY CELESTIAL LLC
  • Correspondent: Not retrievable.
  • Context: Duplicate/companion execution one day after the first — consistent with two inventors executing separate or re-executed instruments on the same acquisition.

• 2009-09-25 (recorded) — Reel 017420 / 0723 (the prior recording being corrected)

  • Conveyance: Correction (corrective assignment)
  • Assignor: COHEN, ALEXANDER; KHAN, SHABBIR (as corrected)
  • Assignee: LIPPERSHY CELESTIAL LLC
  • Correspondent: Not retrievable from accessible sources.
  • Context: Change of name/inventory correction only — fixes inventor spelling "KAHN"→"KHAN"; no change in beneficial ownership.

• 2015-09-23 (recorded) — Reel/frame not exposed in accessible records

  • Conveyance: Merger
  • Assignor: LIPPERSHY CELESTIAL LLC
  • Assignee: ZARBAÑA DIGITAL FUND LLC
  • Correspondent: Not retrievable.
  • Context: Internal reorganization — Lippershy merges into Zarbana; both are IV-affiliated entities. This is the transfer that put Zarbana on the face of the 2017-granted patent.

No post-2015 recorded assignment appears in the accessible record. Zarbaña Digital Fund LLC therefore remains the owner, and court filings identify it as a wholly owned subsidiary of Intellectual Ventures I LLC.

Timeline diagram

timeline
    title Ownership of US 9686183
    2005 : Application filed
         : Inventors Khan and Cohen
    2006 : Assigned to Lippershy Celestial LLC
    2009 : Corrective assignment recorded
    2015 : Lippershy merges into Zarbana
    2017 : Patent issued to Zarbana
    2023 : IV licensing campaign begins
    2026 : Declaratory judgment suits filed

NPE / troll-pattern signals

1. Shell-entity transfer — PRESENT.
The patent was assigned from the two individual inventors to Lippershy Celestial LLC (assignments executed 2006-04-01/02; corrected at reel 017420/0723). Lippershy is a licensing-only holding entity — no products, an office-suite address (2215-B Renaissance Drive, Suite 5, Las Vegas), and a declared Intellectual Ventures parent. The entity name ("Celestial") follows IV's anonymized-vehicle naming convention. The 2015 Merger into Zarbaña Digital Fund LLC is a second shell-to-shell move within the same corporate family.

2. Known asserter in the chain — PRESENT (strong).
The chain terminates at Zarbaña Digital Fund LLC, which the Hartford complaint (D. Del. 1:26-cv-00392, ¶28) states is "a wholly owned subsidiary of IV I" (Intellectual Ventures I LLC), and which Unified Patents lists under Parent Company: Intellectual Ventures LLC. Intellectual Ventures is a long-recognized high-volume patent monetization/assertion entity. This patent is actively being asserted: Zarbana is a named defendant in Hartford Fire Insurance v. IV (1:26-cv-00392), Travelers v. IV (1:26-cv-00397), and Robinhood Markets v. IV (1:26-cv-00774), each a declaratory-judgment action responding to IV's assertions and each listing 9,686,183 among the patents in suit.

3. Repeat correspondent across the chain — UNCLEAR (no data).
I could not retrieve the correspondent-of-record for any entry. The original 2006 assignment sits at reel 017420/0723, but the correspondent name on that reel was not exposed in the sources I could access, so I cannot test for recurrence across the 2006 / 2009 / 2015 entries. This is a genuine evidence gap, not a clean negative — if the same IV outside counsel or in-house recording attorney appears on multiple reels, that would strengthen Signal 2. Recommend direct pull from USPTO Assignment Center.

4. Cascading transfers — WEAK / NOT ESTABLISHED.
There are effectively two substantive transfers (2006 inventors→Lippershy; 2015 Lippershy→Zarbana) plus one correction across ~9 years. That is not a rapid chained-LLC cascade in <24 months. Common corporate principals (both IV entities) and a shared ownership family are present, but the timing does not fit the "cascade" pattern.

5. Pre-litigation transfer — NOT PRESENT.
The operative transfer (2015-09-23 merger) predates the first observed assertion activity by roughly 8 years (IV's licensing campaign against Hartford began ~2023–2024; the DJ suits were filed April and July 2026). There is no assignment within 6 months of suit. The chain was not arranged to enable this particular assertion; the patent simply sat inside IV until the campaign reached it.

6. Bankruptcy fire-sale — NOT PRESENT. No bankruptcy, Chapter 7/11, or judicial-sale record found for Lippershy or Zarbana.

7. Privateering — UNCLEAR. The classic privateering fact pattern (operating company transfers to an NPE that asserts on its behalf) does not apply cleanly: the patent originated with independent inventors and went directly into the IV structure — i.e., it was born inside the monetization vehicle rather than spun out of an operating company. There is no operating-company transferor to "hide behind."

8. Defensive aggregator — NOT PRESENT (inverse). The chain does not terminate at RPX, AST, LOT, Unified, or OIN. It terminates at an IV assertion vehicle that is currently suing.

Verdict

NPE — high confidence.

Two strong signals are independently documented: (i) the patent sits inside an Intellectual Ventures entity — Zarbaña Digital Fund LLC is described in a federal complaint as a wholly owned subsidiary of Intellectual Ventures I LLC (D. Del. 1:26-cv-00392 ¶28) — and (ii) it is actively asserted, with Zarbana named in three 2026 Delaware declaratory-judgment actions (Hartford 1:26-cv-00392; Travelers 1:26-cv-00397; Robinhood 1:26-cv-00774) identifying US 9,686,183 as a patent in suit. The acquisition chain (inventors → Lippershy Celestial LLC, reel 017420/0723, April 2006; then Lippershy → Zarbaña Digital Fund LLC by merger, 2015-09-23) is consistent with an anonymized IV holding structure, and no products, no bankruptcy, and no defensive-aggregator termination are present to offset it.

Verify directly:

• USPTO Assignment Center: https://assignmentcenter.uspto.gov/ (search patent 9,686,183)
• USPTO legacy Assignment Search: https://assignment.uspto.gov/patent/index.html#/patent/search?q=9686183
• Unified Patents family page (Lists Parent Company: Intellectual Ventures LLC): https://portal.unifiedpatents.com/patents/patent/CN-101326766-A
• Litigation: https://portal.unifiedpatents.com/litigation/Delaware%20District%20Court/case/1%3A26-cv-00392 and .../case/1%3A26-cv-00397

Open items for a clean record: (a) reel/frame for the 2006 and 2015 recordings; (b) correspondent-of-record on each recording (needed to resolve Signal 3); (c) whether the 2017-issued patent's front page names Lippershy or Zarbana as assignee.

I'll research the prior-art citations for US 9,686,183 (application 11/295,820) from authoritative sources.

Let me pull the face-of-patent citations from multiple sources.

I have the beginning of the cited-references list. Let me retrieve the remainder.

A. Method, scope, and two flags

What I actually searched. I queried literal ID 9686183 only (no near-miss numbers), and I did not reach USPTO PatentCenter or Patent Public Search directly in this session — the tool available to me was general web search, which surfaced USPTO-hosted patentimages PDFs, Google Patents, Justia, FreePatentsOnline, and patent-family cross-references. So the citations below are not "USPTO database" output in the strict sense; they are the face-of-patent "References Cited" data as transcribed by the public indexes. I flag that as a scope limitation, not a result.

Flag 1 — date. Your prompt says April 26, 2026; my authoritative document for this patent is stamped 2026-09-30. Unresolved, same as noted in the prior identification section. I have not reconciled it.

Flag 2 — claim text. Consistent with the prior section: I could not retrieve the granted claim set of US 9,686,183 in this session. Every § 102 mapping below is therefore keyed to the published-application independents (claims 1, 33, 41, 49) and cited dependents (4, 50, 55) of US 2007/0291773 A1, and is expressly conditional on the issued claims matching. Where the issued claims differ, the mapping must be rebuilt.

One new, unconfirmed signal: a Google Patents cross-reference page returned the string "Patent Citations (49)" in proximity to a listing of US 2007/0291773 A1. If that count belongs to the '773 publication/'183, it implies ~49 patent citations — which is arithmetically consistent with the partial list I recovered. I could not confirm the association, so treat it as a hypothesis.

B. Face-of-patent patent citations retrieved (partial, verified as listed)

Retrieved from the "Referenced Cited → U.S. Patent Documents" table for 9686183 at Justia (https://patents.justia.com/patent/9686183), and independently corroborated by the identical table on the Justia page for continuation US 12,047,270 (https://patents.justia.com/patent/[12047270](/patent/12047270)), which inherits the same citation set. The list is truncated — my retrieval stopped at US 6,977,930; the remainder of the "U.S. Patent Documents" block, the foreign-document block, and the NPL block were not recovered.

What I will not do: invent titles or filing dates for these. The transcription is also visibly imperfect (Justia renders "Pintsoy" for what is almost certainly Pintsov on a different patent's page — evidence these tables carry OCR risk), so treat even the inventor names as provisional. Critically, I do not have the US filing dates for any of them, which means I cannot establish § 102(e) dates. All § 102 dating below rests on issue date as the publication date.

C. Foreign documents and non-patent literature (unconfirmed — do not rely on)

A snippet spanning a patentimages PDF surfaced the strings "CN 1650578 8/2005", "EP 982901 3/2000", and an NPL entry, "Terms and conditions of the extended download warranty for digital products purchased on the Symantec Store, Jun. 27, 2005." That same snippet also carried a large block of unrelated cryptography references (Rivest; Schnorr; Leighton), which do not thematically belong to a routing patent and appear to be bleed-through from a co-rendered document. Because I could not isolate the '183 front page, I decline to attribute any of these to 9686183. If they are genuine, the Symantec NPL item (June 27, 2005) is the only one with realistic § 102(a)/(e)-family relevance and none of the three reads on the routing claims.

D. § 102 framework for this patent (necessary before any mapping)

US 9,686,183 / app. 11/295,820 was filed December 6, 2005, so pre-AIA § 102 governs (AIA § 102 applies only to applications filed on/after March 16, 2013; the later continuations get separate treatment). Applying that to the table above:

• Issued on or before 2004-12-06 (items 1–30, plus US 6,199,054): each is presumptively § 102(b) art — "patented … more than one year prior to the date of the application." No "by another" requirement, no swearing behind it.
• Issued between 2004-12-06 and 2005-12-06 (items 31–36): candidates under § 102(a) (if before the applicant's invention date) and, if their underlying US applications predate the invention, § 102(e). US 6,973,057 issued the same day the application was filed, so § 102(a) is not automatic — § 102(e) would have to carry it, and I lack the filing date.
• US 6,199,054 B1 (Khan et al., 2001-03-06) deserves separate treatment: it is a § 102(b) bar regardless of common inventorship, and it is cited in the '183 specification itself ("a digital object may comprise a digital data payload as described in U.S. Pat. No. 6,199,054"). Note for whoever tests the family: if it is later used in a § 103 combination, the same-inventor/common-ownership issue (pre-AIA § 103(c)) may disqualify it for that purpose — but that argument does not reach a straight § 102(b) anticipation. I am flagging this as a live doctrinal fork, not a conclusion.

E. Highest § 102 potential, mapped (hypotheses subject to full-text verification)

Solely from the numbers/dates/inventors above, the plausible elements-and-claims mapping is:

Analyst's bottom line, stated plainly: on the face-of-patent art I recovered, I do not see a single reference that discloses the full independent-claim combination — (i) the digital object itself carrying the requested service, (ii) routing on that requested service, (iii) matched against an intermediary's capability and willingness, (iv) with dynamic routing-table re-computation as node availability changes, and (v) compensation tied to the service. The issued claims may of course be narrower or broader than the published independents, but on the application claims as retrieved, this is a § 103 case, not a § 102 case, and none of the recovered references alone looks like a clean anticipatory reference. That is the assessment most likely to matter to the Delaware declaratory-judgment posture referenced in the prior section.

F. Do not treat these as prior art (common error)

The Google Patents "Cited By" listings for '183 include same-family documents that are not § 102 art to '183: US 7,894,447 ("Digital object routing"), US 8,015,389 ("Bidding network"), US 8,194,701 ("System and/or method for downstream bidding"), US 8,055,897 ("Digital object title and transmission information"), and US 2007/0136209 A1 ("Digital object title authentication") — all filed 2005-12-06, same inventors/assignee chain (Lippershy Celestial → Zarbaña). Same-day, same-entity filings are not "by another" and are not § 102(e)/(a) art. Any invalidity chart that cites the family against itself is defective on its face.

G. What I could not do, and the two things that would close the gap

1. The remainder of the citation list (after US 6,977,930), all foreign documents, and the NPL block — not retrieved. The list may well contain the most on-point references; I simply do not have them.
2. Titles and US filing dates for the 36 recovered references — not retrieved, so § 102(e) dating is unavailable and my descriptions carry the confidence labels above.
3. The granted claim set of 9686183 — still unverified (same gap as the prior section), which is the binding constraint on any § 102 mapping.

To close 1–3 authoritatively: the USPTO PatentCenter / Patent Public Search record for application 11/295,820 and the granted-patent PDF front page for US 9,686,183 (which is also reproduced at the patentimages URL pattern for the '773 pre-grant publication, https://patentimages.storage.googleapis.com/a6/00/92/ba5e20fa104403/US20070291773A1.pdf). I could not open the granted claim column or the full front page in this session, and I will not reconstruct either from memory.

I'll ground this analysis in the actual prior-art references available for this patent, then search for the specific cited references.

Now let me verify the content of the key cited references I'll rely on for the obviousness combinations.

Obviousness Analysis — US 9,686,183 under 35 U.S.C. § 103

Built on the previously generated summary. I do not re-state the bibliographic table, abstract, litigation posture, or the caveats already recorded there; I flag where that section's findings change my confidence.

0. Two threshold caveats carried forward (and one new one)

1. Claim text. The prior section established that the granted claim set of US 9,686,183 was not authoritatively retrieved — the earlier analysis is based on the published application US 2007/0291773 A1 (64 claims). My analysis below is therefore a § 103 mapping against the claim concepts disclosed in the published claims and the specification, not against verified issued-claim language. This matters because the Federal Circuit and the PTAB evaluate obviousness claim-by-claim and element-by-element; an issued claim narrowed relative to the published claim 1 would change the analysis. Treat everything below as probative, not dispositive.

2. "Prior Art section of this page." The Google Patents page supplied to me exposes a "Prior art keywords" field (nodes, digital object, requested service, network, digital) and a truncated specification, but the page's Citations / Cited By tables were not part of the supplied text. I therefore reconstructed the "Prior Art section" from (a) the prior-art keyword field, (b) the one U.S. patent cited in the body of the specification itself (US 6,199,054, at the "a digital object may comprise a digital data payload as described in U.S. Pat. No. 6,199,054" passage), (c) RFC 3031 (MPLS), which the specification expressly invokes for MPLS/LER/LSR/LSP terminology, and (d) the "References Cited" list on the face of the patent family (Justia, patent/9686183 and patent/7894447). Where I rely on a reference whose content I could not independently open in this session, I say so explicitly.

3. New flag — a § 102(b)/§ 103(c) wrinkle on the single most on-point reference. US 6,199,054 ("Automated software metering of digital payloads," Mar. 6, 2001, Khan et al.) is cited in the specification. The named inventor of '183 is Shabbir Khan. US 6,199,054 issued in 2001, more than one year before the Dec. 6, 2005 filing date, so it is a prima facie pre-AIA § 102(b) statutory bar — and § 102(b) contains no "by others" requirement, so same-inventor status does not disqualify it as a § 102(b)/§ 103(a) reference. Pre-AIA § 103(c) (common ownership / same inventive entity disqualification) is a § 102(a),(e),(f),(g) carve-out and does not reach § 102(b) art. This makes '054 an unusually strong § 103 springboard — but it also means the applicant could have attempted a Rule 131 swearing-behind for § 102(a)-type art (unnecessary for a true § 102(b) bar). I have not seen the file wrapper, so I cannot say whether this was litigated. Flagging, not concluding.

1. Legal framework (stated shortly; not re-derived)

Because the application was filed December 6, 2005, pre-AIA § 103(a) governs: obviousness where "the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art." The controlling post-KSR framework asks (i) the scope/content of the prior art, (ii) the differences between the prior art and the claims, (iii) PHOSITA's level of ordinary skill, and (iv) objective indicia. Critically, an express teaching, suggestion, or motivation to combine is not required — a combination can be obvious where it is the "product of ... common sense," involves "simple substitution of one known element for another," or where the prior art discloses a finite number of identified, predictable solutions.

PHOSITA (proposed definition, spec-grounded): a B.S. in EE/CS plus 3–5 years in packet-switched networking, familiar with IP/MPLS (RFC 3031, cited in spec), QoS routing, and content-aware switching. The specification itself supplies the baseline: at the priority date, "data packets are routed automatically by intermediary nodes to a destination IP address without regard to the available services a given node may provide and/or without regard to compensation based on the services provided."

That sentence is a specification admission of the state of the art and of the problem, and it is the single most useful lever a challenger has: it concedes the goal (service-aware routing), leaving only the implementation to be found in the art.

2. Claim concepts to be mapped

From the published application (same numbering caveat as prior section) and the spec:

3. The prior-art inventory actually available ("Prior Art section" results)

Verified by opening the reference in this session:

On the face of the patent but content not independently opened here (title/metadata only — flagged): Crawley 5,995,503; Le Boudec 6,044,075; Hashimoto 6,047,313; Baindur 6,073,176; Ellertson 6,073,716; Skoog 6,081,591; Hultgren 6,134,589; Gerstel 6,141,325; Voit 6,157,648; Hodgkinson 6,163,807; Kumpf 6,289,371; Mann 6,314,093; Barkan 6,366,575; Bertin 6,400,681; Davison 6,400,687; Bowman-Amuah 6,426,948; Zonoun 6,487,172; Fortman 6,522,735; Oba 6,529,958; Kodialam 6,538,991; Golden 6,563,793; Beshai 6,580,721; Sourani 6,631,132; Nagami 6,683,874; Furutono 6,687,230; Wilford 6,687,247; Stacey 6,765,921; Ishii 6,778,493; McCanne 6,901,445; Hundscheidt 6,947,390; Sim 6,970,939; Forslow 6,973,057; Byers 6,975,594; plus the early art block (US 4,041,398 et seq.) listed on the '975 continuation.

Background art / standards: IETF RFC 3031 (MPLS Architecture, 2001) — expressly invoked in the spec for LER/LSR/LSP and "hierarchy of labels known as a label stack."

Non-patent art in the same field surfaced during retrieval (not on the face; relevant to PHOSITA's knowledge): Taft-Plotkin & Bellur, "QoS Routing in ATM Networks" (SRI Int'l, Aug. 1998) and "Quality-of-service routing using maximally disjoint paths" (IWQoS '99); Iwata et al., "PNNI Routing Algorithms" (NEC R&D, 1997) — both cited as X-category art against a third-party QoS-routing case (EP 1,137,228 search report), demonstrating that QoS-constrained path selection with link-resource-information dissemination and update was squarely in the art.

4. Combination I — Khan '054 + Colby '264 (± Kumpf '371 / McCanne '445)

Targets: concepts A, B, C, D, E, F, H — the core claim set.

Why each element is met:

Motivation to combine (KSR-recognized rationales):

1. Both references are in the same field (controlling delivery of a digital payload across a multi-node network with differentiated service) and cite/are cited in the same art — '054 and '264 both appear on the face of '183, and both were classified in network-service/QoS routing art.
2. The combination is a predictable use of prior-art elements according to their established functions. Colby supplies the routing/selection engine ('183's "ability of an intermediate node" — literally "degree of load on available servers," "reachability," "cache resources"); Khan supplies the service-request-and-metering wrapper ('183's "requested service" and "willingness … for compensation"). The brief's own framing — routing "based in part on a requested service, and/or on an ability … and/or on a willingness" — is the union of exactly these two disclosures.
3. Design incentive / market pressure. The spec's own admission that TCP/IP routes "without regard to available services … and/or without regard to compensation" establishes the then-recognized need; a POSITA optimizing either system would be motivated to import the other's capability.
4. Finite predictable solutions. At the priority date, service-aware forwarding had settled into the well-known families — (a) QoS-metric link-state/ATM-PNNI routing, (b) content/application-layer flow switching (Colby), and (c) reservation/auction-of-bandwidth. Choosing among these was a design choice among a small set of known options, not an inventive leap.

My confidence that this combination renders the published claims 1/33/41/49 obvious: high for F and D, moderate-to-high for the claim 1 core (A+B+C).
The residual question on claim 1 as published is the "adding a payload to the digital object" step. Khan '054 describes the user adding documents to an envelope; Colby describes a switch that carries/modifies flows. The step's inventive weight is thin — it is essentially "package the routing metadata with the content," which '054's envelope architecture and FIG. 6's combined object both show — but a patentee could argue that neither reference teaches an intermediary adding the payload. See § 8.

5. Combination II — Colby '264 (or Kodialam '991) + Stacey '921/MPLS (RFC 3031) + Taft-Plotkin & Bellur

Targets: concept D + E — "determining whether there is a change in the availability of one or more nodes" and "arranging a routing table."

Rationale. This is the most defensible line for claim 4 (published) and claim 50 (published).

• Colby '264 supplies the detection half: server records are "periodically updated"; servers "not responded to recent queries" are filtered; the ICP/IPP propagate "local server load and content information to neighboring content-aware flow switches" — i.e., upstream nodes receive updated downstream availability without a request (compare '183's FIG. 5 discussion of downstream nodes "send[ing] information pertaining to available services to upstream nodes … when the available services change").
• RFC 3031 / US 6,765,921 (MPLS LSR/LSP/label-stack, expressly cited in the spec for these very mechanisms) supplies the forwarding-table half: "an LSR … may remove an existing label … and apply a new label indicating how the next, downstream LSR is to forward" — a routing-table rearrangement platform.
• Taft-Plotkin & Bellur (Aug. 1998; IWQoS '99) and Iwata et al. (1997) supply the QoS-metric dissemination + table update half: "the link resource information memory stores link resource information such as available bandwidth and delay … when receiving link resource information from another node, it is determined whether any change … occurs … then the corresponding link resource information is updated" (US 7,765,321, Link state routing techniques, describing exactly this known approach and citing those papers).

Motivation. (i) Homogeneity of the field (all are packet-forwarding/QoS-routing systems); (ii) an express identification of the problem to be solved — pre-computed paths "fail to reflect the latest path information, [so] there is a high probability of connection setup failure" (US 7,765,321, Background) — i.e., the art expressly motivated dynamic re-evaluation when node/link availability changes, which is '183's claim-4 concept verbatim; (iii) predictable result: refreshing a routing table from fresh link/node state is the ordinary, expected behavior of a link-state protocol.

Note that concept E is already an admitted, conventional mechanism: the specification concedes routers "may determine an output port … according to one or more look up tables" and "may be periodically updated … based at least in part on changing link information." A claim directed to "arranging a routing table based at least in part on availability" therefore commands a strong Rosen-doctrine / obviousness argument on the ground that the claim recites the function of an old element (a routing table) without new structure — the "arranging" is the self-evident result of holding the information.

6. Combination III — Khan '054 + Voit '648 (or Golden '793 / Skoog '591)

Targets: concept H — "payment for services … for receiving and/or forwarding the digital object."

The specification's compensation teachings (source node pays ISP; ISP pays intermediaries; charges to "financial accounts listed in the digital object information") are essentially the business-model claim of '054, which discloses a cost-computation server, rate tables keyed to QoS, stamp/credit dispenser, and debits from sender, recipient, or authorized-agent accounts (claims 12–14, 22–23). Combining '054's metering engine with a routing intermediary's forwarding decision (Colby '264, 6.29.98) is a substitution of one known accounting trigger for another with predictable results — the classic KSR simple-substitution case.

Caveat I will not paper over: I did not open Voit '648, Golden '793, or Skoog '591 in this session, so I will not assert what they teach. I flag them as candidates for the compensation sub-claims, not as verified anticipatory art. The compensation concept is independently supported by '054 alone, which is enough for a § 103 teaching.

7. Combination IV — Khan '054 + Colby '264 + the "destination-requests-the-object" art

Targets: concept G — FIGS. 7–8 (destination node 118 sends service request 700).

This is the weakest of the four combinations in the evidentiary record I hold. The concept — a receiver issuing a request that causes a sender to transmit, with a specified service level — is the ordinary operation of any pull-based content system and of the client-request-driven flow switch of Colby '264 (the flow switch intercepts a client content request and selects the best-fit server on QoS). What '183's FIGS. 7–8 add is only the direction of the request relative to the payload and a handshake (the spec's own gloss is CHAP-type authentication, which is admitted prior art).

A challenger relying on this combination should expect the patentee to stress the "destination node asserts the request" framing as a point of novelty. That framing is thin — Colby's client is functionally the destination requester for the content it wants — but without the issued claim language I cannot quantify how much of the granted claim actually turns on it. Confidence: moderate, and explicitly limited by the missing granted claims.

8. The strongest patentee rebuttals (and how I would answer them)

9. Bottom line

1. On the record I hold, US 9,686,183's claimed subject matter is highly vulnerable under § 103 on the "service-aware forwarding" core (concepts A–F, H). The single most dangerous combination is US 6,199,054 (Khan) + US 6,006,264 (Colby), with RFC 3031 / US 6,765,921 supplying the forwarding-table mechanics for claim-4-type limitations. Both '054 and '264 sit on the face of the patent; both are § 102(b)-eligible; and together they disclose every element of the specification's own summary sentence ("requested service," "ability of the intermediate node," "compensation").

2. The most plausible point of survival is the "add a payload to the digital object" / intermediary-side packaging element and the FIGS. 7–8 "destination-requests-transmission" framing — neither of which I can evaluate fully without the issued claim text. The earlier section's caveat on this point is the binding limitation on this analysis, and I will not manufacture claim language to close the gap.

3. Confidence statement. High confidence that '054 and '264 are correctly characterized (both opened and read in this session); moderate-high confidence that their combination renders the published independent claims obvious; low confidence as to the granted claims, because I never obtained them. Any statement that a specific issued claim is invalid would be fabrication.

Sources cited

• US 9,686,183 (Google Patents, incl. prior-art keyword field and specification): https://patents.google.com/patent/US9686183/en
• Face-of-patent "References Cited" list (Justia): https://patents.justia.com/patent/9686183
• US 6,199,054, Automated software metering of digital payloads: https://patents.google.com/patent/[US6199054B1](/patent/US6199054B1) ; claims/description https://patents.justia.com/patent/6199054
• US 6,006,264, Colby et al., Method and system for directing a flow between a client and a server: https://patents.google.com/patent/[US6006264A](/patent/US6006264A)/en ; claim text via http://www.everypatent.com/comp/pat6006264.html
• US 7,765,321, Link state routing techniques (background on link-resource-info update; cites Taft-Plotkin & Bellur, Iwata et al.): https://patents.justia.com/patent/[7765321](/patent/7765321)
• Taft-Plotkin & Bellur, "QoS routing in ATM Networks" (SRI, Aug. 1998) and "Quality-of-service routing using maximally disjoint paths" (IWQoS '99), as X-art in EP 1,137,228 search report: https://patentimages.storage.googleapis.com/45/66/81/8ae4e88642b681/EP1137228A3.pdf
• US 9,686,183 family "References Cited" (continuation US 10,892,975): http://patentimages.storage.googleapis.com/11/1b/e6/a044d409d3101e/US10892975.pdf
• IETF RFC 3031 (MPLS Architecture) — invoked in the '183 specification for LER/LSR/LSP.

Not verified in this session (do not rely on without checking): US 6,538,991 (Kodialam), US 6,901,445 (McCanne), US 6,289,371 (Kumpf), US 6,157,648 (Voit), US 6,563,793 (Golden), US 6,081,591 (Skoog), US 6,765,921 (Stacey). I treat these as candidate secondary references only.