Summary

  • ARIN’s cumulative transfer original records 100 MERGER_ACQUISITION rows from Crown Castle Fiber LLC to Zayo Bandwidth at the identical timestamp, 16:06:28 UTC on 1 June 2026: 72 disjoint IPv4 ranges containing 674,304 addresses, eight IPv6 /32s and 20 individual ASNs.
  • One IPv4 range, 160.72.0.0/16, had already appeared in three earlier exact-boundary transfers: MacMillan Bloedel to Weyerhaeuser in 2015, Weyerhaeuser to Lightower in 2016, and Lightower to Crown Castle in 2024. Current ARIN RDAP names Zayo, retains a 2016 registration event and records a 2026 last change.

One second is a splendid way to make an archive forget its age. ARIN’s 3 November cumulative export has a hundred rows stamped 2026-06-01T16:06:28Z, all from Crown Castle Fiber LLC to Zayo Bandwidth and all classified MERGER_ACQUISITION. Read the timestamp alone and it looks like a single clean arrival. Read the resource fields and it becomes 72 IPv4 intervals, eight IPv6 blocks and 20 autonomous system numbers. Read backward along one of those intervals and the “arrival” has a 2015 receipt, a 2016 receipt and a 2024 receipt underneath it.

The count needs three different units. The 72 IPv4 transfer sets are distinct, nonoverlapping ranges totalling 674,304 addresses. The eight IPv6 entries are each a /32. The 20 ASN entries each contain one number. None is an IPv4 address to add to 674,304. The ledger puts each resource on a separate row with exactly the same second, which is excellent for recording an administrative batch and terrible for anyone who mistakes a row count for address volume. Six of the IPv4 ranges are full /16s of 65,536 addresses each; a /24 contributes only 256. A hundred rows are not a hundred equal parcels.

Take 160.72.0.0–160.72.255.255, one of those /16s. On 11 December 2015, ARIN records MacMillan Bloedel Limited transferring the exact range to Weyerhaeuser Company as MERGER_ACQUISITION; the row carries a source registration date of 3 October 1994. On 29 April 2016, Weyerhaeuser sends the same boundaries to Lightower Fiber Networks I, LLC under RESOURCE_TRANSFER. Lightower sends them to Crown Castle Fiber LLC on 29 February 2024 under MERGER_ACQUISITION. Crown Castle’s 1 June 2026 row sends the exact same start and end to Zayo. Four receipts, five named parties, one unchanged 65,536-address interval. The joins are literal start and end addresses, not a guess that similar names refer to one company.

Current ARIN RDAP answers the /16 as NET-160-72-0-0-1, ZAYO-CCF-160-72-0-0, with Zayo Bandwidth as registrant. Its registration event is 29 April 2016 at 15:45:07 Eastern time. Its last-changed event is 1 June 2026 at 12:06:25 Eastern time, three seconds before the transfer row’s UTC stamp. Neither date is the 1994 source registration carried in the 2015 transfer entry. The three clocks serve different purposes: an older source-registration date in the transfer history, the present RDAP object’s registration event, and the latest transfer and update. Compress them into “registered in 2026” and the /16’s paper trail disappears.

The extremes of the hundred-row tray are nearly comic. One transferred /16, 131.239.0.0/16, carries a 6 February 1989 source-registration date. The 9.179.0.0/16 and 9.191.0.0/16 rows carry 4 September 2025 source-registration dates. All land under the same 2026 timestamp. Those dates tell a reader the source-record ages listed for the items; they are no inventory of every earlier use or route. ARIN’s current exact RDAP for 9.179.0.0/16 and 170.55.0.0/16 identifies Zayo; the latter still has a 1994 registration event. Selected cross-family checks also return Zayo for 2001:1910::/32, AS11557 and AS394647. The batch is administratively uniform while its registration histories are not.

This changes the way a transfer list should be read. A buyer checking continuity needs the exact range, its transfer chain and its present registration, not just the most recent recipient. An operator examining a route needs an ASN and a prefix kept as separate units; an AS number travelling with a batch is not proof that any particular route changed at 16:06:28. ARIN’s file records transfer approval and resource boundaries. It has no traffic meter and no price field. The missing document that would explain what was operationally cut over, and when, is a dated migration timetable from the parties.

The registry has in fact left enough evidence to resist the one-second illusion. The same exact /16 appears four times, with each source and recipient visible. Its RDAP object still exposes an earlier registration event while naming the present holder. The institutional incentive is to make a large acquisition process as one neat administrative job. The reader’s job is to unstack the sleeves. ARIN’s stamp took one second. Some of the addresses beneath it have been carrying paperwork since the last century.

ARIN originals