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Understanding the report/History and timeline

History and timeline

One timeline for registration events, transfers, routing windows and observed changes.

Every dated event about a resource lands on one timeline, in order, whatever its source.

Event categories

CategoryWhat it is
registrationRegistration of the block and changes to the record.
allocationAllocation events for the resource.
transferRIR records of the space moving between holders or registries.
routingBGP visibility windows: an origin AS announcing the space over a period.
rirThe space appearing in, moving within, or leaving a registry's published holdings.
observedChanges SubnetHistory detected itself.
tagAn analyst label being applied.
peeringdbThe network's PeeringDB record being created or updated.

Events covering a period carry a start, an end, and an ongoing flag while the period is open.

Origin history

One row per AS that has ever originated the space.

ColumnMeaning
AS and holderThe origin network and its name.
PrefixThe exact prefix that AS announced.
ScopeWhether the prefix is the block itself, a covering block, or a more specific inside it.
First seen, last seenThe observed window, marked ongoing while the announcement is current.
WindowsHow many distinct visibility windows the AS has had.
Peak peersThe most full BGP peers that saw the announcement, a rough measure of global visibility.

A cell with no recorded value reads n/a, not zero. The frequent origin change tag exists for exactly that pattern.

What SubnetHistory records itself

Every lookup archives its answers, and a record differing from the previous snapshot writes a change event summarising what moved. These appear in the observed category. The raw archive, change events plus persisted routing observations, is available from the archive endpoint.

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Very large timelines are trimmed, and the report states how many routing announcements were omitted.

Last updated 2026-08-12subnethistory.com