asn.dev

Observed topology

AS21947 BCI - Blackfoot Telephone Cooperative, Inc.

Hosting APNIC NSP

Upstreams 9 carry this network
Downstreams 15 this network carries
Adjacent (IPv4) 24
Adjacent (IPv6) 10
Upstream graph Who carries AS21947, and who carries them, drawn as a map up to the transit-free core. 2 exchanges Where AS21947 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

inferred

Networks observed carrying traffic for AS21947: the AS immediately before it in a routing path. Ranked by how many paths showed the relationship, which reflects how widely it is used, not how much traffic crosses it.

ASNetworkTypeFamiliesPaths seen
AS1299Arelion Sweden ABTransitIPv4 IPv6412
AS6939Hurricane Electric LLCTransitIPv4 IPv6173
AS2914NTT America, Inc.TransitIPv4 IPv6157
AS15305Syringa Networks, LLCUnclassifiedIPv4 IPv658
AS9002RETN LimitedUnclassifiedIPv439
AS24482SG.GSHostingIPv4 IPv616
AS394256Tech Futures Interactive Inc.UnclassifiedIPv4 IPv616
AS3130RGnet OUUnclassifiedIPv413
AS7575Australian Academic and Research Network (AARNet)EducationIPv413

Transit

Downstream networks

All 15

Networks for which AS21947 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS395861Medical Imaging Associates of Idaho Falls, Inc.UnclassifiedIPv4138
AS46324Advanced Stream Inc.UnclassifiedIPv4122
AS27391Washington CorporationsUnclassifiedIPv4118
AS397162SumofiberUnclassifiedIPv4 IPv6111
AS22785GLACIER BANCORP INCUnclassifiedIPv4102
AS15331Blackfoot Telephone Cooperative, Inc.UnclassifiedIPv4 IPv695
AS402935CityUnclassifiedIPv4 IPv678
AS33521Missoula County Public SchoolsUnclassifiedIPv460
AS54410Bozeman Deaconess Health ServicesUnclassifiedIPv455
AS1378Interbel Telephone Cooperative, Inc.UnclassifiedIPv442

All 15 downstreams →

Adjacency

Adjacent networks

All 24

Every AS seen directly next to AS21947 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS1299Arelion Sweden ABTransitIPv4 IPv6826
AS2914NTT America, Inc.TransitIPv4 IPv6393
AS6939Hurricane Electric LLCTransitIPv4 IPv6353
AS15305Syringa Networks, LLCUnclassifiedIPv4 IPv6142
AS395861Medical Imaging Associates of Idaho Falls, Inc.UnclassifiedIPv4138
AS46324Advanced Stream Inc.UnclassifiedIPv4122
AS397162SumofiberUnclassifiedIPv4 IPv6119
AS27391Washington CorporationsUnclassifiedIPv4118
AS22785GLACIER BANCORP INCUnclassifiedIPv4102
AS15331Blackfoot Telephone Cooperative, Inc.UnclassifiedIPv4 IPv695

All 24 adjacent →

Provenance

Where this comes from

Derived from routing tables collected at 2026-11-13 10:00 UTC by route-views2,rrc00, as seen from 75 BGP vantage points across 74.40M route entries. These are observations from those vantage points, not a complete or authoritative view of the internet.

Inferred from path position, not from any declaration by either party. A network appearing here is carrying these routes; whether that is a paid transit arrangement, a backup, or something else is not something routing data can tell you. Adjacency is not the same as peering. Being next to each other in a path covers paid transit, settlement-free peering and customer connections alike, and routing data cannot distinguish them. Treat this as "these networks exchange routes", nothing more specific.

Cross-check against RIPEstat or BGP.tools, which observe from a different and larger set of vantage points.