asn.dev

Observed topology

AS21947 BCI

Upstreams 11 carry this network
Downstreams 14 this network carries
Adjacent (IPv4) 25
Adjacent (IPv6) 10

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 IPv6385
AS6939Hurricane Electric LLCTransitIPv4 IPv6182
AS2914NTT America, Inc.TransitIPv4 IPv6151
AS15305Syringa Networks, LLCUnclassifiedIPv4 IPv6136
AS9002RETN LimitedUnclassifiedIPv428
AS394256Tech Futures Interactive Inc.UnclassifiedIPv4 IPv617
AS24482SG.GSHostingIPv4 IPv617
AS7575Australian Academic and Research Network (AARNet)EducationIPv414
AS3130RGnet OUUnclassifiedIPv414
AS34927iFog GmbHHostingIPv414
AS293ESnetUnclassifiedIPv42

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.

Transit

Downstream networks

inferred

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

ASNetworkTypeFamiliesPaths seen
AS46324Advanced Stream Inc.UnclassifiedIPv4 IPv6157
AS397162SumofiberUnclassifiedIPv4 IPv6148
AS395861Medical Imaging Associates of Idaho Falls, Inc.UnclassifiedIPv4142
AS27391Washington CorporationsUnclassifiedIPv4107
AS22785GLACIER BANCORP INCUnclassifiedIPv498
AS15331Blackfoot Telephone Cooperative, Inc.UnclassifiedIPv4 IPv697
AS54410Bozeman Deaconess Health ServicesUnclassifiedIPv461
AS1378Interbel Telephone Cooperative, Inc.UnclassifiedIPv461
AS33521Missoula County Public SchoolsUnclassifiedIPv461
AS20274Flathead Valley Community CollegeUnclassifiedIPv449
AS33281BRIGHAM YOUNG UNIVERSITY - IDAHOUnclassifiedIPv4 IPv644
AS13590Marcus Daly Memorial Hospital CorporationUnclassifiedIPv435
AS398437Hot Springs Telephone CompanyUnclassifiedIPv419
AS393630Avantguard Monitoring CentersUnclassifiedIPv417

Adjacency

Adjacent networks

35 shown

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

ASNetworkTypeFamiliesPaths seen
AS1299Arelion Sweden ABTransitIPv4 IPv6740
AS6939Hurricane Electric LLCTransitIPv4 IPv6380
AS2914NTT America, Inc.TransitIPv4 IPv6359
AS15305Syringa Networks, LLCUnclassifiedIPv4 IPv6295
AS397162SumofiberUnclassifiedIPv4 IPv6160
AS46324Advanced Stream Inc.UnclassifiedIPv4 IPv6157
AS395861Medical Imaging Associates of Idaho Falls, Inc.UnclassifiedIPv4142
AS27391Washington CorporationsUnclassifiedIPv4107
AS22785GLACIER BANCORP INCUnclassifiedIPv498
AS15331Blackfoot Telephone Cooperative, Inc.UnclassifiedIPv4 IPv697
AS1378Interbel Telephone Cooperative, Inc.UnclassifiedIPv461
AS54410Bozeman Deaconess Health ServicesUnclassifiedIPv461
AS33521Missoula County Public SchoolsUnclassifiedIPv461
AS34927iFog GmbHHostingIPv455
AS3130RGnet OUUnclassifiedIPv455
AS9002RETN LimitedUnclassifiedIPv454
AS394256Tech Futures Interactive Inc.UnclassifiedIPv4 IPv651
AS20274Flathead Valley Community CollegeUnclassifiedIPv449
AS24482SG.GSHostingIPv4 IPv646
AS33281BRIGHAM YOUNG UNIVERSITY - IDAHOUnclassifiedIPv4 IPv644
AS13590Marcus Daly Memorial Hospital CorporationUnclassifiedIPv435
AS7575Australian Academic and Research Network (AARNet)EducationIPv431
AS398437Hot Springs Telephone CompanyUnclassifiedIPv419
AS393630Avantguard Monitoring CentersUnclassifiedIPv417
AS293ESnetUnclassifiedIPv42

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.

Interconnection

Exchange presence

recorded

Internet exchanges where Packet Clearing House has a port recorded for AS21947, largest fabric first. An exchange is shared switching where networks interconnect directly rather than paying a transit provider to carry traffic between them, so turning up at one is a deliberate choice about how this network wants to be reached. Each name opens that exchange's own page, with its peering LANs and every other network recorded on it. Recorded at 2 exchanges across 1 country and 1 region.

ExchangeLocationTheir addressMember ports
Seattle Internet ExchangeSeattle, United States206.81.80.109350
Interconnection eXchange DenverDenver, United States206.53.175.1392

Unlike the tables above, this is recorded rather than inferred. An address on a peering LAN is at that exchange by definition. Two carve-outs all the same. Member ports counts every participant at the exchange, not this network's ports, so read it as a size proxy. And an absent exchange means PCH has no record of it, not that the network is not there.

Provenance

Where this comes from

Derived from routing tables collected at 2026-08-08 10:00 UTC by route-views2,rrc00, as seen from 75 BGP vantage points across 74.02M route entries. These are observations from those vantage points, not a complete or authoritative view of the internet.

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

Exchange presence comes from a separate dataset: the directory collected 2026-08-09 by Packet Clearing House (https://www.pch.net/ixp/data), covering 1,327 exchanges and 93,164 recorded member ports, licensed CC BY-NC-SA 3.0.

PeeringDB is the better-known directory and is deliberately not the source here: its acceptable-use policy forbids the bulk storage this needs. The two answer different questions anyway. PeeringDB reports what an operator declares about itself; this reports what PCH has recorded.