asn.dev

Observed topology

AS209 CENTURYLINK-US-LEGACY-QWEST

Residential ARIN NSP

Upstreams 1 carry this network
Downstreams 294 this network carries
Adjacent (IPv4) 294
Adjacent (IPv6) 29
Upstream graph Who carries AS209, and who carries them, drawn as a map up to the transit-free core. 0 exchanges Where AS209 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

inferred

Networks observed carrying traffic for AS209: 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
AS3356Level 3 Parent, LLCTransitIPv4 IPv697,691

Transit

Downstream networks

All 294

Networks for which AS209 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS22561CenturyLink Communications, LLCUnclassifiedIPv419,316
AS396908Laurens Technologies Internet ServicesHostingIPv4 IPv63,648
AS14921CenturyLink Communications, LLCUnclassifiedIPv42,074
AS18530Isomedia, Inc.HostingIPv4 IPv61,869
AS17402CenturyLink Communications, LLCUnclassifiedIPv41,525
AS54427NetTally, IncUnclassifiedIPv41,342
AS297National Aeronautics and Space AdministrationBusinessIPv4757
AS11255Screamin' Banshee TechnologiesUnclassifiedIPv4732
AS30221T3 Communications, Inc.UnclassifiedIPv4553
AS32083Omnispring, LLCHostingIPv4549

All 294 downstreams →

Adjacency

Adjacent networks

All 296

Every AS seen directly next to AS209 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS3356Level 3 Parent, LLCTransitIPv4 IPv6181,108
AS22561CenturyLink Communications, LLCUnclassifiedIPv434,666
AS297National Aeronautics and Space AdministrationBusinessIPv4 IPv65,917
AS18530Isomedia, Inc.HostingIPv4 IPv65,041
AS396908Laurens Technologies Internet ServicesHostingIPv4 IPv63,681
AS6223CenturyLink Communications, LLCUnclassifiedIPv4 IPv62,177
AS14921CenturyLink Communications, LLCUnclassifiedIPv42,074
AS17402CenturyLink Communications, LLCUnclassifiedIPv41,525
AS54427NetTally, IncUnclassifiedIPv41,342
AS6224CenturyLink Communications, LLCUnclassifiedIPv4 IPv61,179

All 296 adjacent →

Provenance

Where this comes from

Derived from routing tables collected at 2026-10-30 10:00 UTC by route-views2,rrc00, as seen from 76 BGP vantage points across 74.49M 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.