asn.dev

Observed topology

AS209 CENTURYLINK-US-LEGACY-QWEST - CenturyLink Communications, LLC

Residential ARIN

Upstreams 1 carry this network
Downstreams 289 this network carries
Adjacent (IPv4) 289
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 IPv695,585

Transit

Downstream networks

All 289

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

ASNetworkTypeFamiliesPaths seen
AS22561CenturyLink Communications, LLCUnclassifiedIPv419,207
AS396908Laurens Technologies Internet ServicesHostingIPv4 IPv63,540
AS14921CenturyLink Communications, LLCUnclassifiedIPv42,040
AS18530Isomedia, Inc.HostingIPv4 IPv61,812
AS17402CenturyLink Communications, LLCUnclassifiedIPv41,500
AS54427NetTally, IncUnclassifiedIPv41,298
AS297National Aeronautics and Space AdministrationBusinessIPv4750
AS11255Screamin' Banshee TechnologiesUnclassifiedIPv4720
AS30221T3 Communications, Inc.UnclassifiedIPv4542
AS64280Palo Alto Networks, IncUnclassifiedIPv4495

All 289 downstreams →

Adjacency

Adjacent networks

All 291

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

ASNetworkTypeFamiliesPaths seen
AS3356Level 3 Parent, LLCTransitIPv4 IPv6177,398
AS22561CenturyLink Communications, LLCUnclassifiedIPv434,221
AS297National Aeronautics and Space AdministrationBusinessIPv4 IPv65,871
AS18530Isomedia, Inc.HostingIPv4 IPv64,842
AS396908Laurens Technologies Internet ServicesHostingIPv4 IPv63,542
AS6223CenturyLink Communications, LLCUnclassifiedIPv4 IPv62,145
AS14921CenturyLink Communications, LLCUnclassifiedIPv42,040
AS17402CenturyLink Communications, LLCUnclassifiedIPv41,500
AS54427NetTally, IncUnclassifiedIPv41,298
AS6224CenturyLink Communications, LLCUnclassifiedIPv4 IPv61,244

All 291 adjacent →

Provenance

Where this comes from

Derived from routing tables collected at 2026-11-08 10:00 UTC by route-views2,rrc00, as seen from 75 BGP vantage points across 73.00M 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.