Observed topology

AS21554 CYBERLYNK - Wisconsin CyberLynk Network, Inc.

Hosting ARIN

Upstreams 6 carry this network

Downstreams 1 this network carries

Adjacent (IPv4) 7

Adjacent (IPv6) 4

Upstream graph Who carries AS21554, and who carries them, drawn as a map up to the transit-free core. 0 exchanges Where AS21554 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

inferred

Networks observed carrying traffic for AS21554: 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.

AS	Network	Type	Families	Paths seen
AS2914	NTT America, Inc.	Transit	IPv4 IPv6	1,139
AS40264	Charter Communications LLC	Unclassified	IPv4	1,097
AS174	Cogent Communications, LLC	Transit	IPv4 IPv6	707
AS30517	Great Lakes Comnet, Inc.	Unclassified	IPv4	564
AS3356	Level 3 Parent, LLC	Transit	IPv4 IPv6	356
AS7018	AT&T Enterprises, LLC	Residential	IPv4 IPv6	120

Transit

Downstream networks

inferred

Networks for which AS21554 was observed as the last hop before the origin, meaning it appears to provide them transit.

AS	Network	Type	Families	Paths seen
AS54110	Modulis	Unclassified	IPv4	244

Adjacency

Adjacent networks

observed

Every AS seen directly next to AS21554 in a routing path, in either direction.

AS	Network	Type	Families	Paths seen
AS2914	NTT America, Inc.	Transit	IPv4 IPv6	1,216
AS40264	Charter Communications LLC	Unclassified	IPv4	1,097
AS174	Cogent Communications, LLC	Transit	IPv4 IPv6	781
AS30517	Great Lakes Comnet, Inc.	Unclassified	IPv4	568
AS3356	Level 3 Parent, LLC	Transit	IPv4 IPv6	429
AS54110	Modulis	Unclassified	IPv4	244
AS7018	AT&T Enterprises, LLC	Residential	IPv4 IPv6	136

Provenance

Where this comes from

Derived from routing tables collected at 2026-11-02 10:00 UTC by route-views2,rrc00, as seen from 76 BGP vantage points across 74.44M 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.