asn.dev

Observed topology

AS21559 OSNET

Unclassified ARIN

Upstreams 8 carry this network
Downstreams 38 this network carries
Adjacent (IPv4) 49
Adjacent (IPv6) 22
Upstream graph Who carries AS21559, and who carries them, drawn as a map up to the transit-free core. 6 exchanges Where AS21559 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

inferred

Networks observed carrying traffic for AS21559: 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
AS6939Hurricane Electric LLCTransitIPv4 IPv62,100
AS174Cogent Communications, LLCTransitIPv4356
AS3257GTT Communications Inc.TransitIPv4 IPv6159
AS6762TELECOM ITALIA SPARKLE S.p.A.TransitIPv466
AS24482SG.GSHostingIPv4 IPv639
AS3303Swisscom (Schweiz) AGResidentialIPv438
AS37721Virtual Technologies & SolutionsResidentialIPv438
AS1299Arelion Sweden ABTransitIPv4 IPv612

Transit

Downstream networks

All 38

Networks for which AS21559 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS46941XairnetUnclassifiedIPv4672
AS396502HOTSPOTPR BROADBAND INTERNET, LLCUnclassifiedIPv4 IPv6606
AS395471Data@ccess Communication, Inc.UnclassifiedIPv4532
AS393678XDAR Wireless LLCUnclassifiedIPv4 IPv6491
AS398317FIREFI LLCUnclassifiedIPv4391
AS46868VPNET INCUnclassifiedIPv4 IPv6380
AS399126I COMM NETWORKS LLCUnclassifiedIPv4330
AS271945AZTECA TELECOM S.R.L.UnclassifiedIPv4 IPv6326
AS393573Fuse Telecom LLCUnclassifiedIPv4 IPv6326
AS36435M.S. Wifi Zone Inc.UnclassifiedIPv4 IPv6299

All 38 downstreams →

Adjacency

Adjacent networks

All 49

Every AS seen directly next to AS21559 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS6939Hurricane Electric LLCTransitIPv4 IPv69,735
AS271945AZTECA TELECOM S.R.L.UnclassifiedIPv4 IPv62,823
AS174Cogent Communications, LLCTransitIPv41,599
AS3257GTT Communications Inc.TransitIPv4 IPv6933
AS395471Data@ccess Communication, Inc.UnclassifiedIPv4845
AS46941XairnetUnclassifiedIPv4672
AS396502HOTSPOTPR BROADBAND INTERNET, LLCUnclassifiedIPv4 IPv6606
AS6762TELECOM ITALIA SPARKLE S.p.A.TransitIPv4 IPv6577
AS393678XDAR Wireless LLCUnclassifiedIPv4 IPv6491
AS399126I COMM NETWORKS LLCUnclassifiedIPv4396

All 49 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.