asn.dev

Observed topology

AS2603 NORDUNET NORDUnet

Education RIPE Educational/Research

Upstreams 37 carry this network
Downstreams 14 this network carries
Adjacent (IPv4) 51
Adjacent (IPv6) 38
Upstream graph Who carries AS2603, and who carries them, drawn as a map up to the transit-free core. 21 exchanges Where AS2603 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

All 37

Networks observed carrying traffic for AS2603: 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 IPv6158
AS6939Hurricane Electric LLCTransitIPv4 IPv690
AS34549meerfarbig GmbH & Co. KGHostingIPv4 IPv634
AS11537Internet2UnclassifiedIPv424
AS6830Liberty Global Europe Holding B.V.ResidentialIPv421
AS6461Zayo BandwidthTransitIPv4 IPv620
AS4635Hong Kong Internet Exchange--Route Server 1UnclassifiedIPv418
AS33891Core-Backbone GmbHHostingIPv418
AS9002RETN LimitedUnclassifiedIPv4 IPv614
AS1836green.ch AGResidentialIPv4 IPv612

All 37 upstreams →

Transit

Downstream networks

All 14

Networks for which AS2603 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS1653Vetenskapsradet / SUNETUnclassifiedIPv4 IPv62,745
AS1741Tieteen tietotekniikan keskus OyUnclassifiedIPv4 IPv62,309
AS224Sikt - Kunnskapssektorens TjenesteleverandorUnclassifiedIPv4 IPv61,013
AS1835IDDQD-ASUnclassifiedIPv4 IPv6328
AS8674Netnod ABUnclassifiedIPv4 IPv6294
AS15474Rannsokna- og haskolanet Islands hf.UnclassifiedIPv4 IPv6152
AS2847Kauno Technologijos UniversitetasEducationIPv4 IPv6139
AS8501Institute of Bioorganic Chemistry Polish Academy of Science, Poznan Supercomputing and Networking CenterEducationIPv4 IPv6139
AS39590NORDUnetUnclassifiedIPv4 IPv678
AS3221Haridus- ja TeadusministeeriumEducationIPv4 IPv669

All 14 downstreams →

Adjacency

Adjacent networks

All 56

Every AS seen directly next to AS2603 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS21320GEANT VerenigingUnclassifiedIPv4 IPv614,594
AS1653Vetenskapsradet / SUNETUnclassifiedIPv4 IPv66,967
AS34549meerfarbig GmbH & Co. KGHostingIPv4 IPv64,602
AS1299Arelion Sweden ABTransitIPv4 IPv63,513
AS1741Tieteen tietotekniikan keskus OyUnclassifiedIPv4 IPv62,817
AS8501Institute of Bioorganic Chemistry Polish Academy of Science, Poznan Supercomputing and Networking CenterEducationIPv4 IPv62,516
AS6939Hurricane Electric LLCTransitIPv4 IPv61,789
AS3741Dimension DataUnclassifiedIPv41,645
AS42708Glesys Sweden ABUnclassifiedIPv4 IPv61,551
AS224Sikt - Kunnskapssektorens TjenesteleverandorUnclassifiedIPv4 IPv61,543

All 56 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.