asn.dev

Observed topology

AS20521 ASN-BELLNET

Unclassified RIPE

Upstreams 4 carry this network
Downstreams 3 this network carries
Adjacent (IPv4) 7
Adjacent (IPv6) 2
Upstream graph Who carries AS20521, and who carries them, drawn as a map up to the transit-free core. 0 exchanges Where AS20521 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

inferred

Networks observed carrying traffic for AS20521: 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 IPv61,193
AS1299Arelion Sweden ABTransitIPv4 IPv6487
AS19551Incapsula IncHostingIPv461
AS33874Epic Communications LimitedUnclassifiedIPv461

Transit

Downstream networks

inferred

Networks for which AS20521 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS60507Hillside (Technology) LtdUnclassifiedIPv4180
AS51166Ixaris Systems (Malta) LimitedUnclassifiedIPv460
AS201711Privredno Drustvo Za Trgovinu I Usluge Stepanovic & Sipka Doo, BeogradUnclassifiedIPv460

Adjacency

Adjacent networks

observed

Every AS seen directly next to AS20521 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS3356Level 3 Parent, LLCTransitIPv4 IPv61,342
AS1299Arelion Sweden ABTransitIPv4 IPv6638
AS60507Hillside (Technology) LtdUnclassifiedIPv4180
AS19551Incapsula IncHostingIPv461
AS33874Epic Communications LimitedUnclassifiedIPv461
AS51166Ixaris Systems (Malta) LimitedUnclassifiedIPv460
AS201711Privredno Drustvo Za Trgovinu I Usluge Stepanovic & Sipka Doo, BeogradUnclassifiedIPv460

Provenance

Where this comes from

Derived from routing tables collected at 2026-10-29 10:00 UTC by route-views2,rrc00, as seen from 76 BGP vantage points across 74.36M 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.