asn.dev

Observed topology

AS21056 ASN-WELCOMEITALIA Vianova S.p.A

Unclassified APNIC Cable/DSL/ISP

Upstreams 31 carry this network
Downstreams 4 this network carries
Adjacent (IPv4) 34
Adjacent (IPv6) 11
Upstream graph Who carries AS21056, and who carries them, drawn as a map up to the transit-free core. 7 exchanges Where AS21056 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

All 31

Networks observed carrying traffic for AS21056: 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
AS6762TELECOM ITALIA SPARKLE S.p.A.TransitIPv4 IPv6580
AS3356Level 3 Parent, LLCTransitIPv4 IPv6309
AS6939Hurricane Electric LLCTransitIPv4 IPv6275
AS1299Arelion Sweden ABTransitIPv4 IPv6271
AS34549meerfarbig GmbH & Co. KGHostingIPv4123
AS50304Blix Solutions ASUnclassifiedIPv482
AS24482SG.GSHostingIPv4 IPv642
AS34019Hivane AssociationUnclassifiedIPv4 IPv642
AS37721Virtual Technologies & SolutionsResidentialIPv4 IPv642
AS50628Leonix Telecom SASUnclassifiedIPv4 IPv642

All 31 upstreams →

Transit

Downstream networks

inferred

Networks for which AS21056 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS47242Host SpAHostingIPv4382
AS208775COMAC S.P.A.UnclassifiedIPv459
AS198320Telnet Systems s.r.l.UnclassifiedIPv458
AS210224SNAP SYSTEM SRLUnclassifiedIPv431

Adjacency

Adjacent networks

All 37

Every AS seen directly next to AS21056 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS6762TELECOM ITALIA SPARKLE S.p.A.TransitIPv4 IPv6598
AS47242Host SpAHostingIPv4411
AS3356Level 3 Parent, LLCTransitIPv4 IPv6344
AS1299Arelion Sweden ABTransitIPv4 IPv6319
AS6939Hurricane Electric LLCTransitIPv4 IPv6287
AS34549meerfarbig GmbH & Co. KGHostingIPv4246
AS50304Blix Solutions ASUnclassifiedIPv4164
AS37721Virtual Technologies & SolutionsResidentialIPv4 IPv685
AS50628Leonix Telecom SASUnclassifiedIPv4 IPv683
AS4657StarHub LtdResidentialIPv482

All 37 adjacent →

Provenance

Where this comes from

Derived from routing tables collected at 2026-11-10 10:00 UTC by route-views2,rrc00, as seen from 74 BGP vantage points across 71.97M 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.