asn.dev

Observed topology

AS2852 CESNET2 CESNET z.s.p.o.

Education RIPE Educational/Research

Upstreams 25 carry this network
Downstreams 19 this network carries
Adjacent (IPv4) 48
Adjacent (IPv6) 27
Upstream graph Who carries AS2852, and who carries them, drawn as a map up to the transit-free core. 3 exchanges Where AS2852 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

All 25

Networks observed carrying traffic for AS2852: 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
AS174Cogent Communications, LLCTransitIPv4442
AS6939Hurricane Electric LLCTransitIPv4 IPv6211
AS21320GEANT VerenigingUnclassifiedIPv4 IPv6185
AS20965GEANT VerenigingUnclassifiedIPv4 IPv6131
AS1853ACONETUnclassifiedIPv478
AS34549meerfarbig GmbH & Co. KGHostingIPv478
AS6461Zayo BandwidthTransitIPv452
AS3333Reseaux IP Europeens Network Coordination Centre (RIPE NCC)UnclassifiedIPv4 IPv627
AS24482SG.GSHostingIPv4 IPv627
AS29504Freenet Liberec, z.s.UnclassifiedIPv4 IPv627

All 25 upstreams →

Transit

Downstream networks

All 19

Networks for which AS2852 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS208093Moravskoslezsky krajUnclassifiedIPv4261
AS197451Brno University of TechnologyEducationIPv4 IPv6256
AS48091Kraj VysocinaUnclassifiedIPv4 IPv6247
AS197277State Institute for Drug ControlUnclassifiedIPv4 IPv6220
AS199711National Cyber and Information Security AgencyUnclassifiedIPv4 IPv6183
AS201648Plzensky krajUnclassifiedIPv4 IPv6157
AS213152Narodni bezpecnostni urad Czech RepublicUnclassifiedIPv4 IPv6111
AS212876Pardubicky KrajUnclassifiedIPv4 IPv698
AS61110Sprava informacnich technologii mesta Plzne, p.o.UnclassifiedIPv4 IPv697
AS200874Liberecky krajUnclassifiedIPv4 IPv697

All 19 downstreams →

Adjacency

Adjacent networks

All 51

Every AS seen directly next to AS2852 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS6939Hurricane Electric LLCTransitIPv4 IPv6926
AS174Cogent Communications, LLCTransitIPv4876
AS21320GEANT VerenigingUnclassifiedIPv4 IPv6473
AS1853ACONETUnclassifiedIPv4 IPv6340
AS20965GEANT VerenigingUnclassifiedIPv4 IPv6267
AS208093Moravskoslezsky krajUnclassifiedIPv4261
AS197451Brno University of TechnologyEducationIPv4 IPv6256
AS48091Kraj VysocinaUnclassifiedIPv4 IPv6247
AS197277State Institute for Drug ControlUnclassifiedIPv4 IPv6220
AS29504Freenet Liberec, z.s.UnclassifiedIPv4 IPv6201

All 51 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.