asn.dev

Observed topology

AS3662 HARNET Joint Universities Computer Centre Limited

Upstreams 6 carry this network
Downstreams 9 this network carries
Adjacent (IPv4) 15
Adjacent (IPv6) 11

Transit

Upstream networks

inferred

Networks observed carrying traffic for AS3662: 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
AS17824Pacific One Net Limited AS numberUnclassifiedIPv4288
AS6939Hurricane Electric LLCTransitIPv4 IPv6137
AS137207Joint Universities Computer Centre LimitedUnclassifiedIPv4 IPv649
AS4635Hong Kong Internet Exchange--Route Server 1UnclassifiedIPv414
AS24482SG.GSHostingIPv4 IPv69
AS8359MTS PJSCMobileIPv47

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.

Transit

Downstream networks

inferred

Networks for which AS3662 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS7650The Education University of Hong KongEducationIPv4 IPv61,413
AS7651Lingnan UniversityEducationIPv4 IPv6732
AS3363Hong Kong University of Science and TechnologyEducationIPv4 IPv6623
AS4158City University of Hong KongEducationIPv4 IPv6467
AS4528The University of Hong KongEducationIPv4 IPv6451
AS4605Hong Kong Baptist UniversityEducationIPv4 IPv6426
AS4616The Hong Kong Polytechnic UniversityEducationIPv4 IPv6343
AS3661The Chinese University of Hong KongEducationIPv4311
AS17764Hong Kong Metropolitan UniversityUnclassifiedIPv4105

Adjacency

Adjacent networks

26 shown

Every AS seen directly next to AS3662 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS17824Pacific One Net Limited AS numberUnclassifiedIPv43,490
AS7650The Education University of Hong KongEducationIPv4 IPv61,413
AS6939Hurricane Electric LLCTransitIPv4 IPv61,152
AS7651Lingnan UniversityEducationIPv4 IPv6732
AS3363Hong Kong University of Science and TechnologyEducationIPv4 IPv6623
AS4158City University of Hong KongEducationIPv4 IPv6467
AS4528The University of Hong KongEducationIPv4 IPv6451
AS4605Hong Kong Baptist UniversityEducationIPv4 IPv6426
AS4616The Hong Kong Polytechnic UniversityEducationIPv4 IPv6343
AS3661The Chinese University of Hong KongEducationIPv4311
AS4635Hong Kong Internet Exchange--Route Server 1UnclassifiedIPv4 IPv6287
AS137207Joint Universities Computer Centre LimitedUnclassifiedIPv4 IPv6264
AS17764Hong Kong Metropolitan UniversityUnclassifiedIPv4105
AS24482SG.GSHostingIPv4 IPv6103
AS8359MTS PJSCMobileIPv479

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.

Interconnection

Exchange presence

recorded

Internet exchanges where Packet Clearing House has a port recorded for AS3662, largest fabric first. An exchange is shared switching where networks interconnect directly rather than paying a transit provider to carry traffic between them, so turning up at one is a deliberate choice about how this network wants to be reached. Each name opens that exchange's own page, with its peering LANs and every other network recorded on it. Recorded at 1 exchange across 1 country and 1 region.

ExchangeLocationTheir addressMember ports
Hong Kong Internet ExchangeHong Kong, China123.255.91.23307

Unlike the tables above, this is recorded rather than inferred. An address on a peering LAN is at that exchange by definition. Two carve-outs all the same. Member ports counts every participant at the exchange, not this network's ports, so read it as a size proxy. And an absent exchange means PCH has no record of it, not that the network is not there.

Provenance

Where this comes from

Derived from routing tables collected at 2026-08-08 10:00 UTC by route-views2,rrc00, as seen from 75 BGP vantage points across 74.02M route entries. These are observations from those vantage points, not a complete or authoritative view of the internet.

Cross-check against RIPEstat or BGP.tools, which observe from a different and larger set of vantage points.

Exchange presence comes from a separate dataset: the directory collected 2026-08-08 by Packet Clearing House (https://www.pch.net/ixp/data), covering 1,327 exchanges and 93,137 recorded member ports, licensed CC BY-NC-SA 3.0.

PeeringDB is the better-known directory and is deliberately not the source here: its acceptable-use policy forbids the bulk storage this needs. The two answer different questions anyway. PeeringDB reports what an operator declares about itself; this reports what PCH has recorded.