Observed topology
AS721 DNIC-ASBLK-00721-00726
Unclassified ARIN
Transit
Upstream networks
Networks observed carrying traffic for AS721: 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.
| AS | Network | Type | Families | Paths seen |
|---|---|---|---|---|
| AS3356 | Level 3 Parent, LLC | Transit | IPv4 IPv6 | 13,717 |
Transit
Downstream networks
Networks for which AS721 was observed as the last hop before the origin, meaning it appears to provide them transit.
Adjacency
Adjacent networks
Every AS seen directly next to AS721 in a routing path, in either direction.
| AS | Network | Type | Families | Paths seen |
|---|---|---|---|---|
| AS3356 | Level 3 Parent, LLC | Transit | IPv4 IPv6 | 773,188 |
| AS27064 | United States Department of Defense (DoD) | Unclassified | IPv4 IPv6 | 606,100 |
| AS27066 | United States Department of Defense (DoD) | Unclassified | IPv4 IPv6 | 80,210 |
| AS27065 | United States Department of Defense (DoD) | Unclassified | IPv4 IPv6 | 73,161 |
Provenance
Where this comes from
Derived from routing tables collected at 2026-10-19 10:00 UTC by route-views2,rrc00, as seen from 75 BGP vantage points across 73.17M 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.