asn.dev

Observed topology

AS13977 CTELCO - Fidium

Residential ARIN

Upstreams 4 carry this network
Downstreams 51 this network carries
Adjacent (IPv4) 53
Adjacent (IPv6) 10
Upstream graph Who carries AS13977, and who carries them, drawn as a map up to the transit-free core. 1 exchange Where AS13977 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

inferred

Networks observed carrying traffic for AS13977: 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
AS6461Zayo BandwidthTransitIPv4 IPv626,168
AS174Cogent Communications, LLCTransitIPv4 IPv619,226
AS33422New England Telehealth ConsortiumUnclassifiedIPv431
AS63243SynergentUnclassifiedIPv431

Transit

Downstream networks

All 51

Networks for which AS13977 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS13672FidiumUnclassifiedIPv42,542
AS32645FidiumUnclassifiedIPv41,805
AS14671FairPoint CommunicationsUnclassifiedIPv4323
AS13673FidiumUnclassifiedIPv4292
AS399353Netafy, Inc.UnclassifiedIPv4 IPv6260
AS55128McFarlane Associates LLCUnclassifiedIPv4 IPv6181
AS393568ITT CorporationUnclassifiedIPv4169
AS400848DHI TECHNICAL SERVICES LLCHostingIPv4 IPv6145
AS54257Vermont State CollegesUnclassifiedIPv4119
AS33555Stonemarche Network CoOp.UnclassifiedIPv4114

All 51 downstreams →

Adjacency

Adjacent networks

All 54

Every AS seen directly next to AS13977 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS6461Zayo BandwidthTransitIPv4 IPv630,602
AS174Cogent Communications, LLCTransitIPv4 IPv622,293
AS13672FidiumUnclassifiedIPv42,564
AS32645FidiumUnclassifiedIPv41,805
AS14671FairPoint CommunicationsUnclassifiedIPv4323
AS13673FidiumUnclassifiedIPv4292
AS399353Netafy, Inc.UnclassifiedIPv4 IPv6260
AS55128McFarlane Associates LLCUnclassifiedIPv4 IPv6181
AS393568ITT CorporationUnclassifiedIPv4169
AS400848DHI TECHNICAL SERVICES LLCHostingIPv4 IPv6145

All 54 adjacent →

Provenance

Where this comes from

Derived from routing tables collected at 2026-11-11 10:00 UTC by route-views2,rrc00, as seen from 74 BGP vantage points across 73.24M 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.