Observed topology

AS33657 CMCS - Comcast Cable Communications, LLC

Unclassified ARIN

Upstreams 2 carry this network

Downstreams 132 this network carries

Adjacent (IPv4) 127

Adjacent (IPv6) 20

Upstream graph Who carries AS33657, and who carries them, drawn as a map up to the transit-free core. 0 exchanges Where AS33657 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

inferred

Networks observed carrying traffic for AS33657: 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
AS7922	Comcast Cable Communications, LLC	Residential	IPv4 IPv6	8,757
AS3356	Level 3 Parent, LLC	Transit	IPv4	90

Transit

Downstream networks

All 132

Networks for which AS33657 was observed as the last hop before the origin, meaning it appears to provide them transit.

AS	Network	Type	Families	Paths seen
AS27016	United States Nuclear Regulatory Commission	Unclassified	IPv4 IPv6	751
AS394077	Lifebridge Health, Inc.	Unclassified	IPv4	344
AS11790	Random House, Inc.	Unclassified	IPv4	317
AS32073	Montgomery County Public Schools	Unclassified	IPv4	302
AS53373	Mathematica, Inc.	Unclassified	IPv4	236
AS22101	Cyber Point International, LLC	Unclassified	IPv4	232
AS17190	Washington Metropolitan Area Transit Authority	Unclassified	IPv4	195
AS2703	DATAPR-3	Unclassified	IPv4	174
AS16463	Data Processing Solutions, Inc.	Unclassified	IPv4	174
AS25716	Trane Technologies Company LLC	Unclassified	IPv4	174

All 132 downstreams →

Adjacency

Adjacent networks

All 134

Every AS seen directly next to AS33657 in a routing path, in either direction.

AS	Network	Type	Families	Paths seen
AS7922	Comcast Cable Communications, LLC	Residential	IPv4 IPv6	14,523
AS3356	Level 3 Parent, LLC	Transit	IPv4 IPv6	1,940
AS27016	United States Nuclear Regulatory Commission	Unclassified	IPv4 IPv6	751
AS394077	Lifebridge Health, Inc.	Unclassified	IPv4	344
AS11790	Random House, Inc.	Unclassified	IPv4	317
AS32073	Montgomery County Public Schools	Unclassified	IPv4	302
AS53373	Mathematica, Inc.	Unclassified	IPv4	236
AS22101	Cyber Point International, LLC	Unclassified	IPv4	232
AS17190	Washington Metropolitan Area Transit Authority	Unclassified	IPv4	195
AS2703	DATAPR-3	Unclassified	IPv4	174

All 134 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.