subnet.im

AS21928T-Mobile USA, Inc.

United StatesRegistryARINTypeEyeball

As of 26th September 2026, AS21928 (T-Mobile USA, Inc.), an access network registered in the United States with ARIN, originates 283 IPv4 prefixes covering 14M addresses and 257 IPv6 prefixes. By IPv4 address space that makes it the 52nd-largest of the 79,516 networks we see originating IPv4, and the 17th-largest of 18,424 in the United States. It is seen behind 26 upstream networks, most often AS174 (Cogent Communications, LLC) and AS6939 (Hurricane Electric LLC), and in front of 3 downstream networks. Every one of its announcements has a valid RPKI ROA, and none are RPKI-invalid. 39% of its routes reach at least 90% of full-feed peers.

At a glance

IPv4 prefixes

283

IPv6 prefixes

257

IPv4 addresses

14M

IPv6 /64s

77.3B

Upstream graph

The networks AS21928 is seen behind, one and two hops out, drawn from real AS paths.

AS21928Toward the internet core
Upstream graph for AS21928: 12 neighbouring networks observed beyond it across 2 levels. The same networks are listed in the tables below.AS21928T-Mobile USA, Inc.This networkAS174Cogent Communicat…AS3356Lumen (Level 3)AS4637Telstra Internati…AS6461Zayo BandwidthAS6939Hurricane Electri…AS1299Arelion (fka. Tel…AS151326DCConnect Communi…AS2914NTT America, Inc.AS16552Tiggee LLCAS32590Valve CorporationAS18106Viewqwest Pte LtdAS20130Depaul University

Networks observed one and two hops upstream of AS21928 in real AS paths. A thicker line means more vantage points saw that adjacency, so weight tracks how well attested it is — not how much traffic it carries. Adjacency is an observation; whether it is a transit purchase or a settlement-free peering is an inference, and is labelled as one wherever we show it.

Neighbouring networks

125

adjacent networks

Upstreams
2621%
Peers
9677%
Downstreams
32%

Networks carrying this one's traffic toward the rest of the internet.

Upstreams of AS21928
NetworkCountryRelationshipPathsVantage pts
AS174Cogent Communications, LLCUSPeer7,888119
AS6939Hurricane Electric LLCUSPeer4,76534
AS6461Zayo BandwidthUSPeer4,574138
AS4637Telstra International LimitedHKPeer2,11414
AS3356Lumen (Level 3)USPeer1,716145
AS14537Continent 8 LLCUSPeer7554
AS49544i3D.net B.VNLPeer5032
AS7195EdgeUnoCOPeer4834
AS24482SG.GSSGPeer2773
AS58511Swoop (Anycast Global Backbone)AUPeer2722

Prefixes

All 540

The largest blocks AS21928 originates, widest first.

Largest prefixes originated by AS21928
PrefixAddressesVisibility
100.128.0.0/98.4M80/81
162.160.0.0/112.1M80/81
172.32.0.0/112.1M80/81
162.184.0.0/15131k81/81
172.58.0.0/15131k80/81
65.76.0.0/1665.5k81/81
74.60.0.0/1665.5k81/81
162.190.0.0/1665.5k81/81
162.191.0.0/1665.5k81/81
167.20.0.0/1665.5k81/81

Routing health

How AS21928's own announcements validate against RPKI and how far they propagate. The same measures for the whole routing table are on the routing table in numbers.

RPKI origin validation

  • Valid100.0%540
  • Invalid0.0%0
  • No ROA0.0%0

Propagation

  • Globally propagated90% of full-feed peers or more39.3%212
  • Partially propagated40% to 90%35.4%191
  • Seen by few peersUnder 40%25.4%137

Prefix sizes

IPv4 — 283 prefixes

IPv6 — 257 prefixes

  • /2868.7B × /640.4%1
  • /324.3B × /640.4%1
  • /3867.1M × /640.8%2
  • /4016.8M × /6496.9%249
  • /441M × /640.8%2
  • /4865.5k × /640.8%2

Recent changes

Announcements that started or stopped since 28th Aug 2026.

  • Announced162.173.56.0/2122nd Sept 2026
  • Announced2607:f880:ff20::/4422nd Sept 2026
  • Withdrawn172.56.70.0/2321st Sept 2026
  • Withdrawn172.58.104.0/2121st Sept 2026
  • Withdrawn172.58.136.0/2121st Sept 2026

Routing data derived from RouteViews MRT archives, BGPKIT relationship inference and public registry data.