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Autonomous System

AS21928 · T-Mobile USA, Inc.

Overview

AS21928 is announced on the Internet: RIPE RIS route collectors currently see 283 IPv4 prefixes and 258 IPv6 prefixes originated by this network. Together, its IPv4 prefixes cover 13,130,240 addresses, with overlapping prefixes counted once. In the paths the collectors record, it has 26 upstream neighbours (transit providers or peers) and 3 downstream neighbours (customers or networks it carries). Its most visible upstreams are Zayo Bandwidth (AS6461), Level 3 Parent, LLC (AS3356), and Cogent Communications, LLC (AS174). AS21928 was assigned by ARIN, and its registration country is United States.

Source: RIPEstat (RIPE NCC), RIS route collectors. Read on October 16, 2026 at 7:02 PM UTC. This page is refreshed at most every 12 hours.

Go further

Trace a route to this networkOpen in the BGP viewerWHOIS of 100.128.0.1

The trace goes to 100.128.0.1, the first address of 100.128.0.0/9. An address picked inside a prefix may not answer (nothing listens there, or the network filters probes): the trace then shows the path up to the last network that replies.

Announced prefixes

IPv4 prefixes (283 prefixes)

PrefixAddresses
65.76.0.0/1665,536
66.94.0.0/198,192
66.94.3.0/24256
66.94.4.0/24256
66.94.5.0/24256
66.94.6.0/24256
66.94.7.0/24256
66.94.8.0/24256
66.94.13.0/24256
66.94.14.0/24256
66.94.15.0/24256
66.94.17.0/24256
66.94.18.0/23512
66.94.24.0/24256
66.94.26.0/24256
66.94.29.0/24256
66.94.30.0/24256
72.250.0.0/1732,768
74.60.0.0/1665,536
75.122.0.0/1732,768
75.122.128.0/1732,768
75.123.0.0/1732,768
75.123.128.0/1732,768
97.65.105.0/24256
100.128.0.0/98,388,608
104.152.20.0/24256
162.160.0.0/112,097,152
162.173.20.0/24256
162.173.24.0/212,048
162.173.32.0/212,048
162.173.40.0/212,048
162.173.48.0/212,048
162.173.56.0/212,048
162.173.104.0/212,048
162.184.0.0/15131,072
162.186.0.0/1732,768
162.186.128.0/1732,768
162.187.0.0/1732,768
162.187.128.0/1732,768
162.190.0.0/1665,536
162.191.0.0/1665,536
167.20.0.0/1665,536
168.73.0.0/1732,768
168.73.128.0/1732,768
170.206.0.0/1732,768
170.206.128.0/1732,768
172.32.0.0/112,097,152
172.56.0.0/1665,536
172.56.0.0/23512
172.56.2.0/23512
172.56.4.0/23512
172.56.6.0/23512
172.56.8.0/23512
172.56.10.0/23512
172.56.12.0/23512
172.56.14.0/23512
172.56.16.0/23512
172.56.18.0/23512
172.56.20.0/23512
172.56.22.0/23512
172.56.24.0/23512
172.56.26.0/23512
172.56.28.0/23512
172.56.30.0/23512
172.56.32.0/23512
172.56.34.0/23512
172.56.36.0/23512
172.56.38.0/23512
172.56.40.0/23512
172.56.42.0/23512
172.56.44.0/23512
172.56.46.0/23512
172.56.52.0/23512
172.56.54.0/23512
172.56.56.0/23512
172.56.58.0/23512
172.56.60.0/23512
172.56.62.0/23512
172.56.64.0/212,048
172.56.64.0/23512
172.56.66.0/23512
172.56.68.0/23512
172.56.72.0/212,048
172.56.72.0/23512
172.56.74.0/23512
172.56.76.0/23512
172.56.78.0/23512
172.56.80.0/212,048
172.56.80.0/23512
172.56.82.0/23512
172.56.84.0/23512
172.56.86.0/23512
172.56.88.0/212,048
172.56.88.0/23512
172.56.90.0/23512
172.56.92.0/23512
172.56.94.0/23512
172.56.96.0/212,048
172.56.96.0/23512
172.56.98.0/23512

Showing the first 100 of 283, in address order. Complete list on RIPEstat

IPv6 prefixes (258 prefixes)

Prefix
2001:4870:150::/44
2001:4870:e00b::/48
2607:f880:ff20::/44
2607:f880:ff30::/44
2607:fb90::/28
2607:fb90::/32
2607:fb90::/40
2607:fb90:200::/40
2607:fb90:300::/40
2607:fb90:400::/40
2607:fb90:500::/40
2607:fb90:600::/40
2607:fb90:700::/40
2607:fb90:800::/40
2607:fb90:b00::/40
2607:fb90:d00::/40
2607:fb90:e00::/40
2607:fb90:f00::/40
2607:fb90:fff::/48
2607:fb90:1200::/40
2607:fb90:1300::/40
2607:fb90:1700::/40
2607:fb90:1800::/40
2607:fb90:1c00::/40
2607:fb90:2000::/40
2607:fb90:2100::/40
2607:fb90:2200::/40
2607:fb90:2300::/40
2607:fb90:2400::/40
2607:fb90:2500::/40
2607:fb90:2700::/40
2607:fb90:2c00::/40
2607:fb90:2d00::/40
2607:fb90:3300::/40
2607:fb90:3500::/40
2607:fb90:3700::/40
2607:fb90:3900::/40
2607:fb90:3c00::/40
2607:fb90:3d00::/40
2607:fb90:3e00::/40
2607:fb90:3f00::/40
2607:fb90:4000::/40
2607:fb90:4200::/40
2607:fb90:4500::/40
2607:fb90:4800::/40
2607:fb90:4a00::/40
2607:fb90:4f00::/40
2607:fb90:5000::/40
2607:fb90:5200::/40
2607:fb90:5300::/40
2607:fb90:5500::/40
2607:fb90:5700::/40
2607:fb90:5800::/40
2607:fb90:5c00::/40
2607:fb90:5e00::/40
2607:fb90:5f00::/40
2607:fb90:6000::/40
2607:fb90:6100::/40
2607:fb90:6200::/40
2607:fb90:6300::/40
2607:fb90:6400::/40
2607:fb90:6800::/40
2607:fb90:6c00::/38
2607:fb90:6d00::/40
2607:fb90:7100::/40
2607:fb90:7300::/40
2607:fb90:7400::/40
2607:fb90:7500::/40
2607:fb90:7700::/40
2607:fb90:7800::/40
2607:fb90:7900::/40
2607:fb90:7a00::/40
2607:fb90:7e00::/40
2607:fb90:7f00::/40
2607:fb90:8000::/38
2607:fb90:8000::/40
2607:fb90:8100::/40
2607:fb90:8700::/40
2607:fb90:8a00::/40
2607:fb90:8b00::/40
2607:fb90:8d00::/40
2607:fb90:8e00::/40
2607:fb90:8f00::/40
2607:fb90:9000::/40
2607:fb90:9100::/40
2607:fb90:9200::/40
2607:fb90:9300::/40
2607:fb90:9500::/40
2607:fb90:9900::/40
2607:fb90:9a00::/40
2607:fb90:9b00::/40
2607:fb90:9c00::/40
2607:fb90:9d00::/40
2607:fb90:9e00::/40
2607:fb90:9f00::/40
2607:fb90:a000::/40
2607:fb90:a100::/40
2607:fb90:a200::/40
2607:fb90:a500::/40
2607:fb90:a600::/40

Showing the first 100 of 258, in address order. Complete list on RIPEstat

Neighbours

Upstreams (transit or peers) (26)

ASNetworkVisibility
AS6461Zayo Bandwidth1,035
AS3356Level 3 Parent, LLC901
AS174Cogent Communications, LLC335
AS6939Hurricane Electric LLC146
AS9002RETN Limited31
AS4637Telstra Global24
AS137409GSL Networks Pty LTD10
AS60068Datacamp Limited8
AS4230CLARO S.A.7
AS35280F5 Networks SARL7
AS7195EDGEUNO S.A.S4
AS33891Core-Backbone GmbH4
AS6057Administracion Nacional de Telecomunicaciones3
AS37468Angola Cables3
AS58453China Mobile International Limited3
AS1031PEER 1031 LLC2
AS6424EDGOO NETWORKS UNIPESSOAL LDA1
AS7575Australian Academic and Research Network (AARNet)1
AS20326TeraSwitch Networks Inc.1
AS32621Twin City VoIP, Inc.1
AS39120Convergenze S.p.A.1
AS52025ParadoxNetworks Limited1
AS55850Mercury NZ Limited1
AS61568ALOO TELECOM - FSF TECNOLOGIA SA1
AS64126DOMINICAN TELECOM PRIME, DTP, S.R.L.1
AS394256Tech Futures Interactive Inc.1

Downstreams (customers) (3)

ASNetworkVisibility
AS22140T-Mobile USA, Inc.280
AS400318Versa Networks, Inc.266
AS16550Google LLC4

21 more neighbours appear on both sides of this network depending on the path, so they are counted in neither list.

Visibility is RIPEstat's count of how often the route collectors observed the link. It compares neighbours with each other; it is not a traffic volume.

How to read this page

An Autonomous System (AS) is a network run under one routing policy: an internet provider, a cloud, a content network, a university. Each one has a number, its ASN, assigned by a regional registry (ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC), and uses BGP, the protocol networks use to tell each other where addresses are, to announce the blocks of addresses it delivers to.

A prefix such as 203.0.113.0/24 is a block of addresses: the number after the slash says how many bits are fixed, so a /24 holds 256 IPv4 addresses and a /16 holds 65,536. Networks often announce a large block and smaller pieces of it at the same time, which is why the address total counts each address once.

Neighbours come from the paths themselves. A network that appears just before this one in a path, on the collector's side, is an upstream: a transit provider or a peer. One that appears just after it is a downstream, usually a customer. Peering at an internet exchange also shows up as an upstream, so the upstream list is not a list of paid transit.

The data comes from RIPEstat, run by the RIPE NCC, which gathers the routing tables of hundreds of networks through its RIS route collectors. This page reads it when it is visited and keeps it for 12 hours at most; the BGP viewer reads it live.

Frequently asked questions

How do I find the ASN of an IP address?
Type the address in the BGP viewer: it shows the prefix that covers it, the AS that originates that prefix and the paths seen towards it. A traceroute also names the network of each hop, so you can see every AS a connection crosses.
Why does one company have several ASNs?
Large operators split their network by region, by activity or by history: a cloud may use one number for its backbone and another for a region, and every acquisition brings its own numbers. Each number has its own page, with its own prefixes and neighbours.
Why do prefix counts differ from one site to another?
Each source sees the routing table from different collectors, at a different time, and counts differently: some include prefixes withdrawn in recent weeks, some merge a block and its pieces. This page counts the prefixes RIPE RIS collectors see originated by the network at the end of the latest two-week window, and counts each IPv4 address once.
Is this the list of IP ranges of a cloud provider?
It is what its networks announce, which is what the Internet routes to them. Many providers also publish an official list of ranges per service and region; that list is the reference for firewall rules, because a range can be announced before it is used, or announced by another of their AS numbers.