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AS131937Joetsu Cable Vision

JapanRegistryAPNIC

As of 29th September 2026, AS131937 (Joetsu Cable Vision), a network registered in Japan with APNIC, originates 10 IPv4 prefixes covering 33.3k addresses and 2 IPv6 prefixes. By IPv4 address space that makes it the 5,373rd-largest of the 79,607 networks we see originating IPv4, and the 213th-largest of 729 in Japan. It is seen behind 13 upstream networks, most often AS2497 (Internet Initiative Japan Inc.) and AS17676 (SoftBank Corp.). Every one of its announcements has a valid RPKI ROA, and none are RPKI-invalid. 100% of its routes reach at least 90% of full-feed peers.

At a glance

IPv4 prefixes

10

IPv6 prefixes

2

IPv4 addresses

33.3k

IPv6 /64s

8.6B

Upstream graph

The networks AS131937 is seen behind, one and two hops out, drawn from real AS paths.

AS131937Toward the internet core
Upstream graph for AS131937: 10 neighbouring networks observed beyond it across 2 levels. The same networks are listed in the tables below.AS131937Joetsu Cable Visi…This networkAS2497Internet Initiati…AS6939Hurricane Electri…AS9824JCOM Co., Ltd.AS17676SoftBank Corp.AS18106Viewqwest Pte LtdAS20130Depaul UniversityAS1299Arelion (fka. Tel…AS2914NTT America, Inc.AS2516KDDI CorporationAS215859Hetzner Cloud - S…

Networks observed one and two hops upstream of AS131937 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

35

adjacent networks

Upstreams
1337%
Peers
2263%
Downstreams
00%

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

Upstreams of AS131937
NetworkCountryRelationshipPathsVantage pts
AS2497Internet Initiative Japan Inc.JPPeer65789
AS17676SoftBank Corp.JPPeer10316
AS9824JCOM Co., Ltd.JPAdjacent4820
AS6939Hurricane Electric LLCUSPeer303
AS18106Viewqwest Pte LtdSGPeer244
AS8966Etisalat (E&)AEPeer202
AS9002RETN LimitedGBPeer122
AS49544i3D.net B.VNLPeer122
AS35280F5 Networks SARLFRPeer122
AS4775Globe TelecomsPHPeer122

Prefixes

The largest blocks AS131937 originates, widest first.

Largest prefixes originated by AS131937
PrefixAddressesVisibility
126.251.0.0/198.2k82/82
170.249.96.0/198.2k82/82
126.251.128.0/204.1k82/82
126.251.144.0/204.1k82/82
126.251.32.0/212k82/82
126.251.112.0/212k82/82
170.249.64.0/212k82/82
103.118.92.0/221k82/82
202.223.12.0/221k82/82
103.152.66.0/2351282/82

Routing health

How AS131937'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%12
  • Invalid0.0%0
  • No ROA0.0%0

Propagation

  • Globally propagated90% of full-feed peers or more100.0%12
  • Partially propagated40% to 90%0.0%0
  • Seen by few peersUnder 40%0.0%0

Prefix sizes

IPv4 — 10 prefixes

IPv6 — 2 prefixes

  • /324.3B × /64100.0%2

Recent changes

Announcements that started or stopped since 30th Aug 2026.

No announcement by AS131937 started or stopped in this period.

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