AS5400 — BT British Telecommunications Limited

AS5400 announces 72 IPv4 prefixes covering 713,472 addresses and 11 IPv6 prefixes.

About this network

AS5400 is BT's international IP backbone, the network behind BT.net and BT's global network services business. It is the carrier-side network, distinct from BT's UK consumer and broadband ASNs.

What it's used for

• IP transit and global connectivity for BT's enterprise, wholesale and carrier customers across Europe, North America and Asia.
• Peering with thousands of other networks at major exchanges; the ASN sits near the top of transit-ranking tables.
• Backbone for BT's managed WAN, MPLS and internet products sold outside the UK consumer market.

Notable

• Carrier address, not eyeball address: hosts on AS5400 are far more likely to be enterprise sites, corporate edge routers and infrastructure than home broadband subscribers. BT's UK retail broadband is announced from a separate ASN.
• BT's internet capability is deliberately split by role — a European/global backbone (this ASN), a UK network, and in-country networks in several other European markets. Attributing traffic on AS5400 to "BT home users" is a common mistake.

Interesting

• The network grew out of BT's late-1990s/2000s continental fibre build and the IP business that was branded BT Ignite before becoming BT Global Services.

This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy.

Announced prefixes

• 31.95.0.0/21
• 31.95.14.0/23
• 31.95.16.0/20
• 31.95.48.0/21
• 31.95.56.0/24
• 31.95.64.0/21
• 31.95.96.0/19
• 31.95.160.0/20
• 31.95.184.0/21
• 31.95.208.0/21
• 31.95.218.0/23
• 31.95.220.0/22
• 31.95.240.0/22
• 31.95.246.0/23
• 31.95.248.0/22
• 31.95.254.0/23
• 46.248.8.0/22
• 62.5.0.0/17
• 62.102.0.0/17
• 62.134.0.0/16
• 62.172.0.0/21
• 62.173.192.0/18
• 62.180.0.0/16
• 80.255.160.0/20
• 82.138.160.0/19
• 82.150.0.0/19
• 132.244.64.0/21
• 132.244.72.0/22
• 132.244.76.0/23
• 132.244.78.0/24
• 132.244.240.0/24
• 136.238.84.0/23
• 136.238.224.0/24
• 166.49.128.0/17
• 185.94.0.0/22
• 185.249.4.0/24
• 192.109.52.0/24
• 194.33.53.0/24
• 194.33.54.0/23
• 194.50.160.0/24
• 194.74.80.0/21
• 194.76.40.0/24
• 194.107.114.0/24
• 194.213.64.0/19
• 195.36.82.0/24
• 195.36.104.0/24
• 195.60.182.0/23
• 195.66.70.0/24
• 195.90.64.0/19
• 195.99.64.0/20
• 195.100.0.0/16
• 195.163.0.0/16
• 195.171.36.0/22
• 195.182.96.0/19
• 198.178.236.0/24
• 203.158.68.0/23
• 203.158.72.0/23
• 203.158.76.0/23
• 203.158.88.0/23
• 204.52.188.0/24
• 206.73.0.0/16
• 212.8.160.0/19
• 212.21.192.0/19
• 212.31.192.0/19
• 212.41.128.0/19
• 212.108.0.0/19
• 212.127.0.0/19
• 212.162.192.0/18
• 213.15.0.0/16
• 213.137.160.0/19
• 213.194.0.0/18
• 213.236.64.0/18
• 2001:740::/32
• 2402:fb00:8000::/39
• 2402:fb00:8400::/39
• 2402:fb00:8800::/40
• 2402:fb00:c000::/38
• 2606:f100:d000::/39
• 2606:f100:d400::/38
• 2606:f100:d800::/37
• 2606:f100:e400::/39
• 2a00:2000::/22
• 2a0c:7c80::/29

Upstream networks

• AS1299 Arelion Sweden AB
• AS6939 Hurricane Electric LLC
• AS3356 Level 3 Parent, LLC
• AS9002 RETN Limited
• AS174 Cogent Communications, LLC
• AS3257 GTT Communications Inc.
• AS577 Bell Canada
• AS3491 PCCW Global (HK) Ltd.
• AS4637 Telstra Global
• AS6762 TELECOM ITALIA SPARKLE S.p.A.
• AS50304 Blix Solutions AS
• AS42708 Glesys Sweden AB
• AS3333 Reseaux IP Europeens Network Coordination Centre (RIPE NCC)
• AS1836 green.ch AG
• AS1273 IDDQD-AS
• AS6453 TATA COMMUNICATIONS (AMERICA) INC
• AS2914 NTT America, Inc.
• AS20485 Joint Stock Company TransTeleCom
• AS2497 Internet Initiative Japan Inc.
• AS37100 SEACOM Limited
• AS3303 Swisscom (Schweiz) AG
• AS12552 GlobalConnect AB
• AS11164 Internet2
• AS33891 Core-Backbone GmbH
• AS6830 Liberty Global Europe Holding B.V.

Downstream networks

• AS2856 British Telecommunications Limited
• AS199541 EUROCONTROL, the European Organisation for the Safety of Air Navigation
• AS13205 Telecommunications Limited
• AS2110 Enet Communications LIMITED
• AS33873 Arvato Systems GmbH
• AS21489 The North Atlantic Treaty Organization
• AS15442 Procter & Gamble Service GmbH
• AS30614 Dell, Inc.
• AS21000 Atos France SAS
• AS29063 Eviden Netherlands B.V.
• AS72 Schlumberger Limited
• AS25049 Shell Information Technology International B.V.
• AS40934 Fortinet Inc.
• AS8968 RETELIT-X S.R.L.
• AS7246 Bristol-Myers Squibb Company
• AS51046 Bringo Limited
• AS212565 Specsavers Optical Group Limited
• AS15518 Circular Informationssysteme GmbH
• AS40126 Molson Coors Beverage Company
• AS22683 Koninklijke Philips N.V.
• AS15495 BASF Digital Solutions GmbH
• AS34311 LG CNS Europe B.V
• AS51466 Bridgestone Europe NV
• AS59724 Elsevier Limited
• AS16839 SERVICENOW, INC.

Adjacent networks

• AS2856 British Telecommunications Limited
• AS1299 Arelion Sweden AB
• AS3356 Level 3 Parent, LLC
• AS6939 Hurricane Electric LLC
• AS3257 GTT Communications Inc.
• AS174 Cogent Communications, LLC
• AS199541 EUROCONTROL, the European Organisation for the Safety of Air Navigation
• AS8968 RETELIT-X S.R.L.
• AS33891 Core-Backbone GmbH
• AS11164 Internet2
• AS1836 green.ch AG
• AS12552 GlobalConnect AB
• AS37100 SEACOM Limited
• AS6762 TELECOM ITALIA SPARKLE S.p.A.
• AS3333 Reseaux IP Europeens Network Coordination Centre (RIPE NCC)
• AS20485 Joint Stock Company TransTeleCom
• AS2110 Enet Communications LIMITED
• AS2497 Internet Initiative Japan Inc.
• AS6453 TATA COMMUNICATIONS (AMERICA) INC
• AS4637 Telstra Global
• AS9002 RETN Limited
• AS577 Bell Canada
• AS13205 Telecommunications Limited
• AS42708 Glesys Sweden AB
• AS33873 Arvato Systems GmbH

Routing security

• RPKI: 98 valid, 0 invalid and 28 not-found announcements; 149 ROAs.
• ASPA: none published.
• IRR: 100% of announcements registered; 275 route objects.
• Listed in as-sets: AS-ATRATO:AS-PEERS, AS-BNIX, AS-BT-AT, AS-BT-BE, AS-BT-CH, AS-BT-CZ, AS-BT-DE, AS-BT-DK, AS-BT-ES, AS-BT-EU, AS-BT-FR, AS-BT-HU, AS-BT-IE, AS-BT-IT, AS-BT-LU, AS-BT-NL, AS-BT-PL, AS-BT-SE, AS-BT-UK, AS-BT6, AS-CONCERTAT, AS-CONCERTBE, AS-CONCERTCH, AS-CONCERTDE, AS-CONCERTES.

Internet exchanges

• IX.br (PTT.br) São Paulo — São Paulo, Brazil
• DE-CIX Frankfurt — Frankfurt, Germany
• LINX LON1 — London, United Kingdom
• AMS-IX Amsterdam — Amsterdam, Netherlands
• Neutral Internet Exchange — Amsterdam, Netherlands
• France-IX Paris — Paris, France
• Equinix Internet Exchange Singapore — Singapore, Singapore
• Milan Internet Exchange — Milan, Italy
• Equinix Internet Exchange Ashburn — Ashburn, United States
• BroadBand Internet eXchange Tokyo — Tokyo, Japan
• Coresite - Any2 West — Los Angeles, United States
• Seattle Internet Exchange — Seattle, United States
• Any2 California — Los Angeles, United States
• Equinix Internet Exchange Warsaw — Warsaw, Poland
• Toronto Internet Exchange — Toronto, Canada
• Equinix Internet Exchange Chicago — Chicago, United States
• SwissIX — Zurich, Switzerland
• Equinix Internet Exchange Paris — Paris, France
• Equinix Internet Exchange Hong Kong — Hong Kong, China
• Equinix Internet Exchange Dallas — Dallas, United States
• DE-CIX Dusseldorf — Düsseldorf, Germany
• DE-CIX Madrid — Madrid, Spain
• New York International Internet Exchange — New York, United States
• DE-CIX Munich — Munich, Germany
• NIX.CZ - Neutral Internet eXchange for the Czech Republic — Prague, Czech Republic
• Equinix Internet Exchange San Jose (Bay Area) — San Jose, United States
• Vienna Internet Exchange — Vienna, Austria
• Equinix Internet Exchange Miami — Miami, United States
• ESpanix Madrid Lower LAN — Madrid, Spain
• Digital Realty Atlanta Internet Exchange — Atlanta, United States
• Berlin Commercial Internet Exchange — Berlin, Germany
• Megaport IX Melbourne — Melbourne, Australia
• BroadBand Internet eXchange Osaka — Osaka, Japan
• France-IX Marseille — Marseille, France
• Equinix Internet Exchange Tokyo — Tokyo, Japan
• Budapest Internet Exchange — Budapest, Hungary
• Equinix Internet Exchange New York — New York, United States
• Internet Neutral Exchange Association CLG - LAN1 — Dublin, Ireland
• JPIX Osaka — Osaka, Japan
• DE-CIX Marseille — Marseille, France
• Luxembourg Internet Exchange — Luxembourg, Luxembourg
• France-IX Lyon — Lyon, France
• CANIX Internet Exchange - Montreal — Montreal, Canada
• Belgian National Internet Exchange — Brussels, Belgium
• Equinix Internet Exchange Los Angeles — Los Angeles, United States
• Vancouver Internet Exchange — Vancouver, Canada
• Equinix Los Angeles IBX — Los Angeles, United States
• Norwegian Internet Exchange Oslo 1 — Oslo, Norway
• DE-CIX Lisbon — Lisbon, Portugal
• Catalunya Neutral Internet Exchange Point — Barcelona, Spain
• Netnod Sundsvall- Gävle — Sundsvall, Sweden
• Equinix-LA(former Paix) — Los Angeles, United States