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AS2856British Telecommunications

United KingdomRegistryRIPE NCCTypeEyeball

As of 11th November 2026, AS2856 (British Telecommunications), an access network registered in the United Kingdom with RIPE NCC, originates 548 IPv4 prefixes covering 18.5M addresses and 7 IPv6 prefixes. By IPv4 address space that makes it the 35th-largest of the 80,743 networks we see originating IPv4, and the 2nd-largest of 2,122 in the United Kingdom. It is seen behind 20 upstream networks, most often AS5400 (British Telecommunications…) and AS9002 (RETN Limited), and in front of 150 downstream networks. 70% of its announcements have a valid RPKI ROA; 2 are RPKI-invalid. 98% of its routes reach at least 90% of full-feed peers, and 3 prefixes are also originated by another network.

At a glance

IPv4 prefixes

548

IPv6 prefixes

7

IPv4 addresses

18.5M

IPv6 /64s

584B

Upstream graph

The networks AS2856 is seen behind, one and two hops out, drawn from real AS paths.

AS2856Toward the internet core
Upstream graph for AS2856: 8 neighbouring networks observed beyond it across 2 levels. The same networks are listed in the tables below.AS2856British Telecommu…This networkAS5400British Telecommu…AS5413Wavenet LimitedAS6667Elisa OyjAS9002RETN LimitedAS13030Init7 (Switzerlan…AS3356Lumen (Level 3)AS1299Arelion (fka. Tel…AS56662Marcin Gondek

Networks observed one and two hops upstream of AS2856 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

416

adjacent networks

Upstreams
205%
Peers
24659%
Downstreams
15036%

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

Upstreams of AS2856
NetworkCountryRelationshipPathsVantage pts
AS5400British Telecommunications (International) GBPeer48,623126
AS9002RETN LimitedGBPeer5,28618
AS13030Init7 (Switzerland) Ltd.CHPeer1,9785
AS6667Elisa OyjFIPeer1,9494
AS5413Wavenet LimitedGBPeer1,0152
AS39122Blacknight Internet Solutions LimitedIEPeer9782
AS32590Valve CorporationUSPeer9732
AS49544i3D.net B.VNLPeer9482
AS3170VeloxServ Communications LtdGBPeer9392
AS41811CONVERGENCE (GROUP NETWORKS) LIMITEDGBPeer9011

Prefixes

All 555

The largest blocks AS2856 originates, widest first.

Largest prefixes originated by AS2856
PrefixAddressesVisibility
86.128.0.0/104.2M75/76
81.128.0.0/112.1M75/76
86.128.0.0/112.1M75/76
81.128.0.0/121M75/76
86.128.0.0/121M75/76
109.144.0.0/121M75/76
217.32.0.0/121M75/76
31.48.0.0/13524k75/76
95.144.0.0/13524k75/76
31.100.0.0/14262k76/76

Routing health

How AS2856'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

  • Valid70.5%391
  • Invalid0.4%2
  • No ROA29.2%162

Propagation

  • Globally propagated90% of full-feed peers or more97.8%543
  • Partially propagated40% to 90%1.4%8
  • Seen by few peersUnder 40%0.7%4

Prefix sizes

IPv4 — 548 prefixes

IPv6 — 7 prefixes

  • /25550B × /6414.3%1
  • /2934.4B × /6414.3%1
  • /47131k × /6414.3%1
  • /4865.5k × /6457.1%4

Recent changes

Announcements that started or stopped since 12th Oct 2026.

10 announced and 5 withdrawn in all; the most recent are shown.

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