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Autonomous System

AS513 · CERN - European Organization for Nuclear Research

Overview

AS513 is announced on the Internet: RIPE RIS route collectors currently see 20 IPv4 prefixes and 2 IPv6 prefixes originated by this network. Together, its IPv4 prefixes cover 354,816 addresses, with overlapping prefixes counted once. In the paths the collectors record, it has 12 upstream neighbours (transit providers or peers) and 6 downstream neighbours (customers or networks it carries). Its most visible upstreams are IP-Max SA (AS25091), GEANT Vereniging (AS21320), and Cogent Communications, LLC (AS174). AS513 was assigned by ARIN, and its registration country is Switzerland.

Source: RIPEstat (RIPE NCC), RIS route collectors. Read on October 16, 2026 at 8:57 PM UTC. This page is refreshed at most every 12 hours.

Go further

The trace goes to 128.141.0.1, the first address of 128.141.0.0/16. 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 (20 prefixes)

PrefixAddresses
128.141.0.0/1665,536
128.142.0.0/1665,536
137.138.0.0/1665,536
185.249.56.0/221,024
188.184.0.0/1665,536
188.185.0.0/1665,536
192.16.155.0/24256
192.16.156.0/221,024
192.16.160.0/221,024
192.16.164.0/23512
192.16.166.0/24256
192.65.183.0/24256
192.65.184.0/212,048
192.65.192.0/221,024
192.65.196.0/23512
192.91.236.0/221,024
192.91.240.0/221,024
192.91.244.0/23512
192.91.246.0/24256
194.12.128.0/1816,384

IPv6 prefixes (2 prefixes)

Prefix
2001:1458::/32
2001:1459::/32

Neighbours

Upstreams (transit or peers) (12)

ASNetworkVisibility
AS25091IP-Max SA52,491
AS21320GEANT Vereniging43,720
AS174Cogent Communications, LLC39,828
AS6939Hurricane Electric LLC16,810
AS29222Infomaniak Network SA10,684
AS20965GEANT Vereniging5,879
AS6730Sunrise GmbH2,311
AS2907Research Organization of Information and Systems, National Institute of Informatics122
AS30781Free Pro SAS93
AS15576NTS workspace AG55
AS559Switch SWITCH52
AS1103SURF B.V.39

Downstreams (customers) (6)

ASNetworkVisibility
AS20940Akamai International B.V.486
AS28810World Health Organization (WHO)396
AS48751United Nations Logistics Base274
AS21449Etat de Geneve53
AS12654Reseaux IP Europeens Network Coordination Centre (RIPE NCC)45
AS25152Reseaux IP Europeens Network Coordination Centre (RIPE NCC)8

41 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.