Networks and addresses
AS number (ASN)
The number that identifies a network on the internet for routing. Needed to announce your own IP addresses with BGP.
An autonomous system is a network under one administration with its own routing policy: an ISP, a hosting company, a large enterprise, a content network. Each one has a number, the ASN, which is what other networks see in the global routing table. NovaNode is AS199839.
You need an ASN to announce IP prefixes with BGP to more than one neighbour, or to one neighbour under a routing policy of your own. You do not need one to have public addresses on a server or a fixed address at home; your provider's AS announces those for you.
In the RIPE region the RIPE NCC assigns ASNs, either to its members or to end users through a sponsoring LIR. The request asks for two peering partners, the address space you will announce, and a legal entity. Most new assignments are 32-bit numbers; the old 16-bit range is nearly gone.