Network operators need Autonomous System Numbers (ASNs) to control routing within their networks and to exchange routing information with other Internet Service Providers (ISPs). There are two different formats to represent ASNs: 2-byte and 4-byte. A 2-byte ASN is a 16-bit number.

What is my autonomous system number?

Autonomous System Number (ASN) is a globally unique identifier that defines a group of one or more IP prefixes run by one or more network operators that maintain a single, clearly-defined routing policy.

What is autonomous system number in BGP?

An Autonomous System Number (AS number or just ASN) is a special number assigned by IANA used primarilly with Border Gateway Protocol which uniquely identifies an network under a single technical administration that has a unique routing policy, or is multi-homed to the public internet.