Autonomous System Numbers
ASN is an acronym for Autonomous System Numbers, a globally unique number and significant part of the internet routing architecture. The Autonomous System Numbers are taken from a 16-bit number field. There are reserved ASNs which include 0, which can be used to identify non-routed networks, the 65,535 is also reserved. The ASNs starting from 64,512 up to 65,534 are reserved for private use while the ASN 23,456 is dedicated to be used in the ASN pool transition. [1] This means that the available quantity of ASN for internet routing is limited.