# Asn `````{roto:type} Asn An ASN: an Autonomous System Number. An AS number can contain a number of 32-bits and is therefore similar to a [`u32`](u32). However, AS numbers cannot be manipulated with arithmetic operations. An AS number is constructed with the `AS` prefix followed by a number. Can be used to store both 2-byte and 4-byte ASNs. ```roto let a = AS0; let b = AS1010; let c = AS4294967295; ``` ````` ````{roto:function} to_string(self: Asn) -> String Convert this value into a `String`. ````