Autonomous system numbers

Organizations requiring connectivity to the Internet must obtain an Autonomous System Number (ASN). ASNs were originally 2 bytes (16 bit), providing 65,535 ASNs. ASNs 64,512-65,535 are private ASNs within the 16-bit ASN range.


RFC 4893 expands the ASN field to accommodate 4 bytes (32 bit). ArubaOS-CX-10.00 version supports only 2-byte AS (16 bit).