BGP 4-Byte AS Number - Asplain notation
BGP uses AS numbers as a fundamental part of its routing process. Because conventional 2-byte public AS numbers were becoming exhausted, the IANA increased the AS numbers by introducing a 4-byte AS numbers. The Asplain notation to represent these AS numbers is simply to use the decimal value that corresponds to the binary value.
4-Byte AS numbers, which use 32 bits to represent them in binary, range from 0 to 4294967295.