The mathematical algorithm itself requires initialization with 18 32-bit subkeys (equivalent to 72 octets/bytes). The IPv6 packet header has a minimum size of 40 octets (320 bits). All data octets except 0xff are transmitted over Telnet as is. Only few Link Layer protocols can process packets larger than octets. The packet number is a 48-bit number stored across 6 octets. It is encoded as 1 or more octets. It consists of the four octets, written in binary notation&colon; "01111111", "00000000", "00000000", and "00000001". Each segment is less than or equal to 255 octets. Each fragment is a multiple of 8 octets in length, except the last fragment. The very first two octets transmitted by a station is the Frame Control. Each label may contain from 1 to 63 octets. Most Link Layer protocols have MTUs considerably smaller than octets. Lines should be limited to 75 octets (not characters) long. The size of an Ethernet MAC address is six octets. By default, the maximum is 1500 octets.