Lectures notes for 2010 - KTH

IP Options Encoding
Two styles:
• Single byte (only code)
• Multiple byte
Option Code: 1 byte
• Copy (to fragments) (1 bit)
– 0: copy only to the first fragment
– 1: copy the option to all fragements
• Class (2 bits)
– 0 (00): Datagram or network control
– 2 (10): Debugging and measurement
– 1 (01) and 3 (11) reserved
• Option Number (5 bits)
Option Length: 1 byte, defines total length of option
Data: option specific
Code Length Data
copy
class
option
number
Maguire IP Options Encoding 3: 21 of 33
maguire@kth.se 2010.03.21 Internetworking/Internetteknik