Message Type

type  
0 echo reply
3 destination unreachable
4 source quench
5 redirect
8 echo request
11 time exceeded
12 parameter problem
13 timestamp request
14 timestamp reply
15 information request
16 information reply
17 address mask request
18 address mask reply

Datagram

0-78-1516-2324-31
TypeCodeChecksum
Data (variable length)