Value,Description,Reference
0,RESERVED,[RFC4430]
1,CREATE,[RFC4430]
2,DELETE,[RFC4430]
3,REPLY,[RFC4430]
4,GETTGT,[RFC4430]
5,ACK,[RFC4430]
6,STATUS,[RFC4430]
7-127,Unassigned,[RFC4430]
128-255,Private use,[RFC4430]