Number,Operation Code (op),References
0,Reserved,[RFC5494]
1,REQUEST,[RFC826][RFC5227]
2,REPLY,[RFC826][RFC5227]
3,request Reverse,[RFC903]
4,reply Reverse,[RFC903]
5,DRARP-Request,[RFC1931]
6,DRARP-Reply,[RFC1931]
7,DRARP-Error,[RFC1931]
8,InARP-Request,[RFC2390]
9,InARP-Reply,[RFC2390]
10,ARP-NAK,[RFC1577]
11,MARS-Request,[Grenville_Armitage]
12,MARS-Multi,[Grenville_Armitage]
13,MARS-MServ,[Grenville_Armitage]
14,MARS-Join,[Grenville_Armitage]
15,MARS-Leave,[Grenville_Armitage]
16,MARS-NAK,[Grenville_Armitage]
17,MARS-Unserv,[Grenville_Armitage]
18,MARS-SJoin,[Grenville_Armitage]
19,MARS-SLeave,[Grenville_Armitage]
20,MARS-Grouplist-Request,[Grenville_Armitage]
21,MARS-Grouplist-Reply,[Grenville_Armitage]
22,MARS-Redirect-Map,[Grenville_Armitage]
23,MAPOS-UNARP,[Mitsuru_Maruyama][RFC2176]
24,OP_EXP1,[RFC5494]
25,OP_EXP2,[RFC5494]
26-65534,Unassigned,
65535,Reserved,[RFC5494]