Description,Value,Reference
CAPWAP,0,[RFC5415][RFC5416]
L2TP,1,[RFC2661]
L2TPv3,2,[RFC3931]
IP-IP,3,[RFC2003]
PMIPv6-UDP,4,[RFC5844]
GRE,5,[RFC2784]
GTPv1-U,6,[3GPP TS 29.281]
Unassigned,7-65535,