Protocol ID,Protocol,Reference
0,Reserved,[RFC7296]
1,IKE,[RFC7296]
2,AH,[RFC7296]
3,ESP,[RFC7296]
4,FC_ESP_HEADER,[RFC4595]
5,FC_CT_AUTHENTICATION,[RFC4595]
6,GIKE_UPDATE,[RFC-ietf-ipsecme-g-ikev2-21]
7-200,Unassigned,
201-255,Reserved for Private Use,[RFC7296]