Value,Description,Reference
0,Reserved,[RFC5440]
1,Open,[RFC5440]
2,Keepalive,[RFC5440]
3,Path Computation Request,[RFC5440]
4,Path Computation Reply,[RFC5440]
5,Notification,[RFC5440]
6,Error,[RFC5440]
7,Close,[RFC5440]
8,Path Computation Monitoring Request (PCMonReq),[RFC5886]
9,Path Computation Monitoring Reply (PCMonRep),[RFC5886]
10,Report,[RFC8231]
11,Update,[RFC8231]
12,LSP Initiate Request,[RFC8281]
13,StartTLS,[RFC8253]
14-251,Unassigned,
252-255,Experimental Use,[RFC8356]