Value,Description,Reference
0,Reserved,[RFC5971]
1,TCP opened in the forwards direction,[RFC5971]
2,TLS initiated in the forwards direction,[RFC5971]
3,SCTP opened in the forwards direction,[RFC6084]
4,DTLS initiated in the forwards direction,[RFC6084]
5-119,Unassigned,
120-127,Reserved for Private/Experimental Use,[RFC5971]
128-255,Reserved,[RFC5971]