Flag Bit,Meaning,Reference
A,Checksum required,"[RFC8684, Section 3.1]"
B,Extensibility,"[RFC8684, Section 3.1]"
C,Do not attempt to establish new subflows to the source address.,"[RFC8684, Section 3.1]"
D-G,Unassigned,
H,HMAC-SHA256,"[RFC8684, Section 3.2]"