3.1 Common Details
This section documents deviations from "The Internet IP Security Domain of Interpretation for ISAKMP", as specified in [RFC2407]; "Internet Security Association and Key Management Protocol (ISAKMP)", as specified in [RFC2408]; "The Internet Key Exchange (IKE)", as specified in [RFC2409]; "Internet Key Exchange (IKEv2) Protocol", as specified in [RFC4306]; and "Negotiation of NAT-Traversal in the IKE", as specified in [RFC3947]. These deviations affect each of these RFC standards as described in the table in section 1.3.13.
The flags bit semantics used by this document are as follows: for a flag, its "value" signifies a mask which, when its bitwise logical AND with the flags field is computed, yields either a zero value (all zero bits) if the flag is unset (set to FALSE), and a nonzero value otherwise. For example, a flag mask/value of 0x01 signifies that the bitwise logical AND of a single-byte flag field with 0x01 is zero if and only if the flag is set to FALSE. Assuming no other flag masks/values for this field, then, both 0x00 and 0x01 are valid values for this single-byte flag field: the former corresponding to the flag being unset, and the latter to the flag being set.