2.2.3.3 PF2_UNRELATED Flag
These extensions extend the PDU format by defining the reserved_04 bit of the second set of PDU flags (flags2), as specified in [C706] section 12, as PF2_UNRELATED. This flag has meaning only in a REQUEST packet.
The server SHOULD<45> set the PF2_UNRELATED flag in all conv_who_are_you2 and conv_who_are_you_auth requests to indicate to the client that the server can correctly interpret client requests with the flag set.
The client MUST set the PF2_UNRELATED flag in a REQUEST packet if the packet SHOULD NOT cancel the activity's previous call sequence numbers. For usage information, see section 3.