M4 RPID/PAI

RPID headers: Remote-Party-Id and RPID-Privacy

PID headers: P-Asserted-Identity and Privacy

OP and TP have separate options: Forward RPID and forward PAI in their settings.

The logic to pass these headers are in this order:

OP->TP

OP Forward RPID/PAI options tell if it is allowed to pass/forward RPID/PAI headers from OP to TPs.

If headers are passed from OP to TPs, then TP Forward RPID/PAI options tell if these headers should be passed to the TP.

If OP denies RPID/PAI header forward, then RPID/PAI headers coming from this OP will be dropped and TPs will not have any RPID/PAI headers to be forwarded.

In other words - OP makes a call that can pass over some TPs. If OP denies RPID/PAI forward, there is no difference what RPID/PAI settings are on any of the TPs for this call - these headers are already dropped by OP. Only when OP allows RPID/PAI header forward, then separate TPs RPID/PAI settings can have an impact on the result.

OP Setting TP Setting Header is passed

OP setting	TP setting	Result
Forward RPID: yes	Forward RPID: yes	RPID headers are forwarded to TP
Forward RPID: yes	Forward RPID: no	RPID headers are NOT forwarded to TP
Forward RPID: no	Forward RPID: yes/no	RPID headers are NOT forwarded to TP

Same logic applies to the PAI settings.