rfc9753v2.txt		rfc9753.txt
	skipping to change at line 159 ¶		skipping to change at line 159 ¶
	Variation metric [RFC8233]. In some scenarios, it would be useful to		Variation metric [RFC8233]. In some scenarios, it would be useful to
	indicate that this constraint can be relaxed by the PCE in case it		indicate that this constraint can be relaxed by the PCE in case it
	cannot find a path. In these cases, it would be useful to mark the		cannot find a path. In these cases, it would be useful to mark the
	objects as 'optional' so they could be ignored by the PCEP peer.		objects as 'optional' so they could be ignored by the PCEP peer.
	Also, it would be useful for the PCEP speaker to learn if the PCEP		Also, it would be useful for the PCEP speaker to learn if the PCEP
	peer has relaxed the constraint and ignored the processing of the		peer has relaxed the constraint and ignored the processing of the
	PCEP object.		PCEP object.
	Thus, this document specifies how the already existing P and I flags		Thus, this document specifies how the already existing P and I flags
	in the PCEP common object header could be used during the stateful		in the PCEP common object header could be used during the stateful
	PCEP message exchange. It should be noted that similar to handling		PCEP message exchange. The scope of how P and I flags are applied is
	of P and I flags in [RFC5440], the flag applies to full PCEP object		defined in [RFC5440] and is unchanged by this document. Therefore,
	and could not be applied to the granularity of an optional TLVs		these flags can only be applied to an entire PCEP object; they cannot
	encoded in the PCEP object.		be applied at the granularity of optional TLVs encoded in the PCEP
			object.
	3. PCEP Extension		3. PCEP Extension
	3.1. STATEFUL-PCE-CAPABILITY TLV		3.1. STATEFUL-PCE-CAPABILITY TLV
	A PCEP speaker indicates its ability to support the handling of the P		A PCEP speaker indicates its ability to support the handling of the P
	and I flags in the stateful PCEP message exchange during the PCEP		and I flags in the stateful PCEP message exchange during the PCEP
	initialization phase, as follows. During the PCEP initialization		initialization phase, as follows. During the PCEP initialization
	phase, a PCC sends an Open message with an OPEN object that contains		phase, a PCC sends an Open message with an OPEN object that contains
	the STATEFUL-PCE-CAPABILITY TLV, as defined in [RFC8231]. A new		the STATEFUL-PCE-CAPABILITY TLV, as defined in [RFC8231]. A new
	skipping to change at line 277 ¶		skipping to change at line 278 ¶
	Note that when a PCE is unable to find the path that meets all the		Note that when a PCE is unable to find the path that meets all the
	constraints as per the PCEP object that cannot be ignored (i.e. the		constraints as per the PCEP object that cannot be ignored (i.e. the
	P flag is set), the PCUpd message MAY optionally include the PCEP		P flag is set), the PCUpd message MAY optionally include the PCEP
	objects that caused the path computation to fail along with the empty		objects that caused the path computation to fail along with the empty
	ERO.		ERO.
	3.3.2. The PCRpt Message		3.3.2. The PCRpt Message
	The I flag in the PCRpt message [RFC8231] allows a PCC to indicate to		The I flag in the PCRpt message [RFC8231] allows a PCC to indicate to
	a PCE whether or not an optional object was processed in response to		a PCE whether or not an optional object was processed in response to
	a PCUpd or PCinit message. The PCC MAY include the ignored optional		a PCUpd or PCInitiate message. The PCC MAY include the ignored
	object in its report and set the I flag to indicate that the optional		optional object in its report and set the I flag to indicate that the
	object was ignored at PCC. When the I flag is cleared, the PCC		optional object was ignored at PCC. When the I flag is cleared, the
	indicates that the optional object was processed. The I flag has no		PCC indicates that the optional object was processed. The I flag has
	meaning if the PCRpt message is not in response to a PCUpd or		no meaning if the PCRpt message is not in response to a PCUpd or
	PCInitiate message (i.e., without the SRP object in the PCRpt		PCInitiate message (i.e., without the SRP object in the PCRpt
	message).		message).
	Note that when a PCC is unable to set up a path that meets all the		Note that when a PCC is unable to set up a path that meets all the
	parameters as per the PCEP object that cannot be ignored (i.e., the P		parameters as per the PCEP object that cannot be ignored (i.e., the P
	flag is set), the PCRpt message MAY optionally include the PCEP		flag is set), the PCRpt message MAY optionally include the PCEP
	objects that caused the path setup to fail along with the LSP-ERROR-		objects that caused the path setup to fail along with the LSP-ERROR-
	CODE TLV [RFC8231] indicating the reason for the failure.		CODE TLV [RFC8231] indicating the reason for the failure.
	3.3.3. The PCInitiate Message		3.3.3. The PCInitiate Message
	The I flag has no meaning in the PCinitiate message [RFC8281], so the		The I flag has no meaning in the PCInitiate message [RFC8281], so the
	I flag MUST set to 0 on transmission and ignored on receipt.		I flag MUST set to 0 on transmission and ignored on receipt.
	3.4. Unknown Object Handling		3.4. Unknown Object Handling
	This document updates the handling of unknown objects in the stateful		This document updates the handling of unknown objects in the stateful
	PCEP messages by setting the P flag in the common object header in a		PCEP messages by setting the P flag in the common object header in a
	similar way as described in [RFC5440]. That is, if a PCEP speaker		similar way as described in [RFC5440]. That is, if a PCEP speaker
	does not understand an object with the P flag set, or if the PCEP		does not understand an object with the P flag set, or if the PCEP
	speaker understands the object but decides to ignore the object, the		speaker understands the object but decides to ignore the object, the
	entire stateful PCEP message MUST be rejected, and the PCE MUST send		entire stateful PCEP message MUST be rejected, and the PCE MUST send
End of changes. 3 change blocks.
	10 lines changed or deleted		11 lines changed or added
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