rfc9703v3.txt		rfc9703.txt
	skipping to change at line 118 ¶		skipping to change at line 118 ¶
	| X | \\ | K		| X | \\ | K
	| | +===F AS3 |		| | +===F AS3 |
	+---------+ +------+		+---------+ +------+
	Figure 1: Reference Diagram		Figure 1: Reference Diagram
	In Figure 1, EPE-SIDs are configured on AS1 towards AS2 and AS3 and		In Figure 1, EPE-SIDs are configured on AS1 towards AS2 and AS3 and
	advertised in the Border Gateway Protocol - Link State (BGP-LS)		advertised in the Border Gateway Protocol - Link State (BGP-LS)
	[RFC9086]. In certain cases, the EPE-SIDs advertised by the control		[RFC9086]. In certain cases, the EPE-SIDs advertised by the control
	plane may not be in synchronization with the label programmed in the		plane may not be in synchronization with the label programmed in the
	data plane. For example, on C, a PeerAdj SID sub-TLV could be		data plane. For example, on C, a PeerAdj SID could be advertised to
	advertised to indicate it is for the link C->D. Due to some software		indicate it is for the link C->D. Due to some software anomaly, the
	anomaly, the actual data forwarding on this PeerAdj SID sub-TLV could		actual data forwarding on this PeerAdj SID could be happening over
	be happening over the C->E link. If E had relevant data paths for		the C->E link. If E had relevant data paths for further forwarding
	further forwarding the packet, this kind of anomaly would go		the packet, this kind of anomaly would go unnoticed by the network
	unnoticed by the network operator. A detailed example of a correctly		operator. A detailed example of a correctly programmed state and an
	programmed state and an incorrectly programmed state along with a		incorrectly programmed state along with a description of how the
	description of how the incorrect state can be detected is described		incorrect state can be detected is described in Appendix A. A
	in Appendix A. A Forwarding Equivalence Class (FEC) definition for		Forwarding Equivalence Class (FEC) definition for the EPE-SIDs will
	the EPE-SIDs will detail the control plane association of the SID.		detail the control plane association of the SID. The data plane
	The data plane validation of the SID will be done during the MPLS		validation of the SID will be done during the MPLS Traceroute
	Traceroute procedure. When there is a multi-hop External BGP (EBGP)		procedure. When there is a multi-hop External BGP (EBGP) session
	session between the ASBRs, a PeerNode SID is advertised, and the		between the ASBRs, a PeerNode SID is advertised, and the traffic MAY
	traffic MAY be load-balanced between the interfaces connecting the		be load-balanced between the interfaces connecting the two nodes. In
	two nodes. In Figure 1, C and F could have a PeerNode SID		Figure 1, C and F could have a PeerNode SID advertised. When the
	advertised. When the Operations, Administration, and Maintenance		Operations, Administration, and Maintenance (OAM) packet is received
	(OAM) packet is received on F, it needs to be validated that the		on F, it needs to be validated that the packet came from one of the
	packet came from one of the two interfaces connected to C.		two interfaces connected to C.
	This document provides Target Forwarding Equivalence Class (FEC)		This document provides Target Forwarding Equivalence Class (FEC)
	Stack TLV definitions for EPE-SIDs. This solution requires the node		Stack TLV definitions for EPE-SIDs. This solution requires the node
	constructing the Target FEC Stack TLV to determine the types of SIDs		constructing the Target FEC Stack TLV to determine the types of SIDs
	along the path of the LSP. Other procedures for MPLS Ping and		along the path of the LSP. Other procedures for MPLS Ping and
	Traceroute, as defined in Section 7 of [RFC8287] and clarified in		Traceroute, as defined in Section 7 of [RFC8287] and clarified in
	[RFC8690], are applicable for EPE-SIDs as well.		[RFC8690], are applicable for EPE-SIDs as well.
	2. Theory of Operation		2. Theory of Operation
	skipping to change at line 308 ¶		skipping to change at line 308 ¶
	Adj type: 1 octet		Adj type: 1 octet
	Value: Set to 1 when the Adjacency Segment is IPv4. Set to 2 when		Value: Set to 1 when the Adjacency Segment is IPv4. Set to 2 when
	the Adjacency Segment is IPv6.		the Adjacency Segment is IPv6.
	RESERVED: 3 octets. MUST be zero when sending and ignored on		RESERVED: 3 octets. MUST be zero when sending and ignored on
	receiving.		receiving.
	Local AS Number: 4 octets. The unsigned integer representing the AS		Local AS Number: 4 octets. The unsigned integer representing the AS
	number [RFC6793] of the AS to which the PeerAdj SID sub-TLV		number [RFC6793] of the AS to which the PeerAdj SID advertising
	advertising node belongs. If Confederations [RFC5065] are in use,		node belongs. If Confederations [RFC5065] are in use, and if the
	and if the remote node is a member of a different Member-AS within		remote node is a member of a different Member-AS within the local
	the local Confederation, this is the Member-AS Number inside the		Confederation, this is the Member-AS Number inside the
	Confederation and not the Confederation Identifier.		Confederation and not the Confederation Identifier.
	Remote AS Number: 4 octets. The unsigned integer representing the		Remote AS Number: 4 octets. The unsigned integer representing the
	AS number [RFC6793] of the remote node's AS for which the PeerAdj		AS number [RFC6793] of the remote node's AS for which the PeerAdj
	SID sub-TLV is advertised. If Confederations [RFC5065] are in		SID is advertised. If Confederations [RFC5065] are in use, and if
	use, and if the remote node is a member of a different Member-AS		the remote node is a member of a different Member-AS within the
	within the local Confederation, this is the Member-AS Number		local Confederation, this is the Member-AS Number inside the
	inside the Confederation and not the Confederation Identifier.		Confederation and not the Confederation Identifier.
	Local BGP Router ID: 4 octets. The unsigned integer representing		Local BGP Router ID: 4 octets. The unsigned integer representing
	the BGP Identifier of the PeerAdj SID sub-TLV advertising node as		the BGP Identifier of the PeerAdj SID advertising node as defined
	defined in [RFC4271] and [RFC6286].		in [RFC4271] and [RFC6286].
	Remote BGP Router ID: 4 octets. The unsigned integer representing		Remote BGP Router ID: 4 octets. The unsigned integer representing
	the BGP Identifier of the remote node as defined in [RFC4271] and		the BGP Identifier of the remote node as defined in [RFC4271] and
	[RFC6286].		[RFC6286].
	Local Interface Address: 4 octets or 16 octets. In the case of		Local Interface Address: 4 octets or 16 octets. In the case of
	PeerAdj SID sub-TLV, the local interface address corresponding to		PeerAdj SID, the local interface address corresponding to the
	the PeerAdj SID sub-TLV should be specified in this field. For		PeerAdj SID should be specified in this field. For IPv4, this
	IPv4, this field is 4 octets; for IPv6, this field is 16 octets.		field is 4 octets; for IPv6, this field is 16 octets. Link-local
	Link-local IPv6 addresses are not in the scope of this document.		IPv6 addresses are not in the scope of this document.
	Remote Interface Address: 4 octets or 16 octets. In the case of		Remote Interface Address: 4 octets or 16 octets. In the case of
	PeerAdj SID sub-TLV, the remote interface address corresponding to		PeerAdj SID, the remote interface address corresponding to the
	the PeerAdj SID sub-TLV should be specified in this field. For		PeerAdj SID should be specified in this field. For IPv4, this
	IPv4, this field is 4 octets; for IPv6, this field is 16 octets.		field is 4 octets; for IPv6, this field is 16 octets. Link-local
	Link-local IPv6 addresses are not in the scope of this document.		IPv6 addresses are not in the scope of this document.
	[RFC9086] mandates sending a local interface ID and remote interface		[RFC9086] mandates sending a local interface ID and remote interface
	ID in the link descriptors and allows a value of 0 in the remote		ID in the link descriptors and allows a value of 0 in the remote
	descriptors. It is useful to validate the incoming interface for an		descriptors. It is useful to validate the incoming interface for an
	OAM packet, but if the remote descriptor is 0, this validation is not		OAM packet, but if the remote descriptor is 0, this validation is not
	possible. Optional link descriptors of local and remote interface		possible. Optional link descriptors of local and remote interface
	addresses are allowed as described in Section 4.2 of [RFC9086]. In		addresses are allowed as described in Section 4.2 of [RFC9086]. In
	this document, it is RECOMMENDED to send these optional descriptors		this document, it is RECOMMENDED to send these optional descriptors
	and use them to validate incoming interfaces. When these local and		and use them to validate incoming interfaces. When these local and
	remote interface addresses are not available, an ingress node can		remote interface addresses are not available, an ingress node can
	skipping to change at line 420 ¶		skipping to change at line 420 ¶
	SID is advertised. If Confederations [RFC5065] are in use, and if		SID is advertised. If Confederations [RFC5065] are in use, and if
	the remote node is a member of a different Member-AS within the		the remote node is a member of a different Member-AS within the
	local Confederation, this is the Member-AS Number inside the		local Confederation, this is the Member-AS Number inside the
	Confederation and not the Confederation Identifier.		Confederation and not the Confederation Identifier.
	Remote BGP Router ID: 4 octets. The unsigned integer representing		Remote BGP Router ID: 4 octets. The unsigned integer representing
	the BGP Identifier of the remote node as defined in [RFC4271] and		the BGP Identifier of the remote node as defined in [RFC4271] and
	[RFC6286].		[RFC6286].
	PeerSet SID may be associated with a number of PeerNode SIDs and		PeerSet SID may be associated with a number of PeerNode SIDs and
	PeerAdj SID sub-TLVs. The remote AS number and the Router ID of each		PeerAdj SIDs. The remote AS number and the Router ID of each of
	of these PeerNode SIDs and PeerAdj SID sub-TLVs MUST be included in		these PeerNode SIDs and PeerAdj SIDs MUST be included in the FEC.
	the FEC.
	5. EPE-SID FEC Validation		5. EPE-SID FEC Validation
	When a remote ASBR of the EPE-SID advertisement receives the MPLS OAM		When a remote ASBR of the EPE-SID advertisement receives the MPLS OAM
	packet with the top FEC being the EPE-SID, it MUST perform validity		packet with the top FEC being the EPE-SID, it MUST perform validity
	checks on the content of the EPE-SID FEC sub-TLV. The basic length		checks on the content of the EPE-SID FEC sub-TLV. The basic length
	check should be performed on the received FEC.		check should be performed on the received FEC.
	PeerAdj SID sub-TLV		PeerAdj SID sub-TLV
	-----------		-----------
	If Adj type = 1, Length should be 28 octets		If Adj type = 1, Length should be 28 octets
	If Adj type = 2, Length should be 52 octets		If Adj type = 2, Length should be 52 octets
	PeerNode SID		PeerNode SID sub-TLV
	-------------		-------------
	Length = (20 + No. of IPv4 interface pairs * 8 +		Length = (20 + No. of IPv4 interface pairs * 8 +
	No. of IPv6 interface pairs * 32) octets		No. of IPv6 interface pairs * 32) octets
	PeerSet SID		PeerSet SID sub-TLV
	-----------		-----------
	Length = (9 + No. of elements in the set *		Length = (9 + No. of elements in the set *
	(8 + No. of IPv4 interface pairs * 8 +		(8 + No. of IPv4 interface pairs * 8 +
	No. of IPv6 interface pairs * 32) octets		No. of IPv6 interface pairs * 32) octets
	Figure 5: Length Validation		Figure 5: Length Validation
	If a malformed FEC sub-TLV is received, then a return code of 1,		If a malformed FEC sub-TLV is received, then a return code of 1,
	"Malformed echo request received", as defined in [RFC8029] MUST be		"Malformed echo request received", as defined in [RFC8029] MUST be
	sent. The section below is appended to the procedure given in step		sent. The section below is appended to the procedure given in step
	skipping to change at line 726 ¶		skipping to change at line 725 ¶
	C when the OAM packet reaches it		C when the OAM packet reaches it
	* C receives the OAM packet and validates that the top label (16001)		* C receives the OAM packet and validates that the top label (16001)
	is indeed corresponding to the entities populated in the PeerAdj		is indeed corresponding to the entities populated in the PeerAdj
	SID sub-TLV		SID sub-TLV
	Incorrectly programmed state:		Incorrectly programmed state:
	* C assigns label 16001 and binds it to adjacency C->D		* C assigns label 16001 and binds it to adjacency C->D
	* The controller learns that PeerAdj SID sub-TLV label 16001 is		* The controller learns that PeerAdj SID label 16001 is bound to
	bound to adjacency C->E (e.g., via BGP-LS) -- this could be a		adjacency C->E (e.g., via BGP-LS) -- this could be a software bug
	software bug on C or on the controller		on C or on the controller
	* The controller/ingress programs an SR path that has SID/label		* The controller/ingress programs an SR path that has SID/label
	16001 to steer the packet on the exit point from C onto adjacency		16001 to steer the packet on the exit point from C onto adjacency
	C->E		C->E
	* Using MPLS Traceroute procedures defined in this document, the		* Using MPLS Traceroute procedures defined in this document, the
	PeerAdj SID sub-TLV is populated with entities to be validated by		PeerAdj SID sub-TLV is populated with entities to be validated by
	C (including a local/remote interface address of C->E) when the		C (including a local/remote interface address of C->E) when the
	OAM packet reaches it		OAM packet reaches it
End of changes. 10 change blocks.
	44 lines changed or deleted		43 lines changed or added
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