draft-ietf-6man-spring-srv6-oam-02.txt		draft-ietf-6man-spring-srv6-oam-03.txt
	6man Z. Ali		6man Z. Ali
	Internet-Draft C. Filsfils		Internet-Draft C. Filsfils
	Intended status: Standards Track Cisco Systems		Intended status: Standards Track Cisco Systems
	Expires: May 23, 2020 S. Matsushima		Expires: June 20, 2020 S. Matsushima
	Softbank		Softbank
	D. Voyer		D. Voyer
	Bell Canada		Bell Canada
	M. Chen		M. Chen
	Huawei		Huawei
	November 20, 2019		December 18, 2019
	Operations, Administration, and Maintenance (OAM) in Segment Routing		Operations, Administration, and Maintenance (OAM) in Segment Routing
	Networks with IPv6 Data plane (SRv6)		Networks with IPv6 Data plane (SRv6)
	draft-ietf-6man-spring-srv6-oam-02		draft-ietf-6man-spring-srv6-oam-03
	Abstract		Abstract
	This document defines building blocks for Operations, Administration,		This document defines building blocks for Operations, Administration,
	and Maintenance (OAM) in Segment Routing Networks with IPv6 Dataplane		and Maintenance (OAM) in Segment Routing Networks with IPv6 Dataplane
	(SRv6). The document also describes some SRv6 OAM mechanisms.		(SRv6). The document also describes some SRv6 OAM mechanisms.
	Requirements Language		Requirements Language
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	skipping to change at page 1, line 45 ¶		skipping to change at page 1, line 45 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on May 23, 2020.		This Internet-Draft will expire on June 20, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2019 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 30 ¶		skipping to change at page 2, line 30 ¶
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Conventions Used in This Document . . . . . . . . . . . . . . 3		2. Conventions Used in This Document . . . . . . . . . . . . . . 3
	2.1. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3		2.1. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3
	2.2. Terminology and Reference Topology . . . . . . . . . . . 3		2.2. Terminology and Reference Topology . . . . . . . . . . . 3
	3. OAM Building Blocks . . . . . . . . . . . . . . . . . . . . . 5		3. OAM Building Blocks . . . . . . . . . . . . . . . . . . . . . 5
	3.1. O-flag in Segment Routing Header . . . . . . . . . . . . 5		3.1. O-flag in Segment Routing Header . . . . . . . . . . . . 5
	3.1.1. O-flag Processing . . . . . . . . . . . . . . . . . . 6		3.1.1. O-flag Processing . . . . . . . . . . . . . . . . . . 6
	3.2. OAM Segments . . . . . . . . . . . . . . . . . . . . . . 6		3.2. OAM Segments . . . . . . . . . . . . . . . . . . . . . . 6
	3.3. End.OP: OAM Endpoint with Punt . . . . . . . . . . . . . 6		3.3. End.OP: OAM Endpoint with Punt . . . . . . . . . . . . . 7
	3.4. End.OTP: OAM Endpoint with Timestamp and Punt . . . . . . 7		3.4. End.OTP: OAM Endpoint with Timestamp and Punt . . . . . . 7
	3.5. SRH TLV . . . . . . . . . . . . . . . . . . . . . . . . . 8		4. OAM Mechanisms . . . . . . . . . . . . . . . . . . . . . . . 7
	4. OAM Mechanisms . . . . . . . . . . . . . . . . . . . . . . . 8
	4.1. Ping . . . . . . . . . . . . . . . . . . . . . . . . . . 8		4.1. Ping . . . . . . . . . . . . . . . . . . . . . . . . . . 8
	4.1.1. Classic Ping . . . . . . . . . . . . . . . . . . . . 8		4.1.1. Classic Ping . . . . . . . . . . . . . . . . . . . . 8
	4.1.2. Pinging a SID Function . . . . . . . . . . . . . . . 10		4.1.2. Pinging a SID . . . . . . . . . . . . . . . . . . . . 9
	4.1.3. Error Reporting . . . . . . . . . . . . . . . . . . . 12		4.2. Traceroute . . . . . . . . . . . . . . . . . . . . . . . 11
	4.2. Traceroute . . . . . . . . . . . . . . . . . . . . . . . 13		4.2.1. Classic Traceroute . . . . . . . . . . . . . . . . . 11
	4.2.1. Classic Traceroute . . . . . . . . . . . . . . . . . 13		4.2.2. Traceroute to a SID . . . . . . . . . . . . . . . . . 12
	4.2.2. Traceroute to a SID Function . . . . . . . . . . . . 15		4.3. Monitoring of SRv6 Paths . . . . . . . . . . . . . . . . 15
	4.3. Monitoring of SRv6 Paths . . . . . . . . . . . . . . . . 18		5. Implementation Status . . . . . . . . . . . . . . . . . . . . 16
	5. Implementation Status . . . . . . . . . . . . . . . . . . . . 19		6. Security Considerations . . . . . . . . . . . . . . . . . . . 16
	6. Security Considerations . . . . . . . . . . . . . . . . . . . 19		7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
	7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20		7.1. ICMPv6 type Numbers RegistrySEC . . . . . . . . . . . . . 16
	7.1. ICMPv6 type Numbers RegistrySEC . . . . . . . . . . . . . 20		7.2. SRv6 OAM Endpoint Types . . . . . . . . . . . . . . . . . 16
	7.2. SRv6 OAM Endpoint Types . . . . . . . . . . . . . . . . . 20		8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
	8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 20		9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 17
	9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 20		10. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
	10. References . . . . . . . . . . . . . . . . . . . . . . . . . 22		10.1. Normative References . . . . . . . . . . . . . . . . . . 18
	10.1. Normative References . . . . . . . . . . . . . . . . . . 22		10.2. Informative References . . . . . . . . . . . . . . . . . 19
	10.2. Informative References . . . . . . . . . . . . . . . . . 22		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
	1. Introduction		1. Introduction
	This document defines building blocks for Operations, Administration,		This document defines building blocks for Operations, Administration,
	and Maintenance (OAM) in Segment Routing Networks with IPv6 Dataplane		and Maintenance (OAM) in Segment Routing Networks with IPv6 Dataplane
	(SRv6). The document also describes some SRv6 OAM mechanisms.		(SRv6). The document also describes some SRv6 OAM mechanisms.
	2. Conventions Used in This Document		2. Conventions Used in This Document
	2.1. Abbreviations		2.1. Abbreviations
	skipping to change at page 3, line 29 ¶		skipping to change at page 3, line 29 ¶
	SL: Segment Left.		SL: Segment Left.
	SR: Segment Routing.		SR: Segment Routing.
	SRH: Segment Routing Header.		SRH: Segment Routing Header.
	SRv6: Segment Routing with IPv6 Data plane.		SRv6: Segment Routing with IPv6 Data plane.
	TC: Traffic Class.		TC: Traffic Class.
	ICMPv6: multi-part ICMPv6 messages [RFC4884].		ICMPv6: ICMPv6 Specification [RFC4443].
	2.2. Terminology and Reference Topology		2.2. Terminology and Reference Topology
	This document uses the terminology defined in [I-D.ietf- spring-srv6-		This document uses the terminology defined in [I-D.ietf- spring-srv6-
	network-programming]. The readers are expected to be familiar with		network-programming]. The readers are expected to be familiar with
	the same.		the same.
	Throughout the document, the following simple topology is used for		Throughout the document, the following simple topology is used for
	illustration.		illustration.
	skipping to change at page 6, line 7 ¶		skipping to change at page 6, line 7 ¶
	O-flag: OAM flag. When set, it indicates that this packet is an		O-flag: OAM flag. When set, it indicates that this packet is an
	operations and management (OAM) packet. This document defines the		operations and management (OAM) packet. This document defines the
	usage of the O-flag in the SRH.Flags.		usage of the O-flag in the SRH.Flags.
	The document does not define any other flag in the SRH.Flags and		The document does not define any other flag in the SRH.Flags and
	meaning and processing of any other bit in SRH.Flags is outside of		meaning and processing of any other bit in SRH.Flags is outside of
	the scope of this document.		the scope of this document.
	3.1.1. O-flag Processing		3.1.1. O-flag Processing
	The SRH.Flags.O-flag implements the "punt a timestamped copy and		The SRH.Flags.O-flag implements the "punt a timestamped copy of the
	forward" behavior.		packet" behavior. This enables an SRv6 Endpoint node to send a
			timestamped copy of the packets marked with o-flag to a local OAM
			process. To prevent multiple evaluations of the datagram, the OAM
			process MUST NOT respond to any upper-layer header (like ICMP, UDP,
			etc.) payload. However, the OAM process MAY export the time-stamped
			copy of the packet to a controller using e.g., IPFIX [RFC7011]. To
			avoid hitting any performance impact, the processing node SHOULD
			rate-limit the number of packets punted to the OAM process.
			Specification of the OAM process or the external controller
			operations are beyond the scope of this document.
	Implementation of the O-flag is OPTIONAL. If a node does not support		Implementation of the O-flag is OPTIONAL. If a node does not support
	the O-flag, then upon reception it simply ignores it. It is also		the O-flag, then upon reception it simply ignores it.
	possible that a node is capable of supporting the O-bit but based on
	a local decision it MAY ignore it during processing on some local
	SIDs.
	If a node supports the O-flag, it can optionally advertise its		If a node supports the O-flag, it can optionally advertise its
	potential via node capability advertisement in IGP [I-D.ietf-isis-		potential via node capability advertisement in IGP [I-D.ietf-isis-
	srv6- extensions] and BGP-LS [I-D.ietf-idr-bgpls-srv6-ext].		srv6- extensions] and BGP-LS [I-D.ietf-idr-bgpls-srv6-ext].
	When N receives a packet whose IPv6 DA is S and S is a local SID, the		When N receives a packet whose IPv6 DA is S and S is a local SID, the
	pseudo-code associated with the SID S, as defined in section 4.3.1.1		line S01 of the the pseudo-code associated with the SID S, as defined
	of [I-D.ietf-6man-segment-routing-header], is modified as follows for		in section 4.3.1.1 of [I-D.ietf-6man-segment-routing-header], is
	the O-flag processing.		modified as follows for the O-flag processing.
	S01.1. IF SRH.Flags.O-flag is set and local configuration permits		S01.1. IF SRH.Flags.O-flag is set and local configuration permits
	O-flag processing THEN		O-flag processing THEN
	a. Make a copy of the packet.		a. Make a copy of the packet.
	b. Send the copied packet, along with an accurate timestamp		b. Send the copied packet, along with a timestamp
	to the OAM process. ;; Ref1, Ref2		to the OAM process. ;; Ref1
	Ref1: An implementation SHOULD copy and record the timestamp as soon as		Ref1: An implementation SHOULD copy and record the timestamp as soon as
	possible during packet processing. Timestamp is not carried in the packet		possible during packet processing. Timestamp is not carried in the packet
	forwarded to the next hop.		forwarded to the next hop.
	Ref2: An implementation SHOULD NOT generate ICMP error during
	local SID S processing. If local SID S processing requires generation
	of an ICMP error, the error is generated by the local OAM process.
	Please note that the O-flag processing happens before execution of		Please note that the O-flag processing happens before execution of
	regular processing of the local SID S.		regular processing of the local SID S.
	3.2. OAM Segments		3.2. OAM Segments
	OAM Segment IDs (SIDs) is another component of the SRv6 OAM building		The presence of an OAM SID in the Destination address of the IPv6
	Blocks. This document defines a couple of OAM SIDs.		header instructs the segment endpoint implementing the OAM SID that
			the content of the packet is of interest to the node and to process
			the upper-layer payload, accordingly.
	3.3. End.OP: OAM Endpoint with Punt		3.3. End.OP: OAM Endpoint with Punt
	Many scenarios require punting of SRv6 OAM packets at the desired
	nodes in the network. The "OAM Endpoint with Punt" function (End.OP
	for short) represents a particular OAM function to implement the punt
	behavior for an OAM packet. It is described using the pseudocode as
	follows:
	When N receives a packet destined to S and S is a local End.OP SID, N		When N receives a packet destined to S and S is a local End.OP SID, N
	does:		does:
	1. Send the packet to the OAM process ;; Ref1		S01. Send the packet to the OAM process
	Ref1: The local OAM process SHOULD NOT generate ICMP error during
	local SID S processing.
	Please note that in an SRH containing END.OP SID, it is RECOMMENDED		The local OAM process further processes the packet, this MAY involve
	to set the SRH.Flags.O-flag = 0.		processing protocol layers above IPv6. For example, ping and
			traceroute will require ICMP or UDP protocol processing. Once the
			packet leaves the IPv6 layer the processing is considered host
			processing and the upper layer protocols MUST be processed as such.
	3.4. End.OTP: OAM Endpoint with Timestamp and Punt		3.4. End.OTP: OAM Endpoint with Timestamp and Punt
	Scenarios demanding performance management of an SR policy/ path
	requires hardware timestamping before hardware punts the packet to
	the software for OAM processing. The "OAM Endpoint with Timestamp
	and Punt" function (End.OTP for short) represents an OAM SID function
	to implement the timestamp and punt behavior for an OAM packet. It
	is described using the pseudocode as follows:
	When N receives a packet destined to S and S is a local End.OTP SID,		When N receives a packet destined to S and S is a local End.OTP SID,
	N does:		N does:
	1. Timestamp the packet ;; Ref1		S01.1. Timestamp the packet ;; Ref1
			S01.2. Send the packet, along with a timestamp, to the
	2. Send the packet, along with an accurate timestamp, to the		OAM process
	OAM process ;; Ref2
	Ref1: Timestamping SHOULD be done in hardware, as soon as possible		Ref1: Timestamping SHOULD be done in hardware, as soon as possible
	during the packet processing.		during the packet processing.
	Ref2: The local OAM process SHOULD NOT generate ICMP error during
	local SID S processing.
	Please note that in an SRH containing END.OTP SID, it is RECOMMENDED		The local OAM process further processes the packet, this MAY involve
	to set the SRH.Flags.O-flag = 0.		processing protocol layers above IPv6. For example, ping and
			traceroute will require ICMP or UDP protocol processing. Once the
	3.5. SRH TLV		packet leaves the IPv6 layer the processing is considered host
			processing and the upper layer protocols MUST be processed as such.
	[I-D.ietf-6man-segment-routing-header] defines TLVs of the Segment
	Routing Header.
	SRH TLV plays an important role in carrying OAM and Performance
	Management (PM) metadata.
	4. OAM Mechanisms		4. OAM Mechanisms
	This section describes how OAM mechanisms can be implemented using		This section describes how OAM mechanisms can be implemented using
	the OAM building blocks described in the previous section.		the OAM building blocks described in the previous section.
	Additional OAM mechanisms will be added in a future revision of the
	document.
	[RFC4443] describes Internet Control Message Protocol for IPv6		[RFC4443] describes Internet Control Message Protocol for IPv6
	(ICMPv6) that is used by IPv6 devices for network diagnostic and		(ICMPv6) that is used by IPv6 devices for network diagnostic and
	error reporting purposes. As Segment Routing with IPv6 data plane		error reporting purposes. As Segment Routing with IPv6 data plane
	(SRv6) simply adds a new type of Routing Extension Header, existing		(SRv6) simply adds a new type of Routing Extension Header, existing
	ICMPv6 ping mechanisms can be used in an SRv6 network. This section		ICMPv6 ping mechanisms can be used in an SRv6 network. This section
	describes the applicability of ICMPv6 in the SRv6 network and how the		describes the applicability of ICMPv6 in the SRv6 network and how the
	existing ICMPv6 mechanisms can be used for providing OAM		existing ICMPv6 mechanisms can be used for providing OAM
	functionality.		functionality.
	The document does not propose any changes to the standard ICMPv6		The document does not propose any changes to the standard ICMPv6
	[RFC4443], [RFC4884] or standard ICMPv4 [RFC792].		[RFC4443], [RFC4884] or standard ICMPv4 [RFC792].
	4.1. Ping		4.1. Ping
	There is no hardware or software change required for ping operation
	at the classic IPv6 nodes in an SRv6 network. That includes the
	classic IPv6 node with ingress, egress or transit roles.
	Furthermore, no protocol changes are required to the standard ICMPv6
	[RFC4443], [RFC4884] or standard ICMPv4 [RFC792]. In other words,
	existing ICMP ping mechanisms work seamlessly in the SRv6 networks.
	The following subsections outline some use cases of the ICMP ping in		The following subsections outline some use cases of the ICMP ping in
	the SRv6 networks.		the SRv6 networks.
	4.1.1. Classic Ping		4.1.1. Classic Ping
	The existing mechanism to ping a remote IP prefix, along the shortest		The existing mechanism to ping a remote IP prefix, along the shortest
	path, continues to work without any modification. The initiator may		path, continues to work without any modification. The initiator may
	be an SRv6 node or a classic IPv6 node. Similarly, the egress or		be an SRv6 node or a classic IPv6 node. Similarly, the egress or
	transit may be an SRv6 capable node or a classic IPv6 node.		transit may be an SRv6 capable node or a classic IPv6 node.
	skipping to change at page 10, line 7 ¶		skipping to change at page 9, line 20 ¶
	processing. Specifically, it observes the END.X function		processing. Specifically, it observes the END.X function
	(B:4:C52) with PSP (Penultimate Segment POP) on the echo request		(B:4:C52) with PSP (Penultimate Segment POP) on the echo request
	packet and removes the SRH and forwards the packet across link10		packet and removes the SRH and forwards the packet across link10
	to N5.		to N5.
	o The echo request packet at N5 arrives as an IPv6 packet without an		o The echo request packet at N5 arrives as an IPv6 packet without an
	SRH. Node N5, which is a classic IPv6 node, performs the standard		SRH. Node N5, which is a classic IPv6 node, performs the standard
	IPv6/ ICMPv6 processing on the echo request and responds,		IPv6/ ICMPv6 processing on the echo request and responds,
	accordingly.		accordingly.
	4.1.2. Pinging a SID Function		4.1.2. Pinging a SID
	The classic ping described in the previous section cannot be used to		The classic ping described in the previous section cannot be used to
	ping a remote SID function, as explained using an example in the		ping a remote SID function, as explained using an example in the
	following.		following.
	Consider the case where the user wants to ping the remote SID		Consider the case where the user wants to ping the remote SID
	function B:4:C52, via B:2:C31, from node N1. Node N1 constructs the		function B:4:C52 from node N1. Node N1 constructs the ping packet
	ping packet (A:1::, B:2:C31)(B:4:C52, B:2:C31, SL=1;		(A:1::, B:4:C52)(ICMPv6 Echo Request). The ping fails because the
	NH=ICMPv6)(ICMPv6 Echo Request). The ping fails because the node N4		node N4 receives the ICMPv6 echo request with DA set to B:4:C52 but
	receives the ICMPv6 echo request with DA set to B:4:C52 but the next		the next header is ICMPv6, instead of SRH.
	header is ICMPv6, instead of SRH. To solve this problem, the
	initiator needs to mark the ICMPv6 echo request as an OAM packet.
	The OAM packets are identified either by setting the O-flag in SRH or		To perform ICMPv6 ping to a target SID an echo request message is
	by inserting the END.OP/ END.OTP SIDs at an appropriate place in the		generated by the initiator with the END.OP or END.OTP SID in the
	SRH. The following illustration uses END.OTP SID but the procedures		segment-list of the SRH immediately preceding the target SID. There
	are equally applicable to the END.OP SID.		MAY or MAY NOT be additional segments preceding the END.OP/ END.OTP
			SID.
	In an SRv6 network, the user can exercise two flavors of the ping:		When the node instantiating a SID S of type END.OP or END.OTP
	end-to-end ping or segment-by-segment ping, as outlined in the		receives a packet with S in the destination address of the IPv6
	following subsection.		header it sends it to the OAM process. The OAM process verifies the
			segment following S is a locally instantiated SID. It then processes
			the Upper layer header of the packet, as a host, responding to the
			echo request message in the ICMPv6 payload.
	4.1.2.1. End-to-end ping using END.OP/ END.OTP		When the segment following S is not verified by the OAM process an
			ICMPv6 error message type 4 (parameter problem) code 0 (erroneous
			header field encountered) with pointer set to the segment following S
			(the target SID) is generated for the packet and the packet is
			discarded.
	The end-to-end ping illustration uses the END.OTP SID but the		An implementation of the OAM process SID verification SHOULD do the
			following:
			o Verify that the SID is locally instantiated.
			o Verify that the SID is instantiated in the data plane (this may
			include verification of the SID in NPUs or forwarding hardware, as
			applicable).
			4.1.2.1. Ping using END.OP/ END.OTP
			This section uses END.OTP SID for the ping illustration but the
	procedures are equally applicable to the END.OP SID.		procedures are equally applicable to the END.OP SID.
	Consider the same example where the user wants to ping a remote SID		Consider the example where the user wants to ping a remote SID
	function B:4:C52, via B:2:C31, from node N1. To force a punt of the		function B:4:C52, via B:2:C31, from node N1. To force a punt of the
	ICMPv6 echo request at the node N4, node N1 inserts the END.OTP SID		ICMPv6 echo request at the node N4, node N1 inserts the END.OTP SID
	just before the target SID B:4:C52 in the SRH. The ICMPv6 echo		just before the target SID B:4:C52 in the SRH. The ICMPv6 echo
	request is processed at the individual nodes along the path as		request is processed at the individual nodes along the path as
	follows:		follows:
	o Node N1 initiates an ICMPv6 ping packet with SRH as follows		o Node N1 initiates an ICMPv6 ping packet with SRH as follows
	(A:1::, B:2:C31)(B:4:C52, B:4:OTP, B:2:C31; SL=2;		(A:1::, B:2:C31)(B:4:C52, B:4:OTP, B:2:C31; SL=2;
	NH=ICMPv6)(ICMPv6 Echo Request).		NH=ICMPv6)(ICMPv6 Echo Request).
	skipping to change at page 11, line 11 ¶		skipping to change at page 10, line 40 ¶
	o Node N3 receives the packet as follows (A:1::, B:4:OTP)(B:4:C52,		o Node N3 receives the packet as follows (A:1::, B:4:OTP)(B:4:C52,
	B:4:OTP, B:2:C31 ; SL=1; NH=ICMPv6)(ICMPv6 Echo Request). Node		B:4:OTP, B:2:C31 ; SL=1; NH=ICMPv6)(ICMPv6 Echo Request). Node
	N3, which is a classic IPv6 node, performs the standard IPv6		N3, which is a classic IPv6 node, performs the standard IPv6
	processing. Specifically, it forwards the echo request based on		processing. Specifically, it forwards the echo request based on
	DA B:4:OTP in the IPv6 header.		DA B:4:OTP in the IPv6 header.
	o When node N4 receives the packet (A:1::, B:4:OTP)(B:4:C52,		o When node N4 receives the packet (A:1::, B:4:OTP)(B:4:C52,
	B:4:OTP, B:2:C31 ; SL=1; NH=ICMPv6)(ICMPv6 Echo Request), it		B:4:OTP, B:2:C31 ; SL=1; NH=ICMPv6)(ICMPv6 Echo Request), it
	processes the END.OTP SID, as described in the pseudocode in		processes the END.OTP SID, as described in the pseudocode in
	Section 3. The packet gets time-stamped and punted to the ICMPv6		Section 3. The packet gets time-stamped and punted to the OAM
	process for processing. The ICMPv6 process checks if the next SID		process for processing. The OAM process checks if the next SID in
	in SRH (the target SID B:4:C52) is locally programmed.		SRH (the target SID B:4:C52) is locally programmed.
	o If the target SID is not locally programmed, N4 responses with the
	ICMPv6 message (Type: "SRv6 OAM (TBA)", Code: "SID not locally
	implemented (TBA)"); otherwise a success is returned.
	4.1.2.2. Segment-by-segment ping using O-flag (Proof of Transit)
	Consider the same example where the user wants to ping a remote SID
	function B:4:C52, via B:2:C31, from node N1. However, in this ping,
	the node N1 wants to get a response from each segment node in the SRH
	as a "proof of transit". In other words, in the segment-by-segment
	ping case, the node N1 expects a response from node N2 and node N4
	for their respective local SID function. When a response to O-bit is
	desired from the last SID in a SID-list, it is the responsibility of
	the ingress node to use USP as the last SID. E.g., in this example,
	the target SID B:4:C52 is a USP SID.
	To force a punt of the ICMPv6 echo request at node N2 and node N4,
	node N1 sets the O-flag in SRH. The ICMPv6 echo request is processed
	at the individual nodes along the path as follows:
	o Node N1 initiates an ICMPv6 ping packet with SRH as follows
	(A:1::, B:2:C31)(B:4:C52, B:2:C31; SL=1, Flags.O=1;
	NH=ICMPv6)(ICMPv6 Echo Request).
	o When node N2 receives the packet (A:1::, B:2:C31)(B:4:C52,
	B:2:C31; SL=1, Flags.O=1; NH=ICMPv6)(ICMPv6 Echo Request) packet,
	it processes the O-flag in SRH, as described in the pseudocode in
	Section 3. A time-stamped copy of the packet gets punted to the
	ICMPv6 process for processing. Node N2 continues to apply the
	B:2:C31 SID function on the original packet and forwards it,
	accordingly. As B:4:C52 is a USP SID, N2 does not remove the SRH.
	The ICMPv6 process at node N2 checks if its local SID (B:2:C31) is
	locally programmed or not and responds to the ICMPv6 Echo Request.
	o If the target SID is not locally programmed, N4 responses with the
	ICMPv6 message (Type: "SRv6 OAM (TBA)", Code: "SID not locally
	implemented (TBA)"); otherwise a success is returned. Please note
	that, as mentioned in Section 3, if node N2 does not support the
	O-flag, it simply ignores it and process the local SID, B:2:C31.
	o Node N3, which is a classic IPv6 node, performs the standard IPv6
	processing. Specifically, it forwards the echo request based on
	DA B:4:C52 in the IPv6 header.
	o When node N4 receives the packet (A:1::, B:4:C52)(B:4:C52,
	B:2:C31; SL=0, Flags.O=1; NH=ICMPv6)(ICMPv6 Echo Request), it
	processes the O-flag in SRH, as described in the pseudocode in
	Section 3. A time-stamped copy of the packet gets punted to the
	ICMPv6 process for processing. The ICMPv6 process at node N4
	checks if its local SID (B:4:C52) is locally programmed or not and
	responds to the ICMPv6 Echo Request.
	o If the target SID is not locally programmed, N4 responses with the
	ICMPv6 message (Type: "SRv6 OAM (TBA)", Code: "SID not locally
	implemented (TBA)"); otherwise a success is returned.
	Support for O-flag is part of node capability advertisement. That
	enables node N1 to know which segment nodes are capable of responding
	to the ICMPv6 echo request. Node N1 processes the echo responses and
	presents data to the user, accordingly.
	Please note that segment-by-segment ping can be used to address proof
	of transit use-case.
	4.1.3. Error Reporting
	Any IPv6 node can use ICMPv6 control messages to report packet
	processing errors to the host that originated the datagram packet.
	To name a few such scenarios:
	o If the router receives an undeliverable IP datagram, or
	o If the router receives a packet with a Hop Limit of zero, or
	o If the router receives a packet such that if the router decrements
	the packet's Hop Limit it becomes zero, or
	o If the router receives a packet with problem with a field in the
	IPv6 header or the extension headers such that it cannot complete
	processing the packet, or
	o If the router cannot forward a packet because the packet is larger		o If the next SID is not locally programmed, the OAM process returns
	than the MTU of the outgoing link.		an ICMPv6 error message type 4 (parameter problem) code 0
			(erroneous header field encountered) with pointer set to the
			target SID B:4:C52 and the packet is discarded.
	In the scenarios listed above, the ICMPv6 response also contains the		o If the next SID is locally programmed, the node processes the
	IP header, IP extension headers and leading payload octets of the		upper layer header. As part of the upper layer header (ICMPv6)
	"original datagram" to which the ICMPv6 message is a response.		processing node N4 sends the ICMPv6 Echo Reply message [RFC4443].
	Specifically, the "Destination Unreachable Message", "Time Exceeded
	Message", "Packet Too Big Message" and "Parameter Problem Message"
	ICMPV6 messages can contain as much of the invoking packet as
	possible without the ICMPv6 packet exceeding the minimum IPv6 MTU
	[RFC4443], [RFC4884]. In an SRv6 network, the copy of the invoking
	packet contains the SR header. The packet originator can use this
	information for diagnostic purposes. For example, traceroute can use
	this information as detailed in the following subsection.
	4.2. Traceroute		4.2. Traceroute
	There is no hardware or software change required for traceroute		There is no hardware or software change required for traceroute
	operation at the classic IPv6 nodes in an SRv6 network. That		operation at the classic IPv6 nodes in an SRv6 network. That
	includes the classic IPv6 node with ingress, egress or transit roles.		includes the classic IPv6 node with ingress, egress or transit roles.
	Furthermore, no protocol changes are required to the standard		Furthermore, no protocol changes are required to the standard
	traceroute operations. In other words, existing traceroute		traceroute operations. In other words, existing traceroute
	mechanisms work seamlessly in the SRv6 networks.		mechanisms work seamlessly in the SRv6 networks.
	skipping to change at page 14, line 7 ¶		skipping to change at page 11, line 36 ¶
	traceroute probe with an SR header containing the SID list <S1, S2,		traceroute probe with an SR header containing the SID list <S1, S2,
	S3>. That is illustrated using the topology in Figure 1. Assume all		S3>. That is illustrated using the topology in Figure 1. Assume all
	the links have IGP metric 10 except both links between node2 and		the links have IGP metric 10 except both links between node2 and
	node3, which have IGP metric set to 100. User issues a traceroute		node3, which have IGP metric set to 100. User issues a traceroute
	from node N1 to a loopback of node 5, via segment list <B:2:C31,		from node N1 to a loopback of node 5, via segment list <B:2:C31,
	B:4:C52>. Figure 3 contains sample output for the traceroute		B:4:C52>. Figure 3 contains sample output for the traceroute
	request.		request.
	> traceroute A:5:: via segment-list B:2:C31, B:4:C52		> traceroute A:5:: via segment-list B:2:C31, B:4:C52
	Tracing the route to B5::		Tracing the route to A:5::
	1 2001:DB8:1:2:21:: 0.512 msec 0.425 msec 0.374 msec		1 2001:DB8:1:2:21:: 0.512 msec 0.425 msec 0.374 msec
	SRH: (A:5::, B:4:C52, B:2:C31, SL=2)		SRH: (A:5::, B:4:C52, B:2:C31, SL=2)
	2 2001:DB8:2:3:31:: 0.721 msec 0.810 msec 0.795 msec		2 2001:DB8:2:3:31:: 0.721 msec 0.810 msec 0.795 msec
	SRH: (A:5::, B:4:C52, B:2:C31, SL=1)		SRH: (A:5::, B:4:C52, B:2:C31, SL=1)
	3 2001:DB8:3:4::41:: 0.921 msec 0.816 msec 0.759 msec		3 2001:DB8:3:4::41:: 0.921 msec 0.816 msec 0.759 msec
	SRH: (A:5::, B:4:C52, B:2:C31, SL=1)		SRH: (A:5::, B:4:C52, B:2:C31, SL=1)
	4 2001:DB8:4:5::52:: 0.879 msec 0.916 msec 1.024 msec		4 2001:DB8:4:5::52:: 0.879 msec 0.916 msec 1.024 msec
	Figure 3 A sample traceroute output at an SRv6 capable node		Figure 3 A sample traceroute output at an SRv6 capable node
	skipping to change at page 15, line 9 ¶		skipping to change at page 12, line 39 ¶
	useful. This information can also be used to verify if SID functions		useful. This information can also be used to verify if SID functions
	B:2:C31 and B:4:C52 are executed correctly by N2 and N4,		B:2:C31 and B:4:C52 are executed correctly by N2 and N4,
	respectively. Specifically, the information displayed for hop2		respectively. Specifically, the information displayed for hop2
	contains the incoming interface address 2001:DB8:2:3:31:: at N3.		contains the incoming interface address 2001:DB8:2:3:31:: at N3.
	This matches with the expected interface bound to END.X function		This matches with the expected interface bound to END.X function
	B:2:C31 (link3). Similarly, the information displayed for hop5		B:2:C31 (link3). Similarly, the information displayed for hop5
	contains the incoming interface address 2001:DB8:4:5::52:: at N5.		contains the incoming interface address 2001:DB8:4:5::52:: at N5.
	This matches with the expected interface bound to the END.X function		This matches with the expected interface bound to the END.X function
	B:4:C52 (link10).		B:4:C52 (link10).
	4.2.2. Traceroute to a SID Function		4.2.2. Traceroute to a SID
	The classic traceroute described in the previous section cannot be		The classic traceroute described in the previous section cannot be
	used to traceroute a remote SID function, as explained using an		used to traceroute a remote SID function, as explained using an
	example in the following.		example in the following.
	Consider the case where the user wants to traceroute the remote SID		Consider the case where the user wants to traceroute the remote SID
	function B:4:C52, via B:2:C31, from node N1. The trace route fails		function B:4:C52 from node N1. The trace route fails at N4. This is
	at N4. This is because the node N4 trace route probe where next		because the node N4 receives a trace route probe where next header is
	header is UDP or ICMPv6, instead of SRH (even though the hop limit is		UDP or ICMPv6, instead of SRH (even though the hop limit is set to
	set to 1). To solve this problem, the initiator needs to mark the		1).
	ICMPv6 echo request as an OAM packet.
	The OAM packets are identified either by setting the O-flag in SRH or		To traceroute a target SID a probe message is generated by the
	by inserting the END.OP or END.OTP SID at an appropriate place in the		initiator with the END.OP or END.OTP SID in the segment-list of the
	SRH.		SRH immediately preceding the target SID. There MAY or MAY NOT be
			additional segments preceding the END.OP/ END.OTP SID.
	In an SRv6 network, the user can exercise two flavors of the		The node instantiating a SID S of type END.OP or END.OTP receives a
	traceroute: hop-by-hop traceroute or overlay traceroute.		packet with S in the destination address of the IPv6 header and sends
			it to the OAM process (before processing the TTL). The OAM process
			verifies the segment following S is a locally instantiated SID. It
			then processes the Upper layer header of the packet, as a host,
			responding to the probe message.
	o In hop-by-hop traceroute, user gets responses from all nodes		When the segment following S is not verified by the OAM process an
	including classic IPv6 transit nodes, SRv6 capable transit nodes		ICMPv6 error message type 4 (parameter problem) code 0 (erroneous
	as well as SRv6 capable segment endpoints. E.g., consider the		header field encountered) with pointer set to the segment following S
	example where the user wants to traceroute to a remote SID		(the target SID) is generated for the packet and the packet is
	function B:4:C52, via B:2:C31, from node N1. The traceroute		discarded.
	output will also display information about node3, which is a
	transit (underlay) node.
	o The overlay traceroute, on the other hand, does not trace the		An implementation of the OAM process SID verification SHOULD do the
	underlay nodes. In other words, the overlay traceroute only		following:
	displays the nodes that acts as SRv6 segments along the route.
	I.e., in the example where the user wants to traceroute to a
	remote SID function B:4:C52, via B:2:C31, from node N1, the
	overlay traceroute would only display the traceroute information
	from node N2 and node N4; it will not display information from
	node 3.
	4.2.2.1. Hop-by-hop traceroute using END.OP/ END.OTP		o Verify that the SID is locally instantiated.
			o Verify that the SID is instantiated in the data plane (this may
			include verification of the SID in NPUs or forwarding hardware, as
			applicable).
			4.2.2.1. Traceroute using END.OP/ END.OTP
	In this section, hop-by-hop traceroute to a SID function is		In this section, hop-by-hop traceroute to a SID function is
	exemplified using UDP probes. However, the procedure is equally		exemplified using UDP probes. However, the procedure is equally
	applicable to other implementation of traceroute mechanism.		applicable to other implementation of traceroute mechanism.
	Furthermore, the illustration uses the END.OTP SID but the procedures		Furthermore, the illustration uses the END.OTP SID but the procedures
	are equally applicable to the END.OP SID.		are equally applicable to the END.OP SID.
	Consider the same example where the user wants to traceroute to a		Consider the same example where the user wants to traceroute to a
	remote SID function B:4:C52, via B:2:C31, from node N1. To force a		remote SID function B:4:C52, via B:2:C31, from node N1. To force a
	punt of the traceroute probe only at the node N4, node N1 inserts the		punt of the traceroute probe only at the node N4, node N1 inserts the
	END.OTP SID just before the target SID B:4:C52 in the SRH. The		END.OTP SID just before the target SID B:4:C52 in the SRH. The
	traceroute probe is processed at the individual nodes along the path		traceroute probe is processed at the individual nodes along the path
	as follows:		as follows:
	skipping to change at page 16, line 44 ¶		skipping to change at page 14, line 29 ¶
	Transit").		Transit").
	o When node N3, which is a classic IPv6 node, receives the packet		o When node N3, which is a classic IPv6 node, receives the packet
	with hop-count > 1, it performs the standard IPv6 processing.		with hop-count > 1, it performs the standard IPv6 processing.
	Specifically, it forwards the traceroute probe based on DA B:4:OTP		Specifically, it forwards the traceroute probe based on DA B:4:OTP
	in the IPv6 header.		in the IPv6 header.
	o When node N4 receives the packet (A:1::, B:4:OTP)(B:4:C52,		o When node N4 receives the packet (A:1::, B:4:OTP)(B:4:C52,
	B:4:OTP, B:2:C31 ; SL=1; HC=1, NH=UDP)(Traceroute probe), it		B:4:OTP, B:2:C31 ; SL=1; HC=1, NH=UDP)(Traceroute probe), it
	processes the END.OTP SID, as described in the pseudocode in		processes the END.OTP SID, as described in the pseudocode in
	Section 3. The packet gets timestamped and punted to the		Section 3. Before hop-limit processing, the packet gets
	traceroute process for processing. The traceroute process checks		timestamped and punted to the OAM process for processing. The OAM
	if the next SID in SRH (the target SID B:4:C52) is locally		process checks if the next SID in SRH (the target SID B:4:C52) is
	programmed.		locally programmed.
	o If the target SID B:4:C52 is locally programmed, node N4 responses		o If the next SID is not locally programmed, the OAM process returns
	with the ICMPv6 message (Type: Destination unreachable, Code: Port		an ICMPv6 error message type 4 (parameter problem) code 0
	Unreachable). If the target SID B:4:C52 is not a local SID, node		(erroneous header field encountered) with pointer set to the
	N4 silently drops the traceroute probe.		target SID B:4:C52 and the packet is discarded.
			o If the next SID is locally programmed, the node processes the
			upper layer header. As part of the upper layer header processing
			node N4 responses with the ICMPv6 message (Type: Destination
			unreachable, Code: Port Unreachable).
	Figure 4 displays a sample traceroute output for this example.		Figure 4 displays a sample traceroute output for this example.
	> traceroute srv6 B:4:C52 via segment-list B:2:C31		> traceroute srv6 B:4:C52 via segment-list B:2:C31
	Tracing the route to SID function B:4:C52		Tracing the route to SID function B:4:C52
	1 2001:DB8:1:2:21 0.512 msec 0.425 msec 0.374 msec		1 2001:DB8:1:2:21 0.512 msec 0.425 msec 0.374 msec
	SRH: (B:4:C52, B:4:OTP, B:2:C31; SL=2)		SRH: (B:4:C52, B:4:OTP, B:2:C31; SL=2)
	2 2001:DB8:2:3:31 0.721 msec 0.810 msec 0.795 msec		2 2001:DB8:2:3:31 0.721 msec 0.810 msec 0.795 msec
	SRH: (B:4:C52, B:4:OTP, B:2:C31; SL=1)		SRH: (B:4:C52, B:4:OTP, B:2:C31; SL=1)
	3 2001:DB8:3:4::41 0.921 msec 0.816 msec 0.759 msec		3 2001:DB8:3:4::41 0.921 msec 0.816 msec 0.759 msec
	SRH: (B:4:C52, B:4:OTP, B:2:C31; SL=1)		SRH: (B:4:C52, B:4:OTP, B:2:C31; SL=1)
	Figure 4 A sample output for hop-by-hop traceroute to a SID function		Figure 4 A sample output for hop-by-hop traceroute to a SID function
	4.2.2.2. Tracing SRv6 Overlay
	The overlay traceroute does not trace the underlay nodes, i.e., only
	displays the nodes that acts as SRv6 segments along the path. This
	is achieved by setting the SRH.Flags.O bit.
	In this section, overlay traceroute to a SID function is exemplified
	using UDP probes. However, the procedure is equally applicable to
	other implementation of traceroute mechanism.
	Consider the same example where the user wants to traceroute to a
	remote SID function B:4:C52, via B:2:C31, from node N1.
	o Node N1 initiates a traceroute probe with SRH as follows (A:1::,
	B:2:C31)(B:4:C52, B:2:C31; HC=64, SL=1, Flags.O=1;
	NH=UDP)(Traceroute Probe). Please note that the hop-count is set
	to 64 to skip the underlay nodes from tracing. The O-flag in SRH
	is set to make the overlay nodes (nodes processing the SRH)
	respond.
	o When node N2 receives the packet (A:1::, B:2:C31)(B:4:C52,
	B:2:C31; SL=1, HC=64, Flags.O=1; NH=UDP)(Traceroute Probe), it
	processes the O-flag in SRH, as described in the pseudocode in
	Section 3. A time-stamped copy of the packet gets punted to the
	traceroute process for processing. Node N2 continues to apply the
	B:2:C31 SID function on the original packet and forwards it,
	accordingly. The traceroute process at node N2 checks if its
	local SID (B:2:C31) is locally programmed. If the SID is not
	locally programmed, it silently drops the packet. Otherwise, it
	performs the egress check by looking at the SL value in SRH.
	o As SL is not equal to zero (i.e., it's not egress node), node N2
	responses with the ICMPv6 message (Type: "SRv6 OAM (TBA)", Code:
	"O-flag punt at Transit (TBA)"). Please note that, as mentioned
	in Section 3, if node N2 does not support the O-flag, it simply
	ignores it and processes the local SID, B:2:C31.
	o When node N3 receives the packet (A:1::, B:4:C52)(B:4:C52,
	B:2:C31; SL=0, HC=63, Flags.O=1; NH=UDP)(Traceroute Probe),
	performs the standard IPv6 processing. Specifically, it forwards
	the traceroute probe based on DA B:4:C52 in the IPv6 header.
	Please note that there is no hop-count expiration at the transit
	nodes.
	o When node N4 receives the packet (A:1::, B:4:C52)(B:4:C52,
	B:2:C31; SL=0, HC=62, Flags.O=1; NH=UDP)(Traceroute Probe), it
	processes the O-flag in SRH, as described in the pseudocode in
	Section 3. A time-stamped copy of the packet gets punted to the
	traceroute process for processing. The traceroute process at node
	N4 checks if its local SID (B:2:C31) is locally programmed.
	o If the SID is not locally programmed, it silently drops the
	packet. Otherwise, it performs the egress check by looking at the
	SL value in SRH. As SL is equal to zero (i.e., N4 is the egress
	node), node N4 tries to consume the UDP probe. As UDP probe is
	set to access an invalid port, the node N4 responses with the
	ICMPv6 message (Type: Destination unreachable, Code: Port
	Unreachable)
	Figure 5 displays a sample overlay traceroute output for this
	example. Please note that the underlay node N3 does not appear in
	the output.
	Tracing the route to SID function B:4:C52
	1 2001:DB8:1:2:21:: 0.512 msec 0.425 msec 0.374 msec
	SRH: (B:4:C52, B:4:OTP, B:2:C31; SL=1)
	2 2001:DB8:3:4::41:: 0.921 msec 0.816 msec 0.759 msec
	SRH: (B:4:C52, B:4:OTP, B:2:C31; SL=0)
	Figure 5 A sample output for overlay traceroute to a SID function
	4.3. Monitoring of SRv6 Paths		4.3. Monitoring of SRv6 Paths
	In the recent past, network operators are interested in performing		In the recent past, network operators are interested in performing
	network OAM functions in a centralized manner. Various data models		network OAM functions in a centralized manner. Various data models
	like YANG are available to collect data from the network and manage		like YANG are available to collect data from the network and manage
	it from a centralized entity.		it from a centralized entity.
	SR technology enables a centralized OAM entity to perform path		SR technology enables a centralized OAM entity to perform path
	monitoring from centralized OAM entity without control plane		monitoring from centralized OAM entity without control plane
	intervention on monitored nodes. [RFC 8403] describes such a		intervention on monitored nodes. [RFC 8403] describes such a
	skipping to change at page 22, line 25 ¶		skipping to change at page 18, line 39 ¶
	[I-D.ietf-6man-segment-routing-header]		[I-D.ietf-6man-segment-routing-header]
	Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,		Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,
	Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header		Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
	(SRH)", draft-ietf-6man-segment-routing-header-26 (work in		(SRH)", draft-ietf-6man-segment-routing-header-26 (work in
	progress), October 2019.		progress), October 2019.
	[I-D.ietf-spring-srv6-network-programming]		[I-D.ietf-spring-srv6-network-programming]
	Filsfils, C., Camarillo, P., Leddy, J., Voyer, D.,		Filsfils, C., Camarillo, P., Leddy, J., Voyer, D.,
	Matsushima, S., and Z. Li, "SRv6 Network Programming",		Matsushima, S., and Z. Li, "SRv6 Network Programming",
	draft-ietf-spring-srv6-network-programming-05 (work in		draft-ietf-spring-srv6-network-programming-06 (work in
	progress), October 2019.		progress), December 2019.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	10.2. Informative References		10.2. Informative References
	[I-D.matsushima-spring-srv6-deployment-status]		[I-D.matsushima-spring-srv6-deployment-status]
	Matsushima, S., Filsfils, C., Ali, Z., and Z. Li, "SRv6		Matsushima, S., Filsfils, C., Ali, Z., and Z. Li, "SRv6
	Implementation and Deployment Status", draft-matsushima-		Implementation and Deployment Status", draft-matsushima-
	spring-srv6-deployment-status-02 (work in progress),		spring-srv6-deployment-status-04 (work in progress),
	October 2019.		December 2019.
	[RFC0792] Postel, J., "Internet Control Message Protocol", STD 5,		[RFC0792] Postel, J., "Internet Control Message Protocol", STD 5,
	RFC 792, DOI 10.17487/RFC0792, September 1981,		RFC 792, DOI 10.17487/RFC0792, September 1981,
	<https://www.rfc-editor.org/info/rfc792>.		<https://www.rfc-editor.org/info/rfc792>.
	[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet		[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
	Control Message Protocol (ICMPv6) for the Internet		Control Message Protocol (ICMPv6) for the Internet
	Protocol Version 6 (IPv6) Specification", STD 89,		Protocol Version 6 (IPv6) Specification", STD 89,
	RFC 4443, DOI 10.17487/RFC4443, March 2006,		RFC 4443, DOI 10.17487/RFC4443, March 2006,
	<https://www.rfc-editor.org/info/rfc4443>.		<https://www.rfc-editor.org/info/rfc4443>.
End of changes. 47 change blocks.
	312 lines changed or deleted		149 lines changed or added
This html diff was produced by rfcdiff 1.47. The latest version is available from http://tools.ietf.org/tools/rfcdiff/