draft-ietf-mpls-lsp-ping-lag-multipath-05.txt		draft-ietf-mpls-lsp-ping-lag-multipath-06.txt
	Internet Engineering Task Force N. Akiya		Internet Engineering Task Force N. Akiya
	Internet-Draft Big Switch Networks		Internet-Draft Big Switch Networks
	Updates: 8029 (if approved) G. Swallow		Updates: 8029 (if approved) G. Swallow
	Intended status: Standards Track Cisco Systems		Intended status: Standards Track Cisco Systems
	Expires: April 26, 2019 S. Litkowski		Expires: September 6, 2019 S. Litkowski
	B. Decraene		B. Decraene
	Orange		Orange
	J. Drake		J. Drake
	Juniper Networks		Juniper Networks
	M. Chen		M. Chen
	Huawei		Huawei
	October 23, 2018		March 05, 2019
	Label Switched Path (LSP) Ping/Trace Multipath Support for		Label Switched Path (LSP) Ping/Trace Multipath Support for
	Link Aggregation Group (LAG) Interfaces		Link Aggregation Group (LAG) Interfaces
	draft-ietf-mpls-lsp-ping-lag-multipath-05		draft-ietf-mpls-lsp-ping-lag-multipath-06
	Abstract		Abstract
	This document defines extensions to the MPLS Label Switched Path		This document defines extensions to the MPLS Label Switched Path
	(LSP) Ping and Traceroute mechanisms as specified in RFC 8029. The		(LSP) Ping and Traceroute mechanisms as specified in RFC 8029. The
	extensions allow the MPLS LSP Ping and Traceroute mechanisms to		extensions allow the MPLS LSP Ping and Traceroute mechanisms to
	discover and exercise specific paths of Layer 2 (L2) Equal-Cost		discover and exercise specific paths of Layer 2 (L2) Equal-Cost
	Multipath (ECMP) over Link Aggregation Group (LAG) interfaces.		Multipath (ECMP) over Link Aggregation Group (LAG) interfaces.
	Additionally, a mechanism is defined to enable determination of the		Additionally, a mechanism is defined to enable determination of the
	capabilities of an LSR supported.		capabilities of an LSR supported.
	skipping to change at page 2, line 10 ¶		skipping to change at page 2, line 10 ¶
	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 April 26, 2019.		This Internet-Draft will expire on September 6, 2019.
	Copyright Notice		Copyright Notice
	Copyright (c) 2018 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.
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	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
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	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
	1.2. Background . . . . . . . . . . . . . . . . . . . . . . . 3		1.2. Background . . . . . . . . . . . . . . . . . . . . . . . 4
	2. Overview of Solution . . . . . . . . . . . . . . . . . . . . 4		2. Overview of Solution . . . . . . . . . . . . . . . . . . . . 4
	3. LSR Capability Discovery . . . . . . . . . . . . . . . . . . 6		3. LSR Capability Discovery . . . . . . . . . . . . . . . . . . 6
	3.1. Initiator LSR Procedures . . . . . . . . . . . . . . . . 7		3.1. Initiator LSR Procedures . . . . . . . . . . . . . . . . 7
	3.2. Responder LSR Procedures . . . . . . . . . . . . . . . . 7		3.2. Responder LSR Procedures . . . . . . . . . . . . . . . . 7
	4. Mechanism to Discover L2 ECMP Multipath . . . . . . . . . . . 7		4. Mechanism to Discover L2 ECMP Multipath . . . . . . . . . . . 8
	4.1. Initiator LSR Procedures . . . . . . . . . . . . . . . . 7		4.1. Initiator LSR Procedures . . . . . . . . . . . . . . . . 8
	4.2. Responder LSR Procedures . . . . . . . . . . . . . . . . 8		4.2. Responder LSR Procedures . . . . . . . . . . . . . . . . 8
	4.3. Additional Initiator LSR Procedures . . . . . . . . . . . 10		4.3. Additional Initiator LSR Procedures . . . . . . . . . . . 10
	5. Mechanism to Validate L2 ECMP Traversal . . . . . . . . . . . 11		5. Mechanism to Validate L2 ECMP Traversal . . . . . . . . . . . 11
	5.1. Incoming LAG Member Links Verification . . . . . . . . . 11		5.1. Incoming LAG Member Links Verification . . . . . . . . . 11
	5.1.1. Initiator LSR Procedures . . . . . . . . . . . . . . 11		5.1.1. Initiator LSR Procedures . . . . . . . . . . . . . . 11
	5.1.2. Responder LSR Procedures . . . . . . . . . . . . . . 12		5.1.2. Responder LSR Procedures . . . . . . . . . . . . . . 12
	5.1.3. Additional Initiator LSR Procedures . . . . . . . . . 12		5.1.3. Additional Initiator LSR Procedures . . . . . . . . . 12
	5.2. Individual End-to-End Path Verification . . . . . . . . . 13		5.2. Individual End-to-End Path Verification . . . . . . . . . 13
	6. LSR Capability TLV . . . . . . . . . . . . . . . . . . . . . 14		6. LSR Capability TLV . . . . . . . . . . . . . . . . . . . . . 14
	7. LAG Description Indicator Flag: G . . . . . . . . . . . . . . 15		7. LAG Description Indicator Flag: G . . . . . . . . . . . . . . 15
	8. Local Interface Index Sub-TLV . . . . . . . . . . . . . . . . 16		8. Local Interface Index Sub-TLV . . . . . . . . . . . . . . . . 16
	9. Remote Interface Index Sub-TLV . . . . . . . . . . . . . . . 17		9. Remote Interface Index Sub-TLV . . . . . . . . . . . . . . . 17
	10. Detailed Interface and Label Stack TLV . . . . . . . . . . . 17		10. Detailed Interface and Label Stack TLV . . . . . . . . . . . 17
	10.1. Sub-TLVs . . . . . . . . . . . . . . . . . . . . . . . . 19		10.1. Sub-TLVs . . . . . . . . . . . . . . . . . . . . . . . . 19
	10.1.1. Incoming Label Stack Sub-TLV . . . . . . . . . . . . 19		10.1.1. Incoming Label Stack Sub-TLV . . . . . . . . . . . . 19
	10.1.2. Incoming Interface Index Sub-TLV . . . . . . . . . . 20		10.1.2. Incoming Interface Index Sub-TLV . . . . . . . . . . 20
	11. Security Considerations . . . . . . . . . . . . . . . . . . . 21		11. Rate Limiting On Echo Request/Reply Messages . . . . . . . . 21
	12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21		12. Security Considerations . . . . . . . . . . . . . . . . . . . 21
	12.1. LSR Capability TLV . . . . . . . . . . . . . . . . . . . 21		13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
	12.1.1. LSR Capability Flags . . . . . . . . . . . . . . . . 21		13.1. LSR Capability TLV . . . . . . . . . . . . . . . . . . . 21
	12.2. Local Interface Index Sub-TLV . . . . . . . . . . . . . 22		13.1.1. LSR Capability Flags . . . . . . . . . . . . . . . . 22
	12.2.1. Interface Index Flags . . . . . . . . . . . . . . . 22		13.2. Local Interface Index Sub-TLV . . . . . . . . . . . . . 22
	12.3. Remote Interface Index Sub-TLV . . . . . . . . . . . . . 22		13.2.1. Interface Index Flags . . . . . . . . . . . . . . . 22
	12.4. Detailed Interface and Label Stack TLV . . . . . . . . . 23		13.3. Remote Interface Index Sub-TLV . . . . . . . . . . . . . 23
	12.4.1. Sub-TLVs for TLV Type TBD4 . . . . . . . . . . . . . 23		13.4. Detailed Interface and Label Stack TLV . . . . . . . . . 23
	12.5. DS Flags . . . . . . . . . . . . . . . . . . . . . . . . 23		13.4.1. Sub-TLVs for TLV Type TBD4 . . . . . . . . . . . . . 23
	13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24		13.5. DS Flags . . . . . . . . . . . . . . . . . . . . . . . . 24
	14. References . . . . . . . . . . . . . . . . . . . . . . . . . 24		14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24
	14.1. Normative References . . . . . . . . . . . . . . . . . . 24		15. References . . . . . . . . . . . . . . . . . . . . . . . . . 24
	14.2. Informative References . . . . . . . . . . . . . . . . . 24		15.1. Normative References . . . . . . . . . . . . . . . . . . 24
			15.2. Informative References . . . . . . . . . . . . . . . . . 25
	Appendix A. LAG with intermediate L2 Switch Issues . . . . . . . 25		Appendix A. LAG with intermediate L2 Switch Issues . . . . . . . 25
	A.1. Equal Numbers of LAG Members . . . . . . . . . . . . . . 25		A.1. Equal Numbers of LAG Members . . . . . . . . . . . . . . 25
	A.2. Deviating Numbers of LAG Members . . . . . . . . . . . . 25		A.2. Deviating Numbers of LAG Members . . . . . . . . . . . . 26
	A.3. LAG Only on Right . . . . . . . . . . . . . . . . . . . . 26		A.3. LAG Only on Right . . . . . . . . . . . . . . . . . . . . 26
	A.4. LAG Only on Left . . . . . . . . . . . . . . . . . . . . 26		A.4. LAG Only on Left . . . . . . . . . . . . . . . . . . . . 26
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
	1. Introduction		1. Introduction
	1.1. Terminology		1.1. Terminology
	The following acronyms/terms are used in this document:		The following acronyms/terms are used in this document:
	o MPLS - Multiprotocol Label Switching.		o MPLS - Multiprotocol Label Switching.
	o LSP - Label Switched Path.		o LSP - Label Switched Path.
	o LSR - Label Switching Router.		o LSR - Label Switching Router.
	o ECMP - Equal-Cost Multipath.		o ECMP - Equal-Cost Multipath.
	o LAG - Link Aggregation Group.		o LAG - Link Aggregation Group.
	o Initiator LSR - LSR which sends MPLS echo request.		o Initiator LSR - The LSR which sends the MPLS echo request message.
	o Responder LSR - LSR which receives MPLS echo request and sends		o Responder LSR - The LSR which receives the MPLS echo request
	MPLS echo reply.		message and sends the MPLS echo reply message.
	1.2. Background		1.2. Background
	The MPLS Label Switched Path (LSP) Ping and Traceroute mechanisms		The MPLS Label Switched Path (LSP) Ping and Traceroute mechanisms
	[RFC8029] are powerful tools designed to diagnose all available Layer		[RFC8029] are powerful tools designed to diagnose all available Layer
	3 (L3) paths of LSPs, including diagnostic coverage of L3 Equal-Cost		3 (L3) paths of LSPs, including diagnostic coverage of L3 Equal-Cost
	Multipath (ECMP). In many MPLS networks, Link Aggregation Group		Multipath (ECMP). In many MPLS networks, Link Aggregation Group
	(LAG) as defined in [IEEE802.1AX], which provides Layer 2 (L2) ECMP,		(LAG) as defined in [IEEE802.1AX], which provides Layer 2 (L2) ECMP,
	is often used for various reasons. MPLS LSP Ping and Traceroute		is often used for various reasons. MPLS LSP Ping and Traceroute
	tools were not designed to discover and exercise specific paths of L2		tools were not designed to discover and exercise specific paths of L2
	ECMP. This raises a limitation for the following scenario when an		ECMP. This raises a limitation for the following scenario when an
	LSP traverses over a LAG:		LSP traverses over a LAG:
	o Label switching over some member links of the LAG is successful,		o Label switching over some member links of the LAG is successful,
	but will be failed over other member links of the LAG.		but will be failed over other member links of the LAG.
	o MPLS echo request for the LSP over the LAG is load balanced on one		o MPLS echo request for the LSP over the LAG is load balanced on one
	of the member links which is label switching successfully.		of the member links which is label switching successfully.
	With the above scenarios, MPLS LSP Ping and Traceroute will not be		With the above scenario, MPLS LSP Ping and Traceroute will not be
	able to detect the label switching failure of the problematic member		able to detect the label switching failure of the problematic member
	link(s) of the LAG. In other words, lack of L2 ECMP diagnostic		link(s) of the LAG. In other words, lack of L2 ECMP diagnostic
	coverage can produce an outcome where MPLS LSP Ping and Traceroute		coverage can produce an outcome where MPLS LSP Ping and Traceroute
	can be blind to label switching failures over a problematic LAG		can be blind to label switching failures over a problematic LAG
	interface. It is, thus, desirable to extend the MPLS LSP Ping and		interface. It is, thus, desirable to extend the MPLS LSP Ping and
	Traceroute to have deterministic diagnostic coverage of LAG		Traceroute to have deterministic diagnostic coverage of LAG
	interfaces.		interfaces.
	The need for a solution of this problem was motivated by issues		The need for a solution of this problem was motivated by issues
	encountered in live networks.		encountered in live networks.
	2. Overview of Solution		2. Overview of Solution
	This document defines an optional TLV to discover the capabilities of		This document defines an optional TLV to discover the capabilities of
	a responder LSR and extensions for use with the MPLS LSP Ping and		a responder LSR and extensions for use with the MPLS LSP Ping and
	Traceroute mechanisms to describe Multipath Information for		Traceroute mechanisms to describe Multipath Information for
	individual LAG member links, thus allowing MPLS LSP Ping and		individual LAG member links, thus allowing MPLS LSP Ping and
	Traceroute to discover and exercise specific paths of L2 ECMP over		Traceroute to discover and exercise specific paths of L2 ECMP over
	LAG interfaces. The reader is expected to be familiar with mechanics		LAG interfaces. The reader is expected to be familiar with mechanics
	of Downstream Mapping described in Section 3.3 of [RFC8029] and
	Downstream Detailed Mapping TLV (DDMAP) described in Section 3.4 of		Downstream Detailed Mapping TLV (DDMAP) described in Section 3.4 of
	[RFC8029].		[RFC8029].
	The solution consists of the MPLS echo request containing a DDMAP TLV		The solution consists of the MPLS echo request containing a DDMAP TLV
	and the optional LSR capability TLV to indicate that separate load		and the optional LSR capability TLV to indicate that separate load
	balancing information for each L2 nexthop over LAG is desired in the		balancing information for each L2 nexthop over LAG is desired in the
	MPLS echo reply. The Responder LSR places the same optional LSR		MPLS echo reply. The Responder LSR places the same optional LSR
	capability TLV in the MPLS echo reply to provide acknowledgement back		capability TLV in the MPLS echo reply to provide acknowledgement back
	to the initiator LSR. It also adds, for each downstream LAG member,		to the initiator LSR. It also adds, for each downstream LAG member,
	load balance information (i.e., multipath information and interface		load balance information (i.e., multipath information and interface
	skipping to change at page 9, line 14 ¶		skipping to change at page 9, line 20 ¶
	+ The responder LSR MUST add an Multipath Data Sub-TLV for		+ The responder LSR MUST add an Multipath Data Sub-TLV for
	this LAG member link, if the received DDMAP TLV requested		this LAG member link, if the received DDMAP TLV requested
	multipath information.		multipath information.
	Based on the procedures described above, every LAG member link will		Based on the procedures described above, every LAG member link will
	have a Local Interface Index Sub-TLV and a Multipath Data Sub-TLV		have a Local Interface Index Sub-TLV and a Multipath Data Sub-TLV
	entries in the DDMAP TLV. The order of the Sub-TLVs in the DDMAP TLV		entries in the DDMAP TLV. The order of the Sub-TLVs in the DDMAP TLV
	for a LAG member link MUST be Local Interface Index Sub-TLV		for a LAG member link MUST be Local Interface Index Sub-TLV
	immediately followed by Multipath Data Sub-TLV. A LAG member link		immediately followed by Multipath Data Sub-TLV. A LAG member link
	may also have a corresponding Remote Interface Index Sub-TLV. When a		MAY also have a corresponding Remote Interface Index Sub-TLV. When a
	Local Interface Index Sub-TLV, a Remote Interface Index-Sub-TLV and a		Local Interface Index Sub-TLV, a Remote Interface Index-Sub-TLV and a
	Multipath Data Sub-TLV are placed in the DDMAP TLV to describe a LAG		Multipath Data Sub-TLV are placed in the DDMAP TLV to describe a LAG
	member link, they MUST be placed in the order of Local Interface		member link, they MUST be placed in the order of Local Interface
	Index Sub-TLV, Remote Interface Index-Sub-TLV and Multipath Data Sub-		Index Sub-TLV, Remote Interface Index-Sub-TLV and Multipath Data Sub-
	TLV.		TLV.
	A responder LSR possessing a LAG interface with two member links		A responder LSR possessing a LAG interface with two member links
	would send the following DDMAP for this LAG interface:		would send the following DDMAP for this LAG interface:
	0 1 2 3		0 1 2 3
	skipping to change at page 11, line 21 ¶		skipping to change at page 11, line 25 ¶
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Multipath Data Sub-TLV LAG member link #1 |		| Multipath Data Sub-TLV LAG member link #1 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Label Stack Sub-TLV |		| Label Stack Sub-TLV |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 3: Example of DDMAP in MPLS Echo Request		Figure 3: Example of DDMAP in MPLS Echo Request
	5. Mechanism to Validate L2 ECMP Traversal		5. Mechanism to Validate L2 ECMP Traversal
	Section 4 defines the responder LSR procedures to constructs a DDMAP		Section 4 defines the responder LSR procedures to construct a DDMAP
	for a downstream LAG. The Remote Interface Index Sub-TLVs that		for a downstream LAG. The Remote Interface Index Sub-TLVs that
	describes the incoming LAG member links of the downstream LSR is		describes the incoming LAG member links of the downstream LSR is
	optional, because this information from the downstream LSR is often		optional, because this information from the downstream LSR is often
	not available on the responder LSR. In such case, the traversal of		not available on the responder LSR. In such case, the traversal of
	LAG member links can be validated with procedures described in		LAG member links can be validated with procedures described in
	Section 5.1. If LSRs can provide the Remote Interface Index Sub-		Section 5.1. If LSRs can provide the Remote Interface Index Sub-
	TLVs, then the validation procedures described in Section 5.2 can be		TLVs, then the validation procedures described in Section 5.2 can be
	used.		used.
	5.1. Incoming LAG Member Links Verification		5.1. Incoming LAG Member Links Verification
	skipping to change at page 13, line 5 ¶		skipping to change at page 13, line 5 ¶
	o With specific entropy, the interface index of the incoming LAG		o With specific entropy, the interface index of the incoming LAG
	member link at TTL=n+1.		member link at TTL=n+1.
	Expectation is that there's a relationship between the interface		Expectation is that there's a relationship between the interface
	index of the outgoing LAG member link at TTL=n and the interface		index of the outgoing LAG member link at TTL=n and the interface
	index of the incoming LAG member link at TTL=n+1 for all discovered		index of the incoming LAG member link at TTL=n+1 for all discovered
	entropies. In other words, set of entropies that load balances to		entropies. In other words, set of entropies that load balances to
	outgoing LAG member link X at TTL=n should all reach the nexthop on		outgoing LAG member link X at TTL=n should all reach the nexthop on
	same incoming LAG member link Y at TTL=n+1.		same incoming LAG member link Y at TTL=n+1.
	With additional logics, the initiator LSR can perform the following		With additional logic, the initiator LSR can perform the following
	checks in a scenario where the initiator LSR knows that there is a		checks in a scenario where the initiator LSR knows that there is a
	LAG, with two LAG members, between TTL=n and TTL=n+1, and has the		LAG, with two LAG members, between TTL=n and TTL=n+1, and has the
	multipath information to traverse the two LAG member links.		multipath information to traverse the two LAG member links.
	The initiator LSR sends two MPLS echo request messages to traverse		The initiator LSR sends two MPLS echo request messages to traverse
	the two LAG member links at TTL=n+1:		the two LAG member links at TTL=n+1:
	o Success case:		o Success case:
	* One MPLS echo request message reaches TTL=n+1 on an LAG member		* One MPLS echo request message reaches TTL=n+1 on an LAG member
	skipping to change at page 14, line 50 ¶		skipping to change at page 14, line 50 ¶
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Type | Length |		| Type | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| LSR Capability Flags |		| LSR Capability Flags |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 4: LSR Capability TLV		Figure 4: LSR Capability TLV
	Where:		Where:
	The Type is 2 octets in length and the value is TBD1.		The Type field is 2 octets in length and the value is TBD1.
	The Length filed is 2 octets in length, and the value is 4.		The Length field is 2 octets in length, and the value is 4.
	The LSR Capability Flags is 4 octets in length, this document		The "LSR Capability Flags" field is 4 octets in length, this
	defines following flags:		document defines the following flags:
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Must Be Zero (Reserved) |U|D|		| Must Be Zero (Reserved) |U|D|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	This document defines two flags. The remaining flags MUST be set		This document defines two flags. The remaining flags MUST be set
	to zero when sending and ignored on receipt. Both the U and the D		to zero when sending and ignored on receipt. Both the U and the D
	flag MUST be cleared in the MPLS echo request message when		flag MUST be cleared in the MPLS echo request message when
	skipping to change at page 15, line 41 ¶		skipping to change at page 15, line 41 ¶
	D Downstream LAG Info Accommodation		D Downstream LAG Info Accommodation
	An LSR sets this flag when the LSR is capable of		An LSR sets this flag when the LSR is capable of
	describing LAG member links in the Local Interface		describing LAG member links in the Local Interface
	Index Sub-TLV and the Multipath Data Sub-TLV in the		Index Sub-TLV and the Multipath Data Sub-TLV in the
	Downstream Detailed Mapping TLV.		Downstream Detailed Mapping TLV.
	7. LAG Description Indicator Flag: G		7. LAG Description Indicator Flag: G
	This document defines a flag, the "G" flag (LAG Description		This document defines a new flag, the "G" flag (LAG Description
	Indicator), in the DS Flags field of the DDMAP TLV.		Indicator), in the DS Flags field of the DDMAP TLV.
	The "G" flag in the MPLS echo request message indicates the request		The "G" flag in the MPLS echo request message indicates the request
	for detailed LAG information from the responder LSR. In the MPLS		for detailed LAG information from the responder LSR. In the MPLS
	echo reply message, the "G" flag MUST be set if the DDMAP TLV		echo reply message, the "G" flag MUST be set if the DDMAP TLV
	describes a LAG interface. It MUST be cleared otherwise.		describes a LAG interface. It MUST be cleared otherwise.
	The "G" flag is defined as below:		The "G" flag is defined as below:
	The Bit Number is TBD5.		The Bit Number is TBD5.
	skipping to change at page 21, line 5 ¶		skipping to change at page 21, line 5 ¶
	M LAG Member Link Indicator		M LAG Member Link Indicator
	When this flag is set, interface index described in		When this flag is set, interface index described in
	this sub-TLV is a member of a LAG.		this sub-TLV is a member of a LAG.
	Incoming Interface Index		Incoming Interface Index
	An Index assigned by the LSR to this interface.		An Index assigned by the LSR to this interface.
	11. Security Considerations		11. Rate Limiting On Echo Request/Reply Messages
	This document extends LSP Traceroute mechanism to discover and		For an LSP path, it may be over several LAGs. Each LAG may have many
	exercise L2 ECMP paths. As a result of supporting the code points		member links. To exercise all the links, many Echo Request/Reply
	and procedures described in this document, additional processing are		messages will be sent in a short period. It's possible that those
	required by initiator LSRs and responder LSRs, especially to compute		messages may traverse a common path as a burst. Under some
	and handle the additional multipath information. Due to additional		circumstances this might cause congestion at the common path. To
	processing, it is critical that proper security measures described in		avoid potential congestion, it is RECOMMENDED that implementations to
	[RFC8029] are followed.		randomly delay the Echo Request and Reply messages at the Initiating
			LSRs and Responder LSRs.
	The LSP Traceroute allows an initiator LSR to discover the paths of		12. Security Considerations
	tested LSPs, providing detailed knowledge of the MPLS network.
	Exposing such information to a malicious user is considered
	dangerous. To prevent leakage of vital information to untrusted
	users, a responder LSR MUST only accept MPLS echo request messages
	from trusted sources via filtering source IP address field of
	received MPLS echo request messages.[RFC8029] provides additional
	recommendations to avoid attacks and recommendations to follow if an
	operator desires to prevent tracing.
	12. IANA Considerations		This document extends LSP Traceroute mechanism [RFC8029] to discover
			and exercise L2 ECMP paths to determine problematic member link(s) of
			a LAG. These on-demand diagnostic mechanisms are used by an operator
			within an MPLS control domain.
	12.1. LSR Capability TLV		[RFC8029] reviews the possible attacks and approaches to mitigate
			possible threats when using these mechanisms.
			To prevent leakage of vital information to untrusted users, a
			responder LSR MUST only accept MPLS echo request messages from
			designated trusted sources via filtering source IP address field of
			received MPLS echo request messages. As noted in [RFC8029], spoofing
			attacks only have a small window of opportunity. If these messages
			are indeed hijacked (non-delivery) by an intermediate node, the use
			of these mechanisms will determine the data plane is not working (as
			it should). Hijacking of a responder node such that it provides a
			legitimate reply would involve compromising the node itself and the
			MPLS control domain. [RFC5920] provides additional MPLS network-wide
			operation recommendations to avoid attacks and recommendations to
			follow.
			13. IANA Considerations
			13.1. LSR Capability TLV
	The IANA is requested to assign new value TBD1 for LSR Capability TLV		The IANA is requested to assign new value TBD1 for LSR Capability TLV
	from the "Multiprotocol Label Switching Architecture (MPLS) Label		from the "Multiprotocol Label Switching Architecture (MPLS) Label
	Switched Paths (LSPs) Ping Parameters - TLVs" registry.		Switched Paths (LSPs) Ping Parameters - TLVs" registry.
	Value Meaning Reference		Value Meaning Reference
	----- ------- ---------		----- ------- ---------
	TBD1 LSR Capability TLV this document		TBD1 LSR Capability TLV this document
	12.1.1. LSR Capability Flags		13.1.1. LSR Capability Flags
	The IANA is requested to create and maintain a registry entitled "LSR		The IANA is requested to create and maintain a registry entitled "LSR
	Capability Flags" with following registration procedures:		Capability Flags" with following registration procedures:
	Registry Name: LAG Interface Info Flags		Registry Name: LAG Interface Info Flags
	Bit number Name Reference		Bit number Name Reference
	---------- ---------------------------------------- ---------		---------- ---------------------------------------- ---------
	31 D: Downstream LAG Info Accommodation this document		31 D: Downstream LAG Info Accommodation this document
	30 U: Upstream LAG Info Accommodation this document		30 U: Upstream LAG Info Accommodation this document
	0-29 Unassigned		0-29 Unassigned
	Assignments of LSR Capability Flags are via Standards Action		Assignments of LSR Capability Flags are via Standards Action
	[RFC8126].		[RFC8126].
	12.2. Local Interface Index Sub-TLV		13.2. Local Interface Index Sub-TLV
	The IANA is requested to assign new value TBD2 (from the range		The IANA is requested to assign new value TBD2 (from the range
	4-31743) for the Local Interface Index Sub-TLV from the		4-31743) for the Local Interface Index Sub-TLV from the
	"Multiprotocol Label Switching Architecture (MPLS) Label Switched		"Multiprotocol Label Switching Architecture (MPLS) Label Switched
	Paths (LSPs) Ping Parameters - TLVs" registry, "Sub-TLVs for TLV		Paths (LSPs) Ping Parameters - TLVs" registry, "Sub-TLVs for TLV
	Types 20" sub-registry.		Types 20" sub-registry.
	Value Meaning Reference		Value Meaning Reference
	----- ------- ---------		----- ------- ---------
	TBD2 Local Interface Index Sub-TLV this document		TBD2 Local Interface Index Sub-TLV this document
	12.2.1. Interface Index Flags		13.2.1. Interface Index Flags
	The IANA is requested to create and maintain a registry entitled		The IANA is requested to create and maintain a registry entitled
	"Interface Index Flags" with following registration procedures:		"Interface Index Flags" with following registration procedures:
	Registry Name: Interface Index Flags		Registry Name: Interface Index Flags
	Bit number Name Reference		Bit number Name Reference
	---------- ---------------------------------------- ---------		---------- ---------------------------------------- ---------
	15 M: LAG Member Link Indicator this document		15 M: LAG Member Link Indicator this document
	0-14 Unassigned		0-14 Unassigned
	skipping to change at page 22, line 44 ¶		skipping to change at page 23, line 11 ¶
	o The Local Interface Index Sub-TLV which may be present in the		o The Local Interface Index Sub-TLV which may be present in the
	"Downstream Detailed Mapping" TLV.		"Downstream Detailed Mapping" TLV.
	o The Remote Interface Index Sub-TLV which may be present in the		o The Remote Interface Index Sub-TLV which may be present in the
	"Downstream Detailed Mapping" TLV.		"Downstream Detailed Mapping" TLV.
	o The Incoming Interface Index Sub-TLV which may be present in the		o The Incoming Interface Index Sub-TLV which may be present in the
	"Detailed Interface and Label Stack" TLV.		"Detailed Interface and Label Stack" TLV.
	12.3. Remote Interface Index Sub-TLV		13.3. Remote Interface Index Sub-TLV
	The IANA is requested to assign new value TBD3 (from the range		The IANA is requested to assign new value TBD3 (from the range
	32768-49161) for the Remote Interface Index Sub-TLV from the		32768-49161) for the Remote Interface Index Sub-TLV from the
	"Multiprotocol Label Switching Architecture (MPLS) Label Switched		"Multiprotocol Label Switching Architecture (MPLS) Label Switched
	Paths (LSPs) Ping Parameters - TLVs" registry, "Sub-TLVs for TLV		Paths (LSPs) Ping Parameters - TLVs" registry, "Sub-TLVs for TLV
	Types 20" sub-registry.		Types 20" sub-registry.
	Value Meaning Reference		Value Meaning Reference
	----- ------- ---------		----- ------- ---------
	TBD3 Remote Interface Index Sub-TLV this document		TBD3 Remote Interface Index Sub-TLV this document
	12.4. Detailed Interface and Label Stack TLV		13.4. Detailed Interface and Label Stack TLV
	The IANA is requested to assign new value TBD4 for Detailed Interface		The IANA is requested to assign new value TBD4 for Detailed Interface
	and Label Stack TLV from the "Multiprotocol Label Switching		and Label Stack TLV from the "Multiprotocol Label Switching
	Architecture (MPLS) Label Switched Paths (LSPs) Ping Parameters -		Architecture (MPLS) Label Switched Paths (LSPs) Ping Parameters -
	TLVs" registry ([IANA-MPLS-LSP-PING]).		TLVs" registry ([IANA-MPLS-LSP-PING]).
	Value Meaning Reference		Value Meaning Reference
	----- ------- ---------		----- ------- ---------
	TBD4 Detailed Interface and Label Stack TLV this document		TBD4 Detailed Interface and Label Stack TLV this document
	12.4.1. Sub-TLVs for TLV Type TBD4		13.4.1. Sub-TLVs for TLV Type TBD4
	The IANA is requested to create and maintain a sub-registry entitled		The IANA is requested to create and maintain a sub-registry entitled
	"Sub-TLVs for TLV Type TBD4" under "Multiprotocol Label Switching		"Sub-TLVs for TLV Type TBD4" under "Multiprotocol Label Switching
	Architecture (MPLS) Label Switched Paths (LSPs) Ping Parameters -		Architecture (MPLS) Label Switched Paths (LSPs) Ping Parameters -
	TLVs" registry.		TLVs" registry.
	Initial values for this sub-registry, "Sub-TLVs for TLV Types TBD4",		Initial values for this sub-registry, "Sub-TLVs for TLV Types TBD4",
	are described below.		are described below.
	Sub-Type Name Reference		Sub-Type Name Reference
	skipping to change at page 23, line 43 ¶		skipping to change at page 24, line 9 ¶
	2 Incoming Interface Index this document		2 Incoming Interface Index this document
	3-16383 Unassigned (mandatory TLVs)		3-16383 Unassigned (mandatory TLVs)
	16384-31743 Experimental		16384-31743 Experimental
	32768-49161 Unassigned (optional TLVs)		32768-49161 Unassigned (optional TLVs)
	49162-64511 Experimental		49162-64511 Experimental
	Assignments of Sub-Types in the mandatory and optional spaces are via		Assignments of Sub-Types in the mandatory and optional spaces are via
	Standards Action [RFC8126]. Assignments of Sub-Types in the		Standards Action [RFC8126]. Assignments of Sub-Types in the
	experimental space is via Specification Required [RFC8126].		experimental space is via Specification Required [RFC8126].
	12.5. DS Flags		13.5. DS Flags
	The IANA is requested to assign a new bit number from the "DS flags"		The IANA is requested to assign a new bit number from the "DS flags"
	sub-registry from the "Multi-Protocol Label Switching (MPLS) Label		sub-registry from the "Multi-Protocol Label Switching (MPLS) Label
	Switched Paths (LSPs) Ping Parameters - TLVs" registry		Switched Paths (LSPs) Ping Parameters - TLVs" registry
	([IANA-MPLS-LSP-PING]).		([IANA-MPLS-LSP-PING]).
	Note: the "DS flags" sub-registry is created by [RFC8029].		Note: the "DS flags" sub-registry is created by [RFC8029].
	Bit number Name Reference		Bit number Name Reference
	---------- ---------------------------------------- ---------		---------- ---------------------------------------- ---------
	TBD5 G: LAG Description Indicator this document		TBD5 G: LAG Description Indicator this document
	13. Acknowledgements		14. Acknowledgements
	The authors would like to thank Nagendra Kumar, Sam Aldrin, for		The authors would like to thank Nagendra Kumar, Sam Aldrin, for
	providing useful comments and suggestions. The authors would like to		providing useful comments and suggestions. The authors would like to
	thank Loa Andersson for performing a detailed review and providing		thank Loa Andersson for performing a detailed review and providing
	number of comments.		number of comments.
	The authors also would like to extend sincere thanks to the MPLS RT		The authors also would like to extend sincere thanks to the MPLS RT
	review members who took time to review and provide comments. The		review members who took time to review and provide comments. The
	members are Eric Osborne, Mach Chen and Yimin Shen. The suggestion		members are Eric Osborne, Mach Chen and Yimin Shen. The suggestion
	by Mach Chen to generalize and create the LSR Capability TLV was		by Mach Chen to generalize and create the LSR Capability TLV was
	tremendously helpful for this document and likely for future		tremendously helpful for this document and likely for future
	documents extending the MPLS LSP Ping and Traceroute mechanism. The		documents extending the MPLS LSP Ping and Traceroute mechanism. The
	suggestion by Yimin Shen to create two separate validation procedures		suggestion by Yimin Shen to create two separate validation procedures
	had a big impact to the contents of this document.		had a big impact to the contents of this document.
	14. References		15. References
	14.1. Normative References		15.1. Normative References
	[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>.
	[RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,		[RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
	Aldrin, S., and M. Chen, "Detecting Multiprotocol Label		Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
	Switched (MPLS) Data-Plane Failures", RFC 8029,		Switched (MPLS) Data-Plane Failures", RFC 8029,
	DOI 10.17487/RFC8029, March 2017,		DOI 10.17487/RFC8029, March 2017,
	<https://www.rfc-editor.org/info/rfc8029>.		<https://www.rfc-editor.org/info/rfc8029>.
	[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC		[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
	2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,		2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
	May 2017, <https://www.rfc-editor.org/info/rfc8174>.		May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	14.2. Informative References		15.2. Informative References
	[IANA-MPLS-LSP-PING]		[IANA-MPLS-LSP-PING]
	IANA, "Multi-Protocol Label Switching (MPLS) Label		IANA, "Multi-Protocol Label Switching (MPLS) Label
	Switched Paths (LSPs) Ping Parameters",		Switched Paths (LSPs) Ping Parameters",
	<http://www.iana.org/assignments/mpls-lsp-ping-parameters/		<http://www.iana.org/assignments/mpls-lsp-ping-parameters/
	mpls-lsp-ping-parameters.xhtml>.		mpls-lsp-ping-parameters.xhtml>.
	[IEEE802.1AX]		[IEEE802.1AX]
	IEEE Std. 802.1AX, "IEEE Standard for Local and		IEEE Std. 802.1AX, "IEEE Standard for Local and
	metropolitan area networks - Link Aggregation", November		metropolitan area networks - Link Aggregation", November
	2008.		2008.
			[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
			Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
			<https://www.rfc-editor.org/info/rfc5920>.
	[RFC7439] George, W., Ed. and C. Pignataro, Ed., "Gap Analysis for		[RFC7439] George, W., Ed. and C. Pignataro, Ed., "Gap Analysis for
	Operating IPv6-Only MPLS Networks", RFC 7439,		Operating IPv6-Only MPLS Networks", RFC 7439,
	DOI 10.17487/RFC7439, January 2015,		DOI 10.17487/RFC7439, January 2015,
	<https://www.rfc-editor.org/info/rfc7439>.		<https://www.rfc-editor.org/info/rfc7439>.
	[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for		[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
	Writing an IANA Considerations Section in RFCs", BCP 26,		Writing an IANA Considerations Section in RFCs", BCP 26,
	RFC 8126, DOI 10.17487/RFC8126, June 2017,		RFC 8126, DOI 10.17487/RFC8126, June 2017,
	<https://www.rfc-editor.org/info/rfc8126>.		<https://www.rfc-editor.org/info/rfc8126>.
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