draft-ietf-mpls-lsp-ping-lag-multipath-07.txt		draft-ietf-mpls-lsp-ping-lag-multipath-08.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: October 5, 2019 S. Litkowski		Expires: October 6, 2019 S. Litkowski
	B. Decraene		B. Decraene
	Orange		Orange
	J. Drake		J. Drake
	Juniper Networks		Juniper Networks
	M. Chen		M. Chen
	Huawei		Huawei
	April 03, 2019		April 04, 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-07		draft-ietf-mpls-lsp-ping-lag-multipath-08
	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 October 5, 2019.		This Internet-Draft will expire on October 6, 2019.
	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 4, line 37 ¶		skipping to change at page 4, line 37 ¶
	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 new TLV to discover the capabilities of a		This document defines a new TLV to discover the capabilities of a
	responder LSR and extensions for use with the MPLS LSP Ping and		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
	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 new LSR Capability TLV to indicate that separate load		and the new 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 LSR capability		MPLS echo reply. The Responder LSR places the same LSR Capability
	TLV in the MPLS echo reply to provide acknowledgement back to the		TLV in the MPLS echo reply to provide acknowledgement back to the
	initiator LSR. It also adds, for each downstream LAG member, load		initiator LSR. It also adds, for each downstream LAG member, load
	balance information (i.e., multipath information and interface		balance information (i.e., multipath information and interface
	index). This mechanism is applicable to all types of LSPs which can		index). This mechanism is applicable to all types of LSPs which can
	traverse over LAG interfaces. Many LAGs are built from p2p links,		traverse over LAG interfaces. Many LAGs are built from p2p links,
	with router X and router X+1 having direct connectivity and the same		with router X and router X+1 having direct connectivity and the same
	number of LAG members. It is possible to build LAGs asymmetrically		number of LAG members. It is possible to build LAGs asymmetrically
	by using Ethernet switches between two routers. Appendix A lists		by using Ethernet switches between two routers. Appendix A lists
	some use cases for which the mechanisms defined in this document may		some use cases for which the mechanisms defined in this document may
	not be applicable. Note that the mechanisms described in this		not be applicable. Note that the mechanisms described in this
	skipping to change at page 6, line 23 ¶		skipping to change at page 6, line 23 ¶
	3. LSR Capability Discovery		3. LSR Capability Discovery
	The MPLS Ping operates by an initiator LSR sending an MPLS echo		The MPLS Ping operates by an initiator LSR sending an MPLS echo
	request message and receiving back a corresponding MPLS echo reply		request message and receiving back a corresponding MPLS echo reply
	message from a responder LSR. The MPLS Traceroute operates in a		message from a responder LSR. The MPLS Traceroute operates in a
	similar way except the initiator LSR potentially sends multiple MPLS		similar way except the initiator LSR potentially sends multiple MPLS
	echo request messages with incrementing TTL values.		echo request messages with incrementing TTL values.
	There have been many extensions to the MPLS Ping and Traceroute		There have been many extensions to the MPLS Ping and Traceroute
	mechanism over the years. Thus it is often useful, and sometimes		mechanisms over the years. Thus it is often useful, and sometimes
	necessary, for the initiator LSR to deterministically disambiguate		necessary, for the initiator LSR to deterministically disambiguate
	the differences between:		the differences between:
	o The responder LSR sent the MPLS echo reply message with contents C		o The responder LSR sent the MPLS echo reply message with contents C
	because it has feature X, Y and Z implemented.		because it has feature X, Y and Z implemented.
	o The responder LSR sent the MPLS echo reply message with contents C		o The responder LSR sent the MPLS echo reply message with contents C
	because it has subset of features X, Y and Z implemented but not		because it has subset of features X, Y and Z implemented but not
	all.		all.
	skipping to change at page 7, line 48 ¶		skipping to change at page 7, line 48 ¶
	4. Mechanism to Discover L2 ECMP Multipath		4. Mechanism to Discover L2 ECMP Multipath
	4.1. Initiator LSR Procedures		4.1. Initiator LSR Procedures
	Through the "LSR Capability Discovery" as defined in Section 3, the		Through the "LSR Capability Discovery" as defined in Section 3, the
	initiator LSR can understand whether the responder LSR can describe		initiator LSR can understand whether the responder LSR can describe
	incoming/outgoing LAG member links separately in the DDMAP TLV.		incoming/outgoing LAG member links separately in the DDMAP TLV.
	Once the initiator LSR knows that a responder can support this		Once the initiator LSR knows that a responder can support this
	meachanims, then it sends an MPLS echo request carrying a DDMAP TLV		mechanism, then it sends an MPLS echo request carrying a DDMAP TLV
	with the "LAG Description Indicator flag" (G) set to the responder		with the "LAG Description Indicator flag" (G) set to the responder
	LSR. The "LAG Description Indicator flag" (G) indicates that		LSR. The "LAG Description Indicator flag" (G) indicates that
	separate load balancing information for each L2 nexthop over a LAG is		separate load balancing information for each L2 nexthop over a LAG is
	desired in the MPLS echo reply. The new "LAG Description Indicator		desired in the MPLS echo reply. The new "LAG Description Indicator
	flag" is described in Section 7.		flag" is described in Section 7.
	4.2. Responder LSR Procedures		4.2. Responder LSR Procedures
	When a responder LSR received an MPLS echo request message with the		When a responder LSR received an MPLS echo request message with the
	"LAG Description Indicator flag" set in the DDMAP TLV, if the		"LAG Description Indicator flag" set in the DDMAP TLV, if the
	responder LSR understands the "LAG Description Indicator flag" and is		responder LSR understands the "LAG Description Indicator flag" and is
	capable of describing outgoing LAG member links separately, the		capable of describing outgoing LAG member links separately, the
	following procedures are used, regardless of whether or not outgoing		following procedures are used, regardless of whether or not outgoing
	interfaces include LAG interfaces:		interfaces include LAG interfaces:
	o For each downstream that is a LAG interface:		o For each downstream that is a LAG interface:
	* The responder LSR MUST include a DDMAP TLV when sending the		* The responder LSR MUST include a DDMAP TLV when sending the
	MPLS echo reply.There is a single DDMAP TLV for the LAG		MPLS echo reply. There is a single DDMAP TLV for the LAG
	interface, with member links described using sub-TLVs.		interface, with member links described using sub-TLVs.
	* The responder LSR MUST set the "LAG Description Indicator flag"		* The responder LSR MUST set the "LAG Description Indicator flag"
	in the DS Flags field of the DDMAP TLV.		in the DS Flags field of the DDMAP TLV.
	* In the DDMAP TLV, the Local Interface Index Sub-TLV, Remote		* In the DDMAP TLV, the Local Interface Index Sub-TLV, Remote
	Interface Index Sub-TLV and Multipath Data Sub-TLV are used to		Interface Index Sub-TLV and Multipath Data Sub-TLV are used to
	describe each LAG member link. All other fields of the DDMAP		describe each LAG member link. All other fields of the DDMAP
	TLV are used to describe the LAG interface.		TLV are used to describe the LAG interface.
	skipping to change at page 9, line 9 ¶		skipping to change at page 9, line 9 ¶
	outside the scope of this document.		outside the scope of this document.
	+ 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 except as follows. A
	MAY also have a corresponding Remote Interface Index Sub-TLV. When a		LAG member link MAY also have a corresponding Remote Interface Index
	Local Interface Index Sub-TLV, a Remote Interface Index-Sub-TLV and a		Sub-TLV. When a Local Interface Index Sub-TLV, a Remote Interface
	Multipath Data Sub-TLV are placed in the DDMAP TLV to describe a LAG		Index-Sub-TLV and a Multipath Data Sub-TLV are placed in the DDMAP
	member link, they MUST be placed in the order of Local Interface		TLV to describe a LAG member link, they MUST be placed in the order
	Index Sub-TLV, Remote Interface Index-Sub-TLV and Multipath Data Sub-		of Local Interface Index Sub-TLV, Remote Interface Index-Sub-TLV and
	TLV. The block of local interface index, (optional remote interface		Multipath Data Sub-TLV. The block of local interface index,
	index) and multipath data sub-TLVs for each member link MUST appear		(optional remote interface index) and multipath data sub-TLVs for
	adjacent to each other in order of increasing local interface index.		each member link MUST appear adjacent to each other in order of
			increasing local interface index.
	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
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ DDMAP fields describing LAG interface with DS Flags G set ~		~ DDMAP fields describing LAG interface with DS Flags G set ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Local Interface Index Sub-TLV of LAG member link #1 |		| Local Interface Index Sub-TLV of LAG member link #1 |
	skipping to change at page 16, line 19 ¶		skipping to change at page 16, line 19 ¶
	G LAG Description Indicator		G LAG Description Indicator
	When this flag is set in the MPLS echo request, the responder LSR		When this flag is set in the MPLS echo request, the responder LSR
	is requested to respond with detailed LAG information. When this		is requested to respond with detailed LAG information. When this
	flag is set in the MPLS echo reply, the corresponding DDMAP TLV		flag is set in the MPLS echo reply, the corresponding DDMAP TLV
	describes a LAG interface.		describes a LAG interface.
	8. Local Interface Index Sub-TLV		8. Local Interface Index Sub-TLV
	The Local Interface Index Sub-TLV is an optional TLV, it describes		The Local Interface Index Sub-TLV describes the interface index
	the interface index assigned by the local LSR to an egress interface.		assigned by the local LSR to an egress interface. One or more Local
	One or more Local Interface Index sub-TLVs MAY appear in a DDMAP TLV.		Interface Index sub-TLVs MAY appear in a DDMAP TLV.
	The format of the Local Interface Index Sub-TLV is below:		The format of the Local Interface Index Sub-TLV is below:
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Type | Length |		| Type | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Local Interface Index |		| Local Interface Index |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	skipping to change at page 21, line 42 ¶		skipping to change at page 21, line 42 ¶
	attacks only have a small window of opportunity. If these messages		attacks only have a small window of opportunity. If these messages
	are indeed hijacked (non-delivery) by an intermediate node, the use		are indeed hijacked (non-delivery) by an intermediate node, the use
	of these mechanisms will determine the data plane is not working (as		of these mechanisms will determine the data plane is not working (as
	it should). Hijacking of a responder node such that it provides a		it should). Hijacking of a responder node such that it provides a
	legitimate reply would involve compromising the node itself and the		legitimate reply would involve compromising the node itself and the
	MPLS control domain. [RFC5920] provides additional MPLS network-wide		MPLS control domain. [RFC5920] provides additional MPLS network-wide
	operation recommendations to avoid attacks and recommendations to		operation recommendations to avoid attacks and recommendations to
	follow. Please note that source IP address filtering provides only a		follow. Please note that source IP address filtering provides only a
	weak form of access control and is not, in general, a reliable		weak form of access control and is not, in general, a reliable
	security mechanism. Nonetheless, it is required here in the absence		security mechanism. Nonetheless, it is required here in the absence
	of any more robust mechanism that might be used.		of any more robust mechanisms that might be used.
	13. IANA Considerations		13. IANA Considerations
	13.1. LSR Capability TLV		13.1. LSR Capability TLV
	The IANA is requested to assign new value TBD1 (from the range		The IANA is requested to assign new value TBD1 (from the range
	4-16383) for LSR Capability TLV from the "Multiprotocol Label		4-16383) for LSR Capability TLV from the "Multiprotocol Label
	Switching Architecture (MPLS) Label Switched Paths (LSPs) Ping		Switching Architecture (MPLS) Label Switched Paths (LSPs) Ping
	Parameters - TLVs" registry.		Parameters - TLVs" registry.
	skipping to change at page 25, line 5 ¶		skipping to change at page 25, line 5 ¶
	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 mechanisms. 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.
	15. References		15. References
	15.1. 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,
End of changes. 13 change blocks.
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