draft-wijnands-mpls-mldp-node-protection-03.txt		draft-wijnands-mpls-mldp-node-protection-04.txt
	Network Working Group IJ. Wijnands, Ed.		Network Working Group IJ. Wijnands, Ed.
	Internet-Draft E. Rosen		Internet-Draft E. Rosen
	Intended status: Standards Track K. Raza		Intended status: Standards Track K. Raza
	Expires: December 23, 2013 Cisco Systems, Inc.		Expires: December 25, 2013 Cisco Systems, Inc.
	J. Tantsura		J. Tantsura
	Ericsson		Ericsson
	A. Atlas		A. Atlas
	Juniper Networks		Juniper Networks
	Q. Quintin		Q. Quintin
	Huawei Technology		Huawei Technology
	June 21, 2013		June 23, 2013
	mLDP Node Protection		mLDP Node Protection
	draft-wijnands-mpls-mldp-node-protection-03		draft-wijnands-mpls-mldp-node-protection-04
	Abstract		Abstract
	This document describes procedures to support node protection for		This document describes procedures to support node protection for
	Point-to-Multipoint and Multipoint-to-Multipoint Label Switched Paths		Point-to-Multipoint and Multipoint-to-Multipoint Label Switched Paths
	(MP LSPs) built by LDP ("Label Distribution Protocol"), or simply		(MP LSPs) built by LDP ("Label Distribution Protocol"), or simply
	mLDP. In order to protect a node N, the Point of Local Repair (PLR)		mLDP. In order to protect a node N, the Point of Local Repair (PLR)
	LSR of N must learn the Merge Point (MPT) LSR(s) of node N such that		LSR of N must learn the Merge Point (MPT) LSR(s) of node N such that
	traffic can be redirected to them in case node N fails. Redirecting		traffic can be redirected to them in case node N fails. Redirecting
	the traffic around the failed node N depends on existing P2P LSPs		the traffic around the failed node N depends on existing P2P LSPs
	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 http://datatracker.ietf.org/drafts/current/.		Drafts is at http://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 December 23, 2013.		This Internet-Draft will expire on December 25, 2013.
	Copyright Notice		Copyright Notice
	Copyright (c) 2013 IETF Trust and the persons identified as the		Copyright (c) 2013 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
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://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 25		skipping to change at page 2, line 25
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1. Conventions used in this document . . . . . . . . . . . . 3		1.1. Conventions used in this document . . . . . . . . . . . . 3
	1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
	2. PLR Determination . . . . . . . . . . . . . . . . . . . . . . 4		2. PLR Determination . . . . . . . . . . . . . . . . . . . . . . 4
	2.1. Transit node procedure . . . . . . . . . . . . . . . . . . 4		2.1. Transit node procedure . . . . . . . . . . . . . . . . . . 4
	2.2. MP2MP root node procedure . . . . . . . . . . . . . . . . 5		2.2. MP2MP root node procedure . . . . . . . . . . . . . . . . 5
	2.3. PLR information encoding . . . . . . . . . . . . . . . . . 5		2.3. PLR information encoding . . . . . . . . . . . . . . . . . 5
	3. Using the T-LDP session . . . . . . . . . . . . . . . . . . . 7		3. Using the tLDP session . . . . . . . . . . . . . . . . . . . . 7
	4. Link or node failure . . . . . . . . . . . . . . . . . . . . . 9		4. Link or node failure . . . . . . . . . . . . . . . . . . . . . 9
	4.1. Re-convergence after node/link failure . . . . . . . . . . 10		4.1. Re-convergence after node/link failure . . . . . . . . . . 10
	4.1.1. Node failure . . . . . . . . . . . . . . . . . . . . . 10		4.1.1. Node failure . . . . . . . . . . . . . . . . . . . . . 10
	4.1.2. Link failure . . . . . . . . . . . . . . . . . . . . . 11		4.1.2. Link failure . . . . . . . . . . . . . . . . . . . . . 10
	4.1.3. Switching to new primary path . . . . . . . . . . . . 11		4.1.3. Switching to new primary path . . . . . . . . . . . . 11
	5. mLDP Capabilities for Node Protection . . . . . . . . . . . . 11		5. mLDP Capabilities for Node Protection . . . . . . . . . . . . 11
	5.1. PLR capability . . . . . . . . . . . . . . . . . . . . . . 12		5.1. PLR capability . . . . . . . . . . . . . . . . . . . . . . 12
	5.2. MPT capability . . . . . . . . . . . . . . . . . . . . . . 12		5.2. MPT capability . . . . . . . . . . . . . . . . . . . . . . 12
	5.3. The Protected LSR . . . . . . . . . . . . . . . . . . . . 12		5.3. The Protected LSR . . . . . . . . . . . . . . . . . . . . 12
	5.4. The Node Protection Capability . . . . . . . . . . . . . . 13		5.4. The Node Protection Capability . . . . . . . . . . . . . . 13
	6. Security Considerations . . . . . . . . . . . . . . . . . . . 14		6. Security Considerations . . . . . . . . . . . . . . . . . . . 14
	7. IANA considerations . . . . . . . . . . . . . . . . . . . . . 14		7. IANA considerations . . . . . . . . . . . . . . . . . . . . . 14
	8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14		8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14		9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
	skipping to change at page 3, line 20		skipping to change at page 3, line 20
	mLDP. In order to protect a node N, the Point of Local Repair (PLR)		mLDP. In order to protect a node N, the Point of Local Repair (PLR)
	of N must learn the Merge Point (MPT) LSR(s) of node N such that		of N must learn the Merge Point (MPT) LSR(s) of node N such that
	traffic can be redirected to them in case node N fails. Redirecting		traffic can be redirected to them in case node N fails. Redirecting
	the traffic around the failed node N depends on existing P2P LSPs		the traffic around the failed node N depends on existing P2P LSPs
	originating from the PLR LSR to the MPT LSR(s) while bypassing node		originating from the PLR LSR to the MPT LSR(s) while bypassing node
	N. The procedures to setup these P2P LSPs are outside the scope of		N. The procedures to setup these P2P LSPs are outside the scope of
	this document, but one can imagine using RSVP-TE or LDP LFA based		this document, but one can imagine using RSVP-TE or LDP LFA based
	techniques to accomplish this.		techniques to accomplish this.
	The solution described in this document signals the MPT LSR(s) to the		The solution described in this document signals the MPT LSR(s) to the
	PLR LSR(s) via a Targeted LDP (T-LDP) session [RFC5036]. By having a		PLR LSR(s) via a Targeted LDP (tLDP) session [RFC5036]. By having a
	T-LDP session with the PLR, most of the (m)LDP features currently		tLDP session with the PLR, most of the (m)LDP features currently
	defined should just work, like Make-Before-Break (MBB), Graceful		defined should just work, like Make-Before-Break (MBB), Graceful
	Restart (GR), Typed Wildcard FEC support, etc. All this is achieved		Restart (GR), Typed Wildcard FEC support, etc. All this is achieved
	at the expense of having an additional T-LDP session between an MPT		at the expense of having an additional tLDP session between an MPT
	and PLR LSR.		and PLR LSR.
	1.1. Conventions used in this document		1.1. Conventions used in this document
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in RFC 2119 [RFC2119].		document are to be interpreted as described in RFC 2119 [RFC2119].
	The terms "node" is used to refer to an LSR and used interchangeably.		The terms "node" is used to refer to an LSR and used interchangeably.
	The terms "PLR" and "MPT" are used as shorthand to refer to "PLR LSR"		The terms "PLR" and "MPT" are used as shorthand to refer to "PLR LSR"
	skipping to change at page 3, line 48		skipping to change at page 3, line 48
	mLDP: Multipoint extensions to LDP.		mLDP: Multipoint extensions to LDP.
	PLR: Point of Local Repair (the LSR that redirects the traffic to		PLR: Point of Local Repair (the LSR that redirects the traffic to
	one or more Merge Point LSRs).		one or more Merge Point LSRs).
	MPT: Merge Point (the LSR that merges the backup LSP with primary		MPT: Merge Point (the LSR that merges the backup LSP with primary
	LSP. Note, there can be multiple MPT LSRs for a single MP-LSP		LSP. Note, there can be multiple MPT LSRs for a single MP-LSP
	node protection).		node protection).
	T-LDP: Targeted LDP session.		tLDP: Targeted LDP session.
	MP LSP: Multi-Point LSP (either a P2MP or MP2MP LSP).		MP LSP: Multi-Point LSP (either a P2MP or MP2MP LSP).
	2. PLR Determination		2. PLR Determination
	In order for a MPT to establish a T-LDP session with the PLR, it		In order for a MPT to establish a tLDP session with the PLR, it first
	first has to learn the PLR for a particular MP LSP. It is the		has to learn the PLR for a particular MP LSP. It is the
	responsibility of the protected node N to advertise the PLR address		responsibility of the protected node N to advertise the PLR address
	to the MPT. The PLR address for a MP LSP on node N is the address of		to the MPT. The PLR address for a MP LSP on node N is the address of
	the upstream LDP peer, but only when node N is NOT the root node of		the upstream LDP peer, but only when node N is NOT the root node of
	the MP2MP LSP. If node N is the root node, the procedures are		the MP2MP LSP. If node N is the root node, the procedures are
	slightly different as described in Section 2.2. The procedures that		slightly different as described in Section 2.2. The procedures that
	follow assume that all the participating nodes (N, PLRs, MPTs) are		follow assume that all the participating nodes (N, PLRs, MPTs) are
	enabled (e.g. by a user configuration) to support and implement this		enabled (e.g. by a user configuration) to support and implement this
	feature.		feature.
	2.1. Transit node procedure		2.1. Transit node procedure
	skipping to change at page 6, line 9		skipping to change at page 6, line 9
	The upstream LSR address is conveyed via an LDP Notification message		The upstream LSR address is conveyed via an LDP Notification message
	with MP Status, where the MP status contains a new "PLR Status Value		with MP Status, where the MP status contains a new "PLR Status Value
	Element" that specifies the address of the PLR.		Element" that specifies the address of the PLR.
	The new "PLR Status Value Element" is encoded as follows;		The new "PLR Status Value Element" is encoded as follows;
	PLR Status Element:		PLR Status Element:
	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 | Address ~		| Type = TBA-1 | Length | Addr Family |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Family | Num PLR entry | |		| Addr Fam cont | Num PLR entry | |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
	| |		| |
	| PLR entry (0 or more) ~		| PLR entry (0 or more) ~
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Where		Where
	Type: PLR (Type=3 to be assigned by IANA)		Type: PLR Status Value Element (Type TBA-1 to be assigned by IANA)
	Length: The Length field encodes the length of the Status Value		Length: The Length field encodes the length of the Status Value
	following the Length field. The encoded Length varies based on		following the Length field. The encoded Length varies based on
	the Address Family and the number of PLR entries.		the Address Family and the number of PLR entries.
	Address Family: Two octet quantity containing a value from IANA's		Address Family: Two octet quantity containing a value from IANA's
	"Address Family Numbers" registry that encodes the address family		"Address Family Numbers" registry that encodes the address family
	for the PLR Address encoded in the PLR entry.		for the PLR Address encoded in the PLR entry.
	Num PLR entry: Number of "PLR entries" encoded in the Status Value		Num PLR entry: Number of "PLR entries" encoded in the Status Value
	Element, followed by "Num PLR entry" field (please see format of a		Element, followed by "Num PLR entry" field (please see format of a
	PLR entry below).		PLR entry below).
	The format of a "PLR Entry" is as follows::		The format of a "PLR Entry" is as follows:
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|A| Reserved | PLR address ~		|A| Reserved | PLR address |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ |		~ PLR address (cont) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Where		Where
	A bit: 0 = Withdraw, 1 = Add.		A bit: 0 = Withdraw, 1 = Add.
	Reserved: 15 bits, must be zero on transmit and ignored on receipt		Reserved: 15 bits, must be zero on transmit and ignored on receipt
	PLR address: PLR Address encoded according to Address Family field		PLR address: PLR Address encoded according to Address Family field
	encoded in the PLR Status Value Element.		encoded in the PLR Status Value Element.
	skipping to change at page 7, line 27		skipping to change at page 7, line 27
	address is likely due to a link failure, see the procedures as		address is likely due to a link failure, see the procedures as
	documented in Section 4.1. To remove all PLR addresses belonging to		documented in Section 4.1. To remove all PLR addresses belonging to
	the encoded Address Family, an LSR N MUST encode PLR Status Value		the encoded Address Family, an LSR N MUST encode PLR Status Value
	Element with no PLR entry and "Num PLR entry" field MUST be set to		Element with no PLR entry and "Num PLR entry" field MUST be set to
	zero.		zero.
	Along with the PLR MP Status a MP FEC TLV MUST be included in the LDP		Along with the PLR MP Status a MP FEC TLV MUST be included in the LDP
	Notification message so that a receiver is able to associate the PLR		Notification message so that a receiver is able to associate the PLR
	Status with the MP LSP.		Status with the MP LSP.
	3. Using the T-LDP session		3. Using the tLDP session
	The receipt of a PLR MP Status (with PLR addresses) for a MP LSP on a		The receipt of a PLR MP Status (with PLR addresses) for a MP LSP on a
	receiving LSR makes it an MPT for node protection. If not already		receiving LSR makes it an MPT for node protection. If not already
	established, the MPT LSR MUST establish a T-LDP session with all of		established, the MPT LSR MUST establish a tLDP session with all of
	the learned PLR addresses using the procedures as documented in		the learned PLR addresses using the procedures as documented in
	[I-D.ietf-mpls-targeted-mldp].		[I-D.ietf-mpls-targeted-mldp].
	Using Figure 1 as the reference topology, let us assume that both		Using Figure 1 as the reference topology, let us assume that both
	LSR2 and LSR3 are MPTs and have established a T-LDP session with the		LSR2 and LSR3 are MPTs and have established a tLDP session with the
	PLR being LSR1. Assume that both LSR2 and LSR3 have a FEC <R,X> with		PLR being LSR1. Assume that both LSR2 and LSR3 have a FEC <R,X> with
	a upstream LSR N and label Ln assigned to FEC towards N. The MPTs		a upstream LSR N and label Ln assigned to FEC towards N. The MPTs
	will create a secondary upstream LSR (using the received PLR address)		will create a secondary upstream LSR (using the received PLR address)
	and assigned a Label Lpx to FEC <R,X> towards PLR for it. The MPTs		and assigned a Label Lpx to FEC <R,X> towards PLR for it. The MPTs
	will do that for each PLR address that was learned for the MP LSP.		will do that for each PLR address that was learned for the MP LSP.
	In this example, the MPTs will have a FEC <R,X> with two local labels		In this example, the MPTs will have a FEC <R,X> with two local labels
	associated with it. Ln that was assigned to N via the normal mLDP		associated with it. Ln that was assigned to N via the normal mLDP
	procedures, and Label Lpx that was assigned for PLR (LSR1) for the		procedures, and Label Lpx that was assigned for PLR (LSR1) for the
	purpose of node protecting MP LSP via node N. Note, when the		purpose of node protecting MP LSP via node N. Note, when the
	protected node is a MP2MP root node, there will be an upstream LSR		protected node is a MP2MP root node, there will be an upstream LSR
	for each PLR address that was advertised along with a unique Label		for each PLR address that was advertised along with a unique Label
	Lpx.		Lpx.
	It is not preferable that a PLR is always sending traffic to an MPT		The receipt of a FEC Label Mapping alone over the tLDP session from
	over the backup P2P LSP. The PLR should only send traffic over the		MPT on a PLR conveys the label information but does not convey the
	backup P2P LSP if node N fails. The receipt of a FEC Label Mapping		node being protected. The information about a protected node is
	alone over the T-LDP session from MPT on a PLR conveys the label		known to the MPT LSR and needs to be communicated to the PLR as well.
	information but does not convey the node being protected. The		For this reason, the FEC Label Mapping (FEC <R,X> : Lpx) sent by the
	information about a protected node is known to the MPT LSR and needs		MPT over the tLDP session to the PLR MUST include a Status TLV with
	to be communicated to the PLR as well. For this reason, the FEC		MP Status including a new LDP MP status Value Element called the
	Label Mapping (FEC <R,X> : Lpx) sent by the MPT over the T-LDP		"Protected Node Status Value Element". This new value element is
	session to the PLR MUST include a Status TLV with MP Status including		used to specify the address of the node being protected. The
	a new LDP MP status Value Element called the "Protected Node Status		"Protected Node Status Value Element" has the following format;
	Value Element". This new value element is used to specify the
	address of the node being protected. The "Protected Node Status
	Value Element" has the following format;
	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 = 4 | Length | Address Family		| Type = TBA-2 | Length | Addr Family |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Node address ~		| Addr Fam cont | Node address |
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			| Node address continued |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ |
	+-+-+-+-+-+-+-+-+
	Type : Protected Node (Type = 4 to be assigned by IANA)		Type : Protected Node Status Value Element (Type TBA-2 to be
			assigned by IANA)
	Length: The Length field encodes the length of the Status Value		Length: The Length field encodes the length of the Status Value
	following the Length field. The encoded Length varies based on		following the Length field. The encoded Length varies based on
	the Address Family and is 4 octets and 16 octets respectively for		the Address Family and is 6 octets (for Address Family + IPv4
	an IPv4 address and an IPv6 address.		address and 18 octets for Address Family + IPv6 address.
	Address Family: Two octet quantity containing a value from IANA's		Address Family: Two octet quantity containing a value from IANA's
	"Address Family Numbers" registry that encodes the address family		"Address Family Numbers" registry that encodes the address family
	for the Node Address.		for the Node Address.
	Node address: Protected node address encoded according to Address		Node address: Protected node address encoded according to Address
	Family field.		Family field.
	When a PLR receives a Label Mapping for FEC <R,X> that includes a		When a PLR receives a Label Mapping for FEC <R,X> that includes a
	Protected Node Status, it will only use that label binding once the		Protected Node Status, it will only use that label binding once the
	skipping to change at page 11, line 34		skipping to change at page 11, line 28
	The network will eventually re-converge and a new best path to the		The network will eventually re-converge and a new best path to the
	root will be found by LSR2 and LSR3. LSR2 will find that P is its		root will be found by LSR2 and LSR3. LSR2 will find that P is its
	new primary upstream LSR to reach the Root and LSR3 will find Q. Note		new primary upstream LSR to reach the Root and LSR3 will find Q. Note
	that although the current active upstream LSR can either be node N or		that although the current active upstream LSR can either be node N or
	LSR1 (depending on link or node failure), it does not matter for the		LSR1 (depending on link or node failure), it does not matter for the
	following procedures. Both LSR2 and LSR3 SHOULD use the Make-Before-		following procedures. Both LSR2 and LSR3 SHOULD use the Make-Before-
	Break (MBB) procedures as described in [RFC6388] section 8 to switch		Break (MBB) procedures as described in [RFC6388] section 8 to switch
	to the new primary upstream node. As soon as the new primary		to the new primary upstream node. As soon as the new primary
	upstream LSRs P and Q are activated, a Label Withdraw message MUST be		upstream LSRs P and Q are activated, a Label Withdraw message MUST be
	sent to the old upstream LSR. Note that an upstream LSR switchover		sent to the old upstream LSR. Note that an upstream LSR switchover
	from a T-LDP neighbor to a directly connected LDP neighbor is no		from a tLDP neighbor to a directly connected LDP neighbor is no
	different compared to switching between two directly connected		different compared to switching between two directly connected
	neighbors. After the Label Withdraw message has been received by		neighbors. After the Label Withdraw message has been received by
	LSR1 or node N, forwarding will stop and a Label Release will be		LSR1 or node N, forwarding will stop and a Label Release will be
	sent.		sent.
	When it is determined that after re-convergence there is no more		When it is determined that after re-convergence there is no more
	interest in the T-LDP session between the MPT and the PLR, the T-LDP		interest in the tLDP session between the MPT and the PLR, the tLDP
	session MAY be taken down. It is possible that having no more		session MAY be taken down. It is possible that having no more
	interest in the T-LDP session is temporarily due to link flapping.		interest in the tLDP session is temporarily due to link flapping. In
	In order to avoid the T-LDP session from flapping, it is RECOMMENDED		order to avoid the tLDP session from flapping, it is RECOMMENDED to
	to apply a delay before tearing down the session. Determining the		apply a delay before tearing down the session. Determining the delay
	delay is a local implementation matter.		is a local implementation matter.
	5. mLDP Capabilities for Node Protection		5. mLDP Capabilities for Node Protection
	In order to describe the capabilities of the participating LSRs , we		In order to describe the capabilities of the participating LSRs , we
	are organizing it per role in the network i.e., Point of Local Repair		are organizing it per role in the network i.e., Point of Local Repair
	(PLR), Merge Point (MPT), and Protected Node (as depicted in Fig 1).		(PLR), Merge Point (MPT), and Protected Node (as depicted in Fig 1).
	5.1. PLR capability		5.1. PLR capability
	A PLR node should handle the following conditions;		A PLR node should handle the following conditions;
	1. Accept an incoming T-LDP session from the MPT LSR.		1. Accept an incoming tLDP session from the MPT LSR.
	2. Support the receipt of a "Protected Node Status Value Element"		2. Support the receipt of a "Protected Node Status Value Element"
	status in a MP Status TLV over T-LDP session.		status in a MP Status TLV over tLDP session.
	3. Upon node failure detection, capable of switching traffic towards		3. Upon node failure detection, capable of switching traffic towards
	one or more MPT(s) over P2P LSP (bypassing N) using the labels		one or more MPT(s) over P2P LSP (bypassing N) using the labels
	previously advertised for MP LSPs over the T-LDP session.		previously advertised for MP LSPs over the tLDP session.
	An LSR capable of performing these actions will advertise it self as		An LSR capable of performing these actions will advertise it self as
	PLR capable in the Node Protection capability (see Section 5.4).		PLR capable in the Node Protection capability (see Section 5.4).
	This is a unidirectional capability announced from PLR to the		This is a unidirectional capability announced from PLR to the
	protected LSR.		protected LSR.
	5.2. MPT capability		5.2. MPT capability
	An MPT node should handle the following conditions;		An MPT node should handle the following conditions;
	skipping to change at page 13, line 9		skipping to change at page 13, line 7
	The protected LSR does not advertise any capability for mLDP Node		The protected LSR does not advertise any capability for mLDP Node
	Protection because it does not need to receive any of the defined MP		Protection because it does not need to receive any of the defined MP
	Status values as described above. However, the protected node does		Status values as described above. However, the protected node does
	play an important role in the signaling and setup of the node		play an important role in the signaling and setup of the node
	protection. For a given FEC, the protected node can only send PLR		protection. For a given FEC, the protected node can only send PLR
	information to a downstream LSR if the PLR has signaled the PLR		information to a downstream LSR if the PLR has signaled the PLR
	capability and the downstream LSR has signaled the MPT capability.		capability and the downstream LSR has signaled the MPT capability.
	When the downstream LSR (acting as MPT) receives the PLR status, it		When the downstream LSR (acting as MPT) receives the PLR status, it
	can implicitly infer that the advertised LSR(s) are PLR capable. The		can implicitly infer that the advertised LSR(s) are PLR capable. The
	MPT LSR can now proceed with setting up a T-LDP session with the		MPT LSR can now proceed with setting up a tLDP session with the
	PLR(s) and MP LSP node protection signaling.		PLR(s) and MP LSP node protection signaling.
	5.4. The Node Protection Capability		5.4. The Node Protection Capability
	We define a single capability "MP Node Protection Capability" to		We define a single capability "MP Node Protection Capability" to
	announce the PLR and MPT capability.		announce the PLR and MPT capability.
	The format of the capability parameter TLV is as follows:		The format of the capability parameter TLV is as follows:
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| MP Node Prot Cap. (IANA) | Length = 2 |		|U|F| Type = TBA-3 | Length = 2 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|S| Reserved |P|M| Reserved |		|S| Reserved |P|M| Reserved |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Where		Where
	U/F bits: MUST be set to 1 and 0 respectively (as per [RF5561])		U/F bits: MUST be set to 1 and 0 respectively (as per [RFC5561])
	MP Node Protection Capability: TLV type (value to be assigned by		Type: MP Node Protection Capability (Type = TBA-3 to be assigned
	IANA)		by IANA)
	Length: MUST be set to 2.		Length: MUST be set to 2.
	S bit: Set to 1 to announce and 0 to withdraw the capability (as		S bit: Set to 1 to announce and 0 to withdraw the capability (as
	per [RFC5561])		per [RFC5561])
	P bit: PLR capable for MP LSP node protection		P bit: PLR capable for MP LSP node protection
	M bit: MPT capable for MP LSP node protection		M bit: MPT capable for MP LSP node protection
	skipping to change at page 14, line 20		skipping to change at page 14, line 17
	to its peers with both "P" and "M" bit set.		to its peers with both "P" and "M" bit set.
	6. Security Considerations		6. Security Considerations
	The same security considerations apply as those for the base mLDP		The same security considerations apply as those for the base mLDP
	specification, as described in [RFC6388].		specification, as described in [RFC6388].
	7. IANA considerations		7. IANA considerations
	IANA is requested to allocate two new code points from the "LDP MP		IANA is requested to allocate two new code points from the "LDP MP
	Status Value Element type" registry;		Status Value Element type" registry within the Label Distribution
			Protocol (LDP) Parameters;
	PLR Status Value Element - 3
	Protected Node Status Value Element - 4		Value | Name | Reference
			------+----------------------------------------+-----------
			TBA-1 | PLR Status Value Element | this doc
			------+----------------------------------------+-----------
			TBA-2 | Protected Node Status Value Element | this doc
	IANA is requested to assign one new code points for a new Capability		IANA is requested to assign a new code points for a new Capability
	Parameter TLVs from the LDP registry "TLV Type Name Space",		Parameter TLV. The code point should be assigned from the IETF
	corresponding to the advertisement of the the new MP Status values.		Consensus range of the "TLV Type Name Space" registry within the LDP
	The values is:		Parameters. The lowest available new code point after 0x0970 should
			be used.
	MP Node Protection Capability - TBD		Value | Description | Reference | Notes/Reg Date
			------+-------------------------------+-----------+---------------
			TBA-3 | MP Node Protection Capability | This doc |
	8. Acknowledgments		8. Acknowledgments
	The authors like to thank Nagendra Kumar, Duan Hong, Martin Vigoureux		The authors like to thank Nagendra Kumar, Duan Hong, Martin
	and Kenji Fujihira for their comments on this draft.		Vigoureux, Kenji Fujihira and Loa Andersson for their comments on
			this draft.
	9. References		9. References
	9.1. Normative References		9.1. 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, March 1997.		Requirement Levels", BCP 14, RFC 2119, March 1997.
	[RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP		[RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP
	Specification", RFC 5036, October 2007.		Specification", RFC 5036, October 2007.
	skipping to change at page 15, line 14		skipping to change at page 15, line 19
	"Label Distribution Protocol Extensions for Point-to-		"Label Distribution Protocol Extensions for Point-to-
	Multipoint and Multipoint-to-Multipoint Label Switched		Multipoint and Multipoint-to-Multipoint Label Switched
	Paths", RFC 6388, November 2011.		Paths", RFC 6388, November 2011.
	[RFC5561] Thomas, B., Raza, K., Aggarwal, S., Aggarwal, R., and JL.		[RFC5561] Thomas, B., Raza, K., Aggarwal, S., Aggarwal, R., and JL.
	Le Roux, "LDP Capabilities", RFC 5561, July 2009.		Le Roux, "LDP Capabilities", RFC 5561, July 2009.
	[I-D.ietf-mpls-targeted-mldp]		[I-D.ietf-mpls-targeted-mldp]
	Napierala, M. and E. Rosen, "Using LDP Multipoint		Napierala, M. and E. Rosen, "Using LDP Multipoint
	Extensions on Targeted LDP Sessions",		Extensions on Targeted LDP Sessions",
	draft-ietf-mpls-targeted-mldp-00 (work in progress),		draft-ietf-mpls-targeted-mldp-01 (work in progress),
	August 2012.		January 2013.
	9.2. Informative References		9.2. Informative References
	[RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute		[RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute
	Extensions to RSVP-TE for LSP Tunnels", RFC 4090,		Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
	May 2005.		May 2005.
	Authors' Addresses		Authors' Addresses
	IJsbrand Wijnands (editor)		IJsbrand Wijnands (editor)
End of changes. 40 change blocks.
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