< draft-ietf-teas-gmpls-resource-sharing-proc-07.txt		draft-ietf-teas-gmpls-resource-sharing-proc-08.txt >
	TEAS Working Group X. Zhang		TEAS Working Group X. Zhang
	Internet-Draft H. Zheng, Ed.		Internet-Draft H. Zheng, Ed.
	Intended Status: Informational Huawei Technologies		Intended Status: Informational Huawei Technologies
	Expires: July 18, 2017 R. Gandhi, Ed.		Expires: July 30, 2017 R. Gandhi, Ed.
	Z. Ali		Z. Ali
	Cisco Systems, Inc.		Cisco Systems, Inc.
	P. Brzozowski		P. Brzozowski
	ADVA Optical		ADVA Optical
	January 14, 2017		January 26, 2017
	RSVP-TE Signaling Procedure for End-to-End GMPLS Restoration and		RSVP-TE Signaling Procedure for End-to-End GMPLS Restoration and
	Resource Sharing		Resource Sharing
	draft-ietf-teas-gmpls-resource-sharing-proc-07		draft-ietf-teas-gmpls-resource-sharing-proc-08
	Abstract		Abstract
	In non-packet transport networks, there are requirements where		In non-packet transport networks, there are requirements where
	Generalized Multi-Protocol Label Switching (GMPLS) end-to-end		Generalized Multi-Protocol Label Switching (GMPLS) end-to-end
	recovery scheme needs to employ restoration Label Switched Path (LSP)		recovery scheme needs to employ restoration Label Switched Path (LSP)
	while keeping resources for the working and/or protecting LSPs		while keeping resources for the working and/or protecting LSPs
	reserved in the network after the failure occurs.		reserved in the network after the failure occurs.
	This document reviews how the LSP association is to be provided using		This document reviews how the LSP association is to be provided using
	skipping to change at page 2, line 36 ¶		skipping to change at page 2, line 36 ¶
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Conventions Used in This Document . . . . . . . . . . . . . . 4		2. Conventions Used in This Document . . . . . . . . . . . . . . 4
	2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4		2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
	2.2. Acronyms and Abbreviations . . . . . . . . . . . . . . . . 4		2.2. Acronyms and Abbreviations . . . . . . . . . . . . . . . . 4
	3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4		3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
	3.1. Examples of Restoration Schemes . . . . . . . . . . . . . 5		3.1. Examples of Restoration Schemes . . . . . . . . . . . . . 5
	3.1.1. 1+R Restoration . . . . . . . . . . . . . . . . . . . 5		3.1.1. 1+R Restoration . . . . . . . . . . . . . . . . . . . 5
	3.1.2. 1+1+R Restoration . . . . . . . . . . . . . . . . . . 5		3.1.2. 1+1+R Restoration . . . . . . . . . . . . . . . . . . 5
	3.1.2.1. 1+1+R Restoration - Variants . . . . . . . . . . . 6		3.1.2.1. 1+1+R Restoration - Variants . . . . . . . . . . . 6
	3.2. Resource Sharing By Restoration LSP . . . . . . . . . . . 7		3.2. Resource Sharing by Restoration LSP . . . . . . . . . . . 7
	4. RSVP-TE Signaling Procedure . . . . . . . . . . . . . . . . . 7		4. RSVP-TE Signaling Procedure . . . . . . . . . . . . . . . . . 8
	4.1. Restoration LSP Association . . . . . . . . . . . . . . . 7		4.1. Restoration LSP Association . . . . . . . . . . . . . . . 8
	4.2. Resource Sharing-based Restoration LSP Setup . . . . . . . 8		4.2. Resource Sharing-based Restoration LSP Setup . . . . . . . 8
	4.3. LSP Reversion . . . . . . . . . . . . . . . . . . . . . . 9		4.3. LSP Reversion . . . . . . . . . . . . . . . . . . . . . . 10
	4.3.1. Make-while-break Reversion . . . . . . . . . . . . . . 10		4.3.1. Make-while-break Reversion . . . . . . . . . . . . . . 10
	4.3.2. Make-before-break Reversion . . . . . . . . . . . . . 11		4.3.2. Make-before-break Reversion . . . . . . . . . . . . . 11
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 12		5. Security Considerations . . . . . . . . . . . . . . . . . . . 12
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12		6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
	7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13		7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
	7.1. Normative References . . . . . . . . . . . . . . . . . . . 13		7.1. Normative References . . . . . . . . . . . . . . . . . . . 13
	7.2. Informative References . . . . . . . . . . . . . . . . . . 13		7.2. Informative References . . . . . . . . . . . . . . . . . . 13
	Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . 14		Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . 14
	Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . 14		Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
	skipping to change at page 3, line 32 ¶		skipping to change at page 3, line 32 ¶
	Path message to identify the LSPs for restoration. Also, an		Path message to identify the LSPs for restoration. Also, an
	ASSOCIATION object with Association Type "Resource Sharing" [RFC4873]		ASSOCIATION object with Association Type "Resource Sharing" [RFC4873]
	can be signaled in the RSVP Path message to identify the LSPs for		can be signaled in the RSVP Path message to identify the LSPs for
	resource sharing. [RFC6689] Section 2.2 reviews the procedure for		resource sharing. [RFC6689] Section 2.2 reviews the procedure for
	providing LSP associations for GMPLS end-to-end recovery and Section		providing LSP associations for GMPLS end-to-end recovery and Section
	2.4 reviews the procedure for providing LSP associations for sharing		2.4 reviews the procedure for providing LSP associations for sharing
	resources.		resources.
	Generally GMPLS end-to-end recovery schemes have the restoration LSP		Generally GMPLS end-to-end recovery schemes have the restoration LSP
	set up after the failure has been detected and notified on the		set up after the failure has been detected and notified on the
	working LSP. For recovery scheme with revertive behaviour, a		working LSP. For recovery scheme with revertive behavior, a
	restoration LSP is set up while working LSP and/or protecting LSP are		restoration LSP is set up while working LSP and/or protecting LSP are
	not torn down in control plane due to a failure. In non-packet		not torn down in control plane due to a failure. In non-packet
	transport networks, as working LSPs are typically set up over		transport networks, as working LSPs are typically set up over
	preferred paths, service providers would like to keep resources		preferred paths, service providers would like to keep resources
	associated with the working LSPs reserved. This is to make sure that		associated with the working LSPs reserved. This is to make sure that
	the service can be reverted to the preferred path (working LSP) when		the service can be reverted to the preferred path (working LSP) when
	the failure is repaired to provide deterministic behavior and		the failure is repaired to provide deterministic behavior and
	guaranteed Service Level Agreement (SLA).		guaranteed Service Level Agreement (SLA).
	In this document, we review procedures for GMPLS LSP associations,		In this document, we review procedures for GMPLS LSP associations,
	skipping to change at page 4, line 23 ¶		skipping to change at page 4, line 23 ¶
	this document.		this document.
	This document is strictly informative in nature and does not define		This document is strictly informative in nature and does not define
	any RSVP-TE signaling extensions.		any RSVP-TE signaling extensions.
	2. Conventions Used in This Document		2. Conventions Used in This Document
	2.1. Terminology		2.1. Terminology
	The reader is assumed to be familiar with the terminology in		The reader is assumed to be familiar with the terminology in
	[RFC3209], [RFC3473], [RFC4872], [RFC4873] and [RFC4427].		[RFC3209], [RFC3473], [RFC4872] and [RFC4873]. The terminology for
			GMPLS recovery is defined in [RFC4427].
	2.2. Acronyms and Abbreviations		2.2. Acronyms and Abbreviations
	GMPLS: Generalized Multi-Protocol Label Switching		GMPLS: Generalized Multi-Protocol Label Switching
	LSP: An MPLS Label Switched Path		LSP: An MPLS Label Switched Path
	MBB: Make Before Break		MBB: Make Before Break
	MPLS: Multi-Protocol Label Switching		MPLS: Multi-Protocol Label Switching
	skipping to change at page 5, line 23 ¶		skipping to change at page 5, line 24 ¶
	signaling techniques.		signaling techniques.
	3.1.1. 1+R Restoration		3.1.1. 1+R Restoration
	One example of the recovery scheme considered in this document is 1+R		One example of the recovery scheme considered in this document is 1+R
	recovery. The 1+R recovery scheme is exemplified in Figure 1. In		recovery. The 1+R recovery scheme is exemplified in Figure 1. In
	this example, a working LSP on path A-B-C-Z is pre-established.		this example, a working LSP on path A-B-C-Z is pre-established.
	Typically after a failure detection and notification on the working		Typically after a failure detection and notification on the working
	LSP, a second LSP on path A-H-I-J-Z is established as a restoration		LSP, a second LSP on path A-H-I-J-Z is established as a restoration
	LSP. Unlike a protecting LSP which is set up before the failure, a		LSP. Unlike a protecting LSP which is set up before the failure, a
	restoration LSP is set up per need basis, after the failure.		restoration LSP is set up when needed, after the failure.
	+-----+ +-----+ +-----+ +-----+		+-----+ +-----+ +-----+ +-----+
	| A +----+ B +-----+ C +-----+ Z |		| A +----+ B +-----+ C +-----+ Z |
	+--+--+ +-----+ +-----+ +--+--+		+--+--+ +-----+ +-----+ +--+--+
	\ /		\ /
	\ /		\ /
	+--+--+ +-----+ +--+--+		+--+--+ +-----+ +--+--+
	| H +-------+ I +--------+ J |		| H +-------+ I +--------+ J |
	+-----+ +-----+ +-----+		+-----+ +-----+ +-----+
	skipping to change at page 7, line 12 ¶		skipping to change at page 7, line 16 ¶
	LSP fails. Two different restoration LSPs may be present, one for		LSP fails. Two different restoration LSPs may be present, one for
	the working LSP and one for the protecting LSP.		the working LSP and one for the protecting LSP.
	o Two different restoration LSPs are set up after both working and		o Two different restoration LSPs are set up after both working and
	protecting LSPs fail, one for the working LSP and one for the		protecting LSPs fail, one for the working LSP and one for the
	protecting LSP.		protecting LSP.
	In all these models, if a restoration LSP also fails, it is torn down		In all these models, if a restoration LSP also fails, it is torn down
	and a new restoration LSP is set up.		and a new restoration LSP is set up.
	3.2. Resource Sharing By Restoration LSP		3.2. Resource Sharing by Restoration LSP
	+-----+ +-----+		+-----+ +-----+
	| F +------+ G +--------+		| F +------+ G +--------+
	+--+--+ +-----+ |		+--+--+ +-----+ |
	| |		| |
	| |		| |
	+-----+ +-----+ +--+--+ +-----+ +--+--+		+-----+ +-----+ +--+--+ +-----+ +--+--+
	| A +----+ B +-----+ C +--X---+ D +-----+ E |		| A +----+ B +-----+ C +--X---+ D +-----+ E |
	+-----+ +-----+ +-----+ +-----+ +-----+		+-----+ +-----+ +-----+ +-----+ +-----+
	Figure 3: Resource Sharing in 1+R Recovery Scheme		Figure 3: Resource Sharing in 1+R Recovery Scheme
	Using the network shown in Figure 3 as an example using 1+R recovery		Using the network shown in Figure 3 as an example using 1+R recovery
	scheme, LSP1 (A-B-C-D-E) is the working LSP, and assume it allows for		scheme, LSP1 (A-B-C-D-E) is the working LSP, and assume it allows for
	resource sharing when the LSP traffic is dynamically restored. Upon		resource sharing when the LSP traffic is dynamically restored. Upon
	detecting the failure of a link along the LSP1, e.g. Link C-D, node A		detecting the failure of a link along the LSP1, e.g. Link C-D, node A
	needs to decide which alternative path it will use to signal		needs to decide which alternative path it will use to signal
	restoration LSP and reroute traffic. In this case, A-B-C-F-G-E is		restoration LSP and reroute traffic. In this case, A-B-C-F-G-E is
	chosen as the restoration LSP path and the resources on the path		chosen as the restoration LSP path and the resources on the path
	segment A-B-C are re-used by this LSP. The working LSP is not torn		segment A-B-C are re-used by this LSP. The working LSP is not torn
	down and co-exists with the restoration LSP. Nodes A and B		down and co-exists with the restoration LSP. When the head-end node
	reconfigure the resources to set up the restoration LSP by sending		A signals the restoration LSP, nodes C, F, G and E reconfigure the
	cross-connection command to the data plane.		resources (as listed in Table 1 of this document) to set up the LSP
			by sending cross-connection command to the data plane.
	In the recovery scheme employing revertive behavior, after the		In the recovery scheme employing revertive behavior, after the
	failure is repaired, the resources on nodes A and B need to be		failure is repaired, the resources on nodes C and E need to be
	reconfigured to set up the working LSP. The traffic is then reverted		reconfigured to set up the working LSP (using a procedure described
	back to the original working LSP.		in Section 4.3 of this document) by sending cross-connection command
			to the data plane. The traffic is then reverted back to the original
			working LSP.
	4. RSVP-TE Signaling Procedure		4. RSVP-TE Signaling Procedure
	4.1. Restoration LSP Association		4.1. Restoration LSP Association
	Where GMPLS end-to-end recovery scheme needs to employ a restoration		Where GMPLS end-to-end recovery scheme needs to employ a restoration
	LSP while keeping resources for the working and/or protecting LSPs		LSP while keeping resources for the working and/or protecting LSPs
	reserved in the network after the failure, the restoration LSP is set		reserved in the network after the failure, the restoration LSP is set
	up with an ASSOCIATION object that has Association Type set to		up with an ASSOCIATION object that has Association Type set to
	"Recovery" [RFC4872], the Association ID and the Association Source		"Recovery" [RFC4872], the Association ID and the Association Source
	skipping to change at page 8, line 36 ¶		skipping to change at page 8, line 43 ¶
	4.2. Resource Sharing-based Restoration LSP Setup		4.2. Resource Sharing-based Restoration LSP Setup
	GMPLS LSPs can share resources during LSP setup if they have Shared		GMPLS LSPs can share resources during LSP setup if they have Shared
	Explicit (SE) flag set in the SESSION_ATTRIBUTE objects [RFC3209] in		Explicit (SE) flag set in the SESSION_ATTRIBUTE objects [RFC3209] in
	the Path messages that create them and:		the Path messages that create them and:
	o As defined in [RFC3209], LSPs have identical SESSION objects		o As defined in [RFC3209], LSPs have identical SESSION objects
	and/or		and/or
	o As defined in [RFC6689], LSPs have matching ASSOCIATION object		o As defined in [RFC6689], LSPs have matching ASSOCIATION object
	with Association Type set to "Resource Sharing" signaled in their		with Association Type set to "Resource Sharing" signaled in their
	Path messages. LSPs in this case can have different SESSION		Path messages. LSPs in this case can have different SESSION
	objects i.e. different Tunnel ID, Source and/or Destination		objects i.e. different Tunnel ID, Source and/or Destination
	signaled in their Path messages.		signaled in their Path messages.
	As described in [RFC3209], Section 2.5, the purpose of make-before-		As described in [RFC3209], Section 2.5, the purpose of make-before-
	break is not to disrupt traffic, or adversely impact network		break is not to disrupt traffic, or adversely impact network
	operations while TE tunnel rerouting is in progress. In non-packet		operations while TE tunnel rerouting is in progress. In non-packet
	transport networks during the RSVP-TE signaling procedure, the nodes		transport networks during the RSVP-TE signaling procedure, the nodes
	set up cross-connections along the LSP accordingly. Because the		set up cross-connections along the LSP accordingly. Because the
	cross-connection cannot simultaneously connect a shared resource to		cross-connection cannot simultaneously connect a shared resource to
	skipping to change at page 14, line 11 ¶		skipping to change at page 14, line 11 ¶
	[RFC4427] Mannie, E., and Papadimitriou, D., "Recovery (Protection		[RFC4427] Mannie, E., and Papadimitriou, D., "Recovery (Protection
	and Restoration) Terminology for Generalized		and Restoration) Terminology for Generalized
	Multi-Protocol Label Switching", RFC 4427, March 2006.		Multi-Protocol Label Switching", RFC 4427, March 2006.
	Acknowledgements		Acknowledgements
	The authors would like to thank George Swallow for the discussions on		The authors would like to thank George Swallow for the discussions on
	the GMPLS restoration. The authors would like to thank Lou Berger		the GMPLS restoration. The authors would like to thank Lou Berger
	for the guidance on this work. The authors would also like to thank		for the guidance on this work. The authors would also like to thank
	Lou Berger, Vishnu Pavan Beeram and Christian Hopps for reviewing		Lou Berger, Vishnu Pavan Beeram and Christian Hopps for reviewing
	this document and providing valuable comments.		this document and providing valuable comments. A special thanks to
			Dale Worley for his thorough review of this document.
	Contributors		Contributors
	Gabriele Maria Galimberti		Gabriele Maria Galimberti
	Cisco Systems, Inc.		Cisco Systems, Inc.
	EMail: ggalimbe@cisco.com		EMail: ggalimbe@cisco.com
	Authors' Addresses		Authors' Addresses
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