draft-ietf-mpls-tp-aps-updates-00.txt		draft-ietf-mpls-tp-aps-updates-01.txt
	MPLS Working Group J. Ryoo		MPLS Working Group J. Ryoo
	Internet-Draft T. Cheung		Internet-Draft T. Cheung
	Updates: 7271 (if approved) ETRI		Updates: 7271 (if approved) ETRI
	Intended status: Standards Track H. van Helvoort		Intended status: Standards Track H. van Helvoort
	Expires: September 20, 2016 Hai Gaoming BV		Expires: March 19, 2017 Hai Gaoming BV
	I. Busi		I. Busi
	G. Weng		G. Weng
	Huawei Technologies		Huawei Technologies
	March 19, 2016		September 15, 2016
	Updates to MPLS Transport Profile (MPLS-TP) Linear Protection in		Updates to MPLS Transport Profile (MPLS-TP) Linear Protection in
	Automatic Protection Switching (APS) Mode		Automatic Protection Switching (APS) Mode
	draft-ietf-mpls-tp-aps-updates-00.txt		draft-ietf-mpls-tp-aps-updates-01.txt
	Abstract		Abstract
	This document contains updates to MPLS Transport Profile (MPLS-TP)		This document contains updates to MPLS Transport Profile (MPLS-TP)
	linear protection in Automatic Protection Switching (APS) mode		linear protection in Automatic Protection Switching (APS) mode
	defined in RFC 7271. The updates provide rules related to the		defined in RFC 7271. The updates provide rules related to the
	initialization of the Protection State Coordination (PSC) Control		initialization of the Protection State Coordination (PSC) Control
	Logic, in which the state machine resides, when operating in APS		Logic, in which the state machine resides, when operating in APS
	mode.		mode, and clarify some operation related to state transition table
			lookup.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	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 September 20, 2016.		This Internet-Draft will expire on March 19, 2017.
	Copyright Notice		Copyright Notice
	Copyright (c) 2016 IETF Trust and the persons identified as the		Copyright (c) 2016 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 20 ¶		skipping to change at page 2, line 23 ¶
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Conventions Used in This Document . . . . . . . . . . . . . . 3		2. Conventions Used in This Document . . . . . . . . . . . . . . 3
	3. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . 3		3. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . 3
	4. Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . 4		4. Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
	4.1. Initialization Behavior . . . . . . . . . . . . . . . . . 4		4.1. Initialization Behavior . . . . . . . . . . . . . . . . . 4
	4.2. State Transition Modification . . . . . . . . . . . . . . 5		4.2. State Transition Modification . . . . . . . . . . . . . . 5
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 5		4.3. Operation related to State Transition Table Lookup . . . 6
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6		5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
	7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6		6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6		7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
	8.1. Normative References . . . . . . . . . . . . . . . . . . 6		8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
	8.2. Informative References . . . . . . . . . . . . . . . . . 6		8.1. Normative References . . . . . . . . . . . . . . . . . . 7
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6		8.2. Informative References . . . . . . . . . . . . . . . . . 7
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
	1. Introduction		1. Introduction
	MPLS Transport Profile (MPLS-TP) linear protection in Automatic		MPLS Transport Profile (MPLS-TP) linear protection in Automatic
	Protection Switching (APS) mode is defined in RFC 7271 [RFC7271]. It		Protection Switching (APS) mode is defined in RFC 7271 [RFC7271]. It
	defines a set of alternate and additional mechanisms to perform some		defines a set of alternate and additional mechanisms to perform some
	of the functions of linear protection described in RFC 6378		of the functions of linear protection described in RFC 6378
	[RFC6378]. The actions performed at initialization of the Protection		[RFC6378]. The actions performed at initialization of the Protection
	State Coordination (PSC) Control Logic are not described in either		State Coordination (PSC) Control Logic are not described in either
	[RFC7271] or [RFC6378]. Although it is a common perception that the		[RFC7271] or [RFC6378]. Although it is a common perception that the
	skipping to change at page 3, line 20 ¶		skipping to change at page 3, line 22 ¶
	of [RFC7271]. The changes in the state transition table have been		of [RFC7271]. The changes in the state transition table have been
	examined to make sure that they do not introduce any new problems.		examined to make sure that they do not introduce any new problems.
	This document does not introduce backward compatibility issues with		This document does not introduce backward compatibility issues with
	implementations of [RFC7271]. In case a node implementing this		implementations of [RFC7271]. In case a node implementing this
	document restarts, the new state changes will not cause problems at		document restarts, the new state changes will not cause problems at
	the remote node implementing [RFC7271] and the two ends will converge		the remote node implementing [RFC7271] and the two ends will converge
	to the same local and remote states. In case a node implementing		to the same local and remote states. In case a node implementing
	[RFC7271] restarts, the two ends behave as today.		[RFC7271] restarts, the two ends behave as today.
			This document also provides some clarifications on the operation
			related to state transition table lookup.
	The reader of this document is assumed to be familiar with [RFC7271].		The reader of this document is assumed to be familiar with [RFC7271].
	2. Conventions Used in This Document		2. 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].
	3. Acronyms		3. Acronyms
	This document uses the following acronyms:		This document uses the following acronyms:
	APS Automatic Protection Switching		APS Automatic Protection Switching
	DNR Do-not-Revert		DNR Do-not-Revert
	E::R Exercise state due to remote EXER message		E::R Exercise state due to remote EXER message
	EXER Exercise		EXER Exercise
	MS-P Manual Switch to Protection path		MS-P Manual Switch to Protection path
	MS-W Manual Switch to Working path		MS-W Manual Switch to Working path
	MPLS-TP MPLS Transport Profile		MPLS-TP MPLS Transport Profile
	N Normal state		N Normal state
	skipping to change at page 4, line 7 ¶		skipping to change at page 4, line 28 ¶
	PSC Protection State Coordination		PSC Protection State Coordination
	RR Reverse Request		RR Reverse Request
	SD Signal Degrade		SD Signal Degrade
	SF-P Signal Fail on Protection path		SF-P Signal Fail on Protection path
	SF-W Signal Fail on Working path		SF-W Signal Fail on Working path
	UA:P:L Unavailable state due to local SF-P		UA:P:L Unavailable state due to local SF-P
	WTR Wait-to-Restore		WTR Wait-to-Restore
	4. Updates		4. Updates
	This document updates [RFC7271] by specifying the actions that will		This section specifies the actions that will be performed at the
	be performed at the initialization of the PSC Control Logic and		initialization of the PSC Control Logic and the modifications of the
	modifies the state transition table defined in Section 11.2 of		state transition table defined in Section 11.2 of [RFC7271]. Some
	[RFC7271].		clarifications on the operation related to state transition table
			lookup are also provided.
	4.1. Initialization Behavior		4.1. Initialization Behavior
	This section defines initialization behavior that is not described in		This section defines initialization behavior that is not described in
	[RFC7271].		[RFC7271].
	When the PSC Control Logic is initialized, the following actions MUST		When the PSC Control Logic is initialized, the following actions MUST
	be performed:		be performed:
	o Stop the WTR timer if it is running.		o Stop the WTR timer if it is running.
	skipping to change at page 5, line 43 ¶		skipping to change at page 6, line 21 ¶
	The changes in two rows of remote protecting failure states lead to		The changes in two rows of remote protecting failure states lead to
	the replacement of note (10) with DNR, therefore note (10) is no		the replacement of note (10) with DNR, therefore note (10) is no
	longer needed. The resultant three rows read:		longer needed. The resultant three rows read:
	| MS-W | MS-P | WTR | EXER | RR | DNR | NR		| MS-W | MS-P | WTR | EXER | RR | DNR | NR
	--------+---------+---------+-----+------+----+------+----		--------+---------+---------+-----+------+----+------+----
	N | SA:MW:R | SA:MP:R | (13)| E::R | i | DNR | i		N | SA:MW:R | SA:MP:R | (13)| E::R | i | DNR | i
	PF:W:R | SA:MW:R | SA:MP:R | (9) | E::R | i | DNR | (11)		PF:W:R | SA:MW:R | SA:MP:R | (9) | E::R | i | DNR | (11)
	PF:DW:R | SA:MW:R | SA:MP:R | (9) | E::R | i | DNR | (11)		PF:DW:R | SA:MW:R | SA:MP:R | (9) | E::R | i | DNR | (11)
			4.3. Operation related to State Transition Table Lookup
			In addition to the rules related to the state transition table lookup
			listed in Section 11 of [RFC7271], the following rule is also applied
			to the operation related to the state transition table lookup:
			o When the local SF-P is cleared and the priorities of the local and
			remote requests are re-evaluated, the last received remote message
			may not be valid any more due to the previous failure of the
			protection path. Therefore, the last received message MUST be
			treated as if it were NR and only the local request shall be
			evaluated.
			The last paragraph in Section 11 of [RFC7271] is modified as follows:
			---------
			Old text:
			---------
			In the state transition tables below, the letter 'i' stands for
			"ignore" and is an indication to remain in the current state and
			continue transmitting the current PSC message.
			---------
			New text:
			---------
			In the state transition tables below, the letter 'i' stands for
			"ignore" and the top-priority global request is ignored.
			Therefore, the next state can be either the current state
			transmitting the current PSC message or the supposed state
			(Normal or DNR depending on the footnotes to the state transition
			tables) in case of re-evaluation.
	5. Security Considerations		5. Security Considerations
	No specific security issue is raised in addition to those ones		No specific security issue is raised in addition to those ones
	already documented in [RFC7271]. It may be noted that tightening the		already documented in [RFC7271]. It may be noted that tightening the
	description of initializing behavior may help to protect networks		description of initializing behavior may help to protect networks
	from re-start attacks.		from re-start attacks.
	6. IANA Considerations		6. IANA Considerations
	This document makes no request of IANA.		This document makes no request of IANA.
End of changes. 10 change blocks.
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