draft-cui-mpls-tp-mfp-use-case-and-requirements-06.txt		draft-cui-mpls-tp-mfp-use-case-and-requirements-07.txt
	Network Working Group Z. Cui		Network Working Group Z. Cui
	Internet-Draft R. Winter		Internet-Draft R. Winter
	Intended status: Informational NEC		Intended status: Informational NEC
	Expires: July 9, 2016 H. Shah		Expires: July 13, 2016 H. Shah
	Ciena		Ciena
	S. Aldrin		S. Aldrin
	Huawei Technologies		Huawei Technologies
	M. Daikoku		M. Daikoku
	KDDI		KDDI
	January 6, 2016		January 10, 2016
	Use Cases and Requirements for MPLS-TP multi-failure protection		Use Cases and Requirements for MPLS-TP multi-failure protection
	draft-cui-mpls-tp-mfp-use-case-and-requirements-06		draft-cui-mpls-tp-mfp-use-case-and-requirements-07
	Abstract		Abstract
	For the Multiprotocol Label Switching Transport Profile (MPLS-TP)		For the Multiprotocol Label Switching Transport Profile (MPLS-TP)
	linear protection capable of 1+1 and 1:1 protection has already been		linear protection capable of 1+1 and 1:1 protection has already been
	defined. That linear protection mechanism has not been designed for		defined. That linear protection mechanism has not been designed for
	handling multiple, simultaneously occuring failures, i.e. multiple		handling multiple, simultaneously occuring failures, i.e. multiple
	failures that affect the working and the protection entity during the		failures that affect the working and the protection entity during the
	same time period. In these situations currently defined protection		same time period. In these situations currently defined protection
	mechanisms would fail.		mechanisms would fail.
	skipping to change at page 1, line 46		skipping to change at page 1, line 46
	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 July 9, 2016.		This Internet-Draft will expire on July 13, 2016.
	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 46		skipping to change at page 2, line 46
	1. Introduction		1. Introduction
	Today's packet optical transport networks concentrate large volumes		Today's packet optical transport networks concentrate large volumes
	of traffic onto a relatively small number of nodes and links. As a		of traffic onto a relatively small number of nodes and links. As a
	result, the failure of a single network element can potentially		result, the failure of a single network element can potentially
	interrupt a large amount of traffic. For this reason, ensuring		interrupt a large amount of traffic. For this reason, ensuring
	survivability through careful network design and appropriate		survivability through careful network design and appropriate
	technical means is important.		technical means is important.
	In MPLS-TP networks, a basic survivability technique is available as		In MPLS-TP networks, a basic end-to-end linear protection
	specified in [RFC6378], [RFC7271] and [RFC7324]. That protocol		survivability technique is available as specified in [RFC6378],
	however is limited to 1+1 and 1:1 protection and not designed to		[RFC7271] and [RFC7324]. That protocol however is limited to 1+1 and
	handle multiple failures that affect both the working and protection		1:1 protection and not designed to handle multiple failures that
	entity at the same time.		affect both the working and protection entity at the same time.
	There are various scenarios where multi-failure protection is an		There are various scenarios where multi-failure protection is an
	important requirement for network survivability. E.g for disaster		important requirement for network survivability. E.g for disaster
	recovery, after catastrophic events such as earthquakes or tsunamis.		recovery, after catastrophic events such as earthquakes or tsunamis.
	During the period after such events, network availability is crucial,		During the period after such events, network availability is crucial,
	in particular for high-priority services such as emergency telephone		in particular for high-priority services such as emergency telephone
	calls. Existing 1+1 or 1:n protection however is limited to cover		calls. Existing 1+1 or 1:n protection however is limited to cover
	single failures which has proven as not sufficient during past		single failures which has proven as not sufficient during past
	events.		events.
	skipping to change at page 6, line 18		skipping to change at page 6, line 18
	entity is configured while the system is in operation.		entity is configured while the system is in operation.
	Additional protection entities are configured by either a control		Additional protection entities are configured by either a control
	plane protocol or static configuration using a management system		plane protocol or static configuration using a management system
	directly after failure detection and/or notification of either the		directly after failure detection and/or notification of either the
	working entity or the protection entities. In case a management		working entity or the protection entities. In case a management
	system is used, there is no need for a standardized solution.		system is used, there is no need for a standardized solution.
	3.2. m:n (m, n > 1, n >= m > 1) protection		3.2. m:n (m, n > 1, n >= m > 1) protection
	In order to reduce the cost of protection entities, in the m:n		Because m:n protecion introduces additional protection entities
	scenario, m dedicated protection transport entities are sharing		compared to 1:1 protection, an additional cost has to be paid. In
	protection resources for n working transport entities.		order to reduce the cost of these additional protection entities, in
			the m:n scenario, m dedicated protection transport entities are
			sharing protection resources for n working transport entities.
	The bandwidth of each protection entity should be allocated in such a		The bandwidth of each protection entity should be allocated in such a
	way that it may be possible to protect any of the n working entities		way that it may be possible to protect any of the n working entities
	in case at least one of the m protection entities is available. When		in case at least one of the m protection entities is available. When
	a working entity is determined to be impaired, its traffic first must		a working entity is determined to be impaired, its traffic first must
	be assigned to an available protection transport entity followed by a		be assigned to an available protection transport entity followed by a
	transition from the working to the assigned protection entity at both		transition from the working to the assigned protection entity at both
	Node A and Node Z of the protected domain. It is noted that when		Node A and Node Z of the protected domain. It is noted that when
	more than m working entities are impaired, only m working entities		more than m working entities are impaired, only m working entities
	can be protected.		can be protected.
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