draft-ietf-mpls-tp-identifiers-04.txt		draft-ietf-mpls-tp-identifiers-05.txt
	MPLS Working Group M. Bocci		MPLS Working Group M. Bocci
	Internet-Draft Alcatel-Lucent		Internet-Draft Alcatel-Lucent
	Intended status: Standards Track G. Swallow		Intended status: Standards Track G. Swallow
	Expires: September 4, 2011 Cisco		Expires: December 16, 2011 Cisco
	E. Gray		E. Gray
	Ericsson		Ericsson
	March 3, 2011		June 14, 2011
	MPLS-TP Identifiers		MPLS-TP Identifiers
	draft-ietf-mpls-tp-identifiers-04		draft-ietf-mpls-tp-identifiers-05
	Abstract		Abstract
	This document specifies identifiers for MPLS-TP objects. Included		This document specifies identifiers for MPLS-TP objects. Included
	are identifiers conformant to existing ITU conventions and		are identifiers conformant to existing ITU conventions and
	identifiers which are compatible with existing IP, MPLS, GMPLS, and		identifiers which are compatible with existing IP, MPLS, GMPLS, and
	Pseudowire definitions.		Pseudowire definitions.
			This document is a product of a joint Internet Engineering Task Force
			(IETF) / International Telecommunication Union Telecommunication
			Standardization Sector (ITU-T) effort to include an MPLS Transport
			Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge
			(PWE3) architectures to support the capabilities and functionalities
			of a packet transport network as defined by the ITU-T.
	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 4, 2011.		This Internet-Draft will expire on December 16, 2011.
	Copyright Notice		Copyright Notice
	Copyright (c) 2011 IETF Trust and the persons identified as the		Copyright (c) 2011 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
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	publication of this document. Please review these documents		publication of this document. Please review these documents
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
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	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
	1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
	1.2. Requirements Language . . . . . . . . . . . . . . . . . . 4		1.2. Requirements Language . . . . . . . . . . . . . . . . . . 5
	1.3. Notational Conventions in Backus-Naur Form . . . . . . . . 4		1.3. Notational Conventions . . . . . . . . . . . . . . . . . . 5
	2. Named Entities . . . . . . . . . . . . . . . . . . . . . . . . 4		2. Named Entities . . . . . . . . . . . . . . . . . . . . . . . . 6
	3. Uniquely Identifying an Operator . . . . . . . . . . . . . . . 5		3. Uniquely Identifying an Operator . . . . . . . . . . . . . . . 6
	3.1. The Global ID . . . . . . . . . . . . . . . . . . . . . . 5		3.1. The Global ID . . . . . . . . . . . . . . . . . . . . . . 7
	3.2. ITU Carrier Code . . . . . . . . . . . . . . . . . . . . . 6		3.2. ITU Carrier Code . . . . . . . . . . . . . . . . . . . . . 7
	4. Node and Interface Identifiers . . . . . . . . . . . . . . . . 6		4. Node and Interface Identifiers . . . . . . . . . . . . . . . . 8
	5. MPLS-TP Tunnel and LSP Identifiers . . . . . . . . . . . . . . 7		5. MPLS-TP Tunnel and LSP Identifiers . . . . . . . . . . . . . . 9
	5.1. MPLS-TP Point to Point Tunnel Identifiers . . . . . . . . 8		5.1. MPLS-TP Point to Point Tunnel Identifiers . . . . . . . . 9
	5.2. MPLS-TP LSP Identifiers . . . . . . . . . . . . . . . . . 8		5.2. MPLS-TP LSP Identifiers . . . . . . . . . . . . . . . . . 10
	5.2.1. MPLS-TP Co-Routed Bidirectional LSP Identifiers . . . 8		5.2.1. MPLS-TP Co-Routed Bidirectional LSP Identifiers . . . 10
	5.2.2. MPLS-TP Associated Bidirectional LSP Identifiers . . . 9		5.2.2. MPLS-TP Associated Bidirectional LSP Identifiers . . . 11
	5.3. Mapping to GMPLS and RSVP-TE Signalling . . . . . . . . . 9		5.3. Mapping to RSVP Signaling . . . . . . . . . . . . . . . . 12
	6. Pseudowire Path Identifiers . . . . . . . . . . . . . . . . . 10		6. Pseudowire Path Identifiers . . . . . . . . . . . . . . . . . 13
	7. Maintenance Identifiers . . . . . . . . . . . . . . . . . . . 11		7. Maintenance Identifiers . . . . . . . . . . . . . . . . . . . 14
	7.1. Maintenance Entity Group Identifiers . . . . . . . . . . . 11		7.1. Maintenance Entity Group Identifiers . . . . . . . . . . . 14
	7.1.1. ICC-based MEG Identifiers . . . . . . . . . . . . . . 12		7.1.1. ICC-based MEG Identifiers . . . . . . . . . . . . . . 14
	7.1.2. IP Compatible MEG_IDs . . . . . . . . . . . . . . . . 12		7.1.2. IP Compatible MEG_IDs . . . . . . . . . . . . . . . . 14
	7.1.2.1. MPLS-TP LSP MEG_IDs . . . . . . . . . . . . . . . 12		7.1.2.1. MPLS-TP Section MEG_IDs . . . . . . . . . . . . . 14
	7.1.2.2. Pseudowire MEG_IDs . . . . . . . . . . . . . . . . 12		7.1.2.2. MPLS-TP LSP MEG_IDs . . . . . . . . . . . . . . . 15
	7.2. MEP_IDs . . . . . . . . . . . . . . . . . . . . . . . . . 12		7.1.2.3. Pseudowire MEG_IDs . . . . . . . . . . . . . . . . 15
	7.2.1. ICC-based MEP Identifiers . . . . . . . . . . . . . . 12		7.2. MEP_IDs . . . . . . . . . . . . . . . . . . . . . . . . . 15
	7.2.2. IP based MEP_IDs . . . . . . . . . . . . . . . . . . . 13		7.2.1. ICC-based MEP Identifiers . . . . . . . . . . . . . . 15
	7.2.2.1. MPLS-TP LSP_MEP_ID . . . . . . . . . . . . . . . . 13		7.2.2. IP based MEP_IDs . . . . . . . . . . . . . . . . . . . 15
	7.2.2.2. MEP_IDs for Pseudowires . . . . . . . . . . . . . 13		7.2.2.1. MPLS-TP LSP_MEP_ID . . . . . . . . . . . . . . . . 15
	7.2.2.3. Pseudowire Segments Endpoint IDs . . . . . . . . . 13		7.2.2.2. MEP_IDs for Pseudowires . . . . . . . . . . . . . 16
	7.3. MIP Identifiers . . . . . . . . . . . . . . . . . . . . . 14		7.2.2.3. Pseudowire Segments Endpoint IDs . . . . . . . . . 16
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15		7.3. MIP Identifiers . . . . . . . . . . . . . . . . . . . . . 17
	9. Security Considerations . . . . . . . . . . . . . . . . . . . 15		8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
	10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15		9. Security Considerations . . . . . . . . . . . . . . . . . . . 18
	10.1. Normative References . . . . . . . . . . . . . . . . . . . 15		10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
	10.2. Informative References . . . . . . . . . . . . . . . . . . 16		10.1. Normative References . . . . . . . . . . . . . . . . . . . 18
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16		10.2. Informative References . . . . . . . . . . . . . . . . . . 18
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
	1. Introduction		1. Introduction
	This document specifies identifiers to be used in within the		This document specifies identifiers to be used in the Transport
	Transport Profile of Multiprotocol Label Switching (MPLS-TP). The		Profile of Multiprotocol Label Switching (MPLS-TP). The MPLS-TP
	MPLS-TP requirements (RFC 5654) [7] require that the elements and		requirements (RFC 5654) [7] require that the elements and objects in
	objects in an MPLS-TP environment are able to be configured and		an MPLS-TP environment are able to be configured and managed without
	managed without a control plane. In such an environment many		a control plane. In such an environment many conventions for
	conventions for defining identifiers are possible. This document		defining identifiers are possible. This document defines identifiers
	defines identifiers for MPLS-TP management and OAM functions suitable		for MPLS-TP management and OAM functions suitable to ITU conventions
	to ITU conventions and to IP/MPLS conventions. Applicability of the		and to IP/MPLS conventions. Applicability of the different
	different identifier schemas to different applications is outside the		identifier schemas to different applications is outside the scope of
	scope of this document.		this document.
			This document is a product of a joint Internet Engineering Task Force
			(IETF) / International Telecommunication Union Telecommunication
			Standardization Sector (ITU-T) effort to include an MPLS Transport
			Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge
			(PWE3) architectures to support the capabilities and functionalities
			of a packet transport network as defined by the ITU-T.
	1.1. Terminology		1.1. Terminology
	AII: Attachment Interface Identifier		AII: Attachment Interface Identifier
	ASN: Autonomous System Number		ASN: Autonomous System Number
			EGP: Exterior Gateway Protocol
	FEC: Forwarding Equivalence Class		FEC: Forwarding Equivalence Class
	GMPLS: Generalized Multi-Protocol Label Switching		GMPLS: Generalized Multi-Protocol Label Switching
	ICC: ITU Carrier Code		ICC: ITU Carrier Code
			IGP: Interior Gateway Protocol
	LSP: Label Switched Path		LSP: Label Switched Path
	LSR: Label Switching Router		LSR: Label Switching Router
	ME: Maintenance Entity		ME: Maintenance Entity
	MEG: Maintenance Entity Group		MEG: Maintenance Entity Group
	MEP: Maintenance Entity Group End Point		MEP: Maintenance Entity Group End Point
	skipping to change at page 4, line 18		skipping to change at page 5, line 30
	S-PE: Switching Provider Edge		S-PE: Switching Provider Edge
	T-PE: Terminating Provider Edge		T-PE: Terminating Provider Edge
	1.2. Requirements Language		1.2. Requirements Language
	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 [1].		document are to be interpreted as described in RFC 2119 [1].
	1.3. Notational Conventions in Backus-Naur Form		1.3. Notational Conventions
	All multiple-word atomic identifiers use underscores (_) between the		All multiple-word atomic identifiers use underscores (_) between the
	words to join the words. Many of the identifiers are composed of a		words to join the words. Many of the identifiers are composed of a
	concatenation of other identifiers. These are expressed using		set of other identifiers. These are expressed by listing the latter
	Backus-Naur Form (using double-colon - "::" - notation).		identifiers joined with double-colon, "::", notation.
	Where the same identifier type is used multiple times in a		Where the same identifier type is used multiple times in a
	concatenation, they are qualified by a prefix joined to the		concatenation, they are qualified by a prefix joined to the
	identifier by a dash (-). For example East-Node_ID is the Node_ID of		identifier by a dash (-). For example A1-Node_ID is the Node_ID of a
	a node referred to as East.		node referred to as A1.
			The notation does define a preferred ordering of the fields.
			Specifically the designation A1 is used to indicate the lower sort
			order of a field or set of fields and Z9 is used to indicated the
			higher sort order of the same. The sort is either alphanumeric or
			numeric depending on the field's definition. Where the sort applies
			to a group of fields, those fields are grouped with {...}.
			Note, however, that the uniqueness of an identifier does not depend
			on the ordering, but rather, upon the uniqueness and scoping of the
			fields that compose the identifier. Further the preferred ordering
			is not intended to constrain protocol designs by dictating a
			particular field sequence or even what fields appear in which
			objects. For example see Section 5.3.
	2. Named Entities		2. Named Entities
	In order to configure, operate and manage a transport network based		In order to configure, operate and manage a transport network based
	on the MPLS Transport Profile, a number of entities require		on the MPLS Transport Profile, a number of entities require
	identification. Identifiers for the follow entities are defined in		identification. Identifiers for the following entities are defined
	this document:		in this document:
	o Operator		* Operator
	* Global_ID		+ Global_ID
	* ICC		+ ICC
	o LSR		* LSR
	o LSP		* LSP
	o PW		* PW
	o Interface		* Interface
	o MEG
	o MEP		* MEG
	o MIP		* MEP
	o Tunnel		* MIP
			* Tunnel
	Note that we have borrowed the term tunnel from RSVP-TE (RFC 3209)		Note that we have borrowed the term tunnel from RSVP-TE (RFC 3209)
	[2] where it is used to describe an entity that provides a logical		[2] where it is used to describe an entity that provides a logical
	association between a source and destination LSR. The tunnel in turn		association between a source and destination LSR. The tunnel in turn
	is instantiated by one or more LSPs, where the additional LSPs are		is instantiated by one or more LSPs, where the additional LSPs are
	used for protection or re-grooming of the tunnel.		used for protection or re-grooming of the tunnel.
	3. Uniquely Identifying an Operator		3. Uniquely Identifying an Operator
	An operator is uniquely identified by an Operator Identifier		An operator is uniquely identified by an identifier which may take
	(Opr_ID). Two formats are defined, one that is compatible with IP		one of two formats. One format is compatible with IP operational
	operational practice called a Global_ID and or one compatible with		practice, and is called a Global_ID. The other format is compatible
	ITU practice, the ICC. An The Opr_ID MAY use either the Global_ID or		with ITU practice and is called ICC. An operator MAY use either the
	ICC format.		Global_ID or ICC format.
	3.1. The Global ID		3.1. The Global ID
	RFC 5003 [3] defines a globally unique Attachment Interface		RFC 5003 [3] defines a globally unique Attachment Interface
	Identifier (AII). That AII is composed of three parts, a Global_ID		Identifier (AII). That AII is composed of three parts, a Global_ID
	which uniquely identifies a operator, a prefix, and finally and		which uniquely identifies an operator, a prefix, and finally, an
	attachment circuit identifier. We have chosen to use that Global ID		attachment circuit identifier. We have chosen to use that Global ID
	for MPLS-TP. Quoting from RFC 5003, section 3.2, "The global ID can		for MPLS-TP. Quoting from RFC 5003, section 3.2, "The global ID can
	contain the 2-octet or 4-octet value of the operator's Autonomous		contain the 2-octet or 4-octet value of the operator's Autonomous
	System Number (ASN). It is expected that the global ID will be		System Number (ASN). It is expected that the global ID will be
	derived from the globally unique ASN of the autonomous system hosting		derived from the globally unique ASN of the autonomous system hosting
	the PEs containing the actual AIIs. The presence of a global ID		the PEs containing the actual AIIs. The presence of a global ID
	based on the operator's ASN ensures that the AII will be globally		based on the operator's ASN ensures that the AII will be globally
	unique."		unique."
	When the Global_ID is derived from a 2-octet AS number, the two high-		A Global_ID must be derived from a 4-octet AS number assigned to the
	order octets of this 4-octet identifier MUST be set to zero. Further		operator. Note that 2-octet AS numbers have been incorporated in the
	ASN 0 is reserved. A Global_ID of zero means that no Global_ID is		4-octet by placing the 2-octet AS number, in the low-order octets and
	present. Note that a Global_ID of zero is limited to entities		setting the two high-order octets to zero.
	contained within a single operator and MUST NOT be used across an
	NNI. A non-zero Global_ID MUST be derived from an ASN owned by the
	operator.
	Note that this Global_ID is used solely to provide a globally unique		ASN 0 is reserved and cannot be assigned. A Global_ID of zero means
	context for other MPLS-TP identifiers. It has nothing to do with the		that no Global_ID is specified. Note that a Global_ID of zero is
	use of the ASN in protocols such as BGP.		limited to entities contained within a single operator and MUST NOT
			be used across an NNI.
			The Global_ID is used solely to provide a globally unique context for
			other MPLS-TP identifiers. While the AS Number used in the Global_ID
			MUST be one which the operator is entitles to use, the use of the
			Global_ID is not related to the use of the ASN in protocols such as
			BGP.
	3.2. ITU Carrier Code		3.2. ITU Carrier Code
	M.1400 defines the ITU Carrier Code (ICC) assigned to a network		M.1400 defines the ITU Carrier Code (ICC) assigned to a network
	operator/service provider and maintained by the ITU-T		operator/service provider and maintained by the ITU-T
	Telecommunication Standardization Bureau (TSB): www.itu.int/ITU-T/		Telecommunication Standardization Bureau (TSB): www.itu.int/ITU-T/
	inr/icc/index.html.		inr/icc/index.html.
	ICCs can be assigned both to ITU-T and non-ITU-T members and the		ICCs can be assigned both to ITU-T and non-ITU-T members and the
	referenced local ICC website may contain ICCs of operators of both		referenced local ICC website may contain ICCs of operators of both
	kinds.		kinds.
	The ICC is a string of one to six characters, each character being		The ICC is a string of one to six characters, each character being
	either alphabetic (i.e. A-Z) or numeric (i.e. 0-9) characters.		either alphabetic (i.e. A-Z) or numeric (i.e. 0-9) characters.
	Alphabetic characters in the ICC SHOULD be represented with upper		Alphabetic characters in the ICC SHOULD be represented with upper
	case letters.		case letters.
	4. Node and Interface Identifiers		4. Node and Interface Identifiers
	An LSR requires identification of the node itself and of its		An LSR requires identification of the node itself and of its
	interfaces. An interface is the attachment point to a server layer		interfaces. An interface is the attachment point to a server
	MPLS-TP section or MPLS-TP tunnel.		(sub-)layer, e.g., MPLS-TP section or MPLS-TP tunnel.
	We call the identifier associated with a node a Node Identifier		We call the identifier associated with a node a Node Identifier
	(Node_ID). The Node_ID is a unique 32-bit value assigned by the		(Node_ID). The Node_ID is a unique 32-bit value assigned by the
	operator within the scope of the Global_ID. The structure of the		operator within the scope of a Global_ID or ICC. The structure of
	Node_ID is operator specific and is outside the scope of this		the Node_ID is operator specific and is outside the scope of this
	document. However, the value zero is reserved and MUST NOT be used.		document. However, the value zero is reserved and MUST NOT be used.
	Where IPv4 addresses are used, it may be convenient to use the Node's		Where IPv4 addresses are used, it may be convenient to use the Node's
	IPv4 loopback address as the Node_ID, however the Node_ID does not		IPv4 loopback address as the Node_ID, however the Node_ID does not
	need to have any association with the IPv4 address space used in the		need to have any association with the IPv4 address space used in the
	operator's IGP or BGP. Where IPv6 addresses are used exclusively, a		operator's IGP or EGP. Where IPv6 addresses are used exclusively, a
	32-bit value unique within the scope of the Global_ID is assigned.		32-bit value unique within the scope of a Global_ID or ICC is
			assigned.
	A LSR can support multiple layers (e.g. hierarchical LSPs) and the		An LSR can support multiple layers (e.g. hierarchical LSPs) and the
	Node_ID belongs to the multiple layer context i.e. it is applicable		Node_ID belongs to the multiple layer context i.e. it is applicable
	to all LSPs or PWs that originate on, have a midpoint on, or		to all LSPs or PWs that originate on, have a intermediate point on,
	terminate on the node.		or terminate on the node.
	In situations where a Node_ID needs to be globally unique, this is		In situations where a Node_ID needs to be globally unique, this is
	accomplished by prefixing the identifier with the operator's Opr_ID.		accomplished by prefixing the identifier with the operator's
	The particular combination of Global_ID::Node_ID we call a Global		Global_ID or ICC.
	Node ID or Global_Node_ID.
	Within the context of a particular node, we call the identifier		Within the context of a particular node, we call the identifier
	associated with an interface an Interface Number or IF_Num. The		associated with an interface an Interface Number (IF_Num). The
	IF_Num is a 32-bit unsigned integer assigned by the operator and MUST		IF_Num is a 32-bit unsigned integer assigned by the operator and MUST
	be unique within the scope of a Node_ID. The IF_Num value 0 has		be unique within the scope of a Node_ID. The IF_Num value 0 has
	special meaning (see section , MIP Identifiers) (Section 7.3) and		special meaning (see Section 7.3, MIP Identifiers) and MUST NOT be
	MUST NOT be used to identify an MPLS-TP interface.		used to identify an MPLS-TP interface.
	An Interface Identifier or IF_ID identifies an interface uniquely		An Interface Identifier (IF_ID) identifies an interface uniquely
	within the context of an Opr_ID. It is formed by concatenating the		within the context of a Global_ID or ICC. It is formed by
	Node_ID with the IF_Num. That is an IF_ID is a 64-bit identifier		concatenating the Node_ID with the IF_Num. That is an IF_ID is a 64-
	formed as Node_ID::IF_Num.		bit identifier formed as Node_ID::IF_Num.
	This convention was chosen to allow compatibility with GMPLS. GMPLS		This convention was chosen to allow compatibility with GMPLS. GMPLS
	signaling [4] requires interface identification. GMPLS allows three		signaling [4] requires interface identification. GMPLS allows three
	formats for the Interface_ID. The third format consists of an IPv4		formats for the Interface_ID. The third format consists of an IPv4
	Address plus a 32-bit unsigned integer for the specific interface.		Address plus a 32-bit unsigned integer for the specific interface.
	The format defined for MPLS-TP is consistent with this format, but		The format defined for MPLS-TP is consistent with this format, but
	uses the Node_ID instead of an IPv4 Address.		uses the Node_ID instead of an IPv4 Address.
	If an IF_ID needs to be globally unique, this is accomplished by		If an IF_ID needs to be globally unique, this is accomplished by
	prefixing the identifier with the operator's Opr_ID.		prefixing the identifier with the operator's Global_ID or ICC.
	The attachment point to an MPLS-TP Tunnel (see section Section 5.1		The attachment point to an MPLS-TP Tunnel (see Section 5.1) also
	also needs an interface identifier. Note that MPLS-TP supports		needs an interface identifier. Note that MPLS-TP supports
	hierarchical tunnels. The attachment point to a MPLS-TP Tunnel at		hierarchical tunnels. The attachment point to a MPLS-TP Tunnel at
	any sub layer requires a unique IF_ID.		any (sub-)layer requires a node-unique IF_Num.
	5. MPLS-TP Tunnel and LSP Identifiers		5. MPLS-TP Tunnel and LSP Identifiers
	In MPLS the actual transport of packets is provided by label switched		In MPLS the actual transport of packets is provided by label switched
	paths (LSPs). A transport service may be composed of multiple LSPs.		paths (LSPs). A transport service may be composed of multiple LSPs.
	Further the LSPs providing a service may change over time due to		Further the LSPs providing a service may change over time due to
	protection and restoration events. In order to clearly identify the		protection and restoration events. In order to clearly identify the
	service we use the term "MPLS-TP Tunnel" or simply "tunnel" for a		service we use the term "MPLS-TP Tunnel" or simply "tunnel" for a
	service provided by (for example) a working LSP and protected by a		service provided by (for example) a working LSP and protected by a
	protection LSP. The Tunnel_ID identifies the transport service and		protection LSP. The Tunnel_ID identifies the transport service and
	provides a stable binding to the client in the face of changes in the		provides a stable binding to the client in the face of changes in the
	the data plane LSPs used to provide the service due to protection and		the data plane LSPs used to provide the service due to protection or
	restoration events. This section defines an MPLS-TP Tunnel_ID to		restoration events. This section defines an MPLS-TP Tunnel_ID to
	uniquely identify a tunnel and MPLS-TP LSP_IDs within the context of		uniquely identify a tunnel and MPLS-TP LSP_IDs within the context of
	that tunnel.		that tunnel.
	For the case where multiple LSPs (for example) are used to support a		For the case where multiple LSPs (for example) are used to support a
	single service with a common set of end-points, using this identifier		single service with a common set of end-points, using this identifier
	allows for a trivial mapping between the server and client layers to		allows for a trivial mapping between the server and client layers,
	a common service identifier which may be either defined by, or used		providing a common service identifier which may be either defined by,
	by, the client.		or used by, the client.
	Note that this usage is not intended to constrain protection schemes,		Note that this usage is not intended to constrain protection schemes,
	and may be used to identify any service (protected or un-protected)		and may be used to identify any service (protected or unprotected)
	that may appear to the client as a single service attachment point.		that may appear to the client as a single service attachment point.
			Keeping the Tunnel_ID consistent across working and protection LSPs
	Keeping the tunnel number consistent across working and protection		is a useful construct currently employed within GMPLS. The Tunnel_ID
	LSPs is a useful construct currently employed within GMPLS. However		for a protection LSP MAY differ from that used by its corresponding
	there is no requirement that a protection LSP use the same tunnel		working LSP.
	number as the working LSP.
	5.1. MPLS-TP Point to Point Tunnel Identifiers		5.1. MPLS-TP Point to Point Tunnel Identifiers
	At each endpoint a tunnel is uniquely identified by the endpoint's		At each endpoint a tunnel is uniquely identified by the endpoint's
	Node_ID and a locally assigned tunnel number. Specifically a		Node_ID and a locally assigned tunnel number. Specifically a
	Tunnel_Num is a 16-bit unsigned integer unique within the context of		Tunnel_Num is a 16-bit unsigned integer unique within the context of
	the Node_ID. The motivation for each endpoint having its own tunnel		the Node_ID. The motivation for each endpoint having its own tunnel
	number is to allow a compact form for the MEP-ID. See section		number is to allow a compact form for the MEP-ID. See
	Section 7.1.2.1.		Section 7.2.2.1.
	Having two tunnel numbers also serves to simplify other signaling		Having two tunnel numbers also serves to simplify other signaling
	(e.g., setup of associated bi-directional tunnels as described in		(e.g., setup of associated bidirectional tunnels as described in
	section Section 5.3.)		Section 5.3).
	The concatenation of the two endpoint identifiers serves as the full		The concatenation of the two endpoint identifiers serves as the full
	identifier. In a configured environment the endpoints are often		identifier. Using the A1 / Z9 convention the format of a Tunnel_ID
	called East and West. Using this convention the format of the format		is:
	of a Tunnel_ID is:
	East-Node_ID::East-Tunnel_Num::West-Node_ID::West-Tunnel_Num		A1-{Node_ID::Tunnel_Num}::Z9-{Node_ID::Tunnel_Num}
	Where the Tunnel_ID needs to be globally unique, this is accomplished		Where the Tunnel_ID needs to be globally unique, this is accomplished
	by using globally unique Node_IDs as defined above. Thus a globally		by using globally unique Node_IDs as defined above. Thus a globally
	unique Tunnel_ID becomes:		unique Tunnel_ID becomes:
	East-Global_Node_ID::East-Tunnel_Num::West-Global_Node_ID::		A1-{Global_ID::Node_ID::Tunnel_Num}::Z9-{Global_Id::Node_ID::
	West-Tunnel_Num		Tunnel_Num}
			The corresponding ICC-based version of this identifier would be:
			A1-{ICC::Node_ID::Tunnel_Num}::Z9-{ICC::Node_ID::Tunnel_Num}
	When an MPLS-TP Tunnel is configured, it MUST be assigned a unique		When an MPLS-TP Tunnel is configured, it MUST be assigned a unique
	IF_ID at both the source and destination endpoints. As usual, the		IF_ID at each endpoint. As usual, the IF_ID is composed of the local
	IF_ID is composed of the local NODE_ID concatenated with a 32-bit		Node_ID concatenated with a 32-bit IF_Num.
	IF_Num.
	5.2. MPLS-TP LSP Identifiers		5.2. MPLS-TP LSP Identifiers
	5.2.1. MPLS-TP Co-Routed Bidirectional LSP Identifiers		5.2.1. MPLS-TP Co-Routed Bidirectional LSP Identifiers
	For a co-routed bidirectional LSP can be uniquely identified by a		A co-routed bidirectional LSP can be uniquely identified by a single
	single LSP number within the scope of an MPLS-TP Tunnel_ID.		LSP number within the scope of an MPLS-TP Tunnel_ID. Specifically an
	Specifically an LSP_Num is a 16-bit unsigned integer unique within		LSP_Num is a 16-bit unsigned integer unique within the Tunnel_ID.
	the Tunnel_ID. Thus the format of a LSP_ID is:		Thus the format of an MPLS-TP co-routed bidirectional LSP_ID is:
	East-Node_ID::East-Tunnel_Num::West-Node_ID::West-		A1-{Node_ID::Tunnel_Num}::Z9-{Node_ID::Tunnel_Num}::LSP_Num
	Tunnel_Num::LSP_Num
			Note that the uniqueness of identifiers does not depend on the A1 /
			Z9 sort ordering. Thus the identifier,
			Z9-{Node_ID::Tunnel_Num}::A1-{Node_ID::Tunnel_Num}::LSP_Num
			is synonymous with the one above.
			At the dataplane level, a co-routed bidirectional LSP is composed of
			two unidirectional LSPs traversing the same links in opposite
			directions. Since a co-routed bidirectional LSP is provisioned or
			signaled as a single entity, a single LSP_Num is used for both
			unidirectional LSPs. The unidirectional LSPs can be referenced by
			the identifiers:
			Z9-Node_ID::Z9-Tunnel_Num::LSP_Num::A1-Node_ID and
			A1-Node_ID::A1-Tunnel_Num::LSP_Num::Z9-Node_ID respectively.
	Where the LSP_ID needs to be globally unique, this is accomplished by		Where the LSP_ID needs to be globally unique, this is accomplished by
	using globally unique Node_IDs as defined above. Thus a globally		using globally unique Node_IDs as defined above. Thus a globally
	unique LSP_ID becomes:		unique LSP_ID becomes:
	East-Global_Node_ID::East-Tunnel_Num::West-Global_Node_ID::		A1-{Global_ID::Node_ID::Tunnel_Num}::Z9-{Global_Id::
	West-Tunnel_Num::LSP_Num		Node_ID::Tunnel_Num}::LSP_Num
	The corresponding ICC-based version of this identifier would be:		The corresponding ICC-based version of this identifier would be:
	East-ICC::East-Node_ID::East-Tunnel_Num::West-ICC::West-Node_ID::
	West-Tunnel_Num::LSP_Num		A1-{ICC::Node_ID::Tunnel_Num}::Z9-{ICC::Node_ID::Tunnel_Num}::
			LSP_Num
	5.2.2. MPLS-TP Associated Bidirectional LSP Identifiers		5.2.2. MPLS-TP Associated Bidirectional LSP Identifiers
	For an associated bidirectional LSP each of the unidirectional LSPs		For an associated bidirectional LSP each of the unidirectional LSPs
	from East to West and West to East require LSP IDs. The each LSP can		from A1 to Z9 and Z9 to A1 require LSP_Nums. Each LSP is uniquely
	be uniquely identified by a single LSP number within the scope of the		identified by a single LSP number within the scope of the ingress's
	senders Tunnel_Num. Specifically an LSP_Num is a 16-bit unsigned		Tunnel_Num. Specifically an LSP_Num is a 16-bit unsigned integer
	integer unique within the Tunnel_Num. Thus the format of a LSP_ID is:		unique within the Tunnel_Num. Thus the format of an MPLS-TP
			associated bidirectional LSP_ID is:
	East-Node_ID::East-Tunnel_Num::East-LSP_Num::		A1-{Node_ID::Tunnel_Num::LSP_Num}::
			Z9-{Node_ID::Tunnel_Num::LSP_Num}
	West-Node_ID::West-Tunnel_Num::West-LSP_Num		At the dataplane level, an associated bidirectional LSP is composed
			of two unidirectional LSPs between two nodes in opposite directions.
			The unidirectional LSPs may be referenced by the identifiers:
			A1-Node_ID::A1-Tunnel_Num::A1-LSP_Num::Z9-Node_ID and
			Z9-Node_ID::Z9-Tunnel_Num::Z9-LSP_Num::A1-Node_ID respectively.
	Where the LSP_ID needs to be globally unique, this is accomplished by		Where the LSP_ID needs to be globally unique, this is accomplished by
	using globally unique Node_IDs as defined above. Thus a globally		using globally unique Node_IDs as defined above. Thus a globally
	unique LSP_ID becomes:		unique LSP_ID becomes:
	East-Global_Node_ID::East-Tunnel_Num::East-LSP_Num::		A1-{Global_ID::Node_ID::Tunnel_Num::LSP_Num}::
	West-Global_Node_ID::West-Tunnel_Num::West-LSP_Num		Z9-{Global_Id::Node_ID::Tunnel_Num::LSP_Num}
	The corresponding ICC-based version of this identifier would be:		The corresponding ICC-based version of this identifier would be:
	East-ICC::East-Node_ID::East-Tunnel_Num::East-LSP_Num::		A1-{ICC::Node_ID::Tunnel_Num::LSP_Num}::
	West-ICC::West-Node_ID::West-Tunnel_Num::West-LSP_Num		Z9-{ICC::Node_ID::Tunnel_Num::LSP_Num}
	5.3. Mapping to GMPLS and RSVP-TE Signalling		5.3. Mapping to RSVP Signaling
	This section defines the mapping from an MPLS-TP LSP_ID to GMPLS. At		This section is informative and exists to help understand the
	this time, GMPLS has yet to be extended to accommodate Global_IDs.		structure of the LSP IDs.
	Thus a mapping is only made for the network unique form of the
	LSP_ID.
	GMPLS signaling [5] uses a 5-tuple to uniquely identify an LSP within		Both GMPLS and RSVP-TE use RSVP signaling. This section defines the
			mapping from an MPLS-TP LSP_ID to RSVP. At this time, RSVP has yet
			to be extended to accommodate Global_IDs. Thus a mapping is only
			made for the network unique form of the LSP_ID.
			RSVP signaling [5] uses a 5-tuple to uniquely identify an LSP within
	a operator's network. This tuple is composed of a Tunnel Endpoint		a operator's network. This tuple is composed of a Tunnel Endpoint
	Address, Tunnel_ID, Extended Tunnel ID, and Tunnel Sender Address and		Address, Tunnel_ID, Extended Tunnel ID, and Tunnel Sender Address and
	(GMPLS) LSP_ID.		(RSVP) LSP_ID.
	In situations where a mapping to the GMPLS 5-tuple is required, the		For a co-routed bidirectional LSP signaled from A1 to Z9, the mapping
	following mapping is used.		to the GMPLS 5-tuple is as follows:
	o Tunnel Endpoint Address = West-Node_ID		* Tunnel Endpoint Address = Z9-Node_ID
	o Tunnel_ID = East-Tunnel_Num		* Tunnel_ID = A1-Tunnel_Num
	o Extended Tunnel_ID = East-Node_ID		* Extended Tunnel_ID = A1-Node_ID
	o Tunnel Sender Address = East-Node_ID		* Tunnel Sender Address = A1-Node_ID
	o LSP_ID = East-LSP_Num		* (RSVP) LSP_ID = LSP_Num
	An associated bi-directional LSP between two nodes East and West		An associated bidirectional LSP between two nodes A1 and Z9 consists
	consists of two uni-directional LSPs, one from East to West and one		of two unidirectional LSPs, one from A1 to Z9 and one from Z9 to A1.
	from West to East. RSVP-TE is capable of signaling such LSPs.
	In situations where a mapping to the RSVP 5-tuples is required, the		In situations where a mapping to the RSVP 5-tuples is required, the
	following mappings are used. For the East to West LSP the mapping		following mappings are used. For the A1 to Z9 LSP the mapping would
	would be:		be:
	o Tunnel Endpoint Address = West-Node_ID		* Tunnel Endpoint Address = Z9-Node_ID
	o Tunnel_ID = East-Tunnel_Num		* Tunnel_ID = A1-Tunnel_Num
	o Extended Tunnel_ID = East-Node_ID		* Extended Tunnel_ID = A1-Node_ID
	o Tunnel Sender Address = East-Node_ID		* Tunnel Sender Address = A1-Node_ID
	o LSP_ID = East-LSP_Num		* (RSVP) LSP_ID = A1-LSP_Num
	Likewise, the East to West LSP the mapping would be:		Likewise, the Z9 to A1 LSP, the mapping would be:
	o Tunnel Endpoint Address = East-Node_ID		* Tunnel Endpoint Address = A1-Node_ID
	o Tunnel_ID = West-Tunnel_Num		* Tunnel_ID = Z9-Tunnel_Num
	o Extended Tunnel_ID = West-Node_ID		* Extended Tunnel_ID = Z9-Node_ID
	o Tunnel Sender Address = West-Node_ID		* Tunnel Sender Address = Z9-Node_ID
	o LSP_ID = West-LSP_Num		* (RSVP) LSP_ID = Z9-LSP_Num
	6. Pseudowire Path Identifiers		6. Pseudowire Path Identifiers
	Pseudowire signaling (RFC 4447 [6]) defines two FECs used to signal		Pseudowire signaling (RFC 4447 [6]) defines two FECs used to signal
	pseudowires. Of these, FEC Type 129 along with AII Type 2 as defined		pseudowires. Of these, FEC Type 129 along with AII Type 2 as defined
	in RFC 5003 [3] fits the identification requirements of MPLS-TP.		in RFC 5003 [3] fits the identification requirements of MPLS-TP.
	In an MPLS-TP environment, a PW is identified by a set of identifiers		In an MPLS-TP environment, a PW is identified by a set of identifiers
	which can be mapped directly to the elements required by FEC 129 and		which can be mapped directly to the elements required by FEC 129 and
	AII Type 2. To distinguish this identifier from other Pseudowire		AII Type 2. To distinguish this identifier from other Pseudowire
	Identifiers, we call this a Pseudowire Path Identifier or PW_Path_Id.		Identifiers, we call this a Pseudowire Path Identifier (PW_Path_Id).
	The AII Type 2 is composed of three fields. These are the Global_ID,		The AII Type 2 is composed of three fields. These are the Global_ID,
	the Prefix, and the AC_ID. The Global_ID used in this document is		the Prefix, and the AC_ID. The Global_ID used in this document is
	identical to the Global_ID defined in RFC 5003. The Node_ID is used		identical to the Global_ID defined in RFC 5003. The Node_ID is used
	as the Prefix. The AC_ID is as defined in RFC 5003.		as the Prefix. The AC_ID is as defined in RFC 5003.
	To complete the FEC 129, all that is required is a Attachment Group		To complete the FEC 129, all that is required is a Attachment Group
	Identifier (AGI). That field is exactly as specified in RFC 4447.		Identifier (AGI). That field is exactly as specified in RFC 4447.
	FEC 129 has a notion of Source AII (SAII) and Target AII (TAII).		FEC 129 has a notion of Source AII (SAII) and Target AII (TAII).
	These terms are used relative to the direction of the signaling. In		These terms are used relative to the direction of the signaling. In
	a purely configured environment when referring to the entire PW, this		a purely configured environment when referring to the entire PW, this
	distinction is not critical. That is a FEC 129 of AGIa::AIIb::AIIc		distinction is not critical. That is a FEC 129 of AGIa::AIIb::AIIc
	is equivalent to AGIa::AIIc::AIIb. We note that in a signaled		is equivalent to AGIa::AIIc::AIIb. We note that in a signaled
	environment, the required convention in RFC 4447 is that at a		environment, the required convention in RFC 4447 is that at a
	particular endpoint, the AII associated with that endpoint comes		particular endpoint, the AII associated with that endpoint comes
	first. The complete PW_Path_Id is:		first. The complete PW_Path_Id is:
	AGI::East-Global_Node_ID::East-AC_ID::West-Global_Node_ID::		AGI::A1-{Global_ID::Node_ID::AC_ID}::
	West-AC_ID.		Z9-{Global_Id::Node_ID::AC_ID}.
	The corresponding ICC-based version for this identifier would be:		The corresponding ICC-based version for this identifier would be:
	AGI::East-ICC::East-Node_ID::East-AC_ID::West-ICC::West-Node_ID::		AGI::A1-{ICC::Node_ID::AC_ID}::Z9-{ICC::Node_ID::AC_ID}
	West-AC_ID
	7. Maintenance Identifiers		7. Maintenance Identifiers
	In MPLS-TP a Maintenance Entity Group (MEG) represents an Entity that		In MPLS-TP a Maintenance Entity Group (MEG) represents an Entity that
	requires management and defines a relationship between a set of		requires management and defines a relationship between a set of
	maintenance points. A maintenance point is either Maintenance Entity		maintenance points. A maintenance point is either a Maintenance
	Group End-point (MEP) or a Maintenance Entity Group Intermediate		Entity Group End-point (MEP) or a Maintenance Entity Group
	Point (MIP). Maintenance points are uniquely associated with a MEG.		Intermediate Point (MIP). Maintenance points are uniquely associated
	Within the context of a MEG, MEPs and MIPs must be uniquely		with a MEG. Within the context of a MEG, MEPs and MIPs must be
	identified. This section defines a means of uniquely identifying		uniquely identified. This section defines a means of uniquely
	Maintenance Entity Groups, Maintenance Entities and uniquely defining		identifying Maintenance Entity Groups, Maintenance Entities and
	MEPs and MIPs within the context of a Maintenance Entity Group.		uniquely defining MEPs and MIPs within the context of a Maintenance
			Entity Group.
	7.1. Maintenance Entity Group Identifiers		7.1. Maintenance Entity Group Identifiers
	Maintenance Entity Group Identifiers (MEG_IDs) are required for		Maintenance Entity Group Identifiers (MEG_IDs) are required for
	MPLS-TP LSPs and Pseudowires. Two classes of MEG_IDs are defined,		MPLS-TP sections, LSPs and Pseudowires. Two classes of MEG_IDs are
	one that follows the IP compatible identifier defined above as well		defined, one that follows the IP compatible identifier defined above
	as the ICC-format.		as well as the ICC-format.
	7.1.1. ICC-based MEG Identifiers		7.1.1. ICC-based MEG Identifiers
	MEG_ID for MPLS-TP LSPs and Pseudowires MAY use the globally unique		MEG_ID for MPLS-TP LSPs and Pseudowires MAY use the globally unique
	ICC-based format.		ICC-based format.
	In this case, the MEG_ID is a string of up to thirteen characters,		In this case, the MEG_ID is a string of up to thirteen characters,
	each character being either alphabetic (i.e. A-Z) or numeric (i.e.		each character being either alphabetic (i.e. A-Z) or numeric (i.e.
	0-9) characters. It consists of two subfields: the ICC (as defined		0-9) characters. It consists of two subfields: the ICC (as defined
	in section 3) followed by a unique MEG code (UMC). The UMC MUST be		in section 3) followed by a unique MEG code (UMC). The UMC MUST be
	unique within the organization identified by the ICC.		unique within the organization identified by the ICC.
	The ICC MEG_ID may be applied equally to a single MPLS-TP LSP or		The ICC MEG_ID may be applied equally to a single MPLS-TP LSP or
	Pseudowires. Note that when encoded in a protocol such as in a TLV,		Pseudowires. Note that when encoded in a protocol such as in a TLV,
	a different type needs to be defined for LSP and PWs as the OAM		a different type needs to be defined for LSP and PWs as the OAM
	capabilities may be different.		capabilities may be different.
	7.1.2. IP Compatible MEG_IDs		7.1.2. IP Compatible MEG_IDs
	7.1.2.1. MPLS-TP LSP MEG_IDs		7.1.2.1. MPLS-TP Section MEG_IDs
			IP compatible MEG_IDs for MPLS-TP sections are formed by
			concatenating the two IF_IDs of the corresponding section. For
			example:
			A1-IF_ID::Z9-IF_ID
			Where the LSP_ID needs to be globally unique, this is accomplished by
			using globally unique Node_IDs as defined above. Thus a globally
			unique Section MEG_ID becomes:
			A1-{Global_ID::IF_ID}::Z9-{Global_Id::IF_ID}
			7.1.2.2. MPLS-TP LSP MEG_IDs
	Since a MEG pertains to a single MPLS-TP LSP, IP compatible MEG_IDs		Since a MEG pertains to a single MPLS-TP LSP, IP compatible MEG_IDs
	for MPLS-TP LSPs are simply the corresponding LSP_IDs. We note that		for MPLS-TP LSPs are simply the corresponding LSP_IDs. We note that
	while the two identifiers are syntactically identical, they have		while the two identifiers are syntactically identical, they have
	different semantics. This semantic difference needs to be made		different semantics. This semantic difference needs to be made
	clear. For instance if both a MPLS-TP LSP_ID and MPLS-TP LSP MEG_IDs		clear. For instance if both a MPLS-TP LSP_ID and MPLS-TP LSP MEG_IDs
	are to be encoded in TLVs different types need to be assigned for		are to be encoded in TLVs, different types need to be assigned for
	these two identifiers.		these two identifiers.
	7.1.2.2. Pseudowire MEG_IDs		7.1.2.3. Pseudowire MEG_IDs
	For Pseudowires a MEG pertains to a single PW. The IP compatible		For Pseudowires a MEG pertains to a single PW. The IP compatible
	MEG_ID for a PW is simply the corresponding PW_Path_ID. We note that		MEG_ID for a PW is simply the corresponding PW_Path_ID. We note that
	while the two identifiers are syntactically identical, they have		while the two identifiers are syntactically identical, they have
	different semantics. This semantic difference needs to be made		different semantics. This semantic difference needs to be made
	clear. For instance if both a PW_Path_ID and a PW_MEG_ID is to be		clear. For instance if both a PW_Path_ID and a PW_MEG_ID are to be
	encoded in TLVs different types need to be assigned for these two		encoded in TLVs, different types need to be assigned for these two
	identifiers.		identifiers.
	7.2. MEP_IDs		7.2. MEP_IDs
	7.2.1. ICC-based MEP Identifiers		7.2.1. ICC-based MEP Identifiers
	ICC-based MEP_IDs for MPLS-TP LSPs and Pseudowires are formed by		ICC-based MEP_IDs for MPLS-TP LSPs and Pseudowires are formed by
	appending a unique number to the MEG_ID defined in section		appending a unique number to the MEG_ID defined in Section 7.1.1
	Section 7.1.1 above. Within the context of a particular MEG, we call		above. Within the context of a particular MEG, we call the
	the identifier associated with a MEP the MEP Index (MEP_Index). The		identifier associated with a MEP the MEP Index (MEP_Index). The
	MEP_Index is administratively assigned. It is encoded as a 16-bit		MEP_Index is administratively assigned. It is encoded as a 16-bit
	unsigned integer and MUST be unique within the MEG. An ICC-based		unsigned integer and MUST be unique within the MEG. An ICC-based
	MEP_ID is:		MEP_ID is:
	MEG_ID::MEP_Index		MEG_ID::MEP_Index
	An ICC-based MEP ID is globally unique by construction given the ICC-		An ICC-based MEP ID is globally unique by construction given the ICC-
	based MEG_ID global uniqueness.		based MEG_ID global uniqueness.
	7.2.2. IP based MEP_IDs		7.2.2. IP based MEP_IDs
	skipping to change at page 13, line 23		skipping to change at page 16, line 9
	7.2.2.1. MPLS-TP LSP_MEP_ID		7.2.2.1. MPLS-TP LSP_MEP_ID
	In order to automatically generate MEP_IDs for MPLS-TP LSPs, we use		In order to automatically generate MEP_IDs for MPLS-TP LSPs, we use
	the elements of identification that are unique to an endpoint. This		the elements of identification that are unique to an endpoint. This
	ensures that MEP_IDs are unique for all LSPs within a operator. When		ensures that MEP_IDs are unique for all LSPs within a operator. When
	Tunnels or LSPs cross operator boundaries, these are made unique by		Tunnels or LSPs cross operator boundaries, these are made unique by
	pre-pending them with the operator's Global_ID.		pre-pending them with the operator's Global_ID.
	The MPLS-TP LSP_MEP_ID is		The MPLS-TP LSP_MEP_ID is
	Node_ID::Tunnel_Num::LSP_Num,		Node_ID::Tunnel_Num::LSP_Num
	where the Node_ID is the node in which the MEP is located and		where the Node_ID is the node in which the MEP is located and
	Tunnel_Num is the tunnel number unique to that node. In the case of		Tunnel_Num is the tunnel number unique to that node. In the case of
	Associated Bi-directional LSPs, the LSP_Num unique to where the MEP		co-routed bidirectional LSPs, the single LSP_Num is used at both
	resides.		ends. In the case of associated bidirectional LSPs, the LSP_Num is
			the one unique to where the MEP resides.
	In situations where global uniqueness is required this becomes:		In situations where global uniqueness is required this becomes:
	Global_ID::Node_ID::Tunnel_Num::LSP_Num		Global_ID::Node_ID::Tunnel_Num::LSP_Num
	7.2.2.2. MEP_IDs for Pseudowires		7.2.2.2. MEP_IDs for Pseudowires
	Like MPLS-TP LSPs, Pseudowire endpoints (T-PEs) require MEP_IDs. In		Like MPLS-TP LSPs, Pseudowire endpoints (T-PEs) require MEP_IDs. In
	order to automatically generate MEP_IDs for PWs, we simply use the		order to automatically generate MEP_IDs for PWs, we simply use the
	AGI plus the AII associated with that end of the PW. Thus a MEP_ID		AGI plus the AII associated with that end of the PW. Thus a MEP_ID
	skipping to change at page 14, line 6		skipping to change at page 16, line 41
	AC_ID is the AC_ID of the Pseudowire at that node.		AC_ID is the AC_ID of the Pseudowire at that node.
	7.2.2.3. Pseudowire Segments Endpoint IDs		7.2.2.3. Pseudowire Segments Endpoint IDs
	In some OAM communications, messages are originated by the node at		In some OAM communications, messages are originated by the node at
	one end of a PW segment and relayed to the other end of that same		one end of a PW segment and relayed to the other end of that same
	segment by setting the TTL of the PW label to one (1). For a multi-		segment by setting the TTL of the PW label to one (1). For a multi-
	segment pseudowire, TTL could be set to any value that would cause		segment pseudowire, TTL could be set to any value that would cause
	OAM messages to reach the target segment end-point (up to and		OAM messages to reach the target segment end-point (up to and
	including 255). In such communications an identifier for the		including 255). In such communications an identifier for the
	pseudowire segment endpoint. We call this a Pseudowire Segments		pseudowire segment endpoint is needed. We call this a Pseudowire
	Endpoint ID or PW_SE_ID.		Segments Endpoint ID or PW_SE_ID.
	The PW_SE_ID is formed by a combination of a PW MEP_ID and the		The PW_SE_ID is formed by a combination of a PW MEP_ID and the
	identification of the local node. At an S-PE, there are two PW		identification of the local node. At an S-PE, there are two PW
	segments. We distinguish the segments by using the MEP_ID which is		segments. We distinguish the segments by using the MEP_ID which is
	upstream of the PW segment in question. To complete the		upstream of the PW segment in question. To complete the
	identification we suffix this with the identification of the local		identification we suffix this with the identification of the local
	node.		node.
	+-------+ +-------+ +-------+ +-------+		+-------+ +-------+ +-------+ +-------+
	| | | | | | | |		| | | | | | | |
	skipping to change at page 14, line 29		skipping to change at page 17, line 18
	| | | | | | | |		| | | | | | | |
	+-------+ +-------+ +-------+ +-------+		+-------+ +-------+ +-------+ +-------+
	(T)PE1 (S)PE2 (S)PE3 (T)PE4		(T)PE1 (S)PE2 (S)PE3 (T)PE4
	Pseudowire Maintenance Points		Pseudowire Maintenance Points
	For example, suppose that in the above figure all of the nodes have		For example, suppose that in the above figure all of the nodes have
	Global_ID GID1; the node are represented as named in the figure; and		Global_ID GID1; the node are represented as named in the figure; and
	The identification for the Pseudowire is:		The identification for the Pseudowire is:
	AGI = AGI1		AGI = AGI1
	East-Global_ID = GID1		A1-Global_ID = GID1
	East-Node_ID = PE1		A1-Node_ID = PE1
	East-AC_ID = AII1		A1-AC_ID = AII1
	West-Global_ID = GID1		Z9-Global_ID = GID1
	West-Node_ID = PE4		Z9-Node_ID = PE4
	West-AC_ID = AII4		Z9-AC_ID = AII4
	The MEP_ID at point A would be -		The MEP_ID at point A would be -
	AGI1::GID1::PE1::AII1		AGI1::GID1::PE1::AII1
			The PW_SE_ID at point B would be -
			AGI1::GID1::PE4::AII4::GID1::PE2
	The PW_SE_ID at point C would be -		The PW_SE_ID at point C would be -
	AGI1::GID1::PE1::AII1::GID1::PE2		AGI1::GID1::PE1::AII1::GID1::PE2
	7.3. MIP Identifiers		7.3. MIP Identifiers
	At a cross-connect point, in order to automatically generate MIP_IDs		At a cross-connect point, in order to automatically generate MIP_IDs
	for MPLS-TP, we simply use the IF_IDs of the two interfaces which are		for MPLS-TP, we simply use the IF_IDs of the two interfaces which are
	cross-connected via the label bindings of the MPLS-TP LSP. This		cross-connected via the label bindings of the MPLS-TP LSP or PW.
	allows, two MIPs to be independently identified in one node where a		This allows, two MIPs to be independently identified in one node
	per-interface MIP model is used. If only a per node MIP model is		where a per-interface MIP model is used. If only a per node MIP
	used then one MIP is configured. In this case the MIP_ID is formed		model is used then one MIP is configured. In this case the MIP_ID is
	using the Node_ID and an IF_Num of 0.		formed using the Node_ID and an IF_Num of 0.
	8. IANA Considerations		8. IANA Considerations
	There are no IANA actions resulting from this document.		There are no IANA actions resulting from this document.
	9. Security Considerations		9. Security Considerations
	This document describes an information model and, as such, does not		This document describes an information model and, as such, does not
	introduce security concerns. Protocol specifications that describe		introduce security concerns. Protocol specifications that describe
	use of this information model - however - may introduce security		use of this information model, however, may introduce security risks
	risks and concerns about authentication of participants. For this		and concerns about authentication of participants. For this reason,
	reason, the writers of protocol specifications for the purpose of		the writers of protocol specifications for the purpose of describing
	describing implementation of this information model need to describe		implementation of this information model need to describe security
	security and authentication concerns that may be raised by the		and authentication concerns that may be raised by the particular
	particular mechanisms defined and how those concerns may be		mechanisms defined and how those concerns may be addressed.
	addressed.
	10. References		10. References
	10.1. Normative References		10.1. Normative References
	[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement		[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
	Levels", BCP 14, RFC 2119, March 1997.		Levels", BCP 14, RFC 2119, March 1997.
	[2] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G.		[2] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G.
	Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels",		Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels",
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