draft-ietf-mpls-cr-ldp-01.txt		draft-ietf-mpls-cr-ldp-02.txt
			MPLS WG Bilel Jamoussi, Editor
	MPLS Working Group Bilel Jamoussi, Editor		Internet Draft Nortel Networks Corp.
	Internet Draft Nortel Networks		Expiration Date: February 2000
	Expiration Date: August 1999		August 1999
	February 1999
	Constraint-Based LSP Setup using LDP		Constraint-Based LSP Setup using LDP
	draft-ietf-mpls-cr-ldp-01.txt		draft-ietf-mpls-cr-ldp-02.txt
	Status of this Memo		Status of this Memo
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	Copyright Notice
	Copyright (C) The Internet Society (1998). All Rights Reserved.
	Abstract		Abstract
	Label Distribution Protocol (LDP) is defined in [LDP] for		Label Distribution Protocol (LDP) is defined in [1] for distribution
	distribution of labels inside one MPLS domain. One of the most		of labels inside one MPLS domain. One of the most important
	important services that may be offered using MPLS in general and LDP		services that may be offered using MPLS in general and LDP in
	in particular is support for constraint-based routing of traffic		particular is support for constraint-based routing of traffic across
	across the routed network. Constraint-based routing offers the		the routed network. Constraint-based routing offers the opportunity
	opportunity to extend the information used to setup paths beyond what		to extend the information used to setup paths beyond what is
	is available for the routing protocol. For instance, an LSP can be		available for the routing protocol. For instance, an LSP can be
	setup based on explicit route constraints, QoS constraints, and		setup based on explicit route constraints, QoS constraints, and
	others. Constraint-based routing (CR) is a mechanism used to meet		other constraints. Constraint-based routing (CR) is a mechanism used
	Traffic Engineering requirements that have been proposed by [FRAME],		to meet Traffic Engineering requirements that have been proposed by
	[ARCH] and [TER]. These requirements may be met by extending LDP for		[2], [3] and [4]. These requirements may be met by extending LDP for
	support of constraint-based routed label switched paths (CRLSPs).		support of constraint-based routed label switched paths (CRLSPs).
			Other uses exist for CRLSPs as well ([5], [6] and [7]).
	CR-LDP Specification - 2 - Exp. August 1999
	Other uses exist for CRLSPs as well ([VPN1], [VPN2] and [VPN3]).
	This draft specifies mechanisms and TLVs for support of CRLSPs using		This draft specifies mechanisms and TLVs for support of CRLSPs using
	LDP. The Explicit Route object and procedures are extracted from		LDP. The Explicit Route object and procedures are extracted from
	[ER].		[8].
	Table of Contents		Table of Contents
	1. Introduction ......................................... 3		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 1 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	2. Constraint-based Routing Overview .................... 3
	2.1 Strict and Loose Explicit Routes ..................... 4
	2.2 Traffic Characteristics .............................. 4
	2.3 Pre-emption .......................................... 5
	2.4 Route Pinning ........................................ 5
	2.5 Resource Class ....................................... 5
	3. Solution Overview .................................... 5
	3.1 Required Messages and TLVs ........................... 7
	3.2 Label Request Message ................................ 7
	3.3 Label Mapping Message ................................ 8
	3.4 Notification Message ................................. 9
	3.5 Release & Withdraw Messages .......................... 9
	4. Protocol Specification .............................. 9
	4.1 Explicit Route TLV (ER-TLV) ......................... 10
	4.2 Explicit Route Hop TLV .............................. 10
	4.3 Traffic Parameters TLV .............................. 12
	4.3.1 Semantics ........................................... 13
	4.3.1.1 Frequency ........................................... 13
	4.3.1.2 Peak Rate ........................................... 14
	4.3.1.3 Committed Rate ...................................... 14
	4.3.1.4 Excess Burst Size .................................... 14
	4.3.1.5 Peak Rate Token Bucket................................ 14
	4.3.1.6 Committed Data Rate Token Bucket ..................... 15
	4.3.1.7 Weight ......................... ..................... 16
	4.3.2 Procedures ........................................... 16
	4.3.2.1 Label Request Message ................................ 16
	4.3.2.2 Label Mapping Message ................................ 16
	4.3.2.3 Notification Message ................................. 17
	4.4 Preemption TLV ....................................... 18
	4.5 LSPID TLV ........................................... 18
	4.6 Resource Class TLV .................................. 19
	4.7 ER-Hop Semantics ..................................... 19
	4.7.1 ER-Hop 1 TLV IPv4 Prefix ............................. 20
	4.7.2 ER-Hop 2 TLV IPv6 Prefix ............................. 20
	4.7.3 ER-Hop 3 TLV AS Number ............................... 21
	4.7.4 ER-Hop 4 TLV LSPID ................................... 21
	4.8 Processing of the ER-TLV ............................. 22
	4.8.1 Selection of the next hop ............................ 22
	4.8.2 Adding the Label Request Message to the next hop ..... 24
	4.9 Route Pinning TLV ................................... 24
	4.10 CR-LSP FEC Element ................................... 24
	4.11 Error Subcodes ...................................... 25
	CR-LDP Specification - 3 - Exp. August 1999
	5. Security Considerations .............................. 26		1. Introduction....................................................3
	6. Acknowledgement ...................................... 26		2. Constraint-based Routing Overview...............................3
	7. References ........................................... 26		2.1 Strict and Loose Explicit Routes...............................3
	8. Author Information ................................... 28		2.2 Traffic Characteristics........................................4
			2.3 Pre-emption....................................................4
			2.4 Route Pinning..................................................5
			2.5 Resource Class.................................................5
			3. Solution Overview...............................................5
			3.1 Required Messages and TLVs.....................................6
			3.2 Label Request Message..........................................7
			3.3 Label Mapping Message..........................................7
			3.4 Notification Message...........................................8
			3.5 Release , Withdraw, and Abort Messages.........................9
			4. Protocol Specification..........................................9
			4.1 Explicit Route TLV (ER-TLV)....................................9
			4.2 Explicit Route Hop TLV (ER-Hop TLV)...........................10
			4.3 Traffic Parameters TLV........................................11
			4.3.1 Semantics...................................................13
			4.3.1.1 Frequency.................................................13
			4.3.1.2 Peak Rate.................................................13
			4.3.1.3 Committed Rate............................................13
			4.3.1.4 Excess Burst Size.........................................14
			4.3.1.5 Peak Rate Token Bucket....................................14
			4.3.1.6 Committed Data Rate Token Bucket..........................14
			4.3.1.7 Weight....................................................15
			4.3.2 Procedures..................................................15
			4.3.2.1 Label Request Message.....................................15
			4.3.2.2 Label Mapping Message.....................................16
			4.3.2.3 Notification Message......................................16
			4.4 Preemption TLV................................................16
			4.5 LSPID TLV.....................................................17
			4.6 Resource Class (Color) TLV....................................18
			4.7 ER-Hop semantics..............................................19
			4.7.1. ER-Hop 1: The IPv4 prefix..................................19
			4.7.2. ER-Hop 2: The IPv6 address.................................19
			4.7.3. ER-Hop 3: The autonomous system number....................20
			4.7.4. ER-Hop 4: LSPID............................................20
			4.8. Processing of the Explicit Route TLV.........................22
			4.8.1. Selection of the next hop..................................22
			4.8.2. Adding ER-Hops to the explicit route TLV...................23
			4.9 Route Pinning TLV.............................................23
			4.10 CRLSP FEC Element............................................24
			4.11 Error subcodes...............................................24
			5. Security.......................................................25
			6. Acknowledgments................................................25
			7. Intellectual Property Consideration............................25
			8. References.....................................................25
			9. Author's Addresses.............................................26
			Appendix A: CRLSP Establishment Examples..........................29
			A.1 Strict Explicit Route Example.................................29
			A.2. Node Groups and Specific Nodes Example.......................30
	Appendix A CRLSP Establishment Examples ......................... 30		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 2 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	A.1 Strict Explicit Route Example ........................ 30
	A.2 Node Groups and Specific Nodes Example ............... 31
	Appendix B QoS Service Examples ................................. 34		Appendix B. QoS Service Examples..................................33
	B.1 Service Examples ..................................... 34		B.1 Service Examples..............................................33
	B.2 Establishing CR-LSP Supporting Real-Time Applications. 35		B.2. Establishing CR-LSP Supporting Real-Time Applications........34
	B.3 Establishing CR-LSP Delay Insensitive Applications ... 36		B.3. Establishing CR-LSP Supporting Delay Insensitive Applications35
	1. Introduction		1. Introduction
	The need for constraint-based routing (CR) in MPLS has been explored		The need for constraint-based routing (CR) in MPLS has been explored
	elsewhere [ARCH], [FRAME], and [TER]. Explicit routing is a subset		elsewhere [3], [2], and [4]. Explicit routing is a subset of the
	of the more general constraint-based routing function. At the MPLS WG		more general constraint-based routing function. At the MPLS WG
	meeting held during the Washington IETF there was consensus that LDP		meeting held during the Washington IETF (December 1997) there was
	should support explicit routing of LSPs with provision for indication		consensus that LDP should support explicit routing of LSPs with
	of associated (forwarding) priority. In the Chicago meeting, a		provision for indication of associated (forwarding) priority. In
	decision was made that support for explicit path setup in LDP will be		the Chicago meeting (August 1998), a decision was made that support
	moved to a separate document. This document provides that support and		for explicit path setup in LDP will be moved to a separate document.
	it has been accepted as a working document in the Orlando meeting.		This document provides that support and it has been accepted as a
			working document in the Orlando meeting (December 1998).
	This specification proposes an end-to-end setup mechanism of a		This specification proposes an end-to-end setup mechanism of a
	constraint-based routed LSP (CRLSP) initiated by the ingress LSR. We		constraint-based routed LSP (CRLSP) initiated by the ingress LSR. We
	also specify mechanisms to provide means for reservation of resources		also specify mechanisms to provide means for reservation of
	using LDP.		resources using LDP.
	This document introduce TLVs and procedures that provide support for:
			This document introduce TLVs and procedures that provide support
			for:
	- Strict and Loose Explicit Routing		- Strict and Loose Explicit Routing
	- Specification of Traffic Parameters		- Specification of Traffic Parameters
	- Route Pinning		- Route Pinning
	- CRLSP Pre-emption though setup/holding priorities		- CRLSP Pre-emption though setup/holding priorities
	- Handling Failures		- Handling Failures
	- LSPID		- LSPID
	- Resource Class		- Resource Class
	Section 2 introduces the various constraints defined in this		Section 2 introduces the various constraints defined in this
	specification. Section 3 outlines the CR-LDP solution. Section 4		specification. Section 3 outlines the CR-LDP solution. Section 4
	defines the TLVs and procedures used to setup constraint-based routed		defines the TLVs and procedures used to setup constraint-based
	label switched paths. Appendix A provides several examples of CR-LSP		routed label switched paths. Appendix A provides several examples
	path setup. Appendix B provides Service Definition Examples.		of CR-LSP path setup. Appendix B provides Service Definition
			Examples.
	2. Constraint-based Routing Overview		2. Constraint-based Routing Overview
	Constraint-based routing is a mechanism that supports the Traffic		Constraint-based routing is a mechanism that supports the Traffic
	Engineering requirements defined in [TER]. Explicit Routing is a		Engineering requirements defined in [4]. Explicit Routing is a
	subset of the more general constraint-based routing where the		subset of the more general constraint-based routing where the
	CR-LDP Specification - 4 - Exp. August 1999
	constraint is the explicit route (ER). Other constraints are defined		constraint is the explicit route (ER). Other constraints are defined
	to provide a network operator with control over the path taken by an		to provide a network operator with control over the path taken by an
	LSP. This section is an overview of the various constraints supported		LSP. This section is an overview of the various constraints
	by this specification.		supported by this specification.
	2.1 Strict and Loose Explicit Routes		2.1 Strict and Loose Explicit Routes
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 3 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	Like any other LSP an CRLSP is a path through an MPLS network. The		Like any other LSP an CRLSP is a path through an MPLS network. The
	difference is that while other paths are setup solely based on		difference is that while other paths are setup solely based on
	information in routing tables or from a management system, the		information in routing tables or from a management system, the
	constraint-based route is calculated at one point at the edge of		constraint-based route is calculated at one point at the edge of
	network based on criteria, including but not limited to routing		network based on criteria, including but not limited to routing
	information. The intention is that this functionality shall give		information. The intention is that this functionality shall give
	desired special characteristics to the LSP in order to better support		desired special characteristics to the LSP in order to better
	the traffic sent over the LSP. The reason for setting up CRLSPs,		support the traffic sent over the LSP. The reason for setting up
	might be that one wants to assign certain bandwidth or other Service		CRLSPs, might be that one wants to assign certain bandwidth or other
	Class characteristics to the LSP, or that one wants to make sure that		Service Class characteristics to the LSP, or that one wants to make
	alternative routes use physically separate paths through the network.		sure that alternative routes use physically separate paths through
			the network.
	An explicit route is represented in a Label Request Message as a		An explicit route is represented in a Label Request Message as a
	list of nodes or groups of nodes along the constraint-based route.		list of nodes or groups of nodes along the constraint-based route.
	When the CRLSP is established, all or a subset of the nodes in a		When the CRLSP is established, all or a subset of the nodes in a
	group may be traversed by the LSP. Certain operations to be		group may be traversed by the LSP. Certain operations to be
	performed along the path can also be encoded in the constraint-based		performed along the path can also be encoded in the constraint-based
	route.		route.
	The capability to specify, in addition to specified nodes, groups of		The capability to specify, in addition to specified nodes, groups of
	nodes, of which a subset will be traversed by the CRLSP, allows the		nodes, of which a subset will be traversed by the CRLSP, allows the
	system a significant amount of local flexibility in fulfilling a		system a significant amount of local flexibility in fulfilling a
	request for a constraint-based route. This allows the generator of		request for a constraint-based route. This allows the generator of
	the constraint-based route to have some degree of imperfect		the constraint-based route to have some degree of imperfect
	information about the details of the path.		information about the details of the path.
	The constraint-based route is encoded as a series of ER-Hops		The constraint-based route is encoded as a series of ER-Hops
	contained in a constraint-based route TLV. Each ER-Hop may identify		contained in a constraint-based route TLV. Each ER-Hop may identify
	a group of nodes in the constraint-based route. A constraint-based		a group of nodes in the constraint-based route. A constraint-based
	route is then a path including all of the identified groups of nodes.		route is then a path including all of the identified groups of
			nodes.
	To simplify the discussion, we call each group of nodes an abstract		To simplify the discussion, we call each group of nodes an abstract
	node. Thus, we can also say that a constraint-based route is a path		node. Thus, we can also say that a constraint-based route is a path
	including all of the abstract nodes, with the specified operations		including all of the abstract nodes, with the specified operations
	occurring along that path.		occurring along that path.
	2.2 Traffic Characteristics		2.2 Traffic Characteristics
	The traffic characteristics of a path are described in the Traffic		The traffic characteristics of a path are described in the Traffic
	Parameters TLV in terms of a peak rate, committed rate, and service		Parameters TLV in terms of a peak rate, committed rate, and service
	granularity. The peak and committed rates describe the bandwidth		granularity. The peak and committed rates describe the bandwidth
	constraints of a path while the service granularity can be used to		constraints of a path while the service granularity can be used to
	specify a constraint on the delay variation that the CRLDP MPLS		specify a constraint on the delay variation that the CRLDP MPLS
	domain may introduce to a path's traffic.		domain may introduce to a path's traffic.
	CR-LDP Specification - 5 - Exp. August 1999
	2.3 Pre-emption		2.3 Pre-emption
	CR-LDP signals the resources required by a path on each hop of the		CR-LDP signals the resources required by a path on each hop of the
	route. If a route with sufficient resources can not be found,		route. If a route with sufficient resources can not be found,
	existing paths may be rerouted to reallocate resources to the new		existing paths may be rerouted to reallocate resources to the new
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 4 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	path. This is the process of path pre-emption. Setup and holding		path. This is the process of path pre-emption. Setup and holding
	priorities are used to rank existing paths (holding priority) and the		priorities are used to rank existing paths (holding priority) and
	new path (setup priority) to determine if the new path can pre-empt		the new path (setup priority) to determine if the new path can pre-
	an existing path.		empt an existing path.
	The setupPriority of a new CRLSP and the holdingPriority attributes		The setupPriority of a new CRLSP and the holdingPriority attributes
	of the existing CRLSP are used to specify priorities. Signaling a		of the existing CRLSP are used to specify priorities. Signaling a
	higher holding priority expresses that the path, once it has been		higher holding priority express that the path, once it has been
	established, should have a lower chance of being pre-empted.		established, should have a lower chance of being pre-empted.
	Signaling a higher setup priority expresses the expectation that, in		Signaling a higher setup priority expresses the expectation that, in
	the case that resource are unavailable, the path is more likely to		the case that resource are unavailable, the path is more likely to
	pre-empt other paths. The exact rules determining bumping are an		pre-empt other paths. The exact rules determining bumping are an
	aspect of network policy.		aspect of network policy.
	The allocation of setup and holding priority values to paths is an		The allocation of setup and holding priority values to paths is an
	aspect of network policy.		aspect of network policy.
	The setup and holding priority values range from zero (0) to seven		The setup and holding priority values range from zero (0) to seven
	(7). The value zero (0) is the priority assigned to the most		(7). The value zero (0) is the priority assigned to the most
	important path. It is referred to as the highest priority. Seven (7)		important path. It is referred to as the highest priority. Seven (7)
	is the priority for the least important path. The use of default		is the priority for the least important path. The use of default
	priority values is an aspect of network policy.		priority values is an aspect of network policy.
	The setupPriority of a CRLSP should not be higher (numerically less)		The setupPriority of a CRLSP should not be higher (numerically less)
	than its holdingPriority since it might bump an LSP and be bumped by		than its holdingPriority since it might bump an LSP and be bumped by
	next "equivalent" request.		next _equivalent_ request.
	2.4 Route Pinning		2.4 Route Pinning
	Route pinning is applicable to segments of an LSP that are loosely		Route pinning is applicable to segments of an LSP that are loosely
	routed - i.e. those segments which are specified with a next hop with		routed - i.e. those segments which are specified with a next hop
	the 'L' bit set or where the next hop is an "abstract node". A CRLSP		with the `L' bit set or where the next hop is an _abstract node_. A
	may be setup using route pinning if it is undesirable to change the		CRLSP may be setup using route pinning if it is undesirable to
	path used by an LSP because a better next hop becomes available at		change the path used by an LSP because a better next hop becomes
	some LSR along the loosely routed portion of the LSP.		available at some LSR along the loosely routed portion of the LSP.
	2.5 Resource Class		2.5 Resource Class
	Network resources may be classified in various ways by the network		The network operator may classify network resources in various ways.
	operator. These classes are also known as "colors" or "administrative		These classes are also known as _colors_ or _administrative groups_.
	groups". When an CR-LSP is being established, it's necessary to		When an CR-LSP is being established, it's necessary to indicate
	indicate which resource classes the CR-LSP can draw from.		which resource classes the CR-LSP can draw from.
	3. Solution Overview		3. Solution Overview
	CRLSP over LDP Specification is designed with the following goals:		CRLSP over LDP Specification is designed with the following goals:
	CR-LDP Specification - 6 - Exp. August 1999		1. Meet the requirements outlined in [4] for performing traffic
			engineering and provide a solid foundation for performing
			more general constraint-based routing.
	1. Meet the requirements outlined in [TER] for performing traffic		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 5 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	engineering and provide a solid foundation for performing more
	general constraint-based routing.
	2. Build on already specified functionality that meets the		2. Build on already specified functionality that meets the
	requirements whenever possible. Hence, this specifications is		requirements whenever possible. Hence, this specification is
	based on [LDP] and the Explicit Route object and procedures		based on [1] and the Explicit Route object and procedures
	defined in [ER].		defined in [8].
	3. Keep the solution simple.		3. Keep the solution simple.
	In this document, support for unidirectional point-to-point CRLSPs is		In this document, support for unidirectional point-to-point CRLSPs
	specified. Support for point-to-multipoint, multipoint-to-point, is		is specified. Support for point-to-multipoint, multipoint-to-point,
	for further study (FFS).		is for further study (FFS).
	Support for constraint-based routed LSPs in this specification		Support for constraint-based routed LSPs in this specification
	depends on the following minimal LDP behaviors as specified in [LDP]:		depends on the following minimal LDP behaviors as specified in [1]:
	- Basic and/or Extended Discovery Mechanisms.		- Basic and/or Extended Discovery Mechanisms.
			- Use the Label Request Message defined in [1] in downstream on
	- Use the Label Request Message defined in [LDP] in downstream on
	demand label advertisement mode with ordered control.		demand label advertisement mode with ordered control.
			- Use the Label Mapping Message defined in [1] in downstream on
	- Use the Label Mapping Message defined in [LDP] in downstream on
	demand mode with ordered control.		demand mode with ordered control.
			- Use the Notification Message defined in [1].
	- Use the Notification Message defined in [LDP].		- Use the Withdraw and Release Messages defined in [1].
	- Use the Withdraw and Release Messages defined in [LDP].
	- Use the Loop Detection (in the case of loosely routed segments		- Use the Loop Detection (in the case of loosely routed segments
	of a CRLSP) mechanisms defined in [LDP].		of a CRLSP) mechanisms defined in [1].
	In addition, the following functionality is added to what's defined		In addition, the following functionality is added to what's defined
	in [LDP]:		in [1]:
	- The Label Request Message used to setup a CRLSP includes one or		- The Label Request Message used to setup a CRLSP includes one or
	more CR-TLVs defined in Section 4. For instance, the Label Request		more CR-TLVs defined in Section 4. For instance, the Label
	Message may include the ER-TLV.		Request Message may include the ER-TLV.
	- An LSR implicitly infers ordered control from the existence of		- An LSR implicitly infers ordered control from the existence of
	one or more CR-TLVs in the Label Request Message. This means that		one or more CR-TLVs in the Label Request Message. This means
	the LSR can still be configured for independent control for LSPs		that the LSR can still be configured for independent control
	established as a result of dynamic routing. However, when a Label		for LSPs established as a result of dynamic routing. However,
	Request Message includes one or more of the CR-TLVs, then ordered		when a Label Request Message includes one or more of the CR-
	control is used to setup the CRLSP. Note that this is also true		TLVs, then ordered control is used to setup the CRLSP. Note
	for the loosely routed parts of a CRLSP.		that this is also true for the loosely routed parts of a CRLSP.
	- New status codes are defined to handle error notification for		- New status codes are defined to handle error notification for
	failure of established paths specified in the CR-TLV.		failure of established paths specified in the CR-TLV.
	CR-LDP Specification - 7 - Exp. August 1999		Optional TLVs are not required in the CR-LDP messages for the
			messages to be compliant with the protocol. Optional parameters CAN
			be required for a particular operation to work (or work correctly),
			however.
	Examples of CRLSP establishment are given in Appendix A to illustrate		Examples of CRLSP establishment are given in Appendix A to
	how the mechanisms described in this draft work.		illustrate how the mechanisms described in this draft work.
	3.1 Required Messages and TLVs		3.1 Required Messages and TLVs
	Any Messages, TLVs, and procedures not defined explicitly in this		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 6 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	document are defined in the [LDP] Specification. The state
	transitions which relate to CR-LDP messages can be found in [LDP-
	STATE].
	The following subsections are meant as a cross reference to the [LDP]		Any Messages, TLVs, and procedures not defined explicitly in this
			document are defined in the LDP Specification [1]. The state
			transitions, which relate to CR-LDP messages, can be found in [9].
			The following subsections are meant as a cross-reference to the [1]
	document and indication of additional functionality beyond what's		document and indication of additional functionality beyond what's
	defined in [LDP] where necessary.		defined in [1] where necessary.
	3.2 Label Request Message		3.2 Label Request Message
	The Label Request Message is as defined in 3.5.8 of [LDP] with the		The Label Request Message is as defined in 3.5.8 of [1] with the
	following modifications (required only if any of the CR-TLVs is		following modifications (required only if any of the CR-TLVs is
	included in the Label Request Message):		included in the Label Request Message):
	- Only a single FEC-TLV may be included in the Label Request		- Only a single FEC-TLV may be included in the Label Request
	Message. The CR-LSP FEC TLV should be used.		Message. The CR-LSP FEC TLV should be used.
	- The Return Message ID TLV is MANDATORY.
	- The Optional Parameters TLV includes the definition of any of		- The Optional Parameters TLV includes the definition of any of
	the Constraint-based TLVs specified in Section 4.		the Constraint-based TLVs specified in Section 4.
	- The Procedures to handle the Label Request Message are augmented		- The Procedures to handle the Label Request Message are
	by the procedures for processing of the CR-TLVs as defined in		augmented by the procedures for processing of the CR-TLVs as
	Section 4.		defined in Section 4.
	The encoding for the CR-LDP Label Request Message is as follows:		The encoding for the CR-LDP Label Request Message is as follows:
	CR-LDP Specification - 8 - Exp. August 1999
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U| Label Request (0x0401) | Message Length |		|0| Label Request (0x0401) | Message Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Message ID |		| Message ID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| FEC TLV |		| FEC TLV |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Return Message ID TLV (mandatory) |		| Message ID TLV (mandatory) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| LSPID TLV (CR-LDP, mandatory) |		| LSPID TLV (CR-LDP, mandatory) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| ER-TLV (CR-LDP, optional) |		| ER-TLV (CR-LDP, optional) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Traffic TLV (CR-LDP, optional) |		| Traffic TLV (CR-LDP, optional) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Pinning TLV (CR-LDP, optional) |		| Pinning TLV (CR-LDP, optional) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Resource Class TLV (CR-LDP, optional) |		| Resource Class TLV (CR-LDP, optional) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Pre-emption TLV (CR-LDP, optional) |		| Pre-emption TLV (CR-LDP, optional) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	3.3 Label Mapping Message		3.3 Label Mapping Message
	The Label Mapping Message is as defined in 3.5.7 of [LDP] with the		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 7 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
			The Label Mapping Message is as defined in 3.5.7 of [1] with the
	following modifications:		following modifications:
	- Only a single Label-TLV may be included in the Label Mapping		- Only a single Label-TLV may be included in the Label Mapping
	Message.		Message.
	- The Label Mapping Message MUST include Label Request Message ID
	TLV.
	- The Label Mapping Message MUST include LSPID TLV.
	- The Label Mapping Message Procedures are limited to downstream		- The Label Mapping Message Procedures are limited to downstream
	on demand ordered control mode.		on demand ordered control mode.
	A Mapping message is transmitted by a downstream LSR to an upstream		A Mapping message is transmitted by a downstream LSR to an upstream
	LSR under one of the following conditions:		LSR under one of the following conditions:
	1. The LSR is the egress end of the CRLSP and an upstream mapping		1. The LSR is the egress end of the CRLSP and an upstream
	has been requested.		mapping has been requested.
	2. The LSR received a mapping from its downstream next hop LSR for		2. The LSR received a mapping from its downstream next hop LSR
	an CRLSP for which an upstream request is still pending.		for an CRLSP for which an upstream request is still pending.
	The encoding for the CR-LDP Label Mapping Message is as follows:		The encoding for the CR-LDP Label Mapping Message is as follows:
	CR-LDP Specification - 9 - Exp. August 1999
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U| Label Mapping (0x0400) | Message Length |		|0| Label Mapping (0x0400) | Message Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Message ID |		| Message ID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| FEC TLV |		| FEC TLV |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Label TLV |		| Label TLV |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Label Request Message ID TLV (mandatory) |		| Label Request Message ID TLV |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| LSPID TLV (CR-LDP, mandatory) |		| LSPID TLV (CR-LDP, optional) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Traffic TLV (CR-LDP, optional) |		| Traffic TLV (CR-LDP, optional) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	3.4 Notification Message		3.4 Notification Message
	The Notification Message is as defined in Section 3.5.1 of [LDP] and		The Notification Message is as defined in Section 3.5.1 of [1] and
	the Status TLV encoding is as defined in Section 3.4.7 of [LDP].		the Status TLV encoding is as defined in Section 3.4.7 of [1].
	Establishment of an Explicitly Routed LSP may fail for a variety of		Establishment of an Explicitly Routed LSP may fail for a variety of
	reasons. All such failures are considered advisory conditions and		reasons. All such failures are considered advisory conditions and
	they are signaled by the Notification Message.		they are signaled by the Notification Message.
	Notification Messages carry Status TLVs to specify events being		Notification Messages carry Status TLVs to specify events being
	signaled. New status codes are defined in Section 4.11 to signal		signaled. New status codes are defined in Section 4.11 to signal
	error notifications associated with the establishment of a CRLSP and		error notifications associated with the establishment of a CRLSP and
	the processing of the CR-TLV.		the processing of the CR-TLV.
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 8 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	The Notification Message must carry the LSPID TLV of the		The Notification Message must carry the LSPID TLV of the
	corresponding CRLSP.		corresponding CRLSP.
	3.5 Release and Withdraw Messages		Notification Messages MUST be forwarded toward the LSR originating
			the Label Request at each hop and at any time that procedures in
			this specification - or in [1] - specify sending of a Notification
			Message in response to a Label Request Message.
	The Label Release and Label Withdraw Messages are used as specified		The encoding of the notification message is as follows:
	in [LDP] to clear CR-LSPs. These message may also carry the LSPID
	TLV.		0 1 2 3
			0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			|0| Notification (0x0001) | Message Length |
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			| Message ID |
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			| Status (TLV) |
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			| Optional Parameters |
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			3.5 Release , Withdraw, and Abort Messages
			The Label Release , Label Withdraw, and Label Abort Request Messages
			are used as specified in [1]. These messages may also carry the
			LSPID TLV.
	4. Protocol Specification		4. Protocol Specification
	The Label Request Messages defined in [LDP] optionally carries one or		The Label Request Messages defined in [1] optionally carries one or
	more of the optional Constraint-based Routing TLVs (CR-TLVs) defined		more of the optional Constraint-based Routing TLVs (CR-TLVs) defined
	in this section. If needed, other constraints can be supported later		in this section. If needed, other constraints can be supported later
	through the definition of new TLVs. In this specification, the		through the definition of new TLVs. In this specification, the
	following TLVs are defined:		following TLVs are defined:
	- Explicit Route TLV		- Explicit Route TLV
	CR-LDP Specification - 10 - Exp. August 1999
	- Explicit Route Hop TLV		- Explicit Route Hop TLV
	- Traffic Parameters TLV		- Traffic Parameters TLV
	- Preemption TLV		- Preemption TLV
	- LSPID TLV		- LSPID TLV
	- Route Pinning TLV		- Route Pinning TLV
	- Resource Class TLV		- Resource Class TLV
	- CRLSP FEC TLV		- CRLSP FEC TLV
	4.1 Explicit Route TLV (ER-TLV)		4.1 Explicit Route TLV (ER-TLV)
	The ER-TLV is an object that specifies the path to be taken by the		The ER-TLV is an object that specifies the path to be taken by the
	LSP being established. It is composed of one or more Explicit Route		LSP being established. It is composed of one or more Explicit Route
	Hop TLVs (ER-Hop TLVs) defined in Section 4.2.		Hop TLVs (ER-Hop TLVs) defined in Section 4.2.
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 9 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| ER-TLV (0x0800) | Length |		|0|0| ER-TLV (0x0800) | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| ER-Hop TLV 1 |		| ER-Hop TLV 1 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| ER-Hop TLV 2 |		| ER-Hop TLV 2 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ ............ ~		~ ............ ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| ER-Hop TLV n |		| ER-Hop TLV n |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	U bit
	Unknown TLV bit. As defined in [LDP].
	F bit
	Forward unknown TLV bit. As defined in [LDP].
	Type		Type
	A two byte field carrying the value of the ER-TLV type which		A two-byte field carrying the value of the ER-TLV type whichis
	is 0x800.		0x800.
	Length		Length
	Specifies the length of the value field in bytes.		Specifies the length of the value field in bytes.
	ER-Hop TLVs		ER-Hop TLVs
	One or more ER-Hop TLVs defined in Section 4.2.		One or more ER-Hop TLVs defined in Section 4.2.
	4.2 Explicit Route Hop TLV (ER-Hop TLV)		4.2 Explicit Route Hop TLV (ER-Hop TLV)
	The contents of an ER-TLV are a series of variable length ER-Hop		The contents of an ER-TLV are a series of variable length ER-Hop
	TLVs. Each ER-Hop TLV has the form:		TLVs.
	CR-LDP Specification - 11 - Exp. August 1999		A node receiving a label request message including an ER-Hop type
			that is not supported should not progress the label request message
			to the downstream LSR and should send back a _No Route_ Notification
			Message.
			Each ER-Hop TLV has the form:
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| ER-Hop-Type | Length |		|0|0| ER-Hop-Type | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|L| Content // |		|L| Content // |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	U bit
	Unknown TLV bit. As defined in [LDP].
	F bit
	Forward unknown TLV bit. As defined in [LDP].
	ER-Hop Type		ER-Hop Type
	A fourteen-bit field indicating the type of contents of		A fourteen-bit field indicating the type of contents of the ER-
	the ER-Hop. Currently defined values are:		Hop. Currently defined values are:
	Value Type		Value Type
	----- ------------------------		----- ------------------------
	0x801 IPv4 prefix		0x801 IPv4 prefix
	0x802 IPv6 prefix		0x802 IPv6 prefix
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 10 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	0x803 Autonomous system number		0x803 Autonomous system number
	0x804 LSPID		0x804 LSPID
	Length		Length
	Specifies the length of the value field in bytes.		Specifies the length of the value field in bytes.
	L bit		L bit
	The L bit is an attribute of the ER-Hop. The L bit is set if the		The L bit is an attribute of the ER-Hop. The L bit is set if
	ER-Hop represents a loose hop in the explicit route. If the bit is		the ER-Hop ER-Hop represents a loose hop in the explicit route.
	not set, the ER-Hop represents a strict hop in the explicit route.		If the bit is not set, the ER-Hop represents a strict hop in
			the explicit route.
	The L bit in the ER-Hop is a one-bit attribute. If the L bit is
	set, then the value of the attribute is "loose." Otherwise, the
	value of the attribute is "strict." For brevity, we say that if
	the value of the ER-Hop attribute is loose then it is a "loose
	ER-Hop." Otherwise, it's a "strict ER-Hop." Further, we say that
	the abstract node of a strict or loose ER-Hop is a strict or a
	loose node, respectively. Loose and strict nodes are always
	interpreted relative to their prior abstract nodes.
			The L bit in the ER-Hop is a one-bit attribute. If the L bit
			is set, then the value of the attribute is _loose._ Otherwise,
			the value of the attribute is _strict._ For brevity, we say
			that if the value of the ER-Hop attribute is loose then it is a
			_loose ER-Hop._ Otherwise, it's a _strict ER-Hop._ Further,
			we say that the abstract node of a strict or loose ER-Hop is a
			strict or a loose node, respectively. Loose and strict nodes
			are always interpreted relative to their prior abstract nodes.
	The path between a strict node and its prior node MUST include		The path between a strict node and its prior node MUST include
	only network nodes from the strict node and its prior abstract		only network nodes from the strict node and its prior abstract
	node.		node.
	The path between a loose node and its prior node MAY include other		The path between a loose node and its prior node MAY include
	network nodes which are not part of the strict node or its prior		other network nodes, which are not part of the strict node or
	abstract node.		its prior abstract node.
	CR-LDP Specification - 12 - Exp. August 1999
	Contents		Contents
	A variable length field containing the node or abstract node that		A variable length field containing the node or abstract node
	is the consecutive nodes that make up the explicit routed LSP.		that is the consecutive nodes that make up the explicit routed
			LSP.
	4.3 Traffic Parameters TLV		4.3 Traffic Parameters TLV
	The following sections describe the CRLSP Traffic Parameters. The		The following sections describe the CRLSP Traffic Parameters. The
	required characteristics of a CRLSP are expressed by the Traffic		required characteristics of a CRLSP are expressed by the Traffic
	Parameter values.		Parameter values.
	A Traffic Parameters TLV, is used to signal the Traffic Parameter		A Traffic Parameters TLV, is used to signal the Traffic Parameter
	values. The Traffic Parameters are defined in the subsequent		values. The Traffic Parameters are defined in the subsequent
	sections.		sections.
	The Traffic Parameters TLV contains a Flags field, a Frequency, a		The Traffic Parameters TLV contains a Flags field, a Frequency, a
	Weight, and the five Traffic Parameters PDR, PBS, CDR, CBS, EBS. The		Weight, and the five Traffic Parameters PDR, PBS, CDR, CBS, EBS.
	Traffic Parameters TLV is shown below:		The Traffic Parameters TLV is shown below:
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 11 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| Traf. Param. TLV (0x0810)| Length |		|0|0| Traf. Param. TLV (0x0810)| Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Flags | Frequency | Reserved | Weight |		| Flags | Frequency | Reserved | Weight |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Peak Data Rate (PDR) |		| Peak Data Rate (PDR) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Peak Burst Size (PBS) |		| Peak Burst Size (PBS) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Committed Data Rate (CDR) |		| Committed Data Rate (CDR) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Committed Burst Size (CBS) |		| Committed Burst Size (CBS) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Excess Burst Size (EBS) |		| Excess Burst Size (EBS) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	U bit
	Unknown TLV bit. As defined in [LDP].
	F bit
	Forward unknown TLV bit. As defined in [LDP].
	Type		Type
	A fourteen-bit field carrying the value of the ER-TLV type which		A fourteen-bit field carrying the value of the ER-TLV type
	is 0x810.		which is 0x810.
	Length		Length
	Specifies the length of the value field in bytes.		Specifies the length of the value field in bytes.
	Flags		Flags
	The Flags field is shown below:		The Flags field is shown below:
	CR-LDP Specification - 13 - Exp. August 1999
	+--+--+--+--+--+--+--+--+		+--+--+--+--+--+--+--+--+
	| Res |F6|F5|F4|F3|F2|F1|		| Res |F6|F5|F4|F3|F2|F1|
	+--+--+--+--+--+--+--+--+		+--+--+--+--+--+--+--+--+
	Res - These bits are reserved.		Res - These bits are reserved.
	Zero on transmission.		Zero on transmission.
	Ignored on receipt.		Ignored on receipt.
	F1 - Corresponds to the PDR.		F1 - Corresponds to the PDR.
	F2 - Corresponds to the PBS.		F2 - Corresponds to the PBS.
	F3 - Corresponds to the CDR.		F3 - Corresponds to the CDR.
	skipping to change at page 13, line 31		skipping to change at line 640
	Each flag Fi is a Negotiable Flag corresponding to a Traffic		Each flag Fi is a Negotiable Flag corresponding to a Traffic
	Parameter. The Negotiable Flag value zero denotes NotNegotiable		Parameter. The Negotiable Flag value zero denotes NotNegotiable
	and value one denotes Negotiable.		and value one denotes Negotiable.
	Frequency		Frequency
	The Frequency field is coded as an 8 bit unsigned integer with		The Frequency field is coded as an 8 bit unsigned integer with
	the following code points defined:		the following code points defined:
	0 - Unspecified		0 - Unspecified
	1 - Frequent		1 - Frequent
	2 - VeryFrequest
	3-255 - Reserved
	Reserved		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 12 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
			2- VeryFrequest 3-255 - Reserved Reserved
	Zero on transmission. Ignored on receipt.		Zero on transmission. Ignored on receipt.
	Weight		Weight
	An 8 bit unsigned integer indicating the weight of the CRLSP.		An 8 bit unsigned integer indicating the weight of the CRLSP.
	Valid weight values are from 1 to 255. The value 0 means		Valid weight values are from 1 to 255. The value 0 means that
	that weight is not applicable for the CRLSP.		weight is not applicable for the CRLSP.
	Traffic Parameters		Traffic Parameters
	Each Traffic Parameter is encoded as a 32 bit IEEE single-		Each Traffic Parameter is encoded as a 32-bit IEEE single-
	precision floating point number. A value of positive infinity is		precision floating-point number. A value of positive infinity
	represented as an IEEE single-precision floating-point number with		is represented as an IEEE single-precision floating-point
	an exponent of all ones (255) and a sign and mantissa of all		number with an exponent of all ones (255) and a sign and
	zeros. The values PDR and CDR are in units of bytes per second.		mantissa of all zeros. The values PDR and CDR are in units of
	The values PBS, CBS and EBS are in units of bytes.		bytes per second. The values PBS, CBS and EBS are in units of
			bytes.
	The value of PDR MUST be greater than or equal to the value of CDR		The value of PDR MUST be greater than or equal to the value of
	in a correctly encoded Traffic Parameters TLV.		CDR in a correctly encoded Traffic Parameters TLV.
	4.3.1 Semantics		4.3.1 Semantics
	4.3.1.1 Frequency		4.3.1.1 Frequency
	CR-LDP Specification - 14 - Exp. August 1999
	The Frequency specifies at what granularity the CDR allocated to the		The Frequency specifies at what granularity the CDR allocated to the
	CRLSP is made available. The value VeryFrequently means that the		CRLSP is made available. The value VeryFrequently means that the
	available rate should average at least the CDR when measured over any		available rate should average at least the CDR when measured over
	time interval equal to or longer than the shortest packet time at the		any time interval equal to or longer than the shortest packet time
	CDR. The value Frequently means that the available rate should		at the CDR. The value Frequently means that the available rate
	average at least the CDR when measured over any time interval equal		should average at least the CDR when measured over any time interval
	to or longer than a small number of shortest packet times at the CDR.		equal to or longer than a small number of shortest packet times at
			the CDR.
	The value Unspecified means that the CDR MAY be provided at any		The value Unspecified means that the CDR MAY be provided at any
	granularity.		granularity.
	4.3.1.2 Peak Rate		4.3.1.2 Peak Rate
	The Peak Rate defines the maximum rate at which traffic SHOULD be		The Peak Rate defines the maximum rate at which traffic SHOULD be
	sent to the CRLSP. The Peak Rate is useful for the purpose of		sent to the CRLSP. The Peak Rate is useful for the purpose of
	resource allocation. If resource allocation within the MPLS domain		resource allocation. If resource allocation within the MPLS domain
	depends on the Peak Rate value then it should be enforced at the		depends on the Peak Rate value then it should be enforced at the
	ingress to the MPLS domain.		ingress to the MPLS domain.
	The Peak Rate is defined in terms of the two Traffic Parameters PDR		The Peak Rate is defined in terms of the two Traffic Parameters PDR
	and PBS, see section 4.3.1.5 below.		and PBS, see section 4.3.1.5 below.
	4.3.1.3 Committed Rate		4.3.1.3 Committed Rate
	The Committed Rate defines the rate that the MPLS domain commits to		The Committed Rate defines the rate that the MPLS domain commits to
	be available to the CRLSP.		be available to the CRLSP.
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 13 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	The Committed Rate is defined in terms of the two Traffic Parameters		The Committed Rate is defined in terms of the two Traffic Parameters
	CDR and CBS, see section 4.3.1.6 below.		CDR and CBS, see section 4.3.1.6 below.
	4.3.1.4 Excess Burst Size		4.3.1.4 Excess Burst Size
	The Excess Burst Size may be used at the edge of an MPLS domain for		The Excess Burst Size may be used at the edge of an MPLS domain for
	the purpose of traffic conditioning. The EBS MAY be used to measure		the purpose of traffic conditioning. The EBS MAY be used to measure
	the extent by which the traffic sent on a CRLSP exceeds the committed		the extent by which the traffic sent on a CRLSP exceeds the
	rate.		committed rate.
	The possible traffic conditioning actions, such as passing, marking		The possible traffic conditioning actions, such as passing, marking
	or dropping, are specific to the MPLS domain.		or dropping, are specific to the MPLS domain.
	The Excess Burst Size is defined together with the Committed Rate,		The Excess Burst Size is defined together with the Committed Rate,
	see section 4.3.1.6 below.		see section 4.3.1.6 below.
	4.3.1.5 Peak Rate Token Bucket		4.3.1.5 Peak Rate Token Bucket
	The Peak Rate of a CRLSP is specified in terms of a token bucket P		The Peak Rate of a CRLSP is specified in terms of a token bucket P
	with token rate PDR and maximum token bucket size PBS.		with token rate PDR and maximum token bucket size PBS.
	The token bucket P is initially (at time 0) full, i.e., the token		The token bucket P is initially (at time 0) full, i.e., the token
	count Tp(0) = PBS. Thereafter, the token count Tp, if less than PBS,		count Tp(0) = PBS. Thereafter, the token count Tp, if less than
	is incremented by one PDR times per second. When a packet of size B		PBS, is incremented by one PDR times per second. When a packet of
	bytes arrives at time t, the following happens:		size B bytes arrives at time t, the following happens:
	CR-LDP Specification - 15 - Exp. August 1999
	o If Tp(t)-B >= 0, the packet is not in excess of the peak		- If Tp(t)-B >= 0, the packet is not in excess of the peak rate
	rate and Tp is decremented by B down to the minimum value		and Tp is decremented by B down to the minimum value of 0, else
	of 0, else
	o the packet is in excess of the peak rate and Tp is		- the packet is in excess of the peak rate and Tp is not
	not decremented.		decremented.
	Note that according to the above definition, a positive infinite		Note that according to the above definition, a positive infinite
	value of either PDR or PBS implies that arriving packets are never in		value of either PDR or PBS implies that arriving packets are ever in
	excess of the peak rate.		excess of the peak rate.
	The actual implementation of a LSR doesn't need to be modeled		The actual implementation of a LSR doesn't need to be modeled
	according to the above formal token bucket specification.		according to the above formal token bucket specification.
	4.3.1.6 Committed Data Rate Token Bucket		4.3.1.6 Committed Data Rate Token Bucket
	The committed rate of a CRLSP is specified in terms of a token bucket		The committed rate of a CRLSP is specified in terms of a token
	C with rate CDR. The extent by which the offered rate exceeds the		bucket C with rate CDR. The extent by which the offered rate
	committed rate MAY be measured in terms of another token bucket E,		exceeds the committed rate MAY be measured in terms of another token
	which also operates at rate CDR. The maximum size of the token		bucket E, which also operates at rate CDR. The maximum size of the
	bucket C is CBS and the maximum size of the token bucket E is EBS.		token bucket C is CBS and the maximum size of the token bucket E is
			EBS.
	The token buckets C and E are initially (at time 0) full, i.e., the		The token buckets C and E are initially (at time 0) full, i.e., the
	token count Tc(0) = CBS and the token count Te(0) = EBS. Thereafter,		token count Tc(0) = CBS and the token count Te(0) = EBS.
	the token counts Tc and Te are updated CDR times per second as		Thereafter, the token counts Tc and Te are updated CDR times per
	follows:		second as follows:
	o If Tc is less than CBS, Tc is incremented by one, else
	o if Te is less then EBS, Te is incremented by one, else		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 14 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	o neither Tc nor Te is incremented.		- If Tc is less than CBS, Tc is incremented by one, else
			- if Te is less then EBS, Te is incremented by one, else
			- neither Tc nor Te is incremented.
	When a packet of size B bytes arrives at time t, the following		When a packet of size B bytes arrives at time t, the following
	happens:		happens:
	o If Tc(t)-B >= 0, the packet is not in excess of the Committed		- If Tc(t)-B >= 0, the packet is not in excess of the Committed
	Rate and Tc is decremented		Rate and Tc is decremented by B down to the minimum value of 0,
	by B down to the minimum value of 0, else		else
			- if Te(t)-B >= 0, the packet is in excess of the Committed rate
	o if Te(t)-B >= 0, the packet is in excess of the Committed Rate		but is not in excess of the EBS and Te is decremented by B down
	but is not in excess of the EBS and Te is		to the minimum value of 0, else
	decremented by B down to the minimum value of 0, else		- the packet is in excess of both the Committed Rate and the EBS
	o the packet is in excess of both the Committed Rate and the EBS
	and neither Tc nor Tc is decremented.		and neither Tc nor Tc is decremented.
	Note that according to the above specification, a CDR value of		Note that according to the above specification, a CDR value of
	positive infinity implies that arriving packets are never in excess		positive infinity implies that arriving packets are never in excess
	of either the Committed Rate or EBS. A positive infinite value of		of either the Committed Rate or EBS. A positive infinite value of
	either CBS or EBS implies that the respective limit cannot be		either CBS or EBS implies that the respective limit cannot be
	CR-LDP Specification - 16 - Exp. August 1999
	exceeded.		exceeded.
	The actual implementation of a LSR doesn't need to be modeled		The actual implementation of a LSR doesn't need to be modeled
	according to the above formal specification.		according to the above formal specification.
	4.3.1.7 Weight		4.3.1.7 Weight
	The weight determines the CRLSP's relative share of the possible		The weight determines the CRLSP's relative share of the possible
	excess bandwidth above its committed rate. The definition of		excess bandwidth above its committed rate. The definition of
	"relative share" is MPLS domain specific.		_relative share_ is MPLS domain specific.
	4.3.2 Procedures		4.3.2 Procedures
	4.3.2.1 Label Request Message		4.3.2.1 Label Request Message
	If an LSR receives an incorrectly encoded Traffic Parameters TLV in		If an LSR receives an incorrectly encoded Traffic Parameters TLV in
	which the value of PDR is less than the value of CDR then it MUST		which the value of PDR is less than the value of CDR then it MUST
	send a Notification Message including the Status code Traffic		send a Notification Message including the Status code Traffic
	Parameters Unavailable to the upstream LSR from which it received the		Parameters Unavailable to the upstream LSR from which it received
	erroneous message.		the erroneous message.
	If a Traffic Parameter is indicated as Negotiable in the Label		If a Traffic Parameter is indicated as Negotiable in the Label
	Request Message by the corresponding Negotiable Flag then an LSR MAY		Request Message by the corresponding Negotiable Flag then an LSR MAY
	replace the Traffic Parameter value with a smaller value.		replace the Traffic Parameter value with a smaller value.
	If the Weight is indicated as Negotiable in the Label Request Message		If the Weight is indicated as Negotiable in the Label Request
	by the corresponding Negotiable Flag then an LSR may adjust replace		Message by the corresponding Negotiable Flag then an LSR may adjust
	the Weight value with a lower value (down to 1).		replace the Weight value with a lower value (down to 0).
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 15 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	If, after possible Traffic Parameter negotiation, an LSR can support		If, after possible Traffic Parameter negotiation, an LSR can support
	the CRLSP Traffic Parameters then the LSR MUST reserve the		the CRLSP Traffic Parameters then the LSR MUST reserve the
	corresponding resources for the CRLSP.		corresponding resources for the CRLSP.
	If, after possible Traffic Parameter negotiation, an LSR cannot		If, after possible Traffic Parameter negotiation, an LSR cannot
	support the CRLSP Traffic Parameters then the LSR MUST send a		support the CRLSP Traffic Parameters then the LSR MUST send a
	notification message that contains the Resource Unavailable status		notification message that contains the Resource Unavailable status
	code.		code.
	4.3.2.2 Label Mapping Message		4.3.2.2 Label Mapping Message
	If an LSR receives an incorrectly encoded Traffic Parameters TLV in		If an LSR receives an incorrectly encoded Traffic Parameters TLV in
	which the value of PDR is less than the value of CDR then it MUST		which the value of PDR is less than the value of CDR then it MUST
	send a Label Release message containing the Status code Traffic		send a Label Release message containing the Status code Traffic
	Parameters Unavailable to the LSR from which it received the		Parameters Unavailable to the LSR from which it received the
	erroneous message.		erroneous message.
	The egress LSR MUST include the (possibly negotiated) Traffic		If the negotiation flag was set in the label request message, the
	Parameters and Weight in the Label Mapping message.		egress LSR MUST include the (possibly negotiated) Traffic Parameters
			and Weight in the Label Mapping message.
	The Traffic Parameters and the Weight in a Label Mapping message MUST
	be forwarded unchanged.
	CR-LDP Specification - 17 - Exp. August 1999		The Traffic Parameters and the Weight in a Label Mapping message
			MUST be forwarded unchanged.
	An LSR SHOULD adjust the resources that it reserved for a CRLSP when		An LSR SHOULD adjust the resources that it reserved for a CRLSP when
	it receives a Label Mapping Message if the Traffic Parameters differ		it receives a Label Mapping Message if the Traffic Parameters differ
	from those in the corresponding Label Request Message.		from those in the corresponding Label Request Message.
	4.3.2.3 Notification Message		4.3.2.3 Notification Message
	If an LSR receives a Notification Message for a CRLSP, it SHOULD		If an LSR receives a Notification Message for a CRLSP, it SHOULD
	release any resources that it possibly had reserved for the CRLSP.		release any resources that it possibly had reserved for the CRLSP.
	In addition, on receiving a Notification Message from a Downstream		In addition, on receiving a Notification Message from a Downstream
	LSR that is associated with a Label Request from an upstream LSR, the		LSR that is associated with a Label Request from an upstream LSR,
	local LSR MUST propagate the Notification message using the		the local LSR MUST propagate the Notification message using the
	procedures in [LDP].		procedures in [1].
	4.4 Preemption TLV		4.4 Preemption TLV
			The defualt value of the setup and holding priorities should be in
			the middle of the range (e.g., 4) so that this feature can be turned
			on gradually in an operational network by increasing or decerasing
			the priority starting at the middle of the range.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| Preemption-TLV (0x0820) | Length |		|0|0| Preemption-TLV (0x0820) | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| SetPrio | HoldPrio | Reserved |		| SetPrio | HoldPrio | Reserved |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	U bit		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 16 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	Unknown TLV bit. As defined in [LDP].
	F bit
	Forward unknown TLV bit. As defined in [LDP].
	Type		Type
	A fourteen-bit field carrying the value of the Preemption-TLV		A fourteen-bit field carrying the value of the Preemption-TLV
	type which is 0x810.		type which is 0x810.
	Length		Length
	Specifies the length of the value field in bytes.		Specifies the length of the value field in bytes.
	Reserved		Reserved
	Zero on transmission. Ignored on receipt.		Zero on transmission. Ignored on receipt.
	SetPrio		SetPrio
	A SetupPriority of value zero (0) is the priority assigned to the		A SetupPriority of value zero (0) is the priority assigned to
	most important path. It is referred to as the highest priority.		the most important path. It is referred to as the highest
	Seven (7) is the priority for the least important path. The higher		priority. Seven (7) is the priority for the least important
	the setup priority, the more paths CR-LDP can bump to set up the		path. The higher the setup priority, the more paths CR-LDP can
	path.		bump to set up the path. The default value should be 4.
	HoldPrio		HoldPrio
	A HoldingPriority of value zero (0) is the priority assigned to		A HoldingPriority of value zero (0) is the priority assigned to
	the most important path. It is referred to as the highest		the most important path. It is referred to as the highest
	priority. Seven (7) is the priority for the least important path.		priority. Seven (7) is the priority for the least important
			path. The default value should be 4.
	CR-LDP Specification - 18 - Exp. August 1999		The higher the holding priority, the less likely it is for CR-
			LDP to reallocate its bandwidth to a new path.
	The higher the holding priority, the less likely it is for CR-LDP
	to reallocate its bandwidth to a new path.
	4.5 LSPID TLV		4.5 LSPID TLV
	LSPID is a unique identifier of a CRLSP within an MPLS network.		LSPID is a unique identifier of a CRLSP within an MPLS network.
	The LSPID is composed of the ingress LSR Router ID and a Locally		The LSPID is composed of the ingress LSR Router ID and a Locally
	unique CRLSP ID to that LSR.		unique CRLSP ID to that LSR.
	The LSPID is useful in network management, in CR-LSP repair, and in		The LSPID is useful in network management, in CR-LSP repair, and in
	using an already established CR-LSP as a hop in an ER-TLV.		using an already established CR-LSP as a hop in an ER-TLV. An action
			indicator flag_ is carried in the LSPID TLV. This _action indicator
			flag_ indicates explicitly the action that should be taken if the
			LSP already exists on the LSR receiving the message.
			The procedure for the code point _modify_ is defined in section 2.1.
			of [10]. The procedures for other flags are FFS.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| LSPID-TLV (0x0821) | Length |		|0|0| LSPID-TLV (0x0821) | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Reserved | Local CRLSP ID |		| Reserved |ActFlg | Local CRLSP ID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Ingress LSR Router ID |		| Ingress LSR Router ID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	U bit		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 17 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	Unknown TLV bit. As defined in [LDP].
	F bit
	Forward unknown TLV bit. As defined in [LDP].
	Type		Type
	A fourteen-bit field carrying the value of the LSPID-TLV		A fourteen-bit field carrying the value of the LSPID-TLV type
	type which is 0x821.		which is 0x821.
	Length		Length
	Specifies the length of the value field in bytes.		Specifies the length of the value field in bytes.
			ActFlg
			Action Indicator Flag: A 4-bit field that indicates explicitly
			the action that should be taken if the LSP already exists on
			the LSR receiving the message. A set of indicator code points
			is proposed as follows:
			0001: modify
	Reserved		Reserved
	Zero on transmission. Ignored on receipt.		Zero on transmission. Ignored on receipt.
	Local CRLSP ID		Local CRLSP ID
	The Local LSP ID is an identifier of the CRLSP locally unique		The Local LSP ID is an identifier of the CRLSP locally unique
	within the Ingress LSR originating the CRLDP.		within the Ingress LSR originating the CRLDP.
	Ingress LSR Router ID		Ingress LSR Router ID
	A 4 byte field indicating the Ingress LSR ID.		"An LSR may use any of its own IPv4 in this field"
	4.6 Resource Class (Color) TLV		4.6 Resource Class (Color) TLV
	The Resource Class as defined in [TER] is used to specify which links		The Resource Class as defined in [4] is used to specify which links
	are acceptable by this CRLSP. This information allows for the		are acceptable by this CRLSP. This information allows for the
			network's topology to be pruned.
	CR-LDP Specification - 19 - Exp. August 1999
	networks topology to be pruned.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| ResCls-TLV (0x0822) | Length |		|0|0| ResCls-TLV (0x0822) | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| RsCls |		| RsCls |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	U bit
	Unknown TLV bit. As defined in [LDP].
	F bit
	Forward unknown TLV bit. As defined in [LDP].
	Type		Type
	A fourteen-bit field carrying the value of the ResCls-TLV		A fourteen-bit field carrying the value of the ResCls-TLV type
	type which is 0x822.		which is 0x822.
	Length		Length
	Specifies the length of the value field in bytes.		Specifies the length of the value field in bytes.
	RsCls		RsCls
	The Resource Class bit mask indicating which of the		The Resource Class bit mask indicating which of the 32
	32 "administrative groups" or "colors" of links		_administrative groups_ or _colors_ of links the CRLSP can
	the CRLSP can traverse.		traverse.
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 18 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	4.7 ER-Hop semantics		4.7 ER-Hop semantics
	4.7.1. ER-Hop 1: The IPv4 prefix		4.7.1. ER-Hop 1: The IPv4 prefix
	The abstract node represented by this ER-Hop is the set of nodes		The abstract node represented by this ER-Hop is the set of nodes,
	which have an IP address which lies within this prefix. Note that a		which have an IP address, which lies within this prefix. Note that
	prefix length of 32 indicates a single IPv4 node.		a prefix length of 32 indicates a single IPv4 node.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| 0x801 | Length |		|0|0| 0x801 | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|L| Reserved | PreLen |		|L| Reserved | PreLen |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| IPv4 Address (4 bytes) |		| IPv4 Address (4 bytes) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	U bit
	Unknown TLV bit. As defined in [LDP].
	F bit
	Forward unknown TLV bit. As defined in [LDP].
	CR-LDP Specification - 20 - Exp. August 1999
	Type		Type
	IPv4 Address 0x801		IPv4 Address 0x801
	Length		Length
	Specifies the length of the value field in bytes.		Specifies the length of the value field in bytes.
	L Bit		L Bit
	Set to indicate Loose hop.		Set to indicate Loose hop.
	Cleared to indicate a strict hop.		Cleared to indicate a strict hop.
	Reserved		Reserved
	Zero on transmission. Ignored on receipt.		Zero on transmission. Ignored on receipt.
	PreLen		PreLen
	Prefix Length 1-32		Prefix Length 1-32
	IP Address		IP Address
	A four byte field indicating the IP Address.		A four-byte field indicating the IP Address.
	4.7.2. ER-Hop 2: The IPv6 address		4.7.2. ER-Hop 2: The IPv6 address
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| 0x802 | Length |		|0|0| 0x802 | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|L| Reserved | PreLen |		|L| Reserved | PreLen |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| IPV6 address |		| IPV6 address |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| IPV6 address (continued) |		| IPV6 address (continued) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| IPV6 address (continued) |		| IPV6 address (continued) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| IPV6 address (continued) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	U bit		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 19 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	Unknown TLV bit. As defined in [LDP].
	F bit		| IPV6 address (continued) |
	Forward unknown TLV bit. As defined in [LDP].		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Type		Type
	0x802 IPv6 address		0x802 IPv6 address
	Length		Length
	Specifies the length of the value field in bytes.		Specifies the length of the value field in bytes.
	L Bit		L Bit
	Set to indicate Loose hop.		Set to indicate Loose hop.
	CR-LDP Specification - 21 - Exp. August 1999
	Cleared to indicate a strict hop.		Cleared to indicate a strict hop.
	Reserved		Reserved
	Zero on transmission. Ignored on receipt.		Zero on transmission. Ignored on receipt.
	PreLen		PreLen
	Prefix Length 1-128		Prefix Length 1-128
	IPv6 address		IPv6 address
	A 128-bit unicast host address.		A 128-bit unicast host address.
	4.7.3. ER-Hop 32: The autonomous system number		4.7.3. ER-Hop 3: The autonomous system number
	The abstract node represented by this ER-Hop is the set of nodes		The abstract node represented by this ER-Hop is the set of nodes
	belonging to the autonomous system.		belonging to the autonomous system.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| 0x803 | Length |		|0|0| 0x803 | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|L| Reserved | AS Number |		|L| Reserved | AS Number |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	U bit
	Unknown TLV bit. As defined in [LDP].
	F bit
	Forward unknown TLV bit. As defined in [LDP].
	Type		Type
	AS Number 0x803		AS Number 0x803
	Length		Length
	Specifies the length of the value field in bytes.		Specifies the length of the value field in bytes.
	L Bit		L Bit
	Set to indicate Loose hop.		Set to indicate Loose hop.
	Cleared to indicate a strict hop.		Cleared to indicate a strict hop.
	Reserved		Reserved
	Zero on transmission. Ignored on receipt.		Zero on transmission. Ignored on receipt.
	AS Number		AS Number
	Autonomous System number		Autonomous System number
	4.7.4. ER-Hop 4: LSPID		4.7.4. ER-Hop 4: LSPID
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 20 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	The LSPID is used to identify the tunnel ingress point as the next		The LSPID is used to identify the tunnel ingress point as the next
	hop in the ER. This ER-Hop allows for stacking new CR-LSPs within an		hop in the ER. This ER-Hop allows for stacking new CR-LSPs within an
	already established CR-LSP. It also allows for splicing the CR-LSP		already established CR-LSP. It also allows for splicing the CR-LSP
			being established with an existing CR-LSP.
	CR-LDP Specification - 22 - Exp. August 1999		If an LSPID Hop is the last ER-Hop in an ER-TLV, than the LSR may
			splice the CR-LSP of the incoming Label Request to the CR-LSP that
			currently exists with this LSPID. This is useful, for example, at
			the point at which a Label Request used for local repair arrives at
			the next ER-Hop after the loosely specified CR-LSP segment. Use of
			the LSPID Hop in this scenario eliminates the need for ER-Hops to
			keep the entire remaining ER-TLV at each LSR that is at either
			(upstream or downstream) end of a loosely specified CR-LSP segment
			as part of its state information. This is due to the fact that the
			upstream LSR needs only to keep the next ER-Hop and the LSPID and
			the downstream LSR needs only to keep the LSPID in order for each
			end to be able to recognize that the same LSP is being identified.
	being established with an existing CR-LSP.		If the LSPID Hop is not the last hop in an ER-TLV, the LSR must
			forward the remaining ER-TLV in a Label Request message, using the
			CR-LSP specified by the LSPID, to the LSR that is the CR-LSP's
			egress. That LSR will continue processing of the CR-LSP Label
			Request Message. The result is a tunneled, or stacked, CR-LSP.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| 0x804 | Length |		|0|0| 0x804 | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|L| Reserved | Local LSPID |		|L| Reserved | Local LSPID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Ingress LSR Router ID |		| Ingress LSR Router ID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	U bit
	Unknown TLV bit. As defined in [LDP].
	F bit
	Forward unknown TLV bit. As defined in [LDP].
	Type		Type
	LSPID 0x804		LSPID 0x804
	Length		Length
	Specifies the length of the value field in bytes.		Specifies the length of the value field in bytes.
	L Bit		L Bit
	Set to indicate Loose hop.		Set to indicate Loose hop.
	Cleared to indicate a strict hop.		Cleared to indicate a strict hop.
	Reserved		Reserved
	Zero on transmission. Ignored on receipt.		Zero on transmission. Ignored on receipt.
	Local LSPID		Local LSPID
	A 2 byte field indicating the LSPID which is unique		A 2 byte field indicating the LSPID which is unique with
	with reference to the its Ingress LSR.		reference to its Ingress LSR.
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 21 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	Ingress LSR Router ID		Ingress LSR Router ID
	A 4 byte field indicating the Ingress LSR ID.		"An LSR may use any of its own IPv4 addresses in this field"
	4.8. Processing of the Explicit Route TLV		4.8. Processing of the Explicit Route TLV
	4.8.1. Selection of the next hop		4.8.1. Selection of the next hop
	A Label Request Message containing a explicit route TLV must		A Label Request Message containing a explicit route TLV must
	determine the next hop for this path. Selection of this next hop may		determine the next hop for this path. Selection of this next hop
	involve a selection from a set of possible alternatives. The		may involve a selection from a set of possible alternatives. The
	mechanism for making a selection from this set is implementation		mechanism for making a selection from this set is implementation
	dependent and is outside of the scope of this specification.		dependent and is outside of the scope of this specification.
	Selection of particular paths is also outside of the scope of this		Selection of particular paths is also outside of the scope of this
	specification, but it is assumed that each node will make a best		specification, but it is assumed that each node will make a best
	effort attempt to determine a loop-free path. Note that such best		effort attempt to determine a loop-free path. Note that such best
	CR-LDP Specification - 23 - Exp. August 1999
	efforts may be overridden by local policy.		efforts may be overridden by local policy.
	To determine the next hop for the path, a node performs the following		To determine the next hop for the path, a node performs the
	steps:		following steps:
	1) The node receiving the Label Request Message must first		1. The node receiving the Label Request Message must first
	evaluate the first ER-Hop. If the L bit is not set in the first		evaluate the first ER-Hop. If the L bit is not set in the
	ER-Hop and if the node is not part of the abstract node described		first ER-Hop and if the node is not part of the abstract node
	by the first ER-Hop, it has received the message in error, and		described by the first ER-Hop, it has received the message in
	should return a "Bad initial ER-Hop" error. If the L bit is set		error, and should return a _Bad initial ER-Hop_ error. If the
	and the local node is not part of the abstract node described by		L bit is set and the local node is not part of the abstract
	the first ER-Hop, the node selects a next hop that is along the		node described by the first ER-Hop, the node selects a next
	path to the abstract node described by the first ER-Hop. If there		hop that is along the path to the abstract node described by
	is no first ER-Hop, the message is also in error and the system		the first ER-Hop. If there is no first ER-Hop, the message is
	should return a "Bad Explicit Routing TLV" error.		also in error and the system should return a _Bad Explicit
			Routing TLV_ error.
	2) If there is no second ER-Hop, this indicates the end of the		2. If there is no second ER-Hop, this indicates the end of the
	explicit route. The explicit route TLV should be removed from the		explicit route. The explicit route TLV should be removed from
	Label Request Message. This node may or may not be the end of the		the Label Request Message. This node may or may not be the
	LSP. Processing continues with section 4.8.2, where a new		end of the LSP. Processing continues with section 4.8.2,
	explicit route TLV may be added to the Label Request Message.		where a new explicit route TLV may be added to the Label
			Request Message.
	3) If the node is also a part of the abstract node described by		3. If the node is also a part of the abstract node described by
	the second ER-Hop, then the node deletes the first ER-Hop and		the second ER-Hop, then the node deletes the first ER-Hop and
	continues processing with step 2, above. Note that this makes the		continues processing with step 2, above. Note that this makes
	second ER-Hop into the first ER-Hop of the next iteration.		the second ER-Hop into the first ER-Hop of the next iteration.
	4) The node determines if it is topologically adjacent to the		4. The node determines if it is topologically adjacent to the
	abstract node described by the second ER-Hop. If so, the node		abstract node described by the second ER-Hop. If so, the node
	selects a particular next hop which is a member of the abstract		selects a particular next hop which is a member of the
	node. The node then deletes the first ER-Hop and continues		abstract node. The node then deletes the first ER-Hop and
	processing with section 4.8.2.		continues processing with section 4.8.2.
	5) Next, the node selects a next hop within the abstract node of		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 22 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	the first ER-Hop that is along the path to the abstract node of
	the second ER-Hop. If no such path exists then there are two
	cases:
	5a) If the second ER-Hop is a strict ER-Hop, then there is an		5. Next, the node selects a next hop within the abstract node of
	error and the node should return a "Bad strict node" error.		the first ER-Hop that is along the path to the abstract node
			of the second ER-Hop. If no such path exists then there are
			two cases:
	5b) Otherwise, if the second ER-Hop is a loose ER-Hop, then the		5.a If the second ER-Hop is a strict ER-Hop, then there is
	node selects any next hop that is along the path to the next		an error and the node should return a _Bad strict node_
	abstract node. If no path exists within the MPLS domain, then
	there is an error, and the node should return a "Bad loose node"
	error.		error.
	6) Finally, the node replaces the first ER-Hop with any ER-Hop		5.b Otherwise, if the second ER-Hop is a loose ER-Hop, then
	that denotes an abstract node containing the next hop. This is		the node selects any next hop that is along the path to the
	necessary so that when the explicit route is received by the next		next abstract node. If no path exists within the MPLS
	hop, it will be accepted.		domain, then there is an error, and the node should return a
			_Bad loose node_ error.
	CR-LDP Specification - 24 - Exp. August 1999		6. Finally, the node replaces the first ER-Hop with any ER-Hop
			that denotes an abstract node containing the next hop. This
			is necessary so that when the explicit route is received by
			the next hop, it will be accepted.
	7) Progress the Label Request Message to the next hop.		7. Progress the Label Request Message to the next hop.
	4.8.2. Adding ER-Hops to the explicit route TLV		4.8.2. Adding ER-Hops to the explicit route TLV
	After selecting a next hop, the node may alter the explicit route in		After selecting a next hop, the node may alter the explicit route in
	the following ways.		the following ways.
	If, as part of executing the algorithm in section 4.8.1, the explicit		If, as part of executing the algorithm in section 4.8.1, the
	route TLV is removed, the node may add a new explicit route TLV.		explicit route TLV is removed, the node may add a new explicit route
			TLV.
	Otherwise, if the node is a member of the abstract node for the first		Otherwise, if the node is a member of the abstract node for the
	ER-Hop, then a series of ER-Hops may be inserted before the first		first ER-Hop, then a series of ER-Hops may be inserted before the
	ER-Hop or may replace the first ER-Hop. Each ER-Hop in this series		first ER-Hop or may replace the first ER-Hop. Each ER-Hop in this
	must denote an abstract node that is a subset of the current abstract		series must denote an abstract node that is a subset of the current
	node.		abstract node.
	Alternately, if the first ER-Hop is a loose ER-Hop, an arbitrary		Alternately, if the first ER-Hop is a loose ER-Hop, an arbitrary
	series of ER-Hops may be inserted prior to the first ER-Hop.		series of ER-Hops may be inserted prior to the first ER-Hop.
	4.9 Route Pinning TLV		4.9 Route Pinning TLV
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| 0x823 | Length |		|0|0| 0x823 | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|P| Reserved |		|P| Reserved |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	U bit
	Unknown TLV bit. As defined in [LDP].
	F bit
	Forward unknown TLV bit. As defined in [LDP].
	Type		Type
	Pinning-TLV type 0x823		Pinning-TLV type 0x823
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 23 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	Length		Length
	Specifies the length of the value field in bytes.		Specifies the length of the value field in bytes.
	P Bit		P Bit
	The P bit is set to 1 to indicate that route pinning is requested.		The P bit is set to 1 to indicate that route pinning is
			requested.
	The P bit is set to 0 to indicate that route pinning is not		The P bit is set to 0 to indicate that route pinning is not
	requested		requested
	Reserved		Reserved
	Zero on transmission. Ignored on receipt.		Zero on transmission. Ignored on receipt.
	4.10 CRLSP FEC Element		4.10 CRLSP FEC Element
	CR-LDP Specification - 25 - Exp. August 1999
	A new FEC element is introduced in this specification to support CR-		A new FEC element is introduced in this specification to support CR-
	LSPs. The CRLDP FEC Element is an opaque FEC.		LSPs. This new FEC element does not preclude the use of other FECs
			elements (Type=0x01, 0x02, 0x03) defined in the LDP spec in CR-LDP
			messages. The CRLDP FEC Element is an opaque FEC to be used only in
			Messages of CR-LSPs.
	FEC Element Type Value		FEC Element Type Value
	type name		Type name
	CRLSP 0x04 No value; i.e., 0 value octets;		CRLSP 0x04 No value; i.e., 0 value octets;
	see below.
	CRLSP FEC Element
	To be used only in Messages of CR-LSPs.
	The CR-LSP FEC TLV encoding is as follows:		The CR-LSP FEC TLV encoding is as follows:
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|U|F| FEC(0x0100) | Length |		|0|0| FEC(0x0100) | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| CR-LSP (4) | Reserved |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			| CR-LSP (4) |
	U bit		+-+-+-+-+-+-+-+-+
	Unknown TLV bit. As defined in [LDP].
	F bit
	Forward unknown TLV bit. As defined in [LDP].
	Type		Type
	FEC TLV type 0x0100		FEC TLV type 0x0100
	Length		Length
	Specifies the length of the value field in bytes.		Specifies the length of the value field in bytes.
	CR-LSP FEC Element Type		CR-LSP FEC Element Type
	0x04		0x04
	Reserved
	Zero on transmission. Ignored on receipt.
	4.11 Error subcodes		4.11 Error subcodes
	In the processing described above, certain errors need to be reported		In the processing described above, certain errors need to be
	as part of the Notification Message. This section defines the status		reported as part of the Notification Message. This section defines
	codes for the errors described in this specification.		the status codes for the errors described in this specification.
	CR-LDP Specification - 26 - Exp. August 1999		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 24 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	Status Code Type		Status Code Type
	-------------------------------------- ----------		-------------------------------------- ----------
	Bad Explicit Routing TLV Error 0x04000001		Bad Explicit Routing TLV Error 0x44000001
	Bad Strict Node Error 0x04000002		Bad Strict Node Error 0x44000002
	Bad Loose Node Error 0x04000003		Bad Loose Node Error 0x44000003
	Bad Initial ER-Hop Error 0x04000004		Bad Initial ER-Hop Error 0x44000004
	Resource Unavailable 0x04000005		Resource Unavailable 0x44000005
	Traffic Parameters Unavailable 0x04000006		Traffic Parameters Unavailable 0x44000006
	Setup abort 0x04000007		Setup abort (Label Request Aborted in [1]) 0x04000015
			Modify request not supported 0x44000008
	5. Security		5. Security
	Pre-emption has to be controlled by the MPLS domain.		Pre-emption has to be controlled by the MPLS domain.
	Resource reservation requires the LSRs to have an LSP admission		Resource reservation requires the LSRs to have an LSP admission
	control function.		control function.
	Normal routing can be bypassed by Traffic Engineered LSPs.		Traffic Engineered LSPs can bypass normal routing.
	6. Acknowledgments		6. Acknowledgments
	The messages used to signal the CRLSP setup are based on the work		The messages used to signal the CRLSP setup are based on the work
	done by the [LDP] team. The Explicit Route object and procedures used		done by the [1] team. The Explicit Route object and procedures used
	in this specification are based on [ER].		in this specification are based on [8].
	The authors would also like to acknowledge the careful review and		The authors would also like to acknowledge the careful review and
	comments of Ken Hayward, Greg Wright, Geetha Brown, Brian Williams,		comments of Ken Hayward, Greg Wright, Geetha Brown, Brian Williams,
	Paul Beaubien, Matthew Yuen, Liam Casey, and Ankur Anand.		Paul Beaubien, Matthew Yuen, Liam Casey, and Ankur Anand.
	7. References		7. Intellectual Property Consideration
	[LDP] Andersson et al, "Label Distribution Protocol Specification"		Nortel Networks may seek patent or other intellectual property
	work in progress (draft-ietf-mpls-ldp-03), Feb. 1999.		protection for some or all of the technologies disclosed in this
			document. If any standards arising from this document are or become
			protected by one or more patents assigned to Nortel Networks, Nortel
			Networks is prepared to make a license available to any qualified
			applicant upon reasonable and non-discriminatory terms and
			conditions. Any such licenses will be subject to negotiations
			outside of the IETF.
	[ARCH] Rosen et al, "Multiprotocol Label Switching Architecture",		8. References
	work in progress (draft-ietf-mpls-arch-04), Feb. 1999.
	[FRAME] Callon et al, "Framework for Multiprotocol Label Switching",		1 Andersson et al, "Label Distribution Protocol Specification"
	work in progress (draft-ietf-mpls-framework-02), November		work in progress (draft-ietf-mpls-ldp-05), June 1999.
	1997.
	[TER] Awduche et al, "Requirements for Traffic Engineering Over		2 Callon et al, "Framework for Multiprotocol Label Switching",
	MPLS", work in progress (draft-ietf-mpls-traffic-eng-00),		work in progress (draft-ietf-mpls-framework-04), July 1999.
	August 1998.
	[ER] Guerin et al, "Setting up Reservations on Explicit Paths		3 Rosen et al, "Multiprotocol Label Switching Architecture",
	using RSVP", work in progress (draft-guerin-expl-path-rsvp-		work in progress (draft-ietf-mpls-arch-04), April 1999.
	01)
	November 1997.
	CR-LDP Specification - 27 - Exp. August 1999		Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 25 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	[VPN1] Heinanen et al, "MPLS Mappings of Generic VPN Mechanisms",		4 Awduche et al, "Requirements for Traffic Engineering Over
			MPLS", work in progress (draft-ietf-mpls-traffic-eng-01),
			June 1999.
			5 Heinanen et al, "MPLS Mappings of Generic VPN Mechanisms",
	work in progress (draft-heinanen-generic-vpn-mpls-00),		work in progress (draft-heinanen-generic-vpn-mpls-00),
	August 1998.		August 1998.
	[VPN2] Jamieson et al, "MPLS VPN Architecture" work in progress		6 Jamieson et al, "MPLS VPN Architecture" work in progress
	(draft-jamieson-mpls-vpn-00), August 1998.		(draft-jamieson-mpls-vpn-00), August 1998.
	[VPN3] T. Li, "CPE based VPNs using MPLS", work in progress (draft-		7 T. Li, "CPE based VPNs using MPLS", work in progress (draft-
	li-mpls-vpn-00.txt), October 1998.		li-mpls-vpn-00.txt), October 1998.
	[LDP-STATE] L. Wu, et. al., "LDP State Machine" work in progress		8 Guerin et al, "Setting up Reservations on Explicit Paths using
			RSVP", work in progress (draft-guerin-expl-path-rsvp-01) November
			1997.
			9 L. Wu, et. al., "LDP State Machine" work in progress
	(draft-ietf-mpls-ldp-state-00), Feb 1999.		(draft-ietf-mpls-ldp-state-00), Feb 1999.
	CR-LDP Specification - 28 - Exp. August 1999		10 J. Ash, et. al., _LSP Modification Using CR-LDP_ work in progress
			(draft-ash-crlsp-modify-00.txt), July 1999.
	8. Author Information		9. Author's Addresses
	Osama S. Aboul-Magd Loa Andersson		Osama S. Aboul-Magd Loa Andersson
	Nortel Networks Director Bay Architecture Lab,EMEA		Nortel Networks Nortel Networks
	P O Box 3511 Station C Kungsgatan 34, PO Box 1788		P O Box 3511 Station C Kungsgatan 34, PO Box 1788
	Ottawa, ON K1Y 4H7 111 97 Stockholm, Sweden		Ottawa, ON K1Y 4H7 111 97 Stockholm, Sweden
	Canada phone: +46 8 441 78 34		Canada Phone: +46 8 441 78 34
	phone: +1 613 763-5827 mobile +46 70 522 78 34		Phone: +1 613 763-5827 Mobile +46 70 522 78 34
	osama@NortelNetworks.com loa_andersson@baynetworks.com		Osama@nortelnetworks.com Loa_andersson@beynetworks.com
	Peter Ashwood-Smith Ross Callon		Peter Ashwood-Smith Ross Callon
	Nortel Networks IronBridge Networks		Nortel Networks IronBridge Networks
	P O Box 3511 Station C 55 Hayden Avenue,		P O Box 3511 Station C 55 Hayden Avenue,
	Ottawa, ON K1Y 4H7 Lexington, MA 02173		Ottawa, ON K1Y 4H7 Lexington, MA 02173
	Canada Phone: +1-781-402-8017		Canada Phone: +1-781-402-8017
	phone: +1 613 763-4534 rcallon@ironbridgenetworks.com		Phone: +1 613 763-4534 Rcallon@ironbridgenetworks.com
	petera@NortelNetworks.com		Petera@nortelnetworks.com
	Ram Dantu Paul Doolan		Ram Dantu Paul Doolan
	Alcatel USA Inc. Ennovate Networks		Alcatel USA Inc. Ennovate Networks
	IP Competence Center 330 Codman Hill Rd		IP Competence Center 330 Codman Hill Rd
	1201 E. Campbell Road.,446-315 Marlborough MA 01719		1201 E. Campbell Road.,446-315 Marlborough MA 01719
	Richadson, TX USA., 75081-2206 Phone: 978-263-2002		Richadson, TX USA., 75081-2206 Phone: 978-263-2002
	Phone: 972 996 2938 pdoolan@ennovatenetworks.com		Phone: 972 996 2938 Pdoolan@ennovatenetworks.com
	Fax: 972 996 5902		Fax: 972 996 5902
	ram.dantu@aud.alcatel.com		Ram.dantu@aud.alcatel.com
			Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 26 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	Nancy Feldman Andre Fredette		Nancy Feldman Andre Fredette
	IBM Corp. Nortel Networks		IBM Corp. Nortel Networks
	17 Skyline Drive 3 Federal Street		17 Skyline Drive 3 Federal Street
	Hawthorne NY 10532 Billerica, MA 01821		Hawthorne NY 10532 Billerica, MA 01821
	Phone: 914-784-3254 fredette@baynetworks.com		Phone: 914-784-3254 978-288-8524
	nkf@us.ibm.com		Nkf@us.ibm.com Fredette@baynetworks.com
	Eric Gray Joel M. Halpern		Eric Gray Joel M. Halpern
	Lucent Technologies, Inc Newbridge Networks Inc.		Lucent Technologies, Inc Institutional Venture Partners
	1600 Osgood St. 593 Herndon Parkway		1600 Osgood St. 650-926-5633
	North Andover, MA 01847 Herndon, VA 20170		North Andover, MA 01847 joel@mcquillan.com
	Phone: 603-659-3386 phone: 1-703-736-5954		Phone: 603-659-3386
	ewgray@lucent.com jhalpern@newbridge.com		Ewgray@lucent.com
	Juha Heinanen Fiffi Hellstrand		Juha Heinanen Fiffi Hellstrand
	Telia Finland, Inc. Ericsson Telecom AB		Telia Finland, Inc. Ericsson Telecom AB
	Myyrmaentie 2 S-126 25 STOCKHOLM		Myyrmaentie 2 S-126 25 STOCKHOLM
	01600 VANTAA Sweden		01600 VANTAA Sweden
	Finland Tel: +46 8 719 4933		Finland Tel: +46 8 719 4933
	Tel: +358 41 500 4808 etxfiff@etxb.ericsson.se		Tel: +358 41 500 4808 etxfiff@etxb.ericsson.se
	jh@telia.fi		Jh@telia.fi
	CR-LDP Specification - 29 - Exp. August 1999
	Bilel Jamoussi Timothy E. Kilty		Bilel Jamoussi Timothy E. Kilty
	Nortel Networks Northchurch Communications		Nortel Networks Corp. Northchurch Communications
	P O Box 3511 Station C 5 Corporate Drive,		3 Federal Street 5 Corporate Drive,
	Ottawa, ON K1Y 4H7 Andover, MA 018110		Billerica, MA 01821 Andover, MA 018110
	Canada phone: 978 691-4656		USA phone: 978 691-4656
	phone: +1 613 765-4814 tkilty@northc.com		Phone: +1 978 288-4506 tkilty@northc.com
	jamoussi@NortelNetworks.com		Jamoussi@nortelnetworks.com
	Andrew G. Malis Muckai K Girish		Andrew G. Malis Muckai K Girish
	Ascend Communications, Inc. SBC Technology Resources, Inc.		Ascend Communications, Inc. SBC Technology Resources,
	1 Robbins Road 4698 Willow Road		1 Robbins Road 4698 Willow Road
	Westford, MA 01886 Pleasanton, CA 94588		Westford, MA 01886 Pleasanton, CA 94588
	phone: 978 952-7414 Phone: (925) 598-1263		Phone: 978 952-7414 Phone: (925) 598-1263
	fax: 978 392-2074 Fax: (925) 598-1321		fax: 978 392-2074 Fax: (925) 598-1321
	malis@ascend.com mgirish@tri.sbc.com		Malis@ascend.com mgirish@tri.sbc.com
	Kenneth Sundell Pasi Vaananen		Kenneth Sundell Pasi Vaananen
	Ericsson Nokia Telecommunications		Nortel Networks Nokia Telecommunications
	SE-126 25 Stockholm 3 Burlington Woods Drive, Suite 250		Architecture Lab, EMEA 3 Burlington Woods Drive,
	Sweden Burlington, MA 01803		Kungsgatan 34, PO Box 1788 Burlington, MA 01803
	kenneth.sundell@etx.ericsson.se Phone: +1-781-238-4981		111 97 Stockholm, Sweden Phone: +1-781-238-4981
	pasi.vaananen@ntc.nokia.com		phone: +46 8 441-7838, Pasi.vaananen@ntc.nokia.com
			mobile +46 70 665-7838
			ksundell@nortelnetworks.com
	Tom Worster Liwen Wu		Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 27 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	General DataComm, Inc. Alcatel U.S.A
	5 Mount Royal Ave. 44983 Knoll Square
	Marlboro MA 01752 Ashburn, Va. 20147
	tom.worster@gdc.com USA
	Phone: (703) 724-2619
	FAX: (703) 724-2005
	liwen.wu@adn.alcatel.com
	CR-LDP Specification - 30 - Exp. August 1999		Tom worster Liwen Wu
			Nokia Alcatel U.S.A
			3 Burlington Woods Dr. 44983 Knoll Square
			Suite 250 Ashburn, Va. 20147
			Burlington MA 01803 USA Phone: (703) 724-2619
			+1 617 247 2624 FAX: (703) 724-2005
			tom.worster@nokia.com Liwen.wu@and.alcatel.com
			Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 28 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	Appendix A: CRLSP Establishment Examples		Appendix A: CRLSP Establishment Examples
	A.1 Strict Explicit Route Example		A.1 Strict Explicit Route Example
	This appendix provides an example for the setup of a strictly routed		This appendix provides an example for the setup of a strictly routed
	CRLSP. In this example, each abstract node is represented by a		CRLSP. In this example, a specific node represents each abstract
	specific node.		node.
	The sample network used here is a four node network with two edge		The sample network used here is a four node network with two
	LSRs and two core LSRs as follows:		edge LSRs and two core LSRs as follows:
	a b c		a b c
	LSR1------LSR2------LSR3------LSR4		LSR1------LSR2------LSR3------LSR4
	LSR1 generates a Label Request Message as described in Section 3.1 of		LSR1 generates a Label Request Message as described in Section 3.1
	this draft and sends it to LSR2. This message includes the CR-TLV.		of this draft and sends it to LSR2. This message includes the CR-
			TLV.
	The ER-TLV is composed by a vector of three ER-Hop TLVs <a, b, c>.
	The ER-Hop TLVs used in this example are of type 0x0801 (IPv4 prefix)
	with a prefix length of 32. Hence, each ER-Hop TLV identifies a
	specific node as opposed to a group of nodes.
			A vector of three ER-Hop TLVs <a, b, c> composes the ER-TLV.
			The ER-Hop TLVs used in this example are of type 0x0801 (IPv4
			prefix) with a prefix length of 32. Hence, each ER-Hop TLV
			identifies a specific node as opposed to a group of nodes.
	At LSR2, the following processing of the ER-TLV per Section 4.8.1 of		At LSR2, the following processing of the ER-TLV per Section 4.8.1 of
	this draft takes place:		this draft takes place:
	1) The first hop <a> is part of the abstract node LSR2. Therefore,		1) The first hop <a> is part of the abstract node LSR2.
	the first step passes the test. Go to step 2.		Therefore, the first step passes the test. Go to step 2.
	2) There is a second ER-Hop, <b>. Go to step 3.		2) There is a second ER-Hop, <b>. Go to step 3.
	3) LSR2 is not part of the abstract node described by the second		3) LSR2 is not part of the abstract node described by the
	ER-Hop <b>. Go to Step 4.		second ER-Hop <b>. Go to Step 4.
	4) LSR2 determines that it is topologically adjacent to the		4) LSR2 determines that it is topologically adjacent to the
	abstract node described by the second ER-Hop <b>. LSR2 selects a		abstract node described by the second ER-Hop <b>. LSR2 selects
	next hop (LSR3) which is the abstract node. LSR2 deletes the first		a next hop (LSR3) which is the abstract node. LSR2 deletes the
	ER-Hop <a> from the ER-TLV which now becomes <b , c>. Go to		first ER-Hop <a> from the ER-TLV which now becomes <b , c>. Go
	Section 4.8.2.		to Section 4.8.2.
	At LSR2, the following processing of Section 4.8.2 takes place:		At LSR2, the following processing of Section 4.8.2 takes place:
			Executing algorithm 4.8.1 did not result in the removal of the ER-
	Executing algorithm 4.8.1 did not result in the removal of the		TLV.
	ER-TLV.
	Also, LSR2 is not a member of the abstract node described by the		Also, LSR2 is not a member of the abstract node described by the
	first ER-Hop <b>.		first ER-Hop <b>.
	Finally, the first ER-Hop <b> is a strict hop.		Finally, the first ER-Hop <b> is a strict hop.
	Therefore, processing section 4.8.2 does not result in the		Therefore, processing section 4.8.2 does not result in the insertion
	insertion of new ER-Hops. The selection of the next hop has been		of new ER-Hops. The selection of the next hop has been already done
			is step 4 of Section 4.8.1 and the processing of the ER-TLV is
	CR-LDP Specification - 31 - Exp. August 1999		Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 29 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	already done is step 4 of Section 4.8.1 and the processing of the		completed at LSR2. In this case, the Label Request Message including
	ER-TLV is completed at LSR2. In this case, the Label Request		the ER-TLV <b, c> is progressed by LSR2 to LSR3.
	Message including the ER-TLV <b, c> is progressed by LSR2 to LSR3.
	At LSR3, a similar processing to the ER-TLV takes place except that		At LSR3, a similar processing to the ER-TLV takes place except that
	the incoming ER-TLV = <b, c> and the outgoing ER-TLV is <c>.		the incoming ER-TLV = <b, c> and the outgoing ER-TLV is <c>.
	At LSR4, the following processing of section 4.8.1 takes place:		At LSR4, the following processing of section 4.8.1 takes place:
	1) The first hop <c> is part of the abstract node LSR4. Therefore,		1) The first hop <c> is part of the abstract node LSR4.
	the first step passes the test. Go to step 2.		Therefore, the first step passes the test. Go to step 2.
	2) There is no second ER-Hop, this indicates the end of the CRLSP.		2) There is no second ER-Hop, this indicates the end of the
	The ER-TLV is removed from the Label Request Message. Processing		CRLSP. The ER-TLV is removed from the Label Request Message.
	continues with Section 4.8.2.		Processing continues with Section 4.8.2.
	At LSR4, the following processing of Section 4.8.2 takes place:		At LSR4, the following processing of Section 4.8.2 takes place:
	Executing algorithm 4.8.1 resulted in the removal of the ER-TLV.		Executing algorithm 4.8.1 resulted in the removal of the ER-TLV.
	LSR4 does not add a new ER-TLV.		LSR4 does not add a new ER-TLV.
	Therefore, processing section 4.8.2 does not result in the		Therefore, processing section 4.8.2 does not result in the insertion
	insertion of new ER-Hops. This indicates the end of the CRLSP and		of new ER-Hops. This indicates the end of the CRLSP and the
	the processing of the ER-TLV is completed at LSR4.		processing of the ER-TLV is completed at LSR4.
	At LSR4, processing of Section 3.2 is invoked. The first condition is		At LSR4, processing of Section 3.2 is invoked. The first condition
	satisfied (LSR4 is the egress end of the CRLSP and upstream mapping		is satisfied (LSR4 is the egress end of the CRLSP and upstream
	has been requested). Therefore, a Label Mapping Message is generated		mapping has been requested). Therefore, a Label Mapping Message is
	by LSR4 and sent to LSR3.		generated by LSR4 and sent to LSR3.
	At LSR3, the processing of Section 3.2 is invoked. The second		At LSR3, the processing of Section 3.2 is invoked. The second
	condition is satisfied (LSR3 received a mapping from its downstream		condition is satisfied (LSR3 received a mapping from its downstream
	next hop LSR4 for a CRLSP for which an upstream request is still		next hop LSR4 for a CRLSP for which an upstream request is still
	pending). Therefore, a Label Mapping Message is generated by LSR3 and		pending). Therefore, a Label Mapping Message is generated by LSR3
	sent to LSR2.		and sent to LSR2.
	At LSR2, a similar processing to LSR 3 takes place and a Label		At LSR2, a similar processing to LSR 3 takes place and a Label
	Mapping Message is sent back to LSR1 which completes the end-to-end		Mapping Message is sent back to LSR1 which completes the end-to-end
	CRLSP setup.		CRLSP setup.
	A.2. Node Groups and Specific Nodes Example		A.2. Node Groups and Specific Nodes Example
	A request at an ingress LSR to setup a CRLSP might originate from a		A request at ingress LSR to setup a CRLSP might originate from a
	management system or an application, the details are implementation		management system or an application, the details are implementation
	specific.		specific.
	The ingress LSR uses information provided by the management system or		The ingress LSR uses information provided by the management system
	the application and possibly also information from the routing		or the application and possibly also information from the routing
	database to calculated the explicit route and to create the Label		database to calculate the explicit route and to create the Label
	Request Message.		Request Message.
	CR-LDP Specification - 32 - Exp. August 1999
	The Label request message carries together with other necessary		The Label request message carries together with other necessary
	information a ER-TLV defining the explicitly routed path. In our		information a ER-TLV defining the explicitly routed path. In our
	example the list of hops in the ER-Hop TLV is supposed to contain an		example the list of hops in the ER-Hop TLV is supposed to contain an
			Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 30 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	abstract node representing a group of nodes, an abstract node		abstract node representing a group of nodes, an abstract node
	representing a specific node, another abstract node representing a		representing a specific node, another abstract node representing a
	group of nodes, and an abstract node representing a specific egress		group of nodes, and an abstract node representing a specific egress
	point.		point.
	In--{Group 1}--{Specific A}--{Group 2}--{Specific Out: B}		In--{Group 1}--{Specific A}--{Group 2}--{Specific Out: B}
	The ER-TLV contains four ER-Hop TLVs:		The ER-TLV contains four ER-Hop TLVs:
	1. An ER-Hop TLV that specifies a group of LSR valid for the first		1. An ER-Hop TLV that specifies a group of LSR valid for the
	abstract node representing a group of nodes (Group 1).		first abstract node representing a group of nodes (Group 1).
	2. An ER-Hop TLV that indicates the specific node (Node A).		2. An ER-Hop TLV that indicates the specific node (Node A).
	3. An ER-Hop TLV that specifies a group of LSRs valid for the		3. An ER-Hop TLV that specifies a group of LSRs valid for the
	second abstract node representing a group of nodes (Group 2).		second abstract node representing a group of nodes (Group
			2).
	4. An ER-Hop TLV that indicates the specific egress point for the		4. An ER-Hop TLV that indicates the specific egress point for
	CRLSP (Node B).		the CRLSP (Node B).
	All the ER-Hop TLVs are strictly routed nodes.		All the ER-Hop TLVs are strictly routed nodes.
	The setup procedure for this CRLSP works as follows:		The setup procedure for this CRLSP works as follows:
	1. The ingress node sends the Label Request Message to a node that		1. The ingress node sends the Label Request Message to a node
	is a member the group of nodes indicated in the first ER-Hop TLV,		that is a member the group of nodes indicated in the first
	following normal routing for the specific node (A).		ER-Hop TLV, following normal routing for the specific node
			(A).
	2. The node that receives the message identifies itself as part of		2. The node that receives the message identifies itself as part
	the group indicated in the first ER-Hop TLV, and that it is not		of the group indicated in the first ER-Hop TLV, and that it
	the specific node (A) in the second. Further it realizes that the		is not the specific node (A) in the second. Further it
	specific node (A) is not one of its next hops.		realizes that the specific node (A) is not one of its next
			hops.
	3. It keeps the ER-Hop TLVs intact and sends a Label Request		3. It keeps the ER-Hop TLVs intact and sends a Label Request
	Message to a node that is part of the group indicated in the first		Message to a node that is part of the group indicated in the
	ER-Hop TLV (Group 1), following normal routing for the specific		first ER-Hop TLV (Group 1), following normal routing for the
	node (A).		specific node (A).
	4. The node that receives the message identifies itself as part of		4. The node that receives the message identifies itself as part
	the group indicated in the first ER-Hop TLV, and that it is not		of the group indicated in the first ER-Hop TLV, and that it
	the specific node (A) in the second ER-Hop TLV. Further it		is not the specific node (A) in the second ER-Hop TLV.
	realizes that the specific node (A) is one of its next hops.		Further it realizes that the specific node (A) is one of its
			next hops.
	5. It removes the first ER-Hop TLVs and sends a Label Request		5. It removes the first ER-Hop TLVs and sends a Label Request
	Message to the specific node (A).		Message to the specific node (A).
	6. The specific node (A) recognizes itself in the first ER-Hop		6. The specific node (A) recognizes itself in the first ER-Hop
	TLV. Removes the specific ER-Hop TLV.		TLV. Removes the specific ER-Hop TLV.
	CR-LDP Specification - 33 - Exp. August 1999		Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 31 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	7. It sends a Label Request Message to a node that is a member of		7. It sends a Label Request Message to a node that is a member
	the group (Group 2) indicated in the ER-Hop TLV.		of the group (Group 2) indicated in the ER-Hop TLV.
	8. The node that receives the message identifies itself as part of		8. The node that receives the message identifies itself as part
	the group indicated in the first ER-Hop TLV, further it realizes		of the group indicated in the first ER-Hop TLV, further it
	that the specific egress node (B) is one of its next hops.		realizes that the specific egress node (B) is one of its
			next hops.
	9. It sends a Label Request Message to the specific egress node		9. It sends a Label Request Message to the specific egress node
	(B).		(B).
	10. The specific egress node (B) recognizes itself as the egress		10. The specific egress node (B) recognizes itself as the egress
	for the CRLSP, it returns a Label Mapping Message, that will		for the CRLSP, it returns a Label Mapping Message, that will
	traverse the same path as the Label Request Message in the		traverse the same path as the Label Request Message in the
	opposite direction.		opposite direction.
	CR-LDP Specification - 34 - Exp. August 1999		Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 32 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	Appendix B. QoS Service Examples		Appendix B. QoS Service Examples
	B.1 Service Examples		B.1 Service Examples
	Construction of an end-to-end service is the result of the rules		Construction of an end-to-end service is the result of the rules
	enforced at the edge and the treatment that packets receive at the		enforced at the edge and the treatment that packets receive at the
	network nodes. The rules define the traffic conditioning actions that		network nodes. The rules define the traffic conditioning actions
	are implemented at the edge and they include policing with pass,		that are implemented at the edge and they include policing with
	mark, and drop capabilities. The edge rules are expected to be		pass, mark, and drop capabilities. The edge rules are expected to
	defined by the mutual agreements between the service providers and		be defined by the mutual agreements between the service providers
	their customers and they will constitute an essential part of the		and their customers and they will constitute an essential part of
	SLA. Therefore edge rules are not included in the signaling protocol.		the SLA. Therefore edge rules are not included in the signaling
			protocol.
	Packets treatment at a network node is usually referred to as the		Packet treatment at a network node is usually referred to as the
	local behavior. Local behavior could be specified in many ways. One		local behavior. Local behavior could be specified in many ways. One
	example for local behavior specification is the service frequency		example for local behavior specification is the service frequency
	introduced in section 4.3.2.1., together with the resource		introduced in section 4.3.2.1, together with the resource
	reservation rules implemented at the nodes.		reservation rules implemented at the nodes.
	Edge rules and local behaviors can be viewed as the main building		Edge rules and local behaviors can be viewed as the main building
	blocks for the end-to-end service construction. The following table		blocks for the end-to-end service construction. The following table
	illustrates the applicability of the building block approach for		illustrates the applicability of the building block approach for
	constructing different services including those defined for ATM.		constructing different services including those defined for ATM.
	Service PDR PBS CDR CBS EBS Service Conditioning		Service PDR PBS CDR CBS EBS Service Conditioning
	Examples Frequency Action		Examples Frequency Action
	DS S S =PDR =PBS 0 Frequent drop>PDR		DS S S =PDR =PBS 0 Frequent drop>PDR
	TS S S S S 0 Unspecified drop>PDR,PBS		TS S S S S 0 Unspecified drop>PDR,PBS
	mark>CDR,CBS		mark>CDR,CBS
	BE inf inf inf inf 0 Unspecified -		BE inf inf inf inf 0 Unspecified -
	FRS S S CIR ~B_C ~B_E Unspecified drop>PDR,PBS		FRS S S CIR ~B_C ~B_E Unspecified drop>PDR,PBS
	mark>CDR,CBS,EBS		mark>CDR,CBS,EBS
	skipping to change at page 35, line 5		skipping to change at line 1680
	ATM-VBR.3(rt) PCR CDVT SCR MBS 0 Frequent drop>PCR		ATM-VBR.3(rt) PCR CDVT SCR MBS 0 Frequent drop>PCR
	mark>SCR,MBS		mark>SCR,MBS
	ATM-VBR.3(nrt) PCR CDVT SCR MBS 0 Unspecified drop>PCR		ATM-VBR.3(nrt) PCR CDVT SCR MBS 0 Unspecified drop>PCR
	mark>SCR,MBS		mark>SCR,MBS
	ATM-UBR PCR CDVT - - 0 Unspecified drop>PCR		ATM-UBR PCR CDVT - - 0 Unspecified drop>PCR
	ATM-GFR.1 PCR CDVT MCR MBS 0 Unspecified drop>PCR		ATM-GFR.1 PCR CDVT MCR MBS 0 Unspecified drop>PCR
	CR-LDP Specification - 35 - Exp. August 1999
	ATM-GFR.2 PCR CDVT MCR MBS 0 Unspecified drop>PCR		ATM-GFR.2 PCR CDVT MCR MBS 0 Unspecified drop>PCR
	mark>MCR,MFS		mark>MCR,MFS
			Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 33 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
	int-serv-CL p m r b 0 Frequent drop>p		int-serv-CL p m r b 0 Frequent drop>p
	drop>r,b		drop>r,b
	S= User specified		S= User specified
	In the above table, the DS refers to a delay sensitive service where		In the above table, the DS refers to a delay sensitive service where
	the network commits to deliver with high probability user datagrams		the network commits to deliver with high probability user datagrams
	at a rate of PDR with minimum delay and delay requirements. Datagrams		at a rate of PDR with minimum delay and delay requirements.
	in excess of PDR will be discarded.		Datagrams in excess of PDR will be discarded.
	The TS refers to a generic throughput sensitive service where the		The TS refers to a generic throughput sensitive service where the
	network commit to deliver with high probability user datagrams at a		network commits to deliver with high probability user datagrams at a
	rate of at least CDR. The user may transmit at a rate higher than CDR		rate of at least CDR. The user may transmit at a rate higher than
	but datagrams in excess of CDR would have a lower probability of		CDR but datagrams in excess of CDR would have a lower probability of
	being delivered.		being delivered.
	The BE is the best effort service and it implies that there are no		The BE is the best effort service and it implies that there are no
	expected service guarantees from the network.		expected service guarantees from the network.
	B.2. Establishing CR-LSP Supporting Real-Time Applications		B.2. Establishing CR-LSP Supporting Real-Time Applications
	In this scenario the customer needs to establish an LSP for		In this scenario the customer needs to establish an LSP for
	supporting real-time applications such voice and video. The Delay-		supporting real-time applications such voice and video. The Delay-
	sensitive (DS) service is requested in this case.		sensitive (DS) service is requested in this case.
	The first step is the specification of the traffic parameters in the		The first step is the specification of the traffic parameters in the
	signaling message. The two parameters of interest to the DS service		signaling message. The two parameters of interest to the DS service
	are the PDR and the PBS and their values are specified by the user		are the PDR and the PBS and the user based on his requirements
	based on his requirements. Since all the traffic parameters are		specifies their values. Since all the traffic parameters are
	included in the signaling message, appropriate values must be		included in the signaling message, appropriate values must be
	assigned to all of them. For DS service, the CDR and the CBS values		assigned to all of them. For DS service, the CDR and the CBS values
	are set equal to the PDR and the PBS respectively. An indication of		are set equal to the PDR and the PBS respectively. An indication of
	whether the parameter values are subject to negotiation is flagged.		whether the parameter values are subject to negotiation is flagged.
	The transport characteristics of the DS service requires that		The transport characteristics of the DS service require that
	Frequent frequency to be requested to reflect the real-time delay		Frequent frequency to be requested to reflect the real-time delay
	requirements of the service.		requirements of the service.
	In addition to the transport characteristics, both the network		In addition to the transport characteristics, both the network
	provider and the customer need to agree on the actions enforced at		provider and the customer need to agree on the actions enforced at
	the edge. The specification of those actions is expected to be a part		the edge. The specification of those actions is expected to be a
	of the service level agreement (SLA) negotiation and is not included		part of the service level agreement (SLA) negotiation and is not
	in the signaling protocol. For DS service, the edge action is to drop		included in the signaling protocol. For DS service, the edge action
	packets that exceed the PDR and the PBS specifications.		is to drop packets that exceed the PDR and the PBS specifications.
	The signaling message will be sent in the direction of the ER path		The signaling message will be sent in the direction of the ER path
	and the LSP is established following the normal LDP procedures. Each		and the LSP is established following the normal LDP procedures. Each
	CR-LDP Specification - 36 - Exp. August 1999
	LSR applies its admission control rules. If sufficient resources are		LSR applies its admission control rules. If sufficient resources are
	not available and the parameter values are subject to negotiation,		not available and the parameter values are subject to negotiation,
	then the LSR could negotiate down either the PDR, the PBS, or both.		then the LSR could negotiate down the PDR, the PBS, or both.
	The new parameters values are echoed back in the Label Mapping
			Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 34 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
			The new parameter values are echoed back in the Label Mapping
	Message. LSRs might need to re-adjust their resource reservations		Message. LSRs might need to re-adjust their resource reservations
	based on the new traffic parameter values.		based on the new traffic parameter values.
	B.3. Establishing CR-LSP Supporting Delay Insensitive Applications		B.3. Establishing CR-LSP Supporting Delay Insensitive Applications
	In this example we assume that a throughput sensitive (TS) service is		In this example we assume that a throughput sensitive (TS) service
	requested. For resource allocation the user assigns values for PDR,		is requested. For resource allocation the user assigns values for
	PBS, CDR, and CBS. The negotiation flag is set if the traffic		PDR, PBS, CDR, and CBS. The negotiation flag is set if the traffic
	parameters are subject to negotiation.		parameters are subject to negotiation.
			Since the service is delay insensitive by definition, the
			Unspecified frequency is signaled to indicate that the service
			frequency is not an issue.
	Since the service is delay insensitive by definition, the Unspecified		Similar to the previous example, the edge actions are not subject
	frequency is signaled to indicate that the service frequency is not		for signaling and are specified in the service level agreement
	an issue.		between the user and the network provider.
	Similar to the previous example, the edge actions are not subject for
	signaling and are specified in the service level agreement between
	the user and the network provider.
	For TS service, the edge rules might include marking to indicate high		For TS service, the edge rules might include marking to indicate
	discard precedence values for all packets that exceed CDR and the		high discard precedence values for all packets that exceed CDR and
	CBS. The edge rules will also include dropping of packets that are do		the CBS. The edge rules will also include dropping of packets that
	not conform to either PDR and PBS.		are do not conform to neither PDR nor PBS.
	Each LSR of the LSP is expected to run its admission control rules		Each LSR of the LSP is expected to run its admission control rules
	and negotiate traffic parameters down if sufficient resources do not		and negotiate traffic parameters down if sufficient resources do not
	exist. The new parameters values are echoed back in the Label Mapping		exist. The new parameter values are echoed back in the Label Mapping
	Message. LSRs might need to re-adjust their resources based on the		Message. LSRs might need to re-adjust their resources based on the
	new traffic parameter values.		new traffic parameter values.
			Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 35 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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			Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 36
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