draft-ietf-mpls-ldp-state-01.txt		draft-ietf-mpls-ldp-state-02.txt
	MPLS Working Group Liwen Wu
			MPLS Working Group Christophe Boscher
	Internet Draft Pierrick Cheval		Internet Draft Pierrick Cheval
	Expiration Date: December 1999 Christophe Boscher		Expiration Date: April 2000 Alcatel France
	Alcatel USA
			Liwen Wu
			Cisco
	Eric Gray		Eric Gray
	Lucent		Lucent
	June 1999		October 1999
	LDP State Machine		LDP State Machine
	draft-ietf-mpls-ldp-state-01.txt		draft-ietf-mpls-ldp-state-02.txt
	0. Status of this Memo		Status of this Memo
	This document is an Internet-Draft and is in full conformance with		This document is an Internet-Draft and is in full conformance with
	all provisions of Section 10 of RFC2026.		all provisions of Section 10 of RFC2026.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF), its areas, and its working groups. Note that		Task Force (IETF), its areas, and its working groups. Note that other
	other groups may also distribute working documents as Internet-		groups may also distribute working documents as Internet- Drafts.
	Drafts.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet- Drafts as reference		time. It is inappropriate to use Internet- Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	The list of current Internet-Drafts can be accessed at		The list of current Internet-Drafts can be accessed at
	http://www.ietf.org/ietf/1id-abstracts.txt		http://www.ietf.org/ietf/1id-abstracts.txt
	The list of Internet-Draft Shadow Directories can be accessed at		The list of Internet-Draft Shadow Directories can be accessed at
	http://www.ietf.org/shadow.html.		http://www.ietf.org/shadow.html.
	Distribution of this memo is unlimited.		Distribution of this memo is unlimited.
	Copyright Notice		Copyright Notice
	Copyright (C) The Internet Society (1998). All Rights Reserved.		Copyright (C) The Internet Society (1998). All Rights Reserved.
	1. Abstract		1. Abstract
	In the current LDP draft [Ref5], there is no state machine specified		In the current LDP specification [4], there is no state machine
	for processing the LDP messages. We think that defining a common		specified for processing the LDP messages. We think that defining a
	state machine is very important for interoperability between		common state machine is very important for interoperability between
	different ldp implementations.		different ldp implementations.
	This draft provides state machine tables for ATM switch LSRs. We		This document provides state machine tables for ATM switch LSRs. We
	begin in section 2 by defining a list of terminologies. Then in		begin in section 2 by defining a list of terminologies. Then in
	section 3, we propose two sets of state machine tables for ATM switch		section 3, we propose two sets of state machine tables for ATM switch
	LSRs which use downstream-on-demand mode, one method can be used for		LSRs which use downstream-on-demand mode, one method can be used for
	non-vc mergable ATM LSRs, while the other one can be used for the		non-vc merge-able ATM LSRs, while the other one can be used for the
	vc-mergable ATM LSRs. In section 4, we provides a state machine for		vc-merge-able ATM LSRs. In section 4, we provides a state machine
	downstream mode ATM LSR.		for downstream mode ATM LSR.
			We focus on the LDP state machines and the associated control blocks.
			We not describe the "LDP controller" which is in charge of LDP
			session initialization, address mapping messages management, routing
			interface, etc. Specifically, the LDP specification [4] defines the
			state machine for session management.
	Even though the state machines in this document are specific for		Even though the state machines in this document are specific for
	ATM-LSR, they can be easily adapted for other types of LSRs.		ATM-LSR, they can be easily adapted for other types of LSRs.
	2. Terminologies		2. Terminologies
	- LDP-REQUEST: LDP Label Request message		- LDP-REQUEST: LDP Label Request message
	- LDP-MAPPING: LDP Label Mapping message		- LDP-MAPPING: LDP Label Mapping message
	- LDP-WITHDRAW: LDP Label Withdraw message		- LDP-WITHDRAW: LDP Label Withdraw message
	- LDP-RELEASE: LDP Label Release message		- LDP-RELEASE: LDP Label Release message
	- LDP-ABORT: It is a LDP Abort message which is used to abort a LSP		- LDP-ABORT: LDP Abort message used to abort a LSP setup.
	setup.
	- LDP-NAK: It is a LDP Notification msg which is to reject a LDP		- LDP-NAK: LDP Notification message used to reject an LDP message.
	message.
	3. State Machine for Downstream-on-Demand Mode		3. State Machine for Downstream-on-Demand Mode
	This draft focuses on the LDP state machines and the associated
	control blocks. It does not describe the "LDP controller" which is
	in charge of LDP session initialization, address mapping messages
	management, routing interface, etc.
	In this draft, we provide two sets of state machines: one for the ATM		In this draft, we provide two sets of state machines: one for the ATM
	LSR which does not have VC-merge capability, and the other one for		LSR which does not have VC-merge capability, and the other one for
	the ATM LSR which does have VC-merge capability.		the ATM LSR which does have VC-merge capability.
			State machine descriptions are given in terms of control blocks,
			states, events, response actions and state transitions. Control
			blocks contain the information that is required to support handling
			of events. A control block may also contain any additional
			information that is required either of any specific implementation or
			in support of other required functions. In every case, additional
			information required to support the procedures defined in the LDP
			specification [4] or management objects defined in the LDP MIB [3]
			would be stored in a specific LDP implementation - either as part of
			the control block structure or in some other way.
	The state machines cover both independent LSP control and ordered LSP		The state machines cover both independent LSP control and ordered LSP
	control.		control.
	The loop detection and loop prevention message will be processed in		Loop detection and loop prevention message will be processed as
	the way as specified in [Ref5]. The impact of loop detection and loop		specified in [4]. The impact of loop detection and loop prevention
	prevention messages on a state transition is left for further study.		messages on state transitions is left for further study.
	3.0 An LSR's Behavior in the Case of a Next Hop Change		3.0 An LSR's Behavior in the Case of a Next Hop Change
	When there is a topology change and an LSR detects a new better next		When there is a topology change and an LSR detects a new better next
	hop for an LSP, it may behave in 2 different ways:		hop for an LSP, it may behave in 2 different ways:
	1) It tries to do a "local repair". This means that it extends the		1) It tries to do a "local repair". This means that it extends the
	LSP through the new next hop, releases the old path from this LSR		LSP through the new next hop, releases the old path from this LSR
	forward and then splices into this newly extended LSP.		forward and then splices into this newly extended LSP.
	2) If the LSP is created with the "pinned" option[Ref7,CR-LDP], the		2) If the LSP is created with the "pinned" option (CR-LDP[5]), the
	LSR ignores the new next hop change, and the LSP stays unchanged. The		LSR ignores the new next hop change, and the LSP stays unchanged. The
	LSR may decide to send an LDP-MAPPING which contains the attribute		LSR may decide to send an LDP-MAPPING which contains the attribute
	about this New Next Hop (NH) change.		about this New Next Hop (NH) change.
	3.1. ATM Switch LSR with NO VC-merge		3.1. ATM Switch LSR with NO VC-merge
	In an MPLS domain where some ATM LSRs do not have VC-merge		In an MPLS domain where some ATM LSRs do not have VC-merge
	capability, downstream-on-demand mode is required for these ATM		capability, downstream-on-demand mode is required for these ATM LSRs
	LSRs[Ref1]. Also, "conservative label retention mode" is required in		[1]. Also, "conservative label retention mode" is required in this
	this case[Ref1].		case [1].
	For each LSP, there are 2 kinds of state machines involves:		For each LSP, there are 2 kinds of state machines involves:
	1) the LSP Control Block and its state machine which can be used to		1) the LSP Control Block and its state machine which can be used to
	handle normal LSP setup. It is created when the LSR receives a new		handle normal LSP setup. It is created when the LSR receives a new
	LDP Request and it is deleted when the LSP of this request is torn		LDP Request and it is deleted when the LSP of this request is torn
	down.		down.
	2) the Next Hop Trigger Control Block and its state machine which is		2) the Next Hop Trigger Control Block and its state machine which is
	used to handle switching over to a better LSP through a different		used to handle switching over to a better LSP through a different
	next hop. It is created when the LSR decides to switch over to a		next hop. It is created when the LSR decides to switch over to a
	better next hop and it is deleted when the LSR finishes switching		better next hop and it is deleted when the LSR finishes switching
	over to the better next hop.		over to the better next hop. This state machine uses a timer (and
			has corresponding states) to ensure that switch over occurs in a
			timely fashion.
	3.1.1 LSP Control Block		3.1.1 LSP Control Block
	For each LSP, an LSP_Control_Block is defined which may contain the		For each LSP, an LSP_Control_Block is defined which may contain the
	following information:		following information:
	- Upstream Label Request ID(assigned by the upstream LSR), which is		- Upstream Label Request ID (assigned by the upstream LSR), which
	the 'Message Id' in the Label Request Message received from the		is the 'Message Id' in the Label Request Message received from the
	upstream LSR.		upstream LSR.
	- Downstream Label Request ID (assigned by this LSR itself), which		- Downstream Label Request ID (assigned by this LSR itself), which
	is 'Message Id' in the Label Request Message sent to the		is 'Message Id' in the Label Request Message sent to the downstream
	downstrearm LSR.		LSR.
	- Upstream LDP Identifier		- Upstream LDP Identifier
	- Downstream LDP Identifier		- Downstream LDP Identifier
	- State		- State
	- FEC		- FEC
	- Upstream Label(assigned by this LSR)		- Upstream Label(assigned by this LSR)
	- Downstream Label(assigned by the downstream LSR)		- Downstream Label(assigned by the downstream LSR)
	- Trigger Control Block Pointer, (Only used at the ingress LSR of a		- Trigger Control Block Pointer, (Only used at the ingress LSR of a
	LSP)which points to the control block that triggers setting up this		LSP)which points to the control block that triggers setting up this
	skipping to change at page 4, line 26		skipping to change at page 4, line 39
	- Next Hop Control Block Pointer, which points to the control block		- Next Hop Control Block Pointer, which points to the control block
	which is used for switching over to a better LSP.		which is used for switching over to a better LSP.
	The following index combinations can be used to locate a unique		The following index combinations can be used to locate a unique
	LSP_Control_Block:		LSP_Control_Block:
	- Downstream Label and Downstream LDP Identifier, or		- Downstream Label and Downstream LDP Identifier, or
	- Upstream Label and Upstream LDP Identifier, or		- Upstream Label and Upstream LDP Identifier, or
			- Downstream Label Request ID and Downstream LDP Identifier
	- Upstream Label Request ID and Upstream LDP Identifier		- Upstream Label Request ID and Upstream LDP Identifier
	Here is the relationship between different control blocks, the detail		Here is the relationship between different control blocks, the detail
	definition of Next Hop Trigger Block is described in section 3.1.6.		definition of Next Hop Trigger Block is described in section 3.1.6.
	For example, an LSP which transit through (LSR-A, LSR-B, LSR-C,LSR-		For example, an LSP which transit through (LSR-A, LSR-B, LSR-C,LSR-
	D):		D):
	LSR-A ----> LSR-B ---> LSR-C ---> LSR-D		LSR-A ----> LSR-B ---> LSR-C ---> LSR-D
	The control blocks in LSR-A are:		The control blocks in LSR-A are:
	+-----------------------+		+-----------------------+
	| Trigger Control Block |		| Trigger Control Block |
	| (e.g, by config) |		| (e.g, by config) |
	+-----------------------+		+-----------------------+
	^		^
	|(Trigger Control block pointer)		|(Trigger Control block pointer) |
	|
	|		|
	+-----------------------+		+-----------------------+
	| LSP Control Block |		| LSP Control Block |
	+-----------------------+		+-----------------------+
	When LSR-B detects a better next hop to LSR-D through LSR-E, and it		When LSR-B detects a better next hop to LSR-D through LSR-E, and it
	decides to switch over to it, so control blocks in LSR-B are:		decides to switch over to it, so control blocks in LSR-B are:
	+-----------------------+		+-----------------------+
	| LSP Control Block |		| LSP Control Block |
	| (original LSP) |		| (original LSP) |
	+-----------------------+		+-----------------------+
	(LSP ^ |		(LSP ^ |
	Control | | (Next Hop Control Block Pointer)		Control | | (Next Hop Control Block Pointer)
	Block | |		Block | |
	skipping to change at page 5, line 14		skipping to change at page 5, line 27
	When LSR-B detects a better next hop to LSR-D through LSR-E, and it		When LSR-B detects a better next hop to LSR-D through LSR-E, and it
	decides to switch over to it, so control blocks in LSR-B are:		decides to switch over to it, so control blocks in LSR-B are:
	+-----------------------+		+-----------------------+
	| LSP Control Block |		| LSP Control Block |
	| (original LSP) |		| (original LSP) |
	+-----------------------+		+-----------------------+
	(LSP ^ |		(LSP ^ |
	Control | | (Next Hop Control Block Pointer)		Control | | (Next Hop Control Block Pointer)
	Block | |		Block | |
	Pointer | v		Pointer) | v
	+--------------------------------+		+--------------------------------+
	| Next Hop Trigger Control Block |		| Next Hop Trigger Control Block |
	+--------------------------------+		+--------------------------------+
	^ |		^ |
	(Trigger | | (New Next Hop LSP		(Trigger | | (New Next Hop LSP
	Control | | Control Block Pointer)		Control | | Control Block Pointer)
	Block | |		Block | |
	Pointer)| |		Pointer)| |
	| v		| v
	+------------------------+		+------------------------+
	skipping to change at page 5, line 44		skipping to change at page 6, line 14
	-- IDLE		-- IDLE
	This is the initial LSP state, when the LSP_Control_Block is created.		This is the initial LSP state, when the LSP_Control_Block is created.
	-- RESPONSE_AWAITED		-- RESPONSE_AWAITED
	This state means that the LSR has received and processed an LDP-		This state means that the LSR has received and processed an LDP-
	REQUEST from an upstream LSR, or it has received an internal set up		REQUEST from an upstream LSR, or it has received an internal set up
	request. It has sent a new LDP-REQUEST towards a downstream LSR. The		request. It has sent a new LDP-REQUEST towards a downstream LSR. The
	LSR is waiting for the LDP-MAPPING message from the downstream LSR.		LSR is waiting for the LDP-MAPPING from the downstream LSR.
	-- ESTABLISHED		-- ESTABLISHED
	This state means that the LSR has received the LDP-MAPPING message		This state means that the LSR has received the LDP-MAPPING from the
	from the downstream LSR and the LSP is up and operational.		downstream LSR and the LSP is up and operational.
	-- RELEASE_AWAITED		-- RELEASE_AWAITED
	This state means that the LSR has sent a LDP-WITHDRAW message		This state means that the LSR has sent a LDP-WITHDRAW upstream and is
	upstream and is waiting for the LDP-RELEASE before freeing up the		waiting for the LDP-RELEASE before freeing up the label resource.
	label resource.
	3.1.3 Events		3.1.3 Events
	-- LDP Request		-- LDP Request
	The LSR receives an LDP-REQUEST from an upstream LSR.		The LSR receives an LDP-REQUEST from an upstream LSR.
	-- LDP Mapping		-- LDP Mapping
	The LSR receives an LDP-MAPPING from a downstream LSR.		The LSR receives an LDP-MAPPING from a downstream LSR.
	skipping to change at page 6, line 34		skipping to change at page 6, line 48
	The LSR receives an LDP-RELEASE from an upstream LSR.		The LSR receives an LDP-RELEASE from an upstream LSR.
	-- LDP Withdraw		-- LDP Withdraw
	The LSR receives an LDP-WITHDRAW from a downstream LSR.		The LSR receives an LDP-WITHDRAW from a downstream LSR.
	-- LDP Upstream Abort		-- LDP Upstream Abort
	The LSR receives an LDP-ABORT from an upstream LSR.		The LSR receives an LDP-ABORT from an upstream LSR.
	-- LDP Downstream Nak The LSR receives an LDP-NAK(notification) from		-- LDP Downstream NAK The LSR receives an LDP-NAK (notification) from
	an downstream LSR.		an downstream LSR.
	-- Upstream Lost		-- Upstream Lost
	The LSR loses its LDP session with an upstream LDP peer.		The LSR loses its LDP session with an upstream LDP peer.
	-- Downstream Lost		-- Downstream Lost
	The LSR loses its LDP session with a downstream LDP peer.		The LSR loses its LDP session with a downstream LDP peer.
	-- Internal SetUp		-- Internal SetUp
	For some reason, e.g. a configuration request of a traffic		For some reason, e.g. a configuration request of a traffic
	engineering tunnel, or recognizing a new FEC could trigger an		engineering tunnel, or recognizing a new FEC could trigger an
	skipping to change at page 8, line 17		skipping to change at page 8, line 17
	The following diagram describes briefly the state transitions.		The following diagram describes briefly the state transitions.
	+-------------------+		+-------------------+
	| |		| |
	+-------->| IDLE |<--------------+		+-------->| IDLE |<--------------+
	| | | |		| | | |
	| +-------------------+ |(LDP Release)		| +-------------------+ |(LDP Release)
	|(LDP Upstream | |		|(LDP Upstream | |
	| Abort) |(LDP Request) |(LDP Upstream Abort)		| Abort) |(LDP Request) |(LDP Upstream Abort)
	|(Downstream Lost) |(Internal SetUp) |		|(Downstream Lost) |(Internal SetUp) |
	|(Downstream Nak) | |(LDP Downstream Nak)		|(Downstream NAK) | |(LDP Downstream NAK)
	|(Upstream Lost) v |(Upstream Lost)		|(Upstream Lost) v |(Upstream Lost)
	| +-------------------+ |		| +-------------------+ |
	| | | |		| | | |
	+---------| RESPONSE_AWAITED | |		+---------| RESPONSE_AWAITED | |
	| | |		| | |
	+-------------------+ |		+-------------------+ |
	| |		| |
	|(LDP Mapping) |		|(LDP Mapping) |
	| |		| |
	v |		v |
	skipping to change at page 9, line 4		skipping to change at page 8, line 48
	v |		v |
	+-------------------+ |		+-------------------+ |
	| | |		| | |
	| RELEASE_AWAITED |------------>--+		| RELEASE_AWAITED |------------>--+
	| |		| |
	+-------------------+		+-------------------+
	3.1.5 State Machine		3.1.5 State Machine
	3.1.5.1 State -- "IDLE"		3.1.5.1 State -- "IDLE"
	State: IDLE
			State: IDLE
	Event: LDP Request		Event: LDP Request
	New States: Depends upon the action routine		New State: Depends upon the action routine
	Actions:		Actions:
	If this LSR is the LSP Egress or Proxy Egress [Ref2]		If this LSR is the LSP Egress or Proxy Egress [2]
	Then:		Then:
	Choose an upstream label, connect this upstream label to the local		Choose an upstream label, connect this upstream label to the local
	IP forwarding module, allocate the resources, send the LDP-MAPPING		IP forwarding module, allocate the resources, send the LDP-MAPPING
	message upstream with the upstream label, and go to the new state		upstream with the upstream label, and go to the new state
	`ESTABLISHED'.		`ESTABLISHED'.
	else		else
	Obtain a next hop (or interface) with the FEC specified in the		Obtain a next hop (or interface) with the FEC specified in the
	LDP-REQUEST message, propagate the LDP-REQUEST message, with newly		LDP-REQUEST, propagate the LDP-REQUEST, with newly assigned Message
	assigned Message ID by this LSR, towards the obtained next hop,		ID by this LSR, towards the obtained next hop, and go to the new
	and go to the new state `RESPONSE_AWAITED'.		state `RESPONSE_AWAITED'.
	If the LSR uses the independent control mode[Ref2], choose an		If the LSR uses the independent control mode [2], choose an
	upstream label, connect this upstream label to the local IP		upstream label, connect this upstream label to the local IP
	forwarding module, and send an LDP-MAPPING message upstream with		forwarding module, and send an LDP-MAPPING upstream with the
	the upstream label.		upstream label.
	If unable to process the request for any reason, issue an LDP-NAK		If unable to process the request for any reason, issue an LDP-NAK to
	message to the sender with the appropriate error code and delete the		the sender with the appropriate error code and delete the control
	control block.		block.
	State: IDLE		State: IDLE
	Event: LDP Mapping		Event: LDP Mapping
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	skipping to change at page 10, line 30		skipping to change at page 10, line 29
	Event: LDP Upstream Abort		Event: LDP Upstream Abort
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: LDP Downstream Nak		Event: LDP Downstream NAK
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Upstream Lost		Event: Upstream Lost
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Downstream Lost		Event: Downstream Lost
	New State: IDLE
			New State: IDLE
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Internal SetUp		Event: Internal SetUp
	New State: RESPONSE_AWAITED		New State: RESPONSE_AWAITED
	Actions:		Actions:
	Set up the Trigger Control Block pointer,		Set up the Trigger Control Block pointer,
	Obtain a next hop (or interface) with the FEC specified in the		Obtain a next hop (or interface) with the FEC specified in the
	Internal SetUp message, send a LDP-REQUEST towards the obtained next		Internal SetUp message, send a LDP-REQUEST towards the obtained next
	hop, and go to the new state 'RESPONSE_AWAITED'.		hop, and go to the new state `RESPONSE_AWAITED'.
	State: IDLE		State: IDLE
	Event: Internal Destroy		Event: Internal Destroy
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	skipping to change at page 12, line 5		skipping to change at page 11, line 50
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Internal New NH		Event: Internal New NH
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore. It is an internal implementaion error.		Ignore. It is an internal implementation error.
	3.1.5.2 State -- "RESPONSE_AWAITED"		3.1.5.2 State -- "RESPONSE_AWAITED"
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: LDP Request		Event: LDP Request
	New State: RESPONSE_AWAITED		New State: RESPONSE_AWAITED
	Actions:		Actions:
	skipping to change at page 12, line 30		skipping to change at page 12, line 28
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: LDP Mapping		Event: LDP Mapping
	New State: ESTABLISHED		New State: ESTABLISHED
	Actions:		Actions:
	1) If the LSP is triggered by the local router(Trigger Control Block		1) If the LSP is triggered by the local router(Trigger Control Block
	Pointer is not zero), send event "Internal LSP UP" to the Trigger		Pointer is not zero), send event `Internal LSP UP' to the Trigger
	control block.		control block.
	2) Else If the LSR uses the ordered control mode, choose an upstream		2) Else If the LSR uses the ordered control mode, choose an upstream
	label.		label.
	3) Connect the upstream label to the downstream label. Allocate the		3) Connect the upstream label to the downstream label. Allocate the
	resources. propagate the LDP-MAPPING message upstream with the		resources. Propagate the LDP-MAPPING upstream with the upstream
	upstream label.		label.
	If unable to process the message, disconnect the upstream label from		If unable to process the message, disconnect the upstream label from
	the downstream label, free the upstream label, release the resources,		the downstream label, free the upstream label, release the resources,
	send an LDP-RELEASE message downstream and an LDP-Nak upstream with		send an LDP-RELEASE downstream and an LDP-NAK upstream with status
	status (No Label Resources[ref-5]), and delete the LSP_Control_Block.		(No Label Resources [4]), and delete the LSP_Control_Block.
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: LDP Release		Event: LDP Release
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	If the LSR uses the independent control mode, free the upstream		If the LSR uses the independent control mode, free the upstream
	label.		label.
	Send an LDP-ABORT message downstream and delete the		Send an LDP-ABORT downstream and delete the LSP_Control_Block.
	LSP_Control_Block.
			Note: This should only occur if the LSR uses the independent control
			mode. In the ordered control mode, no upstream label mapping will
			have been sent corresponding to this LSP while waiting for a label
			mapping from downstream.
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: LDP Withdraw		Event: LDP Withdraw
	New State: RESPONSE_AWAITED		New State: RESPONSE_AWAITED
	Actions:		Actions:
	Ignore the event. It's a protocol error from the downstream LSR.		Ignore the event. It's a protocol error from the downstream LSR.
	skipping to change at page 13, line 35		skipping to change at page 13, line 36
	Event: LDP Upstream Abort		Event: LDP Upstream Abort
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	If the LSR uses the independent control mode, free the upstream		If the LSR uses the independent control mode, free the upstream
	label.		label.
	Send an LDP-ABORT message downstream.		Send an LDP-ABORT downstream.
	Delete the LSP_Control_Block.		Delete the LSP_Control_Block.
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: LDP Downstream Nak		Event: LDP Downstream NAK
	New State: Depends on the action routine		New State: Depends on the action routine
	Actions:		Actions:
	1. If the LSP is triggered by the local router(Trigger Control Block		1. If the LSP is triggered by the local router(Trigger Control Block
	Pointer is not zero), send event "Internal LSP DOWN" to the Trigger		Pointer is not zero), send event `Internal LSP DOWN' to the Trigger
	control block.		control block.
	2. Else If the LSR uses the independent control mode, send an LDP-		2. Else If the LSR uses the independent control mode, send an LDP-
	WITHDRAW message upstream and go to state 'RELEASE_AWAITED'.		WITHDRAW upstream and go to state `RELEASE_AWAITED'.
	If the LSR uses the ordered control mode, send an LDP-NAK message		If the LSR uses the ordered control mode, send an LDP-NAK upstream.
	upstream. Then delete the control block.		Then delete the control block.
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: Upstream Lost		Event: Upstream Lost
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	If the LSR uses the independent control mode, free the upstream		If the LSR uses the independent control mode, free the upstream
	skipping to change at page 14, line 33		skipping to change at page 14, line 33
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: Downstream Lost		Event: Downstream Lost
	New State: Depends on the action routine		New State: Depends on the action routine
	Actions:		Actions:
	1. If the LSP is triggered by the local router(Trigger Control Block		1. If the LSP is triggered by the local router(Trigger Control Block
	Pointer is not zero), send event "Internal LSP DOWN" to the trigger		Pointer is not zero), send event `Internal LSP DOWN' to the trigger
	control block.		control block.
	2. Else, If the LSR uses the independent control mode, free the		2. Else, If the LSR uses the independent control mode, free the
	upstream label and send an LDP-WITHDRAW upstream and go to state		upstream label and send an LDP-WITHDRAW upstream and go to state
	'RELEASE_AWAITED'.		`RELEASE_AWAITED'.
	If the LSR uses the ordered control mode, send an LDP-NAK		If the LSR uses the ordered control mode, send an LDP-NAK upstream
	upstream(with a status No Route[Ref-5]) and then delete the control		(with a status `No Route' [4]) and then delete the control block.
	block.
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: Internal SetUp		Event: Internal SetUp
	New State: RESPONSE_AWAITED		New State: RESPONSE_AWAITED
	Actions:		Actions:
	Ignore, it is an internal implementation error.		Ignore, it is an internal implementation error.
	skipping to change at page 16, line 4		skipping to change at page 15, line 51
	New State: ESTABLISHED		New State: ESTABLISHED
	Actions:		Actions:
	Ignore the event. It's an internal implementation error. For non VC-		Ignore the event. It's an internal implementation error. For non VC-
	merge ATM LSR, a new LSP control block is always created for each LDP		merge ATM LSR, a new LSP control block is always created for each LDP
	request.		request.
	State: ESTABLISHED		State: ESTABLISHED
	Event: LDP Mapping
			Event: LDP Mapping
	New State: ESTABLISHED		New State: ESTABLISHED
	Actions:		Actions:
	Process the LDP-MAPPING message, which may contain the new attributes		Process the LDP-MAPPING, which may contain the new attributes of the
	of the label mapping and then propagate the LDP-MAPPING message		label mapping and then propagate the LDP-MAPPING upstream.
	upstream.
	State: ESTABLISHED		State: ESTABLISHED
	Event: LDP Release		Event: LDP Release
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Disconnect the upstream label from the downstream label.		Disconnect the upstream label from the downstream label.
	Free the upstream label.		Free the upstream label.
	Free the resources.		Free the resources.
	Send event "Internal Destroy" to the Next Hop Trigger Block if it was		Send event `Internal Destroy' to the Next Hop Trigger Block if it was
	in the middle of switching over to the better next hop.		in the middle of switching over to the better next hop.
	Propagate the LDP-RELEASE message downstream if the LSR is not the		Propagate the LDP-RELEASE downstream if the LSR is not the end of LSP
	end of LSP and delete the LSP_Control_Block.		and delete the LSP_Control_Block.
	State: ESTABLISHED		State: ESTABLISHED
	Event: LDP Withdraw		Event: LDP Withdraw
	New State: Depends on the action routine.		New State: Depends on the action routine.
	Actions:		Actions:
	1) Free the resources and send LDP-RELEASE downstream.		1) Free the resources and send LDP-RELEASE downstream.
	2) If it is independent control mode, set the state to 'IDLE', create		2) If it is independent control mode, set the state to `IDLE', create
	a internal LDP Request with the information in the LSP_Control_Block,		a internal LDP Request with the information in the LSP_Control_Block,
	and pass event 'LDP Request' to its own state machine.		and pass event `LDP Request' to its own state machine.
	3) Else for the ordered control mode		3) Else for the ordered control mode
	3.1)If the LSP is triggerd to be setup by itself(e.g it is the		3.1)If the LSP is triggered to be setup by itself (e.g it is the
	ingress LSR of this LSP), send event "Internal LSP NAK" to the		ingress LSR of this LSP), send event `Internal LSP NAK' to the
	trigger control block and delete the control block		trigger control block and delete the control block
	3.2) else, if it is triggered by the incoming LDP Request,		3.2) else, if it is triggered by the incoming LDP Request,
	Disconnect the upstream label from the downstream label. And		Disconnect the upstream label from the downstream label. Propagate
	Propagate the LDP-WITHDRAW message upstream and go to state		the LDP-WITHDRAW upstream and go to state `RELEASE_AWAITED'.
	'RELEASE_AWAITED'.
	3.3) If the LSP is in the middle of switching over to a better LSP,		3.3) If the LSP is in the middle of switching over to a better LSP,
	send event 'Internal Destroy' to the state machine of its New Next		send event `Internal Destroy' to the state machine of its New Next
	Hop LSP Control Block.		Hop LSP Control Block.
	State: ESTABLISHED		State: ESTABLISHED
	Event: LDP Upstream Abort		Event: LDP Upstream Abort
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Disconnect the upstream label from the downstream label.		Disconnect the upstream label from the downstream label.
	Free the upstream label.		Free the upstream label.
	Send event "Internal Destroy" if the LSR was in the middle of		Send event `Internal Destroy' if the LSR was in the middle of
	switching over to the better next hop.		switching over to the better next hop.
	Propagate an LDP-RELEASE message downstream and delete the		Propagate an LDP-RELEASE downstream and delete the LSP_Control_Block.
	LSP_Control_Block.
	State: ESTABLISHED		State: ESTABLISHED
	Event: LDP Downstream Nak		Event: LDP Downstream NAK
	New State: ESTABLISHED		New State: ESTABLISHED
	Actions:		Actions:
	Ignore the event. It is a protocol error from the downstream LSR.		Ignore the event. It is a protocol error from the downstream LSR.
	The downstream LSR should always LSP-WITHDRAW msg to tear down the		The downstream LSR should always LSP-WITHDRAW to tear down the LSP
	LSP when the LSP is established.		when the LSP is established.
	State: ESTABLISHED		State: ESTABLISHED
	Event: Upstream Lost		Event: Upstream Lost
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Disconnect the upstream label from the downstream label.		Disconnect the upstream label from the downstream label.
	Free the upstream label.		Free the upstream label.
	Send event "Internal Destroy" to the Next Hop Trigger Control Block		Send event `Internal Destroy' to the Next Hop Trigger Control Block
	if it was in the middle of switching over to the better next hop.		if it was in the middle of switching over to the better next hop.
	Free the resources.		Free the resources.
	Propagate an LDP-RELEASE message downstream and delete the		Propagate an LDP-RELEASE downstream and delete the LSP_Control_Block.
	LSP_Control_Block.
	State: ESTABLISHED		State: ESTABLISHED
	Event: Downstream Lost		Event: Downstream Lost
	New State: Depends on the actions		New State: Depends on the actions
	Actions:		Actions:
	1) If the LSP is triggered by the local router(Trigger Control Block		1) If the LSP is triggered by the local router(Trigger Control Block
	Pointer is not zero), send event "Internal LSP NAK" to the Trigger		Pointer is not zero), send event `Internal LSP NAK' to the Trigger
	control block and delete the control block.		control block and delete the control block.
	2) Else, disconnect the upstream label from the downstream label.		2) Else, disconnect the upstream label from the downstream label.
	Propagate an LDP-WITHDRAW message upstream and go to state		Propagate an LDP-WITHDRAW upstream and go to `RELEASE_AWAITED' state.
	'RELEASE_AWAITED' state.
	3) Send event "Internal Destroy" to the Next Hop Trigger Control		3) Send event `Internal Destroy' to the Next Hop Trigger Control
	Block if it was in the middle of switching over to the better next		Block if it was in the middle of switching over to the better next
	hop.		hop.
	State: ESTABLISHED		State: ESTABLISHED
	Event: Internal Setup		Event: Internal Setup
	New State: ESTABLISHED		New State: ESTABLISHED
	Actions:		Actions:
	skipping to change at page 19, line 4		skipping to change at page 18, line 46
	Actions:		Actions:
	Ignore, it is an internal implementation error.		Ignore, it is an internal implementation error.
	State: ESTABLISHED		State: ESTABLISHED
	Event: Internal Destroy		Event: Internal Destroy
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Disconnect the upstream label from the downstream label if it is not		Disconnect the upstream label from the downstream label if it is not
	the ingress of the LSP.		the ingress of the LSP.
	Free the resources.		Free the resources.
	Send an LDP-RELEASE message downstream and delete the		Send an LDP-RELEASE downstream and delete the LSP_Control_Block.
	LSP_Control_Block.
	State: ESTABLISHED		State: ESTABLISHED
	Event: Internal Cross-Connect		Event: Internal Cross-Connect
	New State: ESTABLISHED		New State: ESTABLISHED
	Actions:		Actions:
	Connect the upstream label to the downstream label		Connect the upstream label to the downstream label
	skipping to change at page 19, line 39		skipping to change at page 19, line 34
	State: ESTABLISHED		State: ESTABLISHED
	Event: Internal New NH		Event: Internal New NH
	New State: ESTABLISHED		New State: ESTABLISHED
	Actions:		Actions:
	1) If the LSR was in the middle of switching over to a better next		1) If the LSR was in the middle of switching over to a better next
	hop(Next Hop Trigger Control Block Pointer is not zero), it send		hop(Next Hop Trigger Control Block Pointer is not zero), it send
	"Internal New NH" to that control block.		`Internal New NH' to that control block.
	2) Else, create a new Next Hop Trigger Control Block, set Next Hop		2) Else, create a new Next Hop Trigger Control Block, set Next Hop
	Trigger Control Block pointer which points this control block. And		Trigger Control Block pointer which points this control block. And
	then pass "Internal New NH" to this control block.		then pass `Internal New NH' to this control block.
	3.1.5.4 State --"RELEASE_AWAITED"		3.1.5.4 State --"RELEASE_AWAITED"
	State RELEASE_AWAITED		State RELEASE_AWAITED
	Event LDP Request		Event LDP Request
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State RELEASE_AWAITED		State: RELEASE_AWAITED
	Event LDP Mapping		Event: LDP Mapping
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	It is an protocol error from the downstream LDP peer, but anyway send		It is an protocol error from the downstream LDP peer, but anyway send
	a LDP-RELEASE downstream.		a LDP-RELEASE downstream.
	State RELEASE_AWAITED		State: RELEASE_AWAITED
	Event LDP Release		Event: LDP Release
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	1) Free the upstream label		1) Free the upstream label
	2) Delete the control block.		2) Delete the control block.
	State RELEASE_AWAITED		State: RELEASE_AWAITED
	Event LDP Withdraw		Event: LDP Withdraw
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	It is an protocol error from the downstream LDP peer, but send a		It is an protocol error from the downstream LDP peer, but send a
	LDP-RELEASE anyway.		LDP-RELEASE anyway.
	State RELEASE_AWAITED		State: RELEASE_AWAITED
	Event LDP Upstream Nak		Event: LDP Upstream NAK
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	1) Free the upstream label		1) Free the upstream label
	2) Delete the control block.		2) Delete the control block.
	State RELEASE_AWAITED		State: RELEASE_AWAITED
	Event LDP Downstream Nak		Event: LDP Downstream NAK
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	Ignore the event. Continue waiting for the LDP-RELEASE from upstream.		Ignore the event. Continue waiting for the LDP-RELEASE from upstream.
	State RELEASE_AWAITED		State: RELEASE_AWAITED
	Event Upstream Lost		Event: Upstream Lost
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	1) Free the upstream label		1) Free the upstream label
	2) Delete the control block.		2) Delete the control block.
	State RELEASE_AWAITED		State: RELEASE_AWAITED
	Event Downstream Lost		Event: Downstream Lost
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	Ignore the event. Continue waiting for the LDP-RELEASE from upstream.		Ignore the event. Continue waiting for the LDP-RELEASE from upstream.
	State RELEASE_AWAITED		State: RELEASE_AWAITED
	Event Internal SetUp		Event: Internal SetUp
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State RELEASE_AWAITED		State: RELEASE_AWAITED
	Event Internal Destroy
			Event: Internal Destroy
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State RELEASE_AWAITED		State: RELEASE_AWAITED
	Event Internal Cross-Connect		Event: Internal Cross-Connect
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	3.1.6 Handling the Next Hop Change		3.1.6 Handling the Next Hop Change
	When an LSR detects a better next hop, it may decides to establish a		When an LSR detects a better next hop, it may decides to establish a
	new LSP through this next hop. For example, an LSR is configured as		new LSP through this next hop. For example, an LSR is configured as
	"local repair", or the LSR is configured as "global repair" and it is		"local repair", or the LSR is configured as "global repair" and it is
	the ingress end of a LSP. It can then create a Next Hop Trigger		the ingress end of a LSP. It can then create a Next Hop Trigger
	Control Block and use the state machine of Next Hop Trigger Control		Control Block and use the state machine of Next Hop Trigger Control
	Block to establish a new LSP through the better next hop.		Block to establish a new LSP through the better next hop.
	3.1.6.1 Next Hop Trigger Control Block		3.1.6.1 Next Hop Trigger Control Block
			-- State
	-- LSP Control Block Pointer, which points to the original LSP		-- LSP Control Block Pointer, which points to the original LSP
	control block.		control block.
	-- New Next Hop LSP Control Block Pointer, which points to the LSP		-- New Next Hop LSP Control Block Pointer, which points to the LSP
	Control Block that is setting up an LSP through the new next hop.		Control Block that is setting up an LSP through the new next hop.
	3.1.6.2 States		3.1.6.2 States
	-- IDLE		-- IDLE
	skipping to change at page 23, line 4		skipping to change at page 22, line 47
	Control Block that is setting up an LSP through the new next hop.		Control Block that is setting up an LSP through the new next hop.
	3.1.6.2 States		3.1.6.2 States
	-- IDLE		-- IDLE
	This is the initial LSP state, when the Trigger_Control_Block is		This is the initial LSP state, when the Trigger_Control_Block is
	created.		created.
	-- NEW_NH_RETRY		-- NEW_NH_RETRY
	This is the state where an LSR waits for a retry timer to expire and		This is the state where an LSR waits for a retry timer to expire and
	then tries to establish an LSP through a new next hop.		then tries to establish an LSP through a new next hop.
	-- NEW_NH_RESPONSE_AWAITED		-- NEW_NH_RESPONSE_AWAITED
	This is the state where an LSR is in the middle of establishing a new		This is the state where an LSR is in the middle of establishing a new
	LSP through a new next hop. It has triggered a LSP control block to		LSP through a new next hop. It has triggered a LSP control block to
	send an LDP-REQUEST towards the new next hop and is waiting for the		send an LDP-REQUEST towards the new next hop and is waiting for the
	LDP-MAPPING message.		LDP-MAPPING.
	3.1.6.3 Events		3.1.6.3 Events
	-- Internal New NH		-- Internal New NH
	The LSR detects there is a new next hop for a FEC.		The LSR detects there is a new next hop for a FEC.
	-- Internal Retry Timeout		-- Internal Retry Timeout
	The LSP retry timer expires.		The LSP retry timer expires.
	skipping to change at page 24, line 43		skipping to change at page 24, line 43
	the control block is deleted		the control block is deleted
	3.01.3 State Machine		3.01.3 State Machine
	3.01.3.1 State -- "IDLE"		3.01.3.1 State -- "IDLE"
	State: IDLE		State: IDLE
	Event: Internal New NH		Event: Internal New NH
	New States: NEW_NH_RETRY		New State: NEW_NH_RETRY
	Actions:		Actions:
	Start the LSP retry timer and go to the 'NEW_NH_RETRY' state.		Start the LSP retry timer and go to the `NEW_NH_RETRY' state.
	State: IDLE		State: IDLE
	Event: Internal retry timeout		Event: Internal retry timeout
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Internal LSP UP		Event: Internal LSP UP
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Internal LSP NAK		Event: Internal LSP NAK
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Internal destroy		Event: Internal destroy
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	3.01.3.2 State -- "NEW_NH_RETRY"		3.01.3.2 State -- "NEW_NH_RETRY"
	State: NEW_NH_RETRY		State: NEW_NH_RETRY
	Event: Internal New NH		Event: Internal New NH
	New States: NEW_NH_RETRY		New State: NEW_NH_RETRY
	Actions:		Actions:
	Restart the LSP retry timer.		Restart the LSP retry timer.
	State: NEW_NH_RETRY		State: NEW_NH_RETRY
	Event: Internal retry timeout		Event: Internal retry timeout
	New States: NEW_NH_RESPONSE_AWAITED		New State: NEW_NH_RESPONSE_AWAITED
	Actions:		Actions:
	If the new next hop is the same one as the old next hop, delete the		If the new next hop is the same one as the old next hop, delete the
	control block.		control block.
	Otherwise, create an LSP control block which will try to establish a		Otherwise, create an LSP control block which will try to establish a
	new LSP through the new next hop. And send event "Internal Setup" to		new LSP through the new next hop. And send event `Internal Setup' to
	its state machine.		its state machine.
	State: NEW_NH_RETRY		State: NEW_NH_RETRY
	Event: Internal LSP UP		Event: Internal LSP UP
	New States: NEW_NH_RETRY		New State: NEW_NH_RETRY
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: NEW_NH_RETRY		State: NEW_NH_RETRY
	Event: Internal LSP NAK		Event: Internal LSP NAK
	New States: NEW_NH_RETRY		New State: NEW_NH_RETRY
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: NEW_NH_RETRY		State: NEW_NH_RETRY
	Event: Internal destroy		Event: Internal destroy
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Stop the timer and delete the control block.		Stop the timer and delete the control block.
	3.01.3.3 State -- "NEW_NH_RESPONSE_AWAITED"		3.01.3.3 State -- "NEW_NH_RESPONSE_AWAITED"
	State: NEW_NH_RESPONSE_AWAITED		State: NEW_NH_RESPONSE_AWAITED
	Event: Internal New NH		Event: Internal New NH
	New States: NEW_NH_RETRY		New State: NEW_NH_RETRY
	Actions:		Actions:
	Restart the LSP retry timer, send "Internal destroy" to the control		Restart the LSP retry timer, send `Internal destroy' to the control
	block of the LSP for the new next hop and go to the 'NEW_NH_RETRY'		block of the LSP for the new next hop and go to the `NEW_NH_RETRY'
	state.		state.
	State: NEW_NH_RESPONSE_AWAITED		State: NEW_NH_RESPONSE_AWAITED
	Event: Internal retry timeout		Event: Internal retry timeout
	New States: NEW_NH_RESPONSE_AWAITED		New State: NEW_NH_RESPONSE_AWAITED
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: NEW_NH_RESPONSE_AWAITED		State: NEW_NH_RESPONSE_AWAITED
	Event: Internal LSP UP		Event: Internal LSP UP
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Send event "Internal cross-connect" event to the LSP control block of		Send event `Internal cross-connect' event to the LSP control block of
	the new next hop.		the new next hop.
	Send event "Internal destroy" event to the original LSP control		Send event `Internal destroy' event to the original LSP control
	block.		block.
	Then delete the control block.		Then delete the control block.
	State: NEW_NH_RESPONSE_AWAITED		State: NEW_NH_RESPONSE_AWAITED
	Event: Internal LSP NAK		Event: Internal LSP NAK
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Delete the control block.		Delete the control block.
	State: NEW_NH_RESPONSE_AWAITED		State: NEW_NH_RESPONSE_AWAITED
	Event: Internal destroy		Event: Internal destroy
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Send event "Internal destroy" the control block for the new LSP		Send event `Internal destroy' the control block for the new LSP
	through the new next hop.		through the new next hop.
	3.1.7 LDP Related Message Handling		3.1.7 LDP Related Message Handling
	- If an LSR receives an LDP-REQUEST from an upstream LSR:		- If an LSR receives an LDP-REQUEST from an upstream LSR:
	a) If this is a duplicate request, discard the msg. A duplicate		a) If this is a duplicate request, discard the message. A duplicate
	request means that there is a LSP_Control_Block which has same FEC,		request means that there is a LSP_Control_Block which has same FEC,
	same Upstream Label Request ID and same Upstream LDP Session		same Upstream Label Request ID and same Upstream LDP Session
	Identifier.		Identifier.
	b) Otherwise, create a new LSP_Control_Block, store the relevant		b) Otherwise, create a new LSP_Control_Block, store the relevant
	information from the message into the control block, then pass the		information from the message into the control block, then pass the
	event `LDP Request' to its state machine.		event `LDP Request' to its state machine.
	- If an LSR receives an LDP-MAPPING from a downstream LSR:		- If an LSR receives an LDP-MAPPING from a downstream LSR:
	a) Extract the 'Label Request Message ID' field and from the LDP-		a) Extract the 'Label Request Message ID' field and from the LDP-
	MAPPING message.		MAPPING.
	b) Find an LSP_Control_Block which has the same Downstream Label		b) Find an LSP_Control_Block which has the same Downstream Label
	Request ID and the same Downstream LDP Session Identifier.		Request ID and the same Downstream LDP Session Identifier.
	c) If an LSP_Control_Block is found, pass the event `LDP Mapping' to		c) If an LSP_Control_Block is found, pass the event `LDP Mapping' to
	its state machine.		its state machine.
	d) If there is no matching LSP_Control_Block found, then try to find		d) If there is no matching LSP_Control_Block found, then try to find
	an LSP_Control_Block which has the same Downstream Lable and the same		an LSP_Control_Block which has the same Downstream Label and the same
	Downstream LDP Session Identifier.		Downstream LDP Session Identifier.
	e) If an LSP_Control_Block is found, pass the event 'LDP Mapping' to		e) If an LSP_Control_Block is found, pass the event `LDP Mapping' to
	its state machine.		its state machine.
	f) Otherwise, ignore the LDP-MAPPING message and send a LDP-RELEASE		f) Otherwise, ignore the LDP-MAPPING and send a LDP-RELEASE
	message downstream.		downstream.
	- If an LSR receives an LDP-RELEASE from an upstream LSR:		- If an LSR receives an LDP-RELEASE from an upstream LSR:
	a) Find an LSP_Control_Block which has the same Upstream Label and		a) Find an LSP_Control_Block which has the same Upstream Label and
	the same Upstream LDP Session Identifier.		the same Upstream LDP Session Identifier.
	b) If an LSP_Control_Block is found, pass the event 'LDP Release' to		b) If an LSP_Control_Block is found, pass the event `LDP Release' to
	its state machine.		its state machine.
	c) Otherwise, ignore the message.		c) Otherwise, ignore the message.
	- If an LSR receives an LDP-WITHDRAW from a downstream LSR:		- If an LSR receives an LDP-WITHDRAW from a downstream LSR:
	a) Find an LSP_Control_Block which has the same Downstream Label and		a) Find an LSP_Control_Block which has the same Downstream Label and
	the same Downstream LDP Session Identifier.		the same Downstream LDP Session Identifier.
	b) If an LSP_Control_Block is found, pass the event 'LDP Withdraw' to		b) If an LSP_Control_Block is found, pass the event `LDP Withdraw' to
	its state machine.		its state machine.
	c) Otherwise, ignore the LDP-WITHDRAW message and send a LDP-RELEASE		c) Otherwise, ignore the LDP-WITHDRAW and send a LDP-RELEASE
	message downstream.		downstream.
	- If an upstream LDP peer is lost:		- If an upstream LDP peer is lost:
	a) Find all the LSP_Control_Blocks whose upstream LDP peer is that		a) Find all the LSP_Control_Blocks whose upstream LDP peer is that
	LSR.		LSR.
	b) Then pass the event 'Upstream Lost' to their state machines.		b) Then pass the event `Upstream Lost' to their state machines.
	- If a downstream LDP peer is lost:		- If a downstream LDP peer is lost:
	a) Find all the LSP_Control_Blocks whose downstream LDP peer is that		a) Find all the LSP_Control_Blocks whose downstream LDP peer is that
	LSR.		LSR.
	b) Then pass the event 'Downstream Lost' to their state machines.		b) Then pass the event `Downstream Lost' to their state machines.
	- If the LSR detects a new next hop for an FEC:		- If the LSR detects a new next hop for an FEC:
	For each LSP which needs "local repair", or it needs "global repair"		For each LSP which needs "local repair", or it needs "global repair"
	and it is the ingress of the LSP, pass event "Internal New NH" to its		and it is the ingress of the LSP, pass event "Internal New NH" to its
	state machine.		state machine.
	- If an LSR receives an LDP-Abort from an upstream LSR:		- If an LSR receives an LDP-Abort from an upstream LSR:
	a) Extract the LDP Request ID value from the LDP-Abort message.		a) Extract the LDP Request ID value from the LDP-Abort message.
	b) Find an LSP_Control_Block which has the same Upstream Label		b) Find an LSP_Control_Block which has the same Upstream Label
	Request ID and the same Upstream LDP Session Identifier.		Request ID and the same Upstream LDP Session Identifier.
	c) If an LSP_Control_Block is found, pass the event 'LDP Upstream		c) If an LSP_Control_Block is found, pass the event `LDP Upstream
	Abort' to its state machine.		Abort' to its state machine.
	d) Otherwise, ignore the message.		d) Otherwise, ignore the message.
	- If the LSR receives an LDP-NAK from a downstream LSR:		- If the LSR receives an LDP-NAK from a downstream LSR:
	a) Extract the LDP Request ID value from the LDP-NAK.		a) Extract the LDP Request ID value from the LDP-NAK.
	b) Find an LSP_Control_Block which has the same Downstream Label		b) Find an LSP_Control_Block which has the same Downstream Label
	Request ID and the same Downstream LDP Session Identifier.		Request ID and the same Downstream LDP Session Identifier.
	c) If an LSP_Control_Block is found, pass the event		c) If an LSP_Control_Block is found, pass the event `LDP Downstream
			NAK' to its state machine.
	d) Otherwise, ignore the message.		d) Otherwise, ignore the message.
	3.2. ATM Switch LSR with VC-merge		3.2. ATM Switch LSR with VC-merge
	3.2.1 VC-merge		3.2.1 VC-merge
	A VC-merge capable LSR can map multiple incoming labels(VPI/VCI) into		A VC-merge capable LSR can map multiple incoming labels (VPI/VCI)
	one outgoing label. It is possible that this LSR can only merge a		into one outgoing label. It is possible that this LSR can only merge
	limited number of incoming labels into a single outgoing label. As		a limited number of incoming labels into a single outgoing label. As
	described in [Ref2], suppose, for example, that due to some hardware		described in [2], suppose, for example, that due to some hardware
	limitation a node is capable of merging four incoming labels into a		limitation a node is capable of merging four incoming labels into a
	single outgoing label. Suppose however, that this particular node has		single outgoing label. Suppose however, that this particular node has
	six incoming labels arriving at it for a particular FEC. In this		six incoming labels arriving at it for a particular FEC. In this
	case, this node may merge these into two outgoing labels.		case, this node may merge these into two outgoing labels.
	When an upstream LSR has a limited merging capability, it is		When an upstream LSR has a limited merging capability, it is
	difficult for a downstream LSR to know how many labels should be		difficult for a downstream LSR to know how many labels should be
	assigned to each FEC. In this case, downstream-on-demand is		assigned to each FEC. In this case, downstream-on-demand is
	recommended.		recommended.
	3.2.2 Control Block		3.2.2 Control Block
	There are 3 types of control blocks involved:		There are 3 types of control blocks involved:
	Upstream_LSP_Control_Block, Downstream_LSP_Control_Block, and Next		Upstream_LSP_Control_Block, Downstream_LSP_Control_Block, and Next
	Hop Trigger Control Block.		Hop Trigger Control Block.
	There is one Upstream_LSP_Control_Block for each LDP-REQUEST		There is one Upstream_LSP_Control_Block for each LDP-REQUEST
	received.		received.
	There is one Downstream_LSP_Control_Block for each unique LDP-		There is one Downstream_LSP_Control_Block for each unique LDP-REQUEST
	REQUEST sent to a downstream LSR. There can be multiple		sent to a downstream LSR. There can be multiple
	Downstream_LSP_Control_Blocks per FEC in an LSR. This can be the		Downstream_LSP_Control_Blocks per FEC in an LSR. This can be the
	result of an upstream LSR asking for a label of an FEC. This LSR must		result of an upstream LSR asking for a label for an FEC. This LSR
	assign a unique upstream label and it can not merge this upstream		must assign a unique upstream label and it can not merge this
	label into an existing downstream label of this FEC.		upstream label into an existing downstream label for this FEC.
	There is one Next Hop Trigger Control Block for each FEC which was		There is one Next Hop Trigger Control Block for each FEC for which a
	detected with a better next hop and the LSR decides to switch over to		better next hop has been detected and the LSR has decided to switch
	this better next hop. It could be the result of "local repair" or		to this better next hop. It could be the result of "local repair" or
	"global repair" if the LSR is the ingress LSR of the LSP.		"global repair" if the LSR is the ingress LSR of the LSP.
	A Downstream_LSP_Control_Block contains a list of pointers to		A Downstream_LSP_Control_Block contains a list of pointers to
	Upstream_LSP_Control_Blocks or the Next Hop Trigger Control Block.		Upstream_LSP_Control_Blocks or the Next Hop Trigger Control Block.
	This means that this LSR has decided to map the multiple labels		This means that this LSR has decided to map the multiple labels
	listed in the Upstream_LSP_Control_Blocks and the Next Hop Trigger		listed in the Upstream_LSP_Control_Blocks and the Next Hop Trigger
	Control Block into a single label listed in the		Control Block into a single label listed in the
	Downstream_LSP_Control_Block.		Downstream_LSP_Control_Block.
	An Upstream_LSP_Control_Block may contain the following information:		An Upstream_LSP_Control_Block may contain the following information:
	- Upstream LDP Session Identifier		- Upstream LDP Session Identifier
	- State		- State
	- Upstream Label(assigned by this LSR)		- Upstream Label(assigned by this LSR)
	- Downstream_LSP_Control_Block pointer		- Downstream_LSP_Control_Block pointer
	- Upstream LDP Request ID (assigned by the Upstream LSR in		- Upstream LDP Request ID (assigned by the upstream LSR in
	downstream-on-demand mode)		downstream-on-demand mode)
	- Next_Hop_Trigger_Block pointer		- Next_Hop_Trigger_Block pointer
	Upstream Label and Upstream LDP Session Identifier can be used to		Upstream Label and Upstream LDP Session Identifier can be used to
	locate a unique Upstream_LSP_Control_Block.		locate a unique Upstream_LSP_Control_Block.
	If an LSR is using downstream-on-demand mode, it can use the Upstream		If an LSR is using downstream-on-demand mode, it can use the Upstream
	LDP Request ID and the Upstream LDP Session Identifier to locate a		LDP Request ID and the Upstream LDP Session Identifier to locate a
	unique Upstream_LSP_Control_Block.		unique Upstream_LSP_Control_Block.
	skipping to change at page 33, line 8		skipping to change at page 32, line 34
	The following diagram details the relationship between these 2 types		The following diagram details the relationship between these 2 types
	of control blocks:		of control blocks:
	For example, the LSR has decided to merge 3 LDP-REQUESTs of a FEC		For example, the LSR has decided to merge 3 LDP-REQUESTs of a FEC
	from upstream LSR1,LSR2,LSR3 into one LDP-REQUEST and sent it to a		from upstream LSR1,LSR2,LSR3 into one LDP-REQUEST and sent it to a
	downstream LSR4.		downstream LSR4.
	+---------------------+		+---------------------+
	| |		| |
	| Upstream_LSP_Control|		| Upstream_LSP_Control|
	| _Block for Upstream|-------+		| _Block for Upstream|------+
	| LSR1 | |		| LSR1 | |
	+---------------------+ |		+---------------------+ |
	|		|
	|
	|
	|
	|
	+---------------------+ |		+---------------------+ |
	| | |		| | |
	| Upstream_LSP_Control| | (merged into)		| Upstream_LSP_Control| | (merged into)
	| _Block for Upstream |-------+		| _Block for Upstream |------+
	| LSR2 | |		| LSR2 | |
	+---------------------+ |		+---------------------+ | +------------------------------+
	|
	|
	|
	| +------------------------------+
	| | |
	+-->| Downstream_LSP_Control_Block |
	| | for Downstream LSR4 |
	| | |		| | |
	| +------------------------------+		+---------------------+ +--->| Downstream_LSP_Control_Block |
	|		| Next_Hop_Trigger_ | | | for Downstream LSR4 |
	+---------------------+ |		| LSP_Control_Block |------+ | |
	| Next_Hop_Trigger_ | |		| | +------------------------------+
	| LSP_Control_Block | |
	| |-------+
	| |
	+---------------------+		+---------------------+
	3.2.3 State Machines for Downstream-on-demand Mode		3.2.3 State Machines for Downstream-on-demand Mode
	The following sections describe the state machines used in		The following sections describe the state machines used in
	downstream-on-demand mode.		downstream-on-demand mode.
	3.2.3.1 State of the Upstream_LSP_Control_Block's State Machine		3.2.3.1 State of the Upstream_LSP_Control_Block's State Machine
	for Downstream-on-demand Mode		for Downstream-on-demand Mode
	skipping to change at page 34, line 4		skipping to change at page 33, line 18
	downstream-on-demand mode.		downstream-on-demand mode.
	3.2.3.1 State of the Upstream_LSP_Control_Block's State Machine		3.2.3.1 State of the Upstream_LSP_Control_Block's State Machine
	for Downstream-on-demand Mode		for Downstream-on-demand Mode
	-- IDLE		-- IDLE
	This is the initial LSP state.		This is the initial LSP state.
	-- RESPONSE_AWAITED		-- RESPONSE_AWAITED
	This state means that the LSR has received and processed an LDP-		This state means that the LSR has received and processed an LDP-
	REQUEST from an upstream LSR, and has sent a new LDP-REQUEST towards		REQUEST from an upstream LSR, and has sent a new LDP-REQUEST towards
	a downstream LSR. The LSR is waiting for the LDP-MAPPING message from		a downstream LSR. The LSR is waiting for the LDP-MAPPING from the
	the downstream LSR.		downstream LSR.
	-- ESTABLISHED		-- ESTABLISHED
	This state means that the LSR has received the LDP-MAPPING message		This state means that the LSR has received the LDP-MAPPING from the
	from the downstream LSR and the LSP is up and operational.		downstream LSR and the LSP is up and operational.
	-- RELEASE_AWAITED		-- RELEASE_AWAITED
	This state means that the LSR has sent a LDP-WITHDRAW message		This state means that the LSR has sent a LDP-WITHDRAW upstream and is
	upstream and is waiting for the LDP-RELEASE before freeing up the		waiting for the LDP-RELEASE before freeing up the label resource.
	label resource.
	3.2.3.2 Events of the Upstream_LSP_Control_Block's State Machine		3.2.3.2 Events of the Upstream_LSP_Control_Block's State Machine
	for Downstream-on-demand Mode		for Downstream-on-demand Mode
	-- LDP Request		-- LDP Request
	The LSR receives an LDP-REQUEST from an upstream LSR.		The LSR receives an LDP-REQUEST from an upstream LSR.
	-- Internal Downstream Mapping		-- Internal Downstream Mapping
	This event is sent by one Downstream_LSP_Control_Block's state		This event is sent by one Downstream_LSP_Control_Block's state
	machine. This Downstream_LSP_Control_Block is the merged		machine. This Downstream_LSP_Control_Block is the merged
	Downstream_LSP_Control_Block of this Upstream_LSP_Control_Block. The		Downstream_LSP_Control_Block of this Upstream_LSP_Control_Block. The
	event is the result of receiving an LDP-MAPPING message by the		event is the result of receiving an LDP-MAPPING by the
	Downstream_LSP_Control_Block's state machine.		Downstream_LSP_Control_Block's state machine.
	-- LDP Release		-- LDP Release
	The LSR receives an LDP-RELEASE from an upstream LSR.		The LSR receives an LDP-RELEASE from an upstream LSR.
	-- Internal Downstream Withdraw		-- Internal Downstream Withdraw
	This event is sent by one Downstream_LSP_Control_Block's state		This event is sent by one Downstream_LSP_Control_Block's state
	machine. This Downstream_LSP_Control_Block is the merged		machine. This Downstream_LSP_Control_Block is the merged
	Downstream_LSP_Control_Block of this Upstream_LSP_Control_Block. The		Downstream_LSP_Control_Block of this Upstream_LSP_Control_Block. The
	event is the result of receiving an LDP-WITHDRAW message by the		event is the result of receiving an LDP-WITHDRAW by the
	Downstream_LSP_Control_Block's state machine.		Downstream_LSP_Control_Block's state machine.
	-- LDP Upstream Abort		-- LDP Upstream Abort
	The LSR receives an LDP-ABORT from an upstream LSR.		The LSR receives an LDP-ABORT from an upstream LSR.
	-- Internal Downstream Nak		-- Internal Downstream NAK
	This event is sent by one Downstream_LSP_Control_Block's state		This event is sent by one Downstream_LSP_Control_Block's state
	machine. This Downstream_LSP_Control_Block is the merged		machine. This Downstream_LSP_Control_Block is the merged
	Downstream_LSP_Control_Block of this Upstream_LSP_Control_Block. The		Downstream_LSP_Control_Block of this Upstream_LSP_Control_Block. The
	event is the result of receiving an LDP-NAK message by the		event is the result of receiving an LDP-NAK by the
	Downstream_LSP_Control_Block's state machine, or it detects an error.		Downstream_LSP_Control_Block's state machine, or it detects an error.
	-- Upstream Lost		-- Upstream Lost
	The LSR loses the LDP session with its upstream LDP peer.		The LSR loses the LDP session with its upstream LDP peer.
	-- Internal New NH		-- Internal New NH
	The LSR detects there is better next hop and decides to establish the		The LSR detects there is better next hop and decides to establish the
	lsp through this better next hop		lsp through this better next hop
	skipping to change at page 36, line 15		skipping to change at page 35, line 15
	3.2.3.3 State Transitions of the Upstream_LSP_Control_Block's State		3.2.3.3 State Transitions of the Upstream_LSP_Control_Block's State
	Machine for Downstream-on-demand Mode		Machine for Downstream-on-demand Mode
	+-------------------+		+-------------------+
	| |		| |
	+-------->| IDLE |<------------+		+-------->| IDLE |<------------+
	| | | |		| | | |
	| +-------------------+ |		| +-------------------+ |
	|(LDP Abort) | |		|(LDP Abort) | |
	|(Internal |(LDP Request) |		|(Internal |(LDP Request) |
	| Downstream Nak) | |		| Downstream NAK) | |
	|(Upstream Lost) | |		|(Upstream Lost) | |
	| v |		| v |
	| +-------------------+ |		| +-------------------+ |
	| | | |		| | | |
	+---------| RESPONSE_AWAITED | |		+---------| RESPONSE_AWAITED | |
	| | |(Upstream Lost)		| | |(Upstream Lost)
	+-------------------+ |		+-------------------+ |
	| |		| |
	|(Internal Downstream |		|(Internal Downstream |
	| mapping) |(LDP Release)		| mapping) |(LDP Release)
	| |		| |
	v |		v |
	+-------------------+ |		+-------------------+ |
	| | |(LDP Abort)		| | |(LDP Abort)
	| ESTABLISHED |------->-----+		| ESTABLISHED |------->-----+
	| | |		| | |
	+-------------------+ |		+-------------------+ |
	| |		| |
	| |		| |
	|(Internal Downstream Withdraw)		|(Internal Downstream Withdraw)
	|(Internal Downstream Nak)		|(Internal Downstream NAK)
	v		v
	+-------------------+ |		+-------------------+ |
	| | |		| | |
	|RELEASE_AWAITED |------->-----+		|RELEASE_AWAITED |------->-----+
	| |		| |
	+-------------------+		+-------------------+
	3.2.3.4 Upstream_LSP_Control_Block's State Machine		3.2.3.4 Upstream_LSP_Control_Block's State Machine
	for Downstream-on-demand Mode		for Downstream-on-demand Mode
	3.2.3.4.1 State -- "IDLE"		3.2.3.4.1 State -- "IDLE"
	State: IDLE		State: IDLE
	Event: LDP Request		Event: LDP Request
	New State: Depends upon the action routine.		New State: Depends upon the action routine.
	Actions:		Actions:
	If this LSR is the LSP Egress or Proxy Egress [Ref2],		If this LSR is the LSP Egress or Proxy Egress [2],
	Then:		Then:
	choose an upstream label, allocate the resources, connect this		choose an upstream label, allocate the resources, connect this
	upstream label to the local IP forwarding module, send an LDP-		upstream label to the local IP forwarding module, send an LDP-
	MAPPING upstream with the upstream label and go to the state		MAPPING upstream with the upstream label and go to the state
	'ESTABLISHED'.		`ESTABLISHED'.
	else		else
	Obtain a next hop(or interface). Find a		Obtain a next hop(or interface). Find a
	Downstream_LSP_Control_Block which has the same FEC and the same		Downstream_LSP_Control_Block which has the same FEC and the same
	next hop and also is able to merge more input labels. If not found,		next hop and also is able to merge more input labels. If not found,
	create a new Downstream_LSP_Control_Block with the state 'IDLE'.		create a new Downstream_LSP_Control_Block with the state `IDLE'.
	If the state of the Downstream_LSP_Control_Block is `ESTABLISHED',		If the state of the Downstream_LSP_Control_Block is `ESTABLISHED',
	choose an upstream label, connect the upstream label with the		choose an upstream label, connect the upstream label with the
	downstream label and send an LDP-MAPPING message upstream with the		downstream label and send an LDP-MAPPING upstream with the upstream
	upstream label, and go to the state `ESTABLISHED'.		label, and go to the state `ESTABLISHED'.
	If the state of Downstream_LSP_Control_Block is not `ESTABLISHED',		If the state of Downstream_LSP_Control_Block is not `ESTABLISHED',
	set the state of the Upstream_LSP_Control_Block to		set the state of the Upstream_LSP_Control_Block to
	'RESPONSE_AWAITED'. If the LSR use the independent control		`RESPONSE_AWAITED'. If the LSR use the independent control mode
	mode[Ref2], choose an upstream label, and send an LDP-MAPPING		[2], choose an upstream label, and send an LDP-MAPPING upstream.
	message upstream.
	Pass the event `Internal AddUpstream' to the		Pass the event `Internal AddUpstream' to the
	Downstream_LSP_Control_Block's state machine.		Downstream_LSP_Control_Block's state machine.
	If unable to process the request for any reason, issue an LDP-NAK		If unable to process the request for any reason, issue an LDP-NAK to
	message to the sender with the appropriate error code and delete the		the sender with the appropriate error code and delete the control
	control block.		block.
	State: IDLE		State: IDLE
	Event: Internal Downstream Mapping		Event: Internal Downstream Mapping
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: LDP Release		Event: LDP Release
	New State: IDLE		New State: IDLE
	skipping to change at page 38, line 40		skipping to change at page 37, line 39
	Event: LDP Upstream Abort		Event: LDP Upstream Abort
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Internal Downstream Nak		Event: Internal Downstream NAK
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Upstream Lost		Event: Upstream Lost
	New State: IDLE
			New State: IDLE
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Internal Re-Cross-Connect		Event: Internal Re-Cross-Connect
	New State: IDLE		New State: IDLE
	skipping to change at page 40, line 10		skipping to change at page 39, line 8
	New State: Depends on the action routine		New State: Depends on the action routine
	Actions:		Actions:
	If the LSR uses the ordered control mode, assign an upstream label.		If the LSR uses the ordered control mode, assign an upstream label.
	Connect the upstream label to the downstream label and allocate the		Connect the upstream label to the downstream label and allocate the
	resources.		resources.
	Send an LDP-MAPPING message upstream with the upstream label.		Send an LDP-MAPPING upstream with the upstream label.
	Then go to the state 'ESTABLISHED'.		Then go to the state `ESTABLISHED'.
	If unable to process the message for any reason, issue an LDP-NAK		If unable to process the message for any reason, issue an LDP-NAK
	message upstream and an LDP-RELEASE message downstream and delete the		upstream and an LDP-RELEASE downstream and delete the control block.
	control block.
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: LDP Release		Event: LDP Release
	New State: RESPONSE_AWAITED		New State: RESPONSE_AWAITED
	Actions		Actions
	Ignore the event. It is an protocol error from the upstream peer.		Ignore the event. It is an protocol error from the upstream peer.
	skipping to change at page 40, line 49		skipping to change at page 39, line 46
	Event: LDP Upstream Abort		Event: LDP Upstream Abort
	New State: IDLE		New State: IDLE
	Actions		Actions
	If the LSR uses the independent control mode, free the upstream label		If the LSR uses the independent control mode, free the upstream label
	and the resources.		and the resources.
	Send the event 'Internal DeleteUpstream' to its		Send the event `Internal DeleteUpstream' to its
	Downstream_LSP_Control_Block's state machine.		Downstream_LSP_Control_Block's state machine.
	Delete the control block.		Delete the control block.
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
			Event: Internal Downstream NAK
	Event: Internal Downstream Nak
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	If the LSR uses the independent control mode, free the upstream label		If the LSR uses the independent control mode, free the upstream label
	and the resources. Then, send an LDP-WITHDRAW message upstream.		and the resources. Then, send an LDP-WITHDRAW upstream.
	If the LSR uses the ordered control mode, propagate the LDP-NAK		If the LSR uses the ordered control mode, propagate the LDP-NAK
	message upstream.		upstream.
	Delete the control block.		Delete the control block.
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: Upstream Lost		Event: Upstream Lost
	New State: IDLE		New State: IDLE
	Actions		Actions
	If the LSR uses the independent control mode, free the upstream label		If the LSR uses the independent control mode, free the upstream label
	and the resources.		and the resources.
	Send the event 'Internal DeleteUpstream' to its		Send the event `Internal DeleteUpstream' to its
	Downstream_LSP_Control_Block's state machine.		Downstream_LSP_Control_Block's state machine.
	Delete the control block.		Delete the control block.
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: Internal Re-Cross-Connect		Event: Internal Re-Cross-Connect
	New State: RESPONSE_AWAITED		New State: RESPONSE_AWAITED
	skipping to change at page 42, line 4		skipping to change at page 40, line 49
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: Internal New NH		Event: Internal New NH
	New State: depends on the actions		New State: depends on the actions
	Actions:		Actions:
	Send event "Internal DeleteUpstream" to its old downstream control		Send event `Internal DeleteUpstream' to its old downstream control
	block.		block.
	Find a Downstream_LSP_Control_Block which has the same FEC and the		Find a Downstream_LSP_Control_Block which has the same FEC and the
	same next hop and also is able to merge more input labels. If not		same next hop and also is able to merge more input labels. If not
	found, create a new Downstream_LSP_Control_Block with the state		found, create a new Downstream_LSP_Control_Block with the state
	'IDLE'.		`IDLE'.
	If the state of the Downstream_LSP_Control_Block is `ESTABLISHED',		If the state of the Downstream_LSP_Control_Block is `ESTABLISHED',
	choose an upstream label, connect the upstream label with the		choose an upstream label, connect the upstream label with the
	downstream label and send an LDP-MAPPING message upstream with the		downstream label and send an LDP-MAPPING upstream with the upstream
	upstream label, and go to the state `ESTABLISHED'.		label, and go to the state `ESTABLISHED'.
	If the state of Downstream_LSP_Control_Block is not `ESTABLISHED',		If the state of Downstream_LSP_Control_Block is not `ESTABLISHED',
	set the state of the Upstream_LSP_Control_Block to		set the state of the Upstream_LSP_Control_Block to
	'RESPONSE_AWAITED'.		`RESPONSE_AWAITED'.
	Pass the event `Internal AddUpstream' to the new		Pass the event `Internal AddUpstream' to the new
	Downstream_LSP_Control_Block's state machine.		Downstream_LSP_Control_Block's state machine.
	3.2.3.4.3 State -- "ESTABLISHED"		3.2.3.4.3 State -- "ESTABLISHED"
	State: ESTABLISHED		State: ESTABLISHED
	Event: LDP Request		Event: LDP Request
	skipping to change at page 42, line 47		skipping to change at page 41, line 46
	State: ESTABLISHED		State: ESTABLISHED
	Event: Internal Downstream Mapping		Event: Internal Downstream Mapping
	New State: ESTABLISHED		New State: ESTABLISHED
	Actions		Actions
	Process the new attributes of the mapping and then propagate the		Process the new attributes of the mapping and then propagate the
	LDP-MAPPING message upstream.		LDP-MAPPING upstream.
	State: ESTABLISHED		State: ESTABLISHED
	Event: LDP Release
			Event: LDP Release
	New State: IDLE		New State: IDLE
	Actions		Actions
	Disconnect the upstream label from the downstream label, free the		Disconnect the upstream label from the downstream label, free the
	upstream label and resources.		upstream label and resources.
	Send the event 'Internal DeleteUpstream' to its		Send the event `Internal DeleteUpstream' to its
	Downstream_LSP_Control_Block's state machine.		Downstream_LSP_Control_Block's state machine.
	Send the event "Internal Destroy' to the Next_Hop_Trigger_Block's		Send the event `Internal Destroy' to the Next_Hop_Trigger_Block's
	state machine if the LSR was in the middle of switching over to the		state machine if the LSR was in the middle of switching over to the
	better next hop.		better next hop.
	Delete the control block.		Delete the control block.
	State: ESTABLISHED		State: ESTABLISHED
	Event: Internal Downstream Withdraw		Event: Internal Downstream Withdraw
	New State: Depends on the action routine		New State: Depends on the action routine
	Actions		Actions
	If it uses independent mode,set its state to 'IDLE' and create a		If it uses independent mode, set its state to `IDLE' and create a
	internal 'LDP Request' and send to its own state machine.		internal `LDP Request' and send to its own state machine.
	Else		Else
	Disconnect the upstream label from the downstream label.		Disconnect the upstream label from the downstream label.
	Propagate the LDP-WITHDRAW upstream and go to state		Propagate the LDP-WITHDRAW upstream and go to state
	'RELEASE_AWAITED'.		`RELEASE_AWAITED'.
	Send the event "Internal Destroy' to the Next_Hop_Trigger_Block's		Send the event `Internal Destroy' to the Next_Hop_Trigger_Block's
	state machine if the LSR was in the middle of switching over to the		state machine if the LSR was in the middle of switching over to the
	better next hop.		better next hop.
	State: ESTABLISHED		State: ESTABLISHED
	Event: LDP Upstream Abort		Event: LDP Upstream Abort
	New State: IDLE		New State: IDLE
	Actions		Actions
	Disconnect the upstream label from the downstream label, free the		Disconnect the upstream label from the downstream label, free the
	upstream label and the resources.		upstream label and the resources.
	Send the event 'Internal DeleteUpstream' to its		Send the event `Internal DeleteUpstream' to its
	Downstream_LSP_Control_Block's state machine.		Downstream_LSP_Control_Block's state machine.
	Send the event "Internal Destroy' to the Next_Hop_Trigger_Block's		Send the event `Internal Destroy' to the Next_Hop_Trigger_Block's
	state machine if the LSR was in the middle of switching over to the		state machine if the LSR was in the middle of switching over to the
	better next hop.		better next hop.
	Delete the control block.		Delete the control block.
	State: ESTABLISHED		State: ESTABLISHED
	Event: Internal Downstream Nak		Event: Internal Downstream NAK
	New State: Depends on the actions		New State: Depends on the actions
	Actions:		Actions:
	If it uses independent mode,set its state to 'IDLE' and create a		If it uses independent mode, set its state to `IDLE' and create a
	internal 'LDP Request' and send to its own state machine.		internal `LDP Request' and send to its own state machine.
	Else		Else
	Disconnect the upstream label from the downstream label		Disconnect the upstream label from the downstream label
	Send an LDP-WITHDRAW upstream and go to state 'RELEASE_AWAITED'.		Send an LDP-WITHDRAW upstream and go to state `RELEASE_AWAITED'.
	Send the event "Internal Destroy' to the Next_Hop_Trigger_Block's		Send the event `Internal Destroy' to the Next_Hop_Trigger_Block's
	state machine if the LSR was in the middle of switching over to the		state machine if the LSR was in the middle of switching over to the
	better next hop.		better next hop.
	State: ESTABLISHED		State: ESTABLISHED
	Event: Upstream Lost		Event: Upstream Lost
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Disconnect the upstream label from the downstream label, free the		Disconnect the upstream label from the downstream label, free the
	upstream label and the resources.		upstream label and the resources.
	Send the event 'Internal DeleteUpstream' to its		Send the event `Internal DeleteUpstream' to its
	Downstream_LSP_Control_Block's state machine.		Downstream_LSP_Control_Block's state machine.
	Send the event "Internal Destroy' to the Next_Hop_Trigger_Block's		Send the event `Internal Destroy' to the Next_Hop_Trigger_Block's
	state machine if the LSR was in the middle of switching over to the		state machine if the LSR was in the middle of switching over to the
	better next hop.		better next hop.
	Delete the control block.		Delete the control block.
	State: ESTABLISH		State: ESTABLISH
	Event: Internal Re-Cross-Connect		Event: Internal Re-Cross-Connect
	New State: ESTABLISH		New State: ESTABLISH
	Actions:		Actions:
	Reconnect the upstream lable to the new downstream lable.		Reconnect the upstream label to the new downstream label.
	Send the event 'Internal DeleteUpstream' to its old		Send the event `Internal DeleteUpstream' to its old
	Downstream_LSP_Control_Block's state machine.		Downstream_LSP_Control_Block's state machine.
	State: ESTABLISH		State: ESTABLISH
	Event: Internal New NH		Event: Internal New NH
	New State: ESTABLISH		New State: ESTABLISH
	Actions:		Actions:
	Create a new Next_Hop_Trigger_Control_Block and pass event		Create a new Next_Hop_Trigger_Control_Block and pass event `Internal
			New NH' to its state machine.
	3.2.3.4.4 State -- "RELEASE_AWAITED"		3.2.3.4.4 State -- "RELEASE_AWAITED"
	State: RELEASE_AWAITED		State: RELEASE_AWAITED
	Event: LDP Request		Event: LDP Request
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	skipping to change at page 45, line 50		skipping to change at page 44, line 49
	Ignore the event. It is a protocol error from the upstream LSR.		Ignore the event. It is a protocol error from the upstream LSR.
	State: RELEASE_AWAITED		State: RELEASE_AWAITED
	Event: Internal Downstream Mapping		Event: Internal Downstream Mapping
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	Ignore the event. It is an internal implementatin error.		Ignore the event. It is an internal implementation error.
	State: RELEASE_AWAITED		State: RELEASE_AWAITED
	Event: LDP Release		Event: LDP Release
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Free the upstream lable resource. and delete the control block.		Free the upstream label resource and delete the control block.
	State: RELEASE_AWAITED		State: RELEASE_AWAITED
	Event: Internal Downstream Withdraw		Event: Internal Downstream Withdraw
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	Ignore the event. It is a protocol error from the downstream LSR.		Ignore the event. It is a protocol error from the downstream LSR.
	State: RELEASE_AWAITED		State: RELEASE_AWAITED
	Event: LDP Upstream Abort		Event: LDP Upstream Abort
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Free the upstream lable resource. and delete the control block.		Free the upstream label resource and delete the control block.
	State: RELEASE_AWAITED		State: RELEASE_AWAITED
	Event: Internal Downstream Nak		Event: Internal Downstream NAK
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	Ignore the event. And continue waiting for the LDP-RELEASE msg.		Ignore the event. And continue waiting for the LDP-RELEASE.
	State: RELEASE_AWAITED		State: RELEASE_AWAITED
	Event: Upstream Lost		Event: Upstream Lost
	New State: IDLE		New State: IDLE
	Actions:		Actions:
	Free the upstream lable resource. and delete the control block.		Free the upstream label resource and delete the control block.
	State: RELEASE_AWAITED		State: RELEASE_AWAITED
	Event: Internal New NH		Event: Internal New NH
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	Ignore the event. And continue waiting for the LDP-RELEASE msg.		Ignore the event. And continue waiting for the LDP-RELEASE.
	State: RELEASE_AWAITED		State: RELEASE_AWAITED
	Event: Internal Re-Cross-Connect		Event: Internal Re-Cross-Connect
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions:		Actions:
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	skipping to change at page 47, line 37		skipping to change at page 46, line 37
	-- IDLE		-- IDLE
	This is the initial LSP state.		This is the initial LSP state.
	-- RESPONSE_AWAITED		-- RESPONSE_AWAITED
	This state means that the LSR has received an LDP-REQUEST from an		This state means that the LSR has received an LDP-REQUEST from an
	upstream LSR, has processed the LDP-REQUEST, and has sent a new LDP-		upstream LSR, has processed the LDP-REQUEST, and has sent a new LDP-
	REQUEST towards a downstream LSR. The LSR is waiting for the LDP-		REQUEST towards a downstream LSR. The LSR is waiting for the LDP-
	MAPPING message from the downstream LSR.		MAPPING from the downstream LSR.
	-- ESTABLISHED		-- ESTABLISHED
	This state means that the LSR has received the LDP-MAPPING message		This state means that the LSR has received the LDP-MAPPING from the
	from the downstream LSR and the LSP is up and operational.		downstream LSR and the LSP is up and operational.
	3.2.3.6 Events of the Downstream_LSP_Control_Block's State Machine		3.2.3.6 Events of the Downstream_LSP_Control_Block's State Machine
	for Downstream-on-demand Mode		for Downstream-on-demand Mode
	-- Internal AddUpstream		-- Internal AddUpstream
	This event is sent by an Upstream_LSP_Control_Block's state machine		This event is sent by an Upstream_LSP_Control_Block's state machine
	when it is created.		when it is created.
	-- Internal DeleteUpstream		-- Internal DeleteUpstream
	This event is sent by an Upstream_LSP_Control_Block's state machine		This event is sent by an Upstream_LSP_Control_Block's state machine
	when it is deleted.		when it is deleted.
	-- LDP Mapping		-- LDP Mapping
	The LSR receives an LDP-MAPPING message from a downstream LSR.		The LSR receives an LDP-MAPPING from a downstream LSR.
	-- LDP Withdraw		-- LDP Withdraw
	The LSR receives an LDP-WITHDRAW message from a downstream LSR.		The LSR receives an LDP-WITHDRAW from a downstream LSR.
	-- LDP Downstream Nak		-- LDP Downstream NAK
	The LSR receives an LDP-NAK from a downstream LSR.		The LSR receives an LDP-NAK from a downstream LSR.
	-- Downstream Lost		-- Downstream Lost
	The LSR loses the LDP session with its downstream LSR.		The LSR loses the LDP session with its downstream LSR.
	3.2.3.7 State Transitions of the Downstream_LSP_Control_Block'S		3.2.3.7 State Transitions of the Downstream_LSP_Control_Block's
	State Machine for Downstream-on-demand mode		State Machine for Downstream-on-demand mode
	+-------------------+		+-------------------+
	| |		| |
	| IDLE |<--------------+		| IDLE |<--------------+
	| | |(last Internal		| | |(last Internal
	+-------------------+ | DeleteUpstream)		+-------------------+ | DeleteUpstream)
	| |(LDP Withdraw)		| |(LDP Withdraw)
	|(1st Internal AddUpstream)|		|(1st Internal AddUpstream)|
	| |(LDP Downstream		| |(LDP Downstream
	v | Nak)		v | NAK)
	+-------------------+ |(Downstream		+-------------------+ |(Downstream
	| | | Lost)		| | | Lost)
	| RESPONSE_AWAITED |---------->----^		| RESPONSE_AWAITED |---------->----^
	| | |		| | |
	+-------------------+ |		+-------------------+ |
	| |		| |
	|(LDP Mapping) |		|(LDP Mapping) |
	| |		| |
	v |		v |
	+-------------------+ |		+-------------------+ |
	| | |		| | |
	| ESTABLISHED |-------->------^		| ESTABLISHED |-------->------^
	| |		| |
	+-------------------+		+-------------------+
	3.2.3.8 Downstream_LSP_Control_Block'S State Machine for		3.2.3.8 Downstream_LSP_Control_Block's State Machine for
	Downstream-on-demand Mode.		Downstream-on-demand Mode.
	3.2.3.8.1 State -- "IDLE"		3.2.3.8.1 State -- "IDLE"
	State: IDLE		State: IDLE
	Event: Internal AddUpstream		Event: Internal AddUpstream
	New State: RESPONSE_AWAITED		New State: RESPONSE_AWAITED
	Actions		Actions
	Initialize the list of pointers in the Upstream_LSP_Control_Block to		Initialize the list of pointers in the Upstream_LSP_Control_Block to
	contain the newly added upstream pointer.		contain the newly added upstream pointer.
	Send a new LDP-REQUEST downstream and go to the state		Send a new LDP-REQUEST downstream and go to the state
	'RESPONSE_AWAITED'.		`RESPONSE_AWAITED'.
	State: IDLE		State: IDLE
	Event: Internal DeleteUpstream		Event: Internal DeleteUpstream
	New State: IDLE		New State: IDLE
	Actions		Actions
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	skipping to change at page 50, line 37		skipping to change at page 49, line 37
	Event: LDP Withdraw		Event: LDP Withdraw
	New State: IDLE		New State: IDLE
	Actions		Actions
	Ignore the event.It is an internal implementation error.		Ignore the event.It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: LDP Downstream Nak		Event: LDP Downstream NAK
	New State: IDLE		New State: IDLE
	Actions		Actions
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Downstream Lost		Event: Downstream Lost
	skipping to change at page 51, line 42		skipping to change at page 50, line 42
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: LDP Mapping		Event: LDP Mapping
	New State: ESTABLISHED		New State: ESTABLISHED
	Actions		Actions
	For each Upstream_LSP_Control_Block in the Upstream_LSP_Control_Block		For each Upstream_LSP_Control_Block in the Upstream_LSP_Control_Block
	pointers list, pass the event 'Internal Downstream Mapping' to its		pointers list, pass the event `Internal Downstream Mapping' to its
	state machine.		state machine.
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: LDP Withdraw		Event: LDP Withdraw
	New State: RESPONSE_AWAITED		New State: RESPONSE_AWAITED
	Actions		Actions
	It is a protocol error from the downstream LDP peer and send a LDP-		It is a protocol error from the downstream LDP peer; send a LDP-
	RELEASE msg downstream		RELEASE downstream
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: LDP Downstream Nak		Event: LDP Downstream NAK
	New State: IDLE		New State: IDLE
	Actions		Actions
	For each Upstream_LSP_Control_Block in the Upstream_LSP_Control_Block		For each Upstream_LSP_Control_Block in the Upstream_LSP_Control_Block
	pointers list, pass the event 'Internal Downstream Nak' to its state		pointers list, pass the event `Internal Downstream NAK' to its state
	machine.		machine.
	Release the resources, and delete the control block.		Release the resources, and delete the control block.
	State: RESPONSE_AWAITED		State: RESPONSE_AWAITED
	Event: Downstream Lost		Event: Downstream Lost
	New State: IDLE		New State: IDLE
	Actions		Actions
	For each Upstream_LSP_Control_Block in the		For each Upstream_LSP_Control_Block in the Upstream_LSP_Control_Block
	Upstream_LSP_Control_Block pointers list, pass the event 'Internal		pointers list, pass the event `Internal Downstream NAK' to its state
	Downstream Nak' to its state machine.		machine.
	Release the resources, and delete the control block.		Release the resources, and delete the control block.
	3.2.3.8.3 State -- "ESTABLISHED"		3.2.3.8.3 State -- "ESTABLISHED"
	State: ESTABLISHED		State: ESTABLISHED
	Event: Internal AddUpstream		Event: Internal AddUpstream
	New State: ESTABLISHED		New State: ESTABLISHED
	skipping to change at page 53, line 23		skipping to change at page 52, line 23
	State: ESTABLISHED		State: ESTABLISHED
	Event: LDP Mapping		Event: LDP Mapping
	New State: ESTABLISHED		New State: ESTABLISHED
	Actions		Actions
	For each Upstream_LSP_Control_Block in the Upstream_LSP_Control_Block		For each Upstream_LSP_Control_Block in the Upstream_LSP_Control_Block
	pointers list, pass the event 'Internal Downstream mapping' to its		pointers list, pass the event `Internal Downstream mapping' to its
	state machine.		state machine.
	State: ESTABLISHED		State: ESTABLISHED
	Event: LDP Withdraw		Event: LDP Withdraw
	New State: IDLE		New State: IDLE
	Actions		Actions
	For each Upstream_LSP_Control_Block in the Upstream_LSP_Control_Block		For each Upstream_LSP_Control_Block in the Upstream_LSP_Control_Block
	pointers list, pass the event 'Internal Downstream withdraw' to its		pointers list, pass the event `Internal Downstream withdraw' to its
	state machine.		state machine.
	Release the resources, and delete the control block and send LDP-		Release the resources, and delete the control block and send LDP-
	RELEASE downstream.		RELEASE downstream.
	State: ESTABLISHED		State: ESTABLISHED
	Event: LDP Downstream Nak		Event: LDP Downstream NAK
	New State: ESTABLISHED		New State: ESTABLISHED
	Actions		Actions
	It is a protocol error from the downstream LDP peer.		It is a protocol error from the downstream LDP peer.
	3.2.3.9 State of the Next_Hop_Trigger_Control_Block's State Machine		3.2.3.9 State of the Next_Hop_Trigger_Control_Block's State Machine
	for Downstream-on-demand Mode		for Downstream-on-demand Mode
	skipping to change at page 54, line 18		skipping to change at page 53, line 18
	This is the initial LSP state.		This is the initial LSP state.
	-- NEW_NH_RETRY		-- NEW_NH_RETRY
	This is the state where an LSR waits for a retry timer to expire and		This is the state where an LSR waits for a retry timer to expire and
	then tries to establish an LSP through a new next hop.		then tries to establish an LSP through a new next hop.
	-- NEW_NH_RESPONSE_AWAITED		-- NEW_NH_RESPONSE_AWAITED
	This state means that the LSR has sent a new LDP-REQUEST towards a		This state means that the LSR has sent a new LDP-REQUEST towards a
	downstream LSR. The LSR is waiting for the LDP-MAPPING message from		downstream LSR. The LSR is waiting for the LDP-MAPPING from the
	the downstream LSR.		downstream LSR.
	3.2.3.10 Events of the Next_Hop_Trigger_Control_Block's State Machine		3.2.3.10 Events of the Next_Hop_Trigger_Control_Block's State Machine
	for Downstream-on-demand Mode		for Downstream-on-demand Mode
	-- Internal New NH		-- Internal New NH
	Trigger to setup an LSP through a better next hop.		Trigger to setup an LSP through a better next hop.
	-- Internal Downstream Mapping		-- Internal Downstream Mapping
	This event is sent by one Downstream_LSP_Control_Block's state		This event is sent by one Downstream_LSP_Control_Block's state
	machine. This Downstream_LSP_Control_Block is the merged		machine. This Downstream_LSP_Control_Block is the merged
	Downstream_LSP_Control_Block of this Upstream_LSP_Control_Block. The		Downstream_LSP_Control_Block of this Upstream_LSP_Control_Block. The
	event is the result of receiving an LDP-MAPPING message by the		event is the result of receiving an LDP-MAPPING by the
	Downstream_LSP_Control_Block's state machine.		Downstream_LSP_Control_Block's state machine.
	-- Internal Downstream Nak		-- Internal Downstream NAK
	This event is sent by one Downstream_LSP_Control_Block's state		This event is sent by one Downstream_LSP_Control_Block's state
	machine. This Downstream_LSP_Control_Block is the merged		machine. This Downstream_LSP_Control_Block is the merged
	Downstream_LSP_Control_Block of this Upstream_LSP_Control_Block. The		Downstream_LSP_Control_Block of this Upstream_LSP_Control_Block. The
	event is the result of receiving an LDP-NAK message by the		event is the result of receiving an LDP-NAK by the
	Downstream_LSP_Control_Block's state machine, or it detects an error.		Downstream_LSP_Control_Block's state machine, or it detects an error.
	-- Internal Destroy This event is used to stop the procedure of		-- Internal Destroy This event is used to stop the procedure of
	switching over to the better next hop.		switching over to the better next hop.
	3.2.3.11 State Transitions of the Next_Hop_Trigger_Control_Block's State		3.2.3.11 State Transitions of the Next_Hop_Trigger_Control_Block's State
	Machine for Downstream-on-demand Mode		Machine for Downstream-on-demand Mode
	|		|
	|		|
	skipping to change at page 55, line 34		skipping to change at page 54, line 34
	+---------------------+ |		+---------------------+ |
	| | Internal |		| | Internal |
	| NEW_NH_RESPONSE | Destroy |		| NEW_NH_RESPONSE | Destroy |
	| _AWAITED |-------------|		| _AWAITED |-------------|
	| | |		| | |
	+---------------------+ |		+---------------------+ |
	| |		| |
	| (Internal Downstream |		| (Internal Downstream |
	| Mapping |		| Mapping |
	| (Internal Downstream |		| (Internal Downstream |
	| Nak) |		| NAK) |
	v v		v v
	the control block is deleted		the control block is deleted
	3.2.3.12 State Machine		3.2.3.12 State Machine
	3.2.3.12.1 State -- "IDLE"		3.2.3.12.1 State -- "IDLE"
	State: IDLE		State: IDLE
	Event: Internal New NH		Event: Internal New NH
	New States: NEW_NH_RETRY		New State: NEW_NH_RETRY
	Actions:		Actions:
	Start the LSP retry timer and go to the 'NEW_NH_RETRY' state.		Start the LSP retry timer and go to the `NEW_NH_RETRY' state.
	State: IDLE		State: IDLE
	Event: Internal retry timeout		Event: Internal retry timeout
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Internal Downstream Mapping		Event: Internal Downstream Mapping
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Internal Downstream Nak		Event: Internal Downstream NAK
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: IDLE		State: IDLE
	Event: Internal destroy		Event: Internal destroy
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	3.2.3.12.2 State -- "NEW_NH_RETRY"		3.2.3.12.2 State -- "NEW_NH_RETRY"
	State: NEW_NH_RETRY		State: NEW_NH_RETRY
	Event: Internal New NH		Event: Internal New NH
	New States: NEW_NH_RETRY		New State: NEW_NH_RETRY
	Actions:		Actions:
	Restart the LSP retry timer.		Restart the LSP retry timer.
	State: NEW_NH_RETRY		State: NEW_NH_RETRY
	Event: Internal retry timeout		Event: Internal retry timeout
	New States: NEW_NH_RESPONSE_AWAITED		New State: NEW_NH_RESPONSE_AWAITED
	Actions:		Actions:
	If the new next hop is the same one as the old next hop, delete the		If the new next hop is the same one as the old next hop, delete the
	control block.		control block.
	Otherwise, find an downstream LSP control block which go through the		Otherwise, find an downstream LSP control block which go through the
	same next hop for the same FEC, if there is no one, create one, and		same next hop for the same FEC, if there is no one, create one, and
	pass "Internal AddUpstream'event to its state machine.		pass `Internal AddUpstream' event to its state machine.
	State: NEW_NH_RETRY		State: NEW_NH_RETRY
	Event: Internal Downstream Mapping		Event: Internal Downstream Mapping
	New States: NEW_NH_RETRY		New State: NEW_NH_RETRY
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: NEW_NH_RETRY		State: NEW_NH_RETRY
	Event: Internal Downstream NAK		Event: Internal Downstream NAK
	New States: NEW_NH_RETRY		New State: NEW_NH_RETRY
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: NEW_NH_RETRY		State: NEW_NH_RETRY
	Event: Internal destroy		Event: Internal destroy
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Stop the timer and delete the control block.		Stop the timer and delete the control block.
	3.2.3.12.3 State -- "NEW_NH_RESPONSE_AWAITED"		3.2.3.12.3 State -- "NEW_NH_RESPONSE_AWAITED"
	State: NEW_NH_RESPONSE_AWAITED		State: NEW_NH_RESPONSE_AWAITED
	Event: Internal New NH		Event: Internal New NH
	New States: NEW_NH_RETRY		New State: NEW_NH_RETRY
	Actions:		Actions:
	Restart the LSP retry timer, send "Internal destroy" to the control		Restart the LSP retry timer, send `Internal destroy' to the control
	block of the LSP for the new next hop and go to the 'NEW_NH_RETRY'		block of the LSP for the new next hop and go to the `NEW_NH_RETRY'
	state.		state.
	State: NEW_NH_RESPONSE_AWAITED		State: NEW_NH_RESPONSE_AWAITED
	Event: Internal retry timeout		Event: Internal retry timeout
	New States: NEW_NH_RESPONSE_AWAITED		New State: NEW_NH_RESPONSE_AWAITED
	Actions:		Actions:
	Ignore. It is an internal implementation error.		Ignore. It is an internal implementation error.
	State: NEW_NH_RESPONSE_AWAITED		State: NEW_NH_RESPONSE_AWAITED
	Event: Internal Downstream Mapping		Event: Internal Downstream Mapping
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Send event "Internal Re-cross-connect" event to the Upstream LSP		Send event `Internal Re-cross-connect' event to the upstream LSP
	control block of the new next hop.		control block of the new next hop.
	Send event "DeleteUpstream" event to the downstream LSP control block		Send event `DeleteUpstream' event to the downstream LSP control block
	of the the new next hop, since the upstream has spliced into the new		of the the new next hop, since the upstream has spliced into the new
	next hop.		next hop.
	Then delete the control block.		Then delete the control block.
	State: NEW_NH_RESPONSE_AWAITED		State: NEW_NH_RESPONSE_AWAITED
	Event: Internal Downstream NAK		Event: Internal Downstream NAK
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Delete the control block.		Delete the control block.
	State: NEW_NH_RESPONSE_AWAITED		State: NEW_NH_RESPONSE_AWAITED
	Event: Internal destroy		Event: Internal destroy
	New States: IDLE		New State: IDLE
	Actions:		Actions:
	Send event "Internal DeleteUpstream" the control block for the new		Send event `Internal DeleteUpstream' the control block for the new
	LSP through the new next hop.		LSP through the new next hop.
	3.2.4 LDP Related Message Processing		3.2.4 LDP Related Message Processing
	- If an LSR receives an LDP-REQUEST message:		- If an LSR receives an LDP-REQUEST:
	a) If this is a duplicate request, discard the msg. A duplicate		a) If this is a duplicate request, discard the message. A duplicate
	request means that there is a LSP_Control_Block which has same FEC,		request means that there is a LSP_Control_Block which has same FEC,
	same Upstream Label Request ID and same Upstream LDP Session		same Upstream Label Request ID and same Upstream LDP Session
	Identifier.		Identifier.
	b) Otherwise, create a new Upstream_LSP_Control_Block. Then pass the		b) Otherwise, create a new Upstream_LSP_Control_Block. Then pass the
	event `LDP Request' to this Upstream_LSP_Control_Block's state		event `LDP Request' to this Upstream_LSP_Control_Block's state
	machine.		machine.
	- If an LSR receives an LDP-MAPPING message:		- If an LSR receives an LDP-MAPPING:
	Locate a Downstream_LSP_Control_Block which has the same FEC, the		Locate a Downstream_LSP_Control_Block which has the same FEC, the
	same Downstream LDP Session Identifier and the same Downstream Label.		same Downstream LDP Session Identifier and the same Downstream Label.
	If a Downstream_LSP_Control_Block is found, pass the event `LDP		If a Downstream_LSP_Control_Block is found, pass the event `LDP
	Mapping' to its state table. This could mean that the attributes of		Mapping' to its state table. This could mean that the attributes of
	label binding have changed.		label binding have changed.
	Otherwise, use the Downstream LDP request ID(the 'Lable Request		Otherwise, use the Downstream LDP request ID (the 'Label Request
	Message ID' field in the LDP-MAPPING MSG) and Downstream LDP Session		Message ID' field in the LDP-MAPPING) and Downstream LDP Session
	Identifier to locate the Downstream_LSP_Control_Block and pass the		Identifier to locate the Downstream_LSP_Control_Block and pass the
	event `LDP Mapping' to its state machine. If no		event `LDP Mapping' to its state machine. If no
	Downstream_LSP_Control_Block is found, ignore the message.		Downstream_LSP_Control_Block is found, ignore the message.
	- If an LSR receives an LDP-RELEASE message:		- If an LSR receives an LDP-RELEASE:
	Locate an Upstream_LSP_Control_Block which has the same FEC, the same		Locate an Upstream_LSP_Control_Block which has the same FEC, the same
	Upstream Label, the same Upstream LDP Session Identifier. If no		Upstream Label, the same Upstream LDP Session Identifier. If no
	Upstream_LSP_Control_Block is found, ignore the message. If an		Upstream_LSP_Control_Block is found, ignore the message. If an
	Upstream_LSP_Control_Block is found, send the event `LDP Release' to		Upstream_LSP_Control_Block is found, send the event `LDP Release' to
	its state machine.		its state machine.
	- If an LSR receives an LDP-WITHDRAW message:		- If an LSR receives an LDP-WITHDRAW:
	Find a Downstream_LSP_Control_Block which has the same FEC, the same		Find a Downstream_LSP_Control_Block which has the same FEC, the same
	Downstream LDP Session Identifier and the same Downstream Label. Pass		Downstream LDP Session Identifier and the same Downstream Label. Pass
	the event `LDP Withdraw' to its state machines.		the event `LDP Withdraw' to its state machines.
	- If an Upstream LDP peer is lost:		- If an Upstream LDP peer is lost:
	Pass the event `Upstream Lost' to the state machines of all the		Pass the event `Upstream Lost' to the state machines of all the
	Upstream_LSP_Control_Blocks whose upstream LDP peer is that LSR.		Upstream_LSP_Control_Blocks whose upstream LDP peer is that LSR.
	- If a Downstream LDP peer is lost:		- If a Downstream LDP peer is lost:
	Pass the event `Downstream Lost' to the state machines of all the		Pass the event `Downstream Lost' to the state machines of all the
	Downstream_LSP_Control_Blocks whose the downstream LDP peer is that		Downstream_LSP_Control_Blocks whose the downstream LDP peer is that
	LSR.		LSR.
	- If a next hop of an FEC is changed:		- If a next hop of an FEC is changed:
	For all the Upstream_LSP_Control_Blocks which are infected by this		For all the Upstream_LSP_Control_Blocks which are infected by this
	change, pass the event 'Internal New NH' to their state machines.		change, pass the event `Internal New NH' to their state machines.
	- If an LSR receives an LDP-ABORT from an Upstream LSR:		- If an LSR receives an LDP-ABORT from an upstream LSR:
	Use the Upstream LDP Request ID and Upstream LDP Session Identifier		Use the Upstream LDP Request ID and Upstream LDP Session Identifier
	to locate the Upstream_LSP_Control_Block and pass the event `LDP		to locate the Upstream_LSP_Control_Block and pass the event `LDP
	Abort' to its state machine.		Abort' to its state machine.
	- If an LSR receives an LDP-NAK from a downstream LSR:		- If an LSR receives an LDP-NAK from a downstream LSR:
	Use the Downstream LDP Request ID and Downstream Session Identifier		Use the Downstream LDP Request ID and Downstream Session Identifier
	to locate a Downstream_LSP_control_block and pass the event `LDP		to locate a Downstream_LSP_control_block and pass the event `LDP
	Downstream Nak' to its state machine.		Downstream NAK' to its state machine.
	4. State Machine for Downstream Unsolicited		4. State Machine for Downstream Unsolicited
	The following sections describe the state machines for the ATM-LSR		The following sections describe the state machines for the ATM-LSR
	which uses downstream unsolicited mode.		which uses downstream unsolicited mode.
	While both independent LSP control and ordered LSP control modes are		While both independent LSP control and ordered LSP control modes are
	possible, only the ordered mode is taken into account, because the		possible, only the ordered mode is taken into account, because the
	independant LSP control mode uses the liberal label retention mode		independent LSP control mode uses the liberal label retention mode
	and so is considered burning too many ATM resources.		and so is considered burning too many ATM resources.
	In downstream unsolicited mode, multiple path is not allowed in this		In downstream unsolicited mode, multiple path is not supported in
	version and will be For Further Study(FFS). We suspect with multiple		this version and will be For Further Study (FFS). We suspect with
	next hops and Downstream mode, it is easy to get into loop condition.		multiple next hops and Downstream mode, it is easy to get into a loop
			condition.
	4.0 Control Block		4.0 Control Block
	There are 2 types of control blocks involved:		There are 2 types of control blocks involved:
	Upstream_LSP_Control_Block, Downstream_LSP_Control_Block.		Upstream_LSP_Control_Block, Downstream_LSP_Control_Block.
	There is a list of Upstream_LSP_Control_Blocks for each FEC in the		There is a list of Upstream_LSP_Control_Blocks for each FEC in the
	routing table, with each one correspondng to a LDP peer. A		routing table, with each one corresponding to a LDP peer. A
	Upstream_LSP_Control_Block is created for each FEC when there is a		Upstream_LSP_Control_Block is created for each FEC when there is a
	label ready to be distributed to that upstream. It is deleted when		label ready to be distributed to that upstream. It is deleted when
	the FEC is deleted from the FEC table, or the LDP peer disappears, or		the FEC is deleted from the FEC table, or the LDP peer disappears, or
	the downstream label is withdrawed.		the downstream label is withdrawed.
	There is one Downstream_LSP_Control_Blocks for each FEC in the		There is one Downstream_LSP_Control_Blocks for each FEC in the
	routing table. It is created when the FEC is inserted into the		routing table. It is created when the FEC is inserted into the
	forwarding table and deleted when the FEC is removed from the		forwarding table and deleted when the FEC is removed from the
	forwarding table.		forwarding table.
	skipping to change at page 61, line 51		skipping to change at page 61, line 4
	- FEC		- FEC
	- State		- State
	- Downstream LDP Session Identifier		- Downstream LDP Session Identifier
	- Downstream Label(assigned by the downstream LSR)		- Downstream Label(assigned by the downstream LSR)
	- Downstream Label Request ID (assigned by the LSR itself)		- Downstream Label Request ID (assigned by the LSR itself)
	Downstream Label and Downstream LDP Session Identifier, or FEC and		Downstream Label and Downstream LDP Session Identifier, or FEC and
	Downsteam LDP Session Identifier can be used to locate a unique		Downstream LDP Session Identifier can be used to locate a unique
	Downstream_LSP_Control_Block.		Downstream_LSP_Control_Block.
	4.1 States of the Upstream_LSP_Control_Block's State Machine		4.1 States of the Upstream_LSP_Control_Block's State Machine
	for Downstream Mode		for Downstream Mode
	-- IDLE		-- IDLE
	This is the initial LSP state.		This is the initial LSP state.
	-- ESTABLISHED		-- ESTABLISHED
	This state means that the LSR has received the LDP-MAPPING message		This state means that the LSR has received the LDP-MAPPING from the
	from the downstream LSR and the LSP is up and operational.		downstream LSR and the LSP is up and operational.
	-- RELEASE_AWAITED		-- RELEASE_AWAITED
	This state means that the LSR is waiting for the LDP-RELEASE msg in		This state means that the LSR is waiting for the LDP-RELEASE in
	respond to the LDP-WITHDRAW sent by this LSR.		respond to the LDP-WITHDRAW sent by this LSR.
	-- RESOUCES_AWAITED		-- RESOURCES_AWAITED
	This state means that the LSR is waiting for the label resources.		This state means that the LSR is waiting for the label resources.
	4.2 Events of the Upstream_LSP_Control_Block's State Machine		4.2 Events of the Upstream_LSP_Control_Block's State Machine
	for Downstream Mode		for Downstream Mode
	-- Internal Downstream Mapping		-- Internal Downstream Mapping
	This event is sent by one Downstream_LSP_Control_Block's state		This event is sent by one Downstream_LSP_Control_Block's state
	machine. The event is the result of receiving an LDP-MAPPING message		machine. The event is the result of receiving an LDP-MAPPING by the
	by the Downstream_LSP_Control_Block's state machine. Or when the LDP		Downstream_LSP_Control_Block's state machine. Or when the LDP peer is
	peer is discovered and there is a downstream Label available for this		discovered and there is a downstream Label available for this FEC.
	FEC.
	-- LDP Release		-- LDP Release
	The LSR receives an LDP-RELEASE from an upstream LSR.		The LSR receives an LDP-RELEASE from an upstream LSR.
	-- Internal Withdraw		-- Internal Withdraw
	This event is sent by Downstream_LSP_Control_Block's state machine.		This event is sent by Downstream_LSP_Control_Block's state machine.
	The event is the result of receiving an LDP-WITHDRAW message by the		The event is the result of receiving an LDP-WITHDRAW by the
	Downstream_LSP_Control_Block's state machine.		Downstream_LSP_Control_Block's state machine.
	-- Resource Available		-- Resource Available
	This event means the local resource(such as label) becomes available.		This event means the local resource (such as label) becomes
			available.
	-- Delete FEC		-- Delete FEC
	This event means that either the FEC is removed from the forwarding		This event means that either the FEC is removed from the forwarding
	table.		table.
	-- Upstream Lost		-- Upstream Lost
	This event means that the upstream LDP peer is lost.		This event means that the upstream LDP peer is lost.
	skipping to change at page 64, line 34		skipping to change at page 63, line 34
	| | |		| | |
	|(no label resource)v |		|(no label resource)v |
	| +-------------------+ |		| +-------------------+ |
	| | | |		| | | |
	| +-----| ESTABLISHED |---------------+		| +-----| ESTABLISHED |---------------+
	| | | | ^		| | | | ^
	| | +-------------------+ |		| | +-------------------+ |
	| |(delete FEC) ^ |		| |(delete FEC) ^ |
	| |(Internal |(Resource Available) | (LDP Release)		| |(Internal |(Resource Available) | (LDP Release)
	| | Withdraw) | | (Internal		| | Withdraw) | | (Internal
	| | | | Downstraem		| | | | Downstream
	| | | | Withdraw)		| | | | Withdraw)
	| | +-------------------+ |		| | +-------------------+ |
	+--------->| | |		+--------->| | |
	| |RESOURCES_AWAITED |---------------+		| |RESOURCES_AWAITED |---------------+
	| | | |		| | | |
	| +-------------------+ |		| +-------------------+ |
	| |		| |
	| (Internal Downstream Withdraw) |(LDP Release)		| (Internal Downstream Withdraw) |(LDP Release)
	| +-------------------+ |		| +-------------------+ |
	| | | |		| | | |
	skipping to change at page 65, line 16		skipping to change at page 64, line 16
	State: IDLE		State: IDLE
	Event: Internal Downstream mapping		Event: Internal Downstream mapping
	New State: Depends on the action.		New State: Depends on the action.
	Actions		Actions
	Choose an upstream label, connect the upstream label with the		Choose an upstream label, connect the upstream label with the
	downstream label. And go to state 'ESTABLISHED'		downstream label. And go to state `ESTABLISHED'
	Propagate the LDP-MAPPING upstream.		Propagate the LDP-MAPPING upstream.
	If there is no resource for the upstream label, go to state		If there is no resource for the upstream label, go to state
	'RESOURCE_AWAITED'.		`RESOURCE_AWAITED'.
	State: IDLE		State: IDLE
	Event: LDP Release		Event: LDP Release
	New State: IDLE		New State: IDLE
	Actions		Actions
	Ignore the event. It is an internal implementation error.		Ignore the event. It is an internal implementation error.
	skipping to change at page 66, line 35		skipping to change at page 65, line 35
	4.4.2 : State -- "ESTABLISHED"		4.4.2 : State -- "ESTABLISHED"
	State: ESTABLISHED		State: ESTABLISHED
	Event: Internal Downstream Mapping		Event: Internal Downstream Mapping
	New State: ESTABLISHED		New State: ESTABLISHED
	Actions		Actions
	Process the new attributes of the new mapping msg.		Process the new attributes of the new mapping message.
	Propagate the LDP-MAPPING upstream.		Propagate the LDP-MAPPING upstream.
	State: ESTABLISHED		State: ESTABLISHED
	Event: LDP Release		Event: LDP Release
	New State: IDLE		New State: IDLE
	Actions		Actions
	skipping to change at page 68, line 8		skipping to change at page 67, line 8
	4.4.2 : State -- "RELEASE_AWAITED"		4.4.2 : State -- "RELEASE_AWAITED"
	State: RELEASE_AWAITED		State: RELEASE_AWAITED
	Event: Internal Downstream Mapping		Event: Internal Downstream Mapping
	New State: RELEASE_AWAITED		New State: RELEASE_AWAITED
	Actions		Actions
	Ignore the msg.		Ignore the message.
	State: RELEASE_AWAITED		State: RELEASE_AWAITED
	Event: LDP Release		Event: LDP Release
	New State: IDLE		New State: IDLE
	Actions		Actions
	Release the upstream label and delete the control block.		Release the upstream label and delete the control block.
	skipping to change at page 69, line 22		skipping to change at page 68, line 22
	4.4.2 : State -- "RESOURCE_AWAITED"		4.4.2 : State -- "RESOURCE_AWAITED"
	State: RESOURCE_AWAITED		State: RESOURCE_AWAITED
	Event: Internal Downstream Mapping		Event: Internal Downstream Mapping
	New State: RESOURCE_AWAITED		New State: RESOURCE_AWAITED
	Actions		Actions
	Ignore the msg.		Ignore the message.
	State: RESOURCE_AWAITED		State: RESOURCE_AWAITED
	Event: LDP Release		Event: LDP Release
	New State: RESOURCE_AWAITED		New State: RESOURCE_AWAITED
	Actions		Actions
	Ignore the msg. It is an internal implementation error.		Ignore the message. It is an internal implementation error.
	State: RESOURCE_AWAITED		State: RESOURCE_AWAITED
	Event: Internal Downstream Withdraw		Event: Internal Downstream Withdraw
	New State: IDLE		New State: IDLE
	Actions		Actions
	Delete the control block.		Delete the control block.
	skipping to change at page 70, line 36		skipping to change at page 69, line 36
	4.5 State of the Downstream_LSP_Control_Block's State Machine		4.5 State of the Downstream_LSP_Control_Block's State Machine
	for Downstream Mode		for Downstream Mode
	-- IDLE		-- IDLE
	This is the initial LSP state.		This is the initial LSP state.
	-- ESTABLISHED		-- ESTABLISHED
	This state means that the LSR has received the LDP-MAPPING msg from		This state means that the LSR has received the LDP-MAPPING from the
	the downstream LSR.		downstream LSR.
	3.2.4.6 Events of the Downstream_LSP_Control_Block's State Machine		3.2.4.6 Events of the Downstream_LSP_Control_Block's State Machine
	for Downstream Mode		for Downstream Mode
	-- LDP Mapping		-- LDP Mapping
	The LSR receives an LDP-MAPPING msg from a downstream LSR.		The LSR receives an LDP-MAPPING from a downstream LSR.
	-- LDP Withdraw		-- LDP Withdraw
	The LSR receives an LDP-WITHDRAW msg from a downstream LSR.		The LSR receives an LDP-WITHDRAW from a downstream LSR.
	-- Delete FEC		-- Delete FEC
	The FEC is deleted from the forwarding table.		The FEC is deleted from the forwarding table.
	-- Next Hop Change		-- Next Hop Change
	The next hop for this FEC is change to different LSR.		The next hop for this FEC is change to different LSR.
	-- Downstream Lost		-- Downstream Lost
	skipping to change at page 75, line 7		skipping to change at page 73, line 18
	New State: IDLE		New State: IDLE
	Actions		Actions
	Send LDP-WITHDRAW to all Upstream_Control_Block's state machine of		Send LDP-WITHDRAW to all Upstream_Control_Block's state machine of
	this FEC.		this FEC.
	4.5 LDP Related Message Processing for downstream mode.		4.5 LDP Related Message Processing for downstream mode.
	- If an LSR receives an LDP-REQUEST message:		- If an LSR receives an LDP-REQUEST:
	If there is a next hop for this FEC and there is a		If there is a next hop for this FEC and there is a
	Downstream_Control_Block for this FEC whose state is 'ESTABLISHED',		Downstream_Control_Block for this FEC whose state is `ESTABLISHED',
	create a new Upstream_Control_Block and pass 'internal Mapping' event		create a new Upstream_Control_Block and pass `internal Mapping' event
	to its state machine.		to its state machine.
	- If an LSR receives an LDP-MAPPING message:		- If an LSR receives an LDP-MAPPING:
	Locate a Downstream_LSP_Control_Block which has the same FEC, the		Locate a Downstream_LSP_Control_Block which has the same FEC, the
	same Downstream LDP Session Identifier and the same Downstream Label.		same Downstream LDP Session Identifier and the same Downstream Label.
	If a Downstream_LSP_Control_Block is found, pass the event `LDP		If a Downstream_LSP_Control_Block is found, pass the event `LDP
	Mapping' to its state table. This could mean that the attributes of		Mapping' to its state table. This could mean that the attributes of
	label binding have changed.		label binding have changed.
	Otherwise, if there is no matching Downstream_LSP_Control_Block		Otherwise, if there is no matching Downstream_LSP_Control_Block
	found, find a Downstream_LSP_Control_Block of this FEC and its next		found, find a Downstream_LSP_Control_Block of this FEC and its next
	hop is the this downstream peer, pass the event `LDP Mapping' to its		hop is the this downstream peer, pass the event `LDP Mapping' to its
	state machine.		state machine.
	- If an LSR receives an LDP-RELEASE message:		- If an LSR receives an LDP-RELEASE:
	Locate an Upstream_LSP_Control_Block which has the same FEC, the same		Locate an Upstream_LSP_Control_Block which has the same FEC, the same
	Upstream Label, the same Upstream LDP Session Identifier. If no		Upstream Label, the same Upstream LDP Session Identifier. If no
	Upstream_LSP_Control_Block is found, ignore the message. If an		Upstream_LSP_Control_Block is found, ignore the message. If an
	Upstream_LSP_Control_Block is found, send the event `LDP Release' to		Upstream_LSP_Control_Block is found, send the event `LDP Release' to
	its state machine.		its state machine.
	- If an LSR receives an LDP-WITHDRAW message:		- If an LSR receives an LDP-WITHDRAW:
	Find a Downstream_LSP_Control_Block which has the same FEC, the same		Find a Downstream_LSP_Control_Block which has the same FEC, the same
	Downstream LDP Session Identifier and the same Downstream Label. Pass		Downstream LDP Session Identifier and the same Downstream Label. Pass
	the event `LDP Withdraw' to its state machines.		the event `LDP Withdraw' to its state machines.
	- If an Upstream LDP peer is lost:		- If an Upstream LDP peer is lost:
	Pass the event `Upstream Lost' to the state machines of all the		Pass the event `Upstream Lost' to the state machines of all the
	Upstream_LSP_Control_Blocks whose upstream LDP peer is that LSR.		Upstream_LSP_Control_Blocks whose upstream LDP peer is that LSR.
	skipping to change at page 76, line 13		skipping to change at page 74, line 24
	LSR.		LSR.
	- If a next hop of an FEC is changed:		- If a next hop of an FEC is changed:
	Find all the Downstream_LSP_Control_Blocks which has the same FEC and		Find all the Downstream_LSP_Control_Blocks which has the same FEC and
	the same next hop and pass the event `Next Hop Change' to their state		the same next hop and pass the event `Next Hop Change' to their state
	machine		machine
	- If there is a FEC being added to the forwarding table		- If there is a FEC being added to the forwarding table
	Create a new Downstream_LSP_Control_Block with state 'IDLE'		Create a new Downstream_LSP_Control_Block with state `IDLE'
	- If the FEC is deleted from the forwarding table		- If the FEC is deleted from the forwarding table
	Send the 'Delete FEC' event to the its control block.		Send the `Delete FEC' event to the its control block.
	- If an LSR receives an LDP-NAK from an Upstream LSR:		- If an LSR receives an LDP-NAK from an upstream LSR:
	Ignore the msg. An LDP-NAK should never appear in the downstream-mode		Ignore the message. An LDP-NAK should never appear in the
	LSR		downstream-mode LSR
	- If an LSR receives an LDP-NAK from a downstream LSR:		- If an LSR receives an LDP-NAK from a downstream LSR:
	Ignore the msg. It is an protocol error from the downstream LSR.		Ignore the message. It is an protocol error from the downstream LSR.
	5. Security Considerations		5. Security Considerations
	Security considerations will be addressed in a future revision of		This document is provided as an informational extension of the LDP
	this document.		specification [4]. State machines presented here are intended to
			clarify procedures defined in the LDP specification, but do not
			supplant or override definitions and procedures provided there.
			Implementations of a state machine may be vulnerable to spurious
			events generated by an external source. In this document, events fall
			in two categories: internal events and external events caused by
			receipt of an LDP message.
			LDP messages may be protected using mechanisms described in the LDP
			specification. See "Security Considerations" in the LDP specification
			[4].
			Security considerations relating to generation of spurious internal
			events are not addressed in this document.
	6. Acknowledgements		6. Acknowledgements
	The authors would like to acknowledge the helpful comments and		The authors would like to acknowledge the helpful comments and
	suggestions of the following people: Bob Thomas		suggestions of the following people: Bob Thomas and Myunghee Son.
	7. Authors's Address		7. Authors' Address
	Liwen Wu		Christophe Boscher
	Alcatel		Alcatel
	44983 Knoll Square		Le Mail
	Ashburn, VA. 20147		44700 Orvault
	U.S.A		France
	Phone: 703-724-2619		Phone: (33) 251781828
	Email:liwen.wu@adn.alcatel.com		Email: christophe.boscher@alcatel.fr
	Pierrick Cheval		Pierrick Cheval
	Alcatel		Alcatel
	44983 Knoll Square		5 rue Noel-Pons
	Ashburn, VA. 20147		92734 Nanterre Cedex
	U.S.A
	Phone: 703-724-2080
	Email: pierrick.cheval@adn.alcatel.com
	Christophe Boscher
	Alcatel CIT
	Le Mail
	44700 Nantes-Orvault
	France		France
	Phone: (33) 251781828		Phone: (33) 146524027
	Email: christophe.boscher@or.cit.alcatel.fr		Email: pierrick.cheval@alcatel.fr
	Eric Gray		Eric Gray
	Lucent Technologies, Inc.		Lucent Technologies, Inc.
	1600 Osgood Street		P.O. Box 710
	North Andover, MA 01845		Durham, NH 03824
			Phone: (603) 659-3386
	Email: ewgray@lucent.com		Email: ewgray@lucent.com
			Liwen Wu
			Cisco Systems, Inc.
			250 Apollo Drive
			Chelmsford, MA 01824
			U.S.A
			Phone: 978-224-3087
			Email:liwwu@cisco.com
	8. References		8. References
	1."Use of Label Switching With ATM", Bruce Davie, Jeremy Lawrence,		1."MPLS Using LDP and ATM Switching", Bruce Davie, Jeremy Lawrence,
	Keith McCloghrie, Yakov Rekhter, Eric Rosen, George Swallow, Paul		Keith McCloghrie, Yakov Rekhter, Eric Rosen, George Swallow, Paul
	Doolan, work in progress, Internet Draft, <draft-ietf-mpls-atm-01.txt>		Doolan, work in progress, Internet Draft, <draft-ietf-mpls-atm-02.txt>
	2."Multiprotocol Label Switching Architecture", Eric C Rosen, Arun		2."Multiprotocol Label Switching Architecture", Eric C Rosen, Arun
	Viswanathan, Ross Callon, work in progress, Internet Draft, <draft-		Viswanathan, Ross Callon, work in progress, Internet Draft, <draft-
	ietf-mpls-arch-02.txt>		ietf-mpls-arch-06.txt>
	3."Definition of Managed Objects for the Multiprotocol Label Switching,		3."Definition of Managed Objects for the Multiprotocol Label Switching,
	Label Distribution Protocol (LDP)", Joan Cucchiara, Hans Sjostrand,		Label Distribution Protocol (LDP)", Joan Cucchiara, Hans Sjostrand,
	James V. Luciani, work in progress, Internet Draft, <draft-ietf-mpls-		James V. Luciani, work in progress, Internet Draft, <draft-ietf-mpls-
	ldp-mib-00.txt>		ldp-mib-02.txt>
	4."Requirements for Traffic Engineering Over MPLS", Daniel O.Awduche,
	Joe Malcolm, Johnson Agogbua, Mike O'Dell, Jim McMaus, work in
	progress,Internet Draft, <draft-ietf-mpls-traffic-eng-00.txt>
	5. "LDP Specification", Loa Andersson, Paul Doolan,Nancy Feldman, Andre		4. "LDP Specification", Loa Andersson, Paul Doolan, Nancy Feldman,
	Fredette, Bob Thomas, work in progress, Internet Draft, <draft-ietf-		Andre Fredette, Bob Thomas, work in progress, Internet Draft, <draft-
	mpls-ldp-04.txt>		ietf-mpls-ldp-06.txt>
	6. "MPLS Loop Prevention Mechanism", Yoshihiro Ohba, Yasuhiro Katsube,		5. "Constraint-Based LSP Set up Using LDP", Bilel Jamoussi, et al.,
	Eric Rosen, Paul Doolan, work in progress, Internet Draft, <draft-		work in progress, Internet Draft, <draft-ietf-mpls-cr-ldp-03.txt>
	ohba-mpls-loop-prevention-02.txt>
	7. "Constraint-Based LSP Set up Using LDP", Bilel Jamoussi, et.al.,
	work in progress, Internet Draft, <draft-ietf-mpls-cr-ldp-01.txt>
End of changes.
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