< draft-cc-ospf-flooding-reduction-03.txt		draft-cc-ospf-flooding-reduction-04.txt >
	Network Working Group H. Chen		Network Working Group H. Chen
	Internet-Draft D. Cheng		Internet-Draft D. Cheng
	Intended status: Standards Track Huawei Technologies		Intended status: Standards Track Huawei Technologies
	Expires: March 16, 2019 M. Toy		Expires: March 24, 2019 M. Toy
	Verizon		Verizon
	Y. Yang		Y. Yang
	IBM		IBM
	September 12, 2018		September 20, 2018
	LS Flooding Reduction		LS Flooding Reduction
	draft-cc-ospf-flooding-reduction-03		draft-cc-ospf-flooding-reduction-04
	Abstract		Abstract
	This document proposes an approach to flood link states on a topology		This document proposes an approach to flood link states on a topology
	that is a subgraph of the complete topology per underline physical		that is a subgraph of the complete topology per underline physical
	network, so that the amount of flooding traffic in the network is		network, so that the amount of flooding traffic in the network is
	greatly reduced, and it would reduce convergence time with a more		greatly reduced, and it would reduce convergence time with a more
	stable and optimized routing environment. The approach can be		stable and optimized routing environment. The approach can be
	applied to any network topology in a single area.		applied to any network topology in a single area.
	skipping to change at page 1, line 45 ¶		skipping to change at page 1, line 45 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on March 16, 2019.		This Internet-Draft will expire on March 24, 2019.
	Copyright Notice		Copyright Notice
	Copyright (c) 2018 IETF Trust and the persons identified as the		Copyright (c) 2018 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 33 ¶		skipping to change at page 2, line 33 ¶
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
	3. Conventions Used in This Document . . . . . . . . . . . . . . 4		3. Conventions Used in This Document . . . . . . . . . . . . . . 4
	4. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 4		4. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 4
	5. Flooding Topology . . . . . . . . . . . . . . . . . . . . . . 5		5. Flooding Topology . . . . . . . . . . . . . . . . . . . . . . 5
	5.1. Construct Flooding Topology . . . . . . . . . . . . . . . 5		5.1. Construct Flooding Topology . . . . . . . . . . . . . . . 5
	5.2. Backup for Flooding Topology Split . . . . . . . . . . . 7		5.2. Backup for Flooding Topology Split . . . . . . . . . . . 7
	6. Extensions to OSPF . . . . . . . . . . . . . . . . . . . . . 7		6. Extensions to OSPF . . . . . . . . . . . . . . . . . . . . . 7
	6.1. Extensions for Operations . . . . . . . . . . . . . . . . 8		6.1. Extensions for Operations . . . . . . . . . . . . . . . . 8
	6.2. Extensions for Centralized Mode . . . . . . . . . . . . . 9		6.2. Extensions for Centralized Mode . . . . . . . . . . . . . 9
	6.2.1. Message for Flooding Topology . . . . . . . . . . . . 9		6.2.1. Message for Flooding Topology . . . . . . . . . . . . 9
	6.2.2. Encodings for Backup Paths . . . . . . . . . . . . . 13		6.2.2. Encodings for Backup Paths . . . . . . . . . . . . . 16
	6.2.3. Message for Incremental Changes . . . . . . . . . . . 21		6.2.3. Message for Incremental Changes . . . . . . . . . . . 24
	6.2.4. Leaders Selection . . . . . . . . . . . . . . . . . . 22		6.2.4. Leaders Selection . . . . . . . . . . . . . . . . . . 25
	7. Extensions to IS-IS . . . . . . . . . . . . . . . . . . . . . 24		7. Extensions to IS-IS . . . . . . . . . . . . . . . . . . . . . 27
	7.1. Extensions for Operations . . . . . . . . . . . . . . . . 24		7.1. Extensions for Operations . . . . . . . . . . . . . . . . 27
	7.2. Extensions for Centralized Mode . . . . . . . . . . . . . 24		7.2. Extensions for Centralized Mode . . . . . . . . . . . . . 27
	7.2.1. TLV for Flooding Topology . . . . . . . . . . . . . . 24		7.2.1. TLV for Flooding Topology . . . . . . . . . . . . . . 27
	7.2.2. Encodings for Backup Paths . . . . . . . . . . . . . 25		7.2.2. Encodings for Backup Paths . . . . . . . . . . . . . 28
	7.2.3. TLVs for Incremental Changes . . . . . . . . . . . . 26		7.2.3. TLVs for Incremental Changes . . . . . . . . . . . . 29
	7.2.4. Leaders Selection . . . . . . . . . . . . . . . . . . 27		7.2.4. Leaders Selection . . . . . . . . . . . . . . . . . . 30
	8. Flooding Behavior . . . . . . . . . . . . . . . . . . . . . . 27		8. Flooding Behavior . . . . . . . . . . . . . . . . . . . . . . 30
	8.1. Nodes Perform Flooding Reduction without Failure . . . . 27		8.1. Nodes Perform Flooding Reduction without Failure . . . . 30
	8.1.1. Receiving an LS . . . . . . . . . . . . . . . . . . . 27		8.1.1. Receiving an LS . . . . . . . . . . . . . . . . . . . 30
	8.1.2. Originating an LS . . . . . . . . . . . . . . . . . . 28		8.1.2. Originating an LS . . . . . . . . . . . . . . . . . . 31
	8.1.3. Establishing Adjacencies . . . . . . . . . . . . . . 28		8.1.3. Establishing Adjacencies . . . . . . . . . . . . . . 31
	8.2. An Exception Case . . . . . . . . . . . . . . . . . . . . 29		8.2. An Exception Case . . . . . . . . . . . . . . . . . . . . 32
	8.2.1. A Critical Failure . . . . . . . . . . . . . . . . . 29		8.2.1. A Critical Failure . . . . . . . . . . . . . . . . . 32
	8.2.2. Multiple Failures . . . . . . . . . . . . . . . . . . 29		8.2.2. Multiple Failures . . . . . . . . . . . . . . . . . . 32
	9. Security Considerations . . . . . . . . . . . . . . . . . . . 30		9. Security Considerations . . . . . . . . . . . . . . . . . . . 33
	10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30		10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33
	10.1. OSPFv2 . . . . . . . . . . . . . . . . . . . . . . . . . 30		10.1. OSPFv2 . . . . . . . . . . . . . . . . . . . . . . . . . 33
	10.2. OSPFv3 . . . . . . . . . . . . . . . . . . . . . . . . . 32		10.2. OSPFv3 . . . . . . . . . . . . . . . . . . . . . . . . . 35
	10.3. IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . 33		10.3. IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . 36
	11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 33		11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 36
	12. References . . . . . . . . . . . . . . . . . . . . . . . . . 33		12. References . . . . . . . . . . . . . . . . . . . . . . . . . 36
	12.1. Normative References . . . . . . . . . . . . . . . . . . 33		12.1. Normative References . . . . . . . . . . . . . . . . . . 36
	12.2. Informative References . . . . . . . . . . . . . . . . . 34		12.2. Informative References . . . . . . . . . . . . . . . . . 37
	Appendix A. Algorithms to Build Flooding Topology . . . . . . . 34		Appendix A. Algorithms to Build Flooding Topology . . . . . . . 37
	A.1. Algorithms to Build Tree without Considering Others . . . 34		A.1. Algorithms to Build Tree without Considering Others . . . 37
	A.2. Algorithms to Build Tree Considering Others . . . . . . . 36		A.2. Algorithms to Build Tree Considering Others . . . . . . . 39
	A.3. Connecting Leaves . . . . . . . . . . . . . . . . . . . . 38		A.3. Connecting Leaves . . . . . . . . . . . . . . . . . . . . 41
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 39		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 42
	1. Introduction		1. Introduction
	For some networks such as dense Data Center (DC) networks, the		For some networks such as dense Data Center (DC) networks, the
	existing Link State (LS) flooding mechanism is not efficient and may		existing Link State (LS) flooding mechanism is not efficient and may
	have some issues. The extra LS flooding consumes network bandwidth.		have some issues. The extra LS flooding consumes network bandwidth.
	Processing the extra LS flooding, including receiving, buffering and		Processing the extra LS flooding, including receiving, buffering and
	decoding the extra LSs, wastes memory space and processor time. This		decoding the extra LSs, wastes memory space and processor time. This
	may cause scalability issues and affect the network convergence		may cause scalability issues and affect the network convergence
	negatively.		negatively.
	skipping to change at page 9, line 30 ¶		skipping to change at page 9, line 30 ¶
	field is not valid.		field is not valid.
	Some optional sub TLVs may be defined in the future, but none is		Some optional sub TLVs may be defined in the future, but none is
	defined now.		defined now.
	6.2. Extensions for Centralized Mode		6.2. Extensions for Centralized Mode
	6.2.1. Message for Flooding Topology		6.2.1. Message for Flooding Topology
	A flooding topology can be represented by the links in the flooding		A flooding topology can be represented by the links in the flooding
	topology. For the links between a local node and a number of remote		topology. For the links between a local node and a number of its
	nodes, we can encode the local node in a way, and encode the remote		adjacent (or remote) nodes, we can encode the local node in a way,
	nodes in the same way or another way. After all the links in the		and encode its adjacent nodes in the same way or another way. After
	flooding topology are encoded, the encoded links can be flooded to		all the links in the flooding topology are encoded, the encoded links
	every node in the network. After receiving the encoded links, every		can be flooded to every node in the network. After receiving the
	node decodes the links and creates and/or updates the flooding		encoded links, every node decodes the links and creates and/or
	topology.		updates the flooding topology.
	For every node in an area, we may use an index to represent it.		For every node in an area, we may use an index to represent it.
	Every node in an area may order the nodes in a rule, which generates		Every node in an area may order the nodes in a rule, which generates
	the same sequence of the nodes on every node in the area. The		the same sequence of the nodes on every node in the area. The
	sequence of nodes have the index 0, 1, 2, and so on respectively.		sequence of nodes have the index 0, 1, 2, and so on respectively.
	For example, every node orders the nodes by their router IDs in		For example, every node orders the nodes by their router IDs in
	ascending order.		ascending order.
			6.2.1.1. Links Encoding
	A local node can be encoded in two parts: encoded node index size		A local node can be encoded in two parts: encoded node index size
	indication (ENSI) and compact node index (CNI). ENSI value plus a		indication (ENSI) and compact node index (CNI). ENSI value plus a
	number (e.g., 9) gives the size of compact node index. For example,		number (e.g., 9) gives the size of compact node index. For example,
	ENSI = 0 indicates that the size of CNIs is 9 bits. In the figure		ENSI = 0 indicates that the size of CNIs is 9 bits. In the figure
	below, Local node LN1 is encoded as ENSI=0 using 3 bits and CNI=LN1's		below, Local node LN1 is encoded as ENSI=0 using 3 bits and CNI=LN1's
	Index using 9 bits. LN1 is encoded in 12 bits in total.		Index using 9 bits. LN1 is encoded in 12 bits in total.
	0 1 2 3 4 5 6 7 8		0 1 2 3 4 5 6 7 8
	+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+
	|0 0 0| ENSI (3 bits) [9 bits CNI]		|0 0 0| ENSI (3 bits) [9 bits CNI]
	+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+
	| LN1 Index Value | CNI (9 bits)		| LN1 Index Value | CNI (9 bits)
	+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+
	One Local Node Encoding		An Example of Local Node Encoding
	The remote nodes can be encoded in two parts: Number of Nodes (NN)		The adjacent nodes can be encoded in two parts: Number of Nodes (NN)
	and compact node indexes (CNIs). The size of CNIs is the same as the		and compact node indexes (CNIs). The size of CNIs is the same as the
	local node. For example, three remote nodes RN10, RN20 and RN30 are		local node. For example, three adjacent nodes RN1, RN2 and RN3 are
	encoded below in 30 bits (i.e., 3.75 bytes).		encoded below in 30 bits (i.e., 3.75 bytes).
	0 1 2 3 4 5 6 7 8		0 1 2 3 4 5 6 7 8
	+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+
	|0 1 1| NN (3 bits) [3 remote nodes]		|0 1 1| NN (3 bits) [3 adjacent nodes]
	+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+
	| RN10's Index | CNI (9 bits) for RN10		| RN1's Index | CNI (9 bits) for RN1
	+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+
	| RN20's Index | CNI (9 bits) for RN20		| RN2's Index | CNI (9 bits) for RN2
	+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+
	| RN30's Index | CNI (9 bits) for RN30		| RN3's Index | CNI (9 bits) for RN3
	+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+
	One Remote Nodes Encoding		An Example of Adjacent Nodes Encoding
	The links between a local node and a number of remote nodes can be		The links between a local node and a number of its adjacent (or
	encoded as the local node followed by the remote nodes. For example,		remote) nodes can be encoded as the local node followed by the
	three links between local node LN1 and three remote nodes RN10, RN20		adjacent nodes. For example, three links between local node LN1 and
	and RN30 are encoded below in 42 bits (i.e., 5.25 bytes).		its three adjacent nodes RN1, RN2 and RN3 are encoded below in 42
			bits (i.e., 5.25 bytes).
	0 1 2 3 4 5 6 7 8		0 1 2 3 4 5 6 7 8
	+-+-+-+-+-+-+-+-+-+ _		+-+-+-+-+-+-+-+-+-+ _
	|0 0 0| ENSI (3 bits) [9 bits CNI] |		|0 0 0| ENSI (3 bits) [9 bits CNI] |
	+-+-+-+-+-+-+-+-+-+ } Encoding for		+-+-+-+-+-+-+-+-+-+ } Encoding for
	| LN1 Index Value | CNI (9 bits) for LN1 _| Local Node LN1		| LN1 Index Value | CNI (9 bits) for LN1 _| Local Node LN1
	+-+-+-+-+-+-+-+-+-+ _		+-+-+-+-+-+-+-+-+-+ _
	|0 1 1| NN (3 bits) [3 nodes] |		|0 1 1| NN (3 bits) [3 nodes] |
	+-+-+-+-+-+-+-+-+-+ | Encoding for		+-+-+-+-+-+-+-+-+-+ | Encoding for
	| RN10's Index | CNI (9 bits) for RN10 | 3 remote nodes		| RN1's Index | CNI (9 bits) for RN1 | 3 adjacent nodes
	+-+-+-+-+-+-+-+-+-+ } RN10, RN20, RN30		+-+-+-+-+-+-+-+-+-+ } RN1, RN2, RN3
	| RN20's Index | CNI (9 bits) for RN20 |		| RN2's Index | CNI (9 bits) for RN2 | of LN1
	+-+-+-+-+-+-+-+-+-+ |		+-+-+-+-+-+-+-+-+-+ |
	| RN30's Index | CNI (9 bits) for RN30 _|		| RN3's Index | CNI (9 bits) for RN3 _|
	+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+
	Links Encoding		An Example of Links Encoding
	For a flooding topology computed by a leader of an area, it may be		For a flooding topology computed by a leader of an area, it may be
	represented by all the links on the flooding topology. A Type-		represented by all the links on the flooding topology. A Type-
	Length-Value (TLV) of the following format for the links encodings		Length-Value (TLV) of the following format for the links encodings
	can be included in an LSA to represent the flooding topology (FT) and		can be included in an LSA to represent the flooding topology (FT) and
	flood the FT to every node in the area.		flood the FT to every node in the area.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| FTLK-TLV-Type (TBD2) | TLV-Length |		| FTLK-TLV-Type (TBD2) | TLV-Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Links Encoding (Node 1 to its Remote Nodes) ~		~ Links Encoding (Node 1 to its adjacent Nodes) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Links Encoding (Node 2 to its Remote Nodes) ~		~ Links Encoding (Node 2 to its adjacent Nodes) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: :		: :
	: :		: :
	Flooding Topology Links TLV		Flooding Topology Links TLV
	Note that a link between a local node LN and a remote node RN can be		Note that a link between a local node LN and its adjacent node RN can
	encoded once. That is that if it is encoded in a Links Encoding from		be encoded once and as a bi-directional link. That is that if it is
	LN to RN, then it is not encoded in a Links Encoding from RN to LN.		encoded in a Links Encoding from LN to RN, then the link from RN to
			LN is implied or assumed.
	For OSPFv2, an Opaque LSA of a new opaque type (TBD3) containing a		For OSPFv2, an Opaque LSA of a new opaque type (TBD3) containing a
	Flooding Topology Links TLV is used to flood the flooding topology		Flooding Topology Links TLV is used to flood the flooding topology
	from the leader of an area to all the other nodes in the area.		from the leader of an area to all the other nodes in the area.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| LS age | Options | LS Type = 10 |		| LS age | Options | LS Type = 10 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	skipping to change at page 13, line 5 ¶		skipping to change at page 13, line 5 ¶
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| LS checksum | Length |		| LS checksum | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Flooding Topology Links TLV ~		~ Flooding Topology Links TLV ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	OSPFv3: Flooding Topology LSA		OSPFv3: Flooding Topology LSA
	The U-bit is set to 1, and the scope is set to 01 for area-scoping.		The U-bit is set to 1, and the scope is set to 01 for area-scoping.
			6.2.1.2. Block Encoding
			Block encoding uses a single structure to encode a block (or part) of
			topology, which can be a block of links in a flooding topology. It
			can also be all the links in the flooding topology. It starts with a
			local node LN and its adjacent (or remote) nodes RNi (i = 1, 2, ...,
			n), and can be considered as an extension to the links encoding.
			The encoding of links between a local node and its adjacent nodes
			described in Section 6.2.1.1 is extended to include the links
			attached to the adjacent nodes.
			The encoding for the adjacent nodes is extended to include Extending
			Flags (E Flags for short) between the NN (Number of Nodes) field and
			the CNIs (Compact Node Indexes) for the adjacent nodes. The length
			of the E Flags field is NN bits. The following is an example
			encoding of the adjacent nodes with E Flags of 3 bits, which is the
			value of the NN (the number of adjacent nodes).
			0 1 2 3 4 5 6 7 8
			+-+-+-+-+-+-+-+-+-+
			|0 1 1| NN (3 bits) [3 adjacent nodes]
			+-+-+-+
			|1 0 1| E Flags [NN=3 bits]
			+-+-+-+-+-+-+-+-+-+
			| RN1's Index | CNI (9 bits) for RN1
			+-+-+-+-+-+-+-+-+-+
			| RN2's Index | CNI (9 bits) for RN2
			+-+-+-+-+-+-+-+-+-+
			| RN3's Index | CNI (9 bits) for RN3
			+-+-+-+-+-+-+-+-+-+
			An Example of Adjacent Nodes with E Flags Encoding
			There is a bit flag (called E flag) in the E Flags field for each
			adjacent node. The first bit (i.e., the most significant bit) in the
			E Flags field is for the first adjacent node (e.g., RN1), the second
			bit is for the second adjacent node (e.g., RN2), and so on. The E
			flag for an adjacent node RNi set to one indicates that the links
			attached to the adjacent node RNi are included below. The E flag for
			an adjacent node RNi set to zero means that no links attached to the
			adjacent node RNi are included below.
			The links attached to the adjacent node RNi are represented by the
			RNi as a local node and the adjacent nodes of RNi. The encoding for
			the adjacent nodes of RNi is the same as that for the adjacent nodes
			of a local node. It consists of an NN field of 3 bits, E Flags field
			of NN bits, and CNIs for the adjacent nodes of RNi.
			The following is an example of a block encoding for a block (or part)
			of flooding topology below.
			o LN1
			/ | \
			/ \
			/ | \
			o RN1 o RN2 o RN3
			/ / \
			/ / \
			/ / \
			o RN11 o RN31 o RN32
			An Example Block of Flooding Topology
			It represents 6 links: 3 links between local node LN1 and its 3
			adjacent nodes RN1, RN2 and RN3; 1 link between RN1 as a local node
			and its 1 adjacent node RN11; and 2 links between RN3 as a local node
			and its 2 adjacent nodes RN31 and RN32.
			It starts with the encoding of the links between local node LN1 and 3
			adjacent nodes RN1, RN2 and RN3 of the local node LN1. The encoding
			for the local node LN1 is the same as that for a local node described
			in Section 6.2.1.1. The encoding for 3 adjacent nodes RN1, RN2 and
			RN3 of local node LN1 comprises an NN field of 3 bits with value of
			3, E Flags field of NN = 3 bits, and the indexes of adjacent nodes
			RN1, RN2 and RN3.
			0 1 2 3 4 5 6 7 8
			+-+-+-+-+-+-+-+-+-+ _
			|0 0 0| ENSI (3 bits) [9 bits CNI] |
			+-+-+-+-+-+-+-+-+-+ } Encoding for
			| LN1 Index Value | CNI (9 bits) _| Local Node LN1
			+-+-+-+-+-+-+-+-+-+ _
			|0 1 1| NN(3 bits)[3 adjacent nodes]|
			+-+-+-+ |
			|1 0 1| E Flags [NN=3 bits] | Encoding for
			+-+-+-+-+-+-+-+-+-+ | 3 adjacent nodes
			| RN1's Index | CNI (9 bits) for RN1 } (RN1, RN2, RN3)
			+-+-+-+-+-+-+-+-+-+ | of LN1
			| RN2's Index | CNI (9 bits) for RN2 |
			+-+-+-+-+-+-+-+-+-+ |
			| RN3's Index | CNI (9 bits) for RN3 _|
			+-+-+-+-+-+-+-+-+-+ _
			|0 0 1| NN (3 bits)[1 adjacent node]|
			+-+-+-+ | Encoding for
			|0| E Flags [NN=1 bit] } 1 adjacent node
			+-+-+-+-+-+-+-+-+-+ | (RN11)
			| RN11's Index | CNI (9 bits) for RN11 _| of RN1
			+-+-+-+-+-+-+-+-+-+ _
			|0 1 0| NN(3 bits)[2 adjacent nodes]|
			+-+-+-+ |
			|0 0| E Flags [NN=2 bits] | Encoding for
			+-+-+-+-+-+-+-+-+-+ } 2 adjacent nodes
			| RN31's Index | CNI (9 bits) for RN31 | (RN31, RN32)
			+-+-+-+-+-+-+-+-+-+ | of RN3 as a
			| RN32's Index | CNI (9 bits) for RN32 | local node
			+-+-+-+-+-+-+-+-+-+ _|
			An Example of Block Encoding
			The first E flag in the encoding for adjacent nodes RN1, RN2 and RN3
			is set to one, which indicates that the links between the first
			adjacent node RN1 as a local node and its adjacent nodes are included
			below. In this example, 1 link between RN1 and its adjacent node
			RN11 is represented by the encoding for the adjacent node RN11 of RN1
			as a local node. The encoding for 1 adjacent node RN11 consists of
			an NN field of 3 bits with value of 1, E Flags field of NN = 1 bits,
			and the index of adjacent node RN11. The size of the index of RN11
			is the same as that of local node LN1 indicated by the ENSI in the
			encoding for local node LN1.
			The second E flag in the encoding for adjacent nodes RN1, RN2 and RN3
			is set to zero, which indicates that no links between the second
			adjacent node RN2 as a local node and its adjacent nodes are included
			below.
			The third E flag in the encoding for adjacent nodes RN1, RN2 and RN3
			is set to one, which indicates that the links between the third
			adjacent node RN3 as a local node and its adjacent nodes are included
			below. In this example, 2 links between RN3 and its 2 adjacent nodes
			RN31 and RN32 are represented by the encoding for the adjacent nodes
			RN31 and RN32 of RN3 as a local node. The encoding for 2 adjacent
			nodes RN31 and RN32 consists of an NN field of 3 bits with value of
			2, E Flags field of NN = 2 bits, and the indexes of adjacent nodes
			RN31 and RN32. The size of the index of RN31 and RN32 is the same as
			that of local node LN1 indicated by the ENSI in the encoding for
			local node LN1.
			The block encoding may be used in the place of the links encoding in
			Section 6.2.1.1 for more efficiency. That is that it may be used in
			a Flooding Topology Links TLV. Alternatively, a new TLV, which is
			similar to the Flooding Topology Links TLV, may be defined to contain
			a number of block encodings.
	6.2.2. Encodings for Backup Paths		6.2.2. Encodings for Backup Paths
	When the leader of an area computes a flooding topology, it may		When the leader of an area computes a flooding topology, it may
	compute a backup path or multiple backup paths for a critical link on		compute a backup path or multiple backup paths for a critical link on
	the flooding topology. When the critical link fails, a link state		the flooding topology. When the critical link fails, a link state
	can be distributed to every node in the area through one backup path		can be distributed to every node in the area through one backup path
	and other links on the flooding topology. In addition, it may		and other links on the flooding topology. In addition, it may
	compute a backup path or multiple backup paths for a node. When the		compute a backup path or multiple backup paths for a node. When the
	node fails, a link state can be distributed to the other nodes in the		node fails, a link state can be distributed to the other nodes in the
	area through the backup paths and the links on the flooding topology.		area through the backup paths and the links on the flooding topology.
	skipping to change at page 14, line 21 ¶		skipping to change at page 17, line 25 ¶
	|PLEN | 4 bits (backup path len) | |		|PLEN | 4 bits (backup path len) | |
	+-+-+-+-+-+-+-+-+ | | Backup		+-+-+-+-+-+-+-+-+ | | Backup
	| PN1 Encoding | Variable bits | One } paths		| PN1 Encoding | Variable bits | One } paths
	+-+-+-+-+-+-+-+-+ } backup path | for Node		+-+-+-+-+-+-+-+-+ } backup path | for Node
	~ ~ | for Node |		~ ~ | for Node |
	+-+-+-+-+-+-+-+-+ | |		+-+-+-+-+-+-+-+-+ | |
	| PNn Encoding | Variable bits _| |		| PNn Encoding | Variable bits _| |
	+-+-+-+-+-+-+-+-+ |		+-+-+-+-+-+-+-+-+ |
	// // _|		// // _|
	One Node Backup Paths Encoding		An Example of Node Backup Paths Encoding
	Another encoding of the sequence of nodes along the path uses one		Another encoding of the sequence of nodes along the path uses one
	encoded node index size indication (ENSI) for all the nodes in the		encoded node index size indication (ENSI) for all the nodes in the
	path. Thus we have the following Node Backup Paths Encoding.		path. Thus we have the following Node Backup Paths Encoding.
	0 1 2 3 4 5 6 7 8		0 1 2 3 4 5 6 7 8
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+
	|K| 1 bit (K=1: Key/Critical Node, K=0: Normal Node)		|K| 1 bit (K=1: Key/Critical Node, K=0: Normal Node)
	+-+-+-+ _		+-+-+-+ _
	|NNBP | 3 bits (number of node backup paths) |		|NNBP | 3 bits (number of node backup paths) |
	skipping to change at page 14, line 45 ¶		skipping to change at page 17, line 49 ¶
	|ENSI | 3 bits(Ix Bits Indication)| | Backup		|ENSI | 3 bits(Ix Bits Indication)| | Backup
	+-+-+-+-+-+-+-+-+ | One } paths		+-+-+-+-+-+-+-+-+ | One } paths
	| PN1 Index | #Bits indicated by ENSI } backup path | for Node		| PN1 Index | #Bits indicated by ENSI } backup path | for Node
	+-+-+-+-+-+-+-+-+ | for Node |		+-+-+-+-+-+-+-+-+ | for Node |
	~ ~ | |		~ ~ | |
	+-+-+-+-+-+-+-+-+ | |		+-+-+-+-+-+-+-+-+ | |
	| PNn Index | #Bits indicated by ENSI _| |		| PNn Index | #Bits indicated by ENSI _| |
	+-+-+-+-+-+-+-+-+ |		+-+-+-+-+-+-+-+-+ |
	// // _|		// // _|
	Another Node Backup Paths Encoding		Another Example of Node Backup Paths Encoding
	A new TLV called Node Backup Paths TLV is defined below. It may		A new TLV called Node Backup Paths TLV is defined below. It may
	include multiple nodes and their backup paths. Each node is		include multiple nodes and their backup paths. Each node is
	represented by its index encoding, which is followed by its node		represented by its index encoding, which is followed by its node
	backup paths encoding.		backup paths encoding.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| NBP-TLV-Type (TBD5) | TLV-Length |		| NBP-TLV-Type (TBD5) | TLV-Length |
	skipping to change at page 15, line 32 ¶		skipping to change at page 18, line 37 ¶
	flooding topology consists of the link encoding such as Link1 Index		flooding topology consists of the link encoding such as Link1 Index
	Encoding and the link backup paths encoding. The former is similar		Encoding and the link backup paths encoding. The former is similar
	to local node encoding. It contains encoded link index size		to local node encoding. It contains encoded link index size
	indication (ELSI) and compact link index (CLI). The latter has the		indication (ELSI) and compact link index (CLI). The latter has the
	following format. It comprises a C flag (Critical link flag) of 1		following format. It comprises a C flag (Critical link flag) of 1
	bit, a 2 bits NLB field (number of link backup paths), and each of		bit, a 2 bits NLB field (number of link backup paths), and each of
	the backup paths encoding, which consists of the path length PLEN of		the backup paths encoding, which consists of the path length PLEN of
	3 bits indicating the length of the path (i.e., the number of nodes),		3 bits indicating the length of the path (i.e., the number of nodes),
	and the encoding of the sequence of nodes along the path such as		and the encoding of the sequence of nodes along the path such as
	encodings for nodes PN1, ..., PNm. Note that two ends of a link		encodings for nodes PN1, ..., PNm. Note that two ends of a link
	(i.e., the local node and the remote node of the link) are not needed		(i.e., the local node and the adjacent/remote node of the link) are
	in the path. The encoding of every node may use the encoding of a		not needed in the path. The encoding of every node may use the
	local node, which comprises encoded node index size indication (ENSI)		encoding of a local node, which comprises encoded node index size
	and compact node index (CNI).		indication (ENSI) and compact node index (CNI).
	0 1 2 3 4 5 6 7 8		0 1 2 3 4 5 6 7 8
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+
	|C| 1 bit (C=1: Critical Link, C=0: Normal Link)		|C| 1 bit (C=1: Critical Link, C=0: Normal Link)
	+-+-+ _		+-+-+ _
	|NLB| 2 bits (number of link backup paths) |		|NLB| 2 bits (number of link backup paths) |
	+-+-+-+ _ |		+-+-+-+ _ |
	|PLEN | 3 bits (backup path len) | |		|PLEN | 3 bits (backup path len) | |
	+-+-+-+-+-+-+-+-+ | | Backup		+-+-+-+-+-+-+-+-+ | | Backup
	| PN1 Encoding | Variable bits | One } paths		| PN1 Encoding | Variable bits | One } paths
	+-+-+-+-+-+-+-+-+ } backup path | for Link		+-+-+-+-+-+-+-+-+ } backup path | for Link
	~ ~ | for Link |		~ ~ | for Link |
	+-+-+-+-+-+-+-+-+ | |		+-+-+-+-+-+-+-+-+ | |
	| PNm Encoding | Variable bits _| |		| PNm Encoding | Variable bits _| |
	+-+-+-+-+-+-+-+-+ |		+-+-+-+-+-+-+-+-+ |
	// // _|		// // _|
	One Link Backup Paths Encoding		An Example of Link Backup Paths Encoding
	Another encoding of the sequence of nodes along the path uses one		Another encoding of the sequence of nodes along the path uses one
	encoded node index size indication (ENSI) for all the nodes in the		encoded node index size indication (ENSI) for all the nodes in the
	path. Thus we have the following Link Backup Paths Encoding.		path. Thus we have the following Link Backup Paths Encoding.
	0 1 2 3 4 5 6 7 8		0 1 2 3 4 5 6 7 8
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+
	|C| 1 bit (C=1: Critical Link, C=0: Normal Link)		|C| 1 bit (C=1: Critical Link, C=0: Normal Link)
	+-+-+ _		+-+-+ _
	|NLB| 2 bits (number of link backup paths) |		|NLB| 2 bits (number of link backup paths) |
	skipping to change at page 16, line 45 ¶		skipping to change at page 19, line 45 ¶
	|ENSI | 3 bits(Ix Bits Indication)| | Backup		|ENSI | 3 bits(Ix Bits Indication)| | Backup
	+-+-+-+-+-+-+-+-+ | One } paths		+-+-+-+-+-+-+-+-+ | One } paths
	| PN1 Index | #Bits indicated by ENSI } backup path | for Link		| PN1 Index | #Bits indicated by ENSI } backup path | for Link
	+-+-+-+-+-+-+-+-+ | for Link |		+-+-+-+-+-+-+-+-+ | for Link |
	~ ~ | |		~ ~ | |
	+-+-+-+-+-+-+-+-+ | |		+-+-+-+-+-+-+-+-+ | |
	| PNm Index | #Bits indicated by ENSI _| |		| PNm Index | #Bits indicated by ENSI _| |
	+-+-+-+-+-+-+-+-+ |		+-+-+-+-+-+-+-+-+ |
	// // _|		// // _|
	Another Link Backup Paths Encoding		Another Example of Link Backup Paths Encoding
	A new TLV called Link Backup Paths TLV is defined below. It may		A new TLV called Link Backup Paths TLV is defined below. It may
	include multiple links and their backup paths. Each link is		include multiple links and their backup paths. Each link is
	represented by its index encoding, which is followed by its link		represented by its index encoding, which is followed by its link
	backup paths encoding.		backup paths encoding.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| LBP-TLV-Type (TBD6) | TLV-Length |		| LBP-TLV-Type (TBD6) | TLV-Length |
	skipping to change at page 17, line 47 ¶		skipping to change at page 20, line 47 ¶
	| LS checksum | Length |		| LS checksum | Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Link Backup Paths TLVs ~		~ Link Backup Paths TLVs ~
	~ Node Backup Paths TLVs ~		~ Node Backup Paths TLVs ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	OSPFv2: Backup Paths Opaque LSA		OSPFv2: Backup Paths Opaque LSA
	For OSPFv3, an area scope LSA of a new LSA function code (TBD8),		For OSPFv3, an area scope LSA of a new LSA function code (TBD8),
	containing node backup paths TLVs and link backup paths TLVs, is used		containing node backup paths TLVs and link backup paths TLVs, is used
	to flood the flooding topology from the leader of an area to all the		to flood the backup paths from the leader of an area to all the other
	other nodes in the area.		nodes in the area.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| LS age |1|0|1| BP-LSA (TBD8) |		| LS age |1|0|1| BP-LSA (TBD8) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Link State ID |		| Link State ID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Advertising Router |		| Advertising Router |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	skipping to change at page 18, line 44 ¶		skipping to change at page 21, line 44 ¶
	+-+-+-+-+-+-+-+-+-+ _		+-+-+-+-+-+-+-+-+-+ _
	|ENSI | 3 bits(#bits indication) |		|ENSI | 3 bits(#bits indication) |
	+-+-+-+-+-+-+-+-+-+ } Local Node LN1		+-+-+-+-+-+-+-+-+-+ } Local Node LN1
	| LN1 Index Value | #bits indicated by ENSI _| Encoding		| LN1 Index Value | #bits indicated by ENSI _| Encoding
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: Local node LN1 backup paths encoding :		: Local node LN1 backup paths encoding :
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Local Node with Backup Paths Encoding		Local Node with Backup Paths Encoding
	A remote node and its backup paths can be encoded in the following		A adjacent node and its backup paths can be encoded in the following
	format. It is the remote node (such as remote node RN10) index value		format. It is the adjacent node (such as adjacent node RN10) index
	followed by the remote node backup paths encoding, which is the same		value followed by the adjacent node backup paths encoding, which is
	as the node backup paths encoding described in Section 6.2.2.1.		the same as the node backup paths encoding described in
			Section 6.2.2.1.
	+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+
	|RN10 Index Value | (#bits indicated by ENSI)		|RN10 Index Value | (#bits indicated by ENSI)
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: Remote node RN10 backup paths encoding :		: adjacent node RN10 backup paths encoding :
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Remote Node with Backup Paths Encoding		Adjacent Node with Backup Paths Encoding
	The links between a local node and a number of remote nodes, the		The links between a local node and a number of its adjacent nodes,
	backup paths for each of the nodes, and the backup paths for each of		the backup paths for each of the nodes, and the backup paths for each
	the links can be encoded in the following format. It is called Links		of the links can be encoded in the following format. It is called
	from Node with Backup Paths Encoding.		Links from Node with Backup Paths Encoding.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: Local Node with backup paths encoding :		: Local Node with backup paths encoding :
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| NN | Number of Remote Nodes (i.e., Number of links)		| NN | Number of adjacent Nodes (i.e., Number of links)
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: Remote Node 1 with backup paths encoding :		: Adjacent Node 1 with backup paths encoding :
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: Link1 backup paths Encoding :		: Link1 backup paths Encoding :
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: Remote Node 2 with backup paths encoding :		: Adjacent Node 2 with backup paths encoding :
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: Link2 backup paths Encoding :		: Link2 backup paths Encoding :
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| |		| |
	Links from Node with Backup Paths Encoding		Links from Node with Backup Paths Encoding
	A new TLV called Links with Backup Paths TLV is defined below. It		A new TLV called Links with Backup Paths TLV is defined below. It
	includes a number of Links from Node with Backup Paths Encodings		includes a number of Links from Node with Backup Paths Encodings
	described above. This TLV contains both the flooding topology and		described above. This TLV contains both the flooding topology and
	skipping to change at page 21, line 42 ¶		skipping to change at page 24, line 42 ¶
	topology with the new links to all the other nodes, it removes the		topology with the new links to all the other nodes, it removes the
	LSA for the new links. When removing the LSA for these new links,		LSA for the new links. When removing the LSA for these new links,
	each of the other nodes does not update the flooding topology (i.e.,		each of the other nodes does not update the flooding topology (i.e.,
	does not remove these links from the flooding topology).		does not remove these links from the flooding topology).
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| ADDLK-TLV-Type (TBDc) | TLV-Length |		| ADDLK-TLV-Type (TBDc) | TLV-Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Links Encoding (Node 1 to its Remote Nodes) ~		~ Links Encoding (Node 1 to its adjacent Nodes) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Links Encoding (Node 2 to its Remote Nodes) ~		~ Links Encoding (Node 2 to its adjacent Nodes) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: :		: :
	: :		: :
	Add Links TLV		Add Links TLV
	For deleting some links from the flooding topology, we define a new		For deleting some links from the flooding topology, we define a new
	TLV called Delete Links TLVs of the following format. When some old		TLV called Delete Links TLVs of the following format. When some old
	links are removed from the flooding topology, the leader may not		links are removed from the flooding topology, the leader may not
	flood the whole flooding topology without the old links to all the		flood the whole flooding topology without the old links to all the
	other nodes. It may just flood these old links. After receiving		other nodes. It may just flood these old links. After receiving
	skipping to change at page 22, line 22 ¶		skipping to change at page 25, line 22 ¶
	flooding topology without the old links to all the other nodes, it		flooding topology without the old links to all the other nodes, it
	removes the LSA for the old links. When removing the LSA for these		removes the LSA for the old links. When removing the LSA for these
	old links, each of the other nodes does not update the flooding		old links, each of the other nodes does not update the flooding
	topology (i.e., does not add these links into the flooding topology).		topology (i.e., does not add these links into the flooding topology).
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| DELLK-TLV-Type (TBDd) | TLV-Length |		| DELLK-TLV-Type (TBDd) | TLV-Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Links Encoding (Node 1 to its Remote Nodes) ~		~ Links Encoding (Node 1 to its adjacent Nodes) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Links Encoding (Node 2 to its Remote Nodes) ~		~ Links Encoding (Node 2 to its adjacent Nodes) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: :		: :
	: :		: :
	Delete Links TLV		Delete Links TLV
	The Add Links TLVs and Delete Links TLVs should be in a separate LSA		The Add Links TLVs and Delete Links TLVs should be in a separate LSA
	instance. The LSA can be a Flooding Topology LSA defined above.		instance. The LSA can be a Flooding Topology LSA defined above.
	Alternatively, we may define a new LSA for these TLVs.		Alternatively, we may define a new LSA for these TLVs.
	6.2.4. Leaders Selection		6.2.4. Leaders Selection
	skipping to change at page 23, line 31 ¶		skipping to change at page 26, line 31 ¶
	A sub-TLV called leaders sub-TLV is defined. It has the following		A sub-TLV called leaders sub-TLV is defined. It has the following
	format.		format.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| LEADS-TLV-Type (TBDf) | TLV-Length |		| LEADS-TLV-Type (TBDf) | TLV-Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| 1st Leader Node/Router ID |		| 1st Leader Node/Router ID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| 2nd Leaader Node/Router ID |		| 2nd Leader Node/Router ID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ ~		~ ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| nth Leader Node/Router ID |		| nth Leader Node/Router ID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Leaders sub-TLV		Leaders sub-TLV
	When a node selects itself as a leader, it originates a RI LSA		When a node selects itself as a leader, it originates a RI LSA
	containing the leader in a leaders sub-TLV.		containing the leader in a leaders sub-TLV.
	skipping to change at page 24, line 41 ¶		skipping to change at page 27, line 41 ¶
	A new TLV for the encodings of the links in the flooding topology is		A new TLV for the encodings of the links in the flooding topology is
	defined. It has the following format and contains the same contents		defined. It has the following format and contains the same contents
	as the Flooding Topology Links TLV defined in OSPF Flooding Topology		as the Flooding Topology Links TLV defined in OSPF Flooding Topology
	Opaque LSA.		Opaque LSA.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|FTL-Type(TBDi2)| Length |		|FTL-Type(TBDi2)| Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Links Encoding (Node 1 to its Remote Nodes) ~		~ Links Encoding (Node 1 to its adjacent Nodes) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Links Encoding (Node 2 to its Remote Nodes) ~		~ Links Encoding (Node 2 to its adjacent Nodes) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: :		: :
	: :		: :
	IS-IS Flooding Topology Links TLV		IS-IS Flooding Topology Links TLV
	7.2.2. Encodings for Backup Paths		7.2.2. Encodings for Backup Paths
	7.2.2.1. TLVs for Backup Paths		7.2.2.1. TLVs for Backup Paths
	For flooding backup paths separately, we define two TLVs: IS-IS Node		For flooding backup paths separately, we define two TLVs: IS-IS Node
	skipping to change at page 26, line 35 ¶		skipping to change at page 29, line 35 ¶
	Similar to Add Links TLV in OSPF, a new TLV called IS-IS Add Links		Similar to Add Links TLV in OSPF, a new TLV called IS-IS Add Links
	TLV is defined. It has the following format and contains the same		TLV is defined. It has the following format and contains the same
	contents as Add Links TLV in OSPF.		contents as Add Links TLV in OSPF.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|ADDL-Type(TBDi6| Length |		|ADDL-Type(TBDi6| Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Links Encoding (Node 1 to its Remote Nodes) ~		~ Links Encoding (Node 1 to its adjacent Nodes) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Links Encoding (Node 2 to its Remote Nodes) ~		~ Links Encoding (Node 2 to its adjacent Nodes) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: :		: :
	: :		: :
	IS-IS Add Links TLV		IS-IS Add Links TLV
	Similar to Delete Links TLV in OSPF, a new TLV called IS-IS Delete		Similar to Delete Links TLV in OSPF, a new TLV called IS-IS Delete
	Links TLV is defined. It has the following format and contains the		Links TLV is defined. It has the following format and contains the
	same contents as Delete Links TLV in OSPF.		same contents as Delete Links TLV in OSPF.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|DELL-Type(TBDi7| Length |		|DELL-Type(TBDi7| Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Links Encoding (Node 1 to its Remote Nodes) ~		~ Links Encoding (Node 1 to its adjacent Nodes) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ Links Encoding (Node 2 to its Remote Nodes) ~		~ Links Encoding (Node 2 to its adjacent Nodes) ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	: :		: :
	: :		: :
	IS-IS Delete Links TLV		IS-IS Delete Links TLV
	7.2.4. Leaders Selection		7.2.4. Leaders Selection
	Similar to Flooding Reduction Information TLV in OSPF, a new TLV		Similar to Flooding Reduction Information TLV in OSPF, a new TLV
	called IS-IS Flooding Reduction Information TLV is defined. It has		called IS-IS Flooding Reduction Information TLV is defined. It has
	the following format and contains the same contents as Flooding		the following format and contains the same contents as Flooding
	skipping to change at page 31, line 15 ¶		skipping to change at page 34, line 15 ¶
	+====================+===============+=======================+		+====================+===============+=======================+
	| Registry Value | Opaque Type | reference |		| Registry Value | Opaque Type | reference |
	+====================+===============+=======================+		+====================+===============+=======================+
	| 10 | FT LSA | This document |		| 10 | FT LSA | This document |
	+--------------------+---------------+-----------------------+		+--------------------+---------------+-----------------------+
	| 11 | BP LSA | This document |		| 11 | BP LSA | This document |
	+--------------------+---------------+-----------------------+		+--------------------+---------------+-----------------------+
	| 12 | FTBP LSA | This document |		| 12 | FTBP LSA | This document |
	+--------------------+---------------+-----------------------+		+--------------------+---------------+-----------------------+
	IANA is requested to create and maintain new registrys:		IANA is requested to create and maintain new registries:
	o OSPFv2 FT LSA TLVs		o OSPFv2 FT LSA TLVs
	Initial values for the registry are given below. The future		Initial values for the registry are given below. The future
	assignments are to be made through IETF Review [RFC5226].		assignments are to be made through IETF Review [RFC5226].
	Value OSPFv2 FT LSA TLV Name Definition		Value OSPFv2 FT LSA TLV Name Definition
	----- ----------------------- ----------		----- ----------------------- ----------
	0 Reserved		0 Reserved
	1 FT Links TLV see Section 6.2.1		1 FT Links TLV see Section 6.2.1
	skipping to change at page 32, line 21 ¶		skipping to change at page 35, line 21 ¶
	+===========+==========================+=======================+		+===========+==========================+=======================+
	| Value | LSA Function Code Name | reference |		| Value | LSA Function Code Name | reference |
	+======================================+=======================+		+======================================+=======================+
	| 16 | FT LSA | This document |		| 16 | FT LSA | This document |
	+-----------+--------------------------+-----------------------+		+-----------+--------------------------+-----------------------+
	| 17 | BP LSA | This document |		| 17 | BP LSA | This document |
	+-----------+--------------------------+-----------------------+		+-----------+--------------------------+-----------------------+
	| 18 | FTBP LSA | This document |		| 18 | FTBP LSA | This document |
	+-----------+--------------------------+-----------------------+		+-----------+--------------------------+-----------------------+
	IANA is requested to create and maintain new registrys:		IANA is requested to create and maintain new registries:
	o OSPFv3 FT LSA TLVs		o OSPFv3 FT LSA TLVs
	Initial values for the registry are given below. The future		Initial values for the registry are given below. The future
	assignments are to be made through IETF Review [RFC5226].		assignments are to be made through IETF Review [RFC5226].
	Value OSPFv3 FT LSA TLV Name Definition		Value OSPFv3 FT LSA TLV Name Definition
	----- ----------------------- ----------		----- ----------------------- ----------
	0 Reserved		0 Reserved
	1 FT Links TLV see Section 6.2.1		1 FT Links TLV see Section 6.2.1
	skipping to change at page 36, line 46 ¶		skipping to change at page 39, line 46 ¶
	flooding reduction.		flooding reduction.
	4. Add Xi (i = 1, 2, ..., n) associated with previous hop PH=A into		4. Add Xi (i = 1, 2, ..., n) associated with previous hop PH=A into
	the end of the candidate queue Cq, and goto step 1.		the end of the candidate queue Cq, and goto step 1.
	Another algorithm for building a tree from node R as root with		Another algorithm for building a tree from node R as root with
	consideration of others' support for flooding reduction starts with a		consideration of others' support for flooding reduction starts with a
	candidate queue Cq containing R associated with previous hop PH=0 and		candidate queue Cq containing R associated with previous hop PH=0 and
	an empty flooding topology Ft:		an empty flooding topology Ft:
	1. Remove the first node A that surpports flooding reduction from		1. Remove the first node A that supports flooding reduction from the
	the candidate queue Cq if there is such a node A; otherwise		candidate queue Cq if there is such a node A; otherwise (i.e., if
	(i.e., if there is not such node A in Cq), then remove the first		there is not such node A in Cq), then remove the first node A
	node A from Cq. Add A into the flooding topology Ft.		from Cq. Add A into the flooding topology Ft.
	2. If Cq is empty or all nodes are on Ft, then return with Ft.		2. If Cq is empty or all nodes are on Ft, then return with Ft.
	3. Suppose that node Xi (i = 1, 2, ..., n) is connected to node A		3. Suppose that node Xi (i = 1, 2, ..., n) is connected to node A
	and not in the flooding topology Ft and X1, X2, ..., Xn are in a		and not in the flooding topology Ft and X1, X2, ..., Xn are in a
	special order considering whether some of them support flooding		special order considering whether some of them support flooding
	reduction. For example, X1, X2, ..., Xn are ordered by the cost		reduction. For example, X1, X2, ..., Xn are ordered by the cost
	of the link between A and Xi. The cost of the link between A and		of the link between A and Xi. The cost of the link between A and
	Xi is less than the cost of the link between A and Xj (j = i +		Xi is less than the cost of the link between A and Xj (j = i +
	1). If two costs are the same, Xi's ID is less than Xj's ID.		1). If two costs are the same, Xi's ID is less than Xj's ID.
	The cost of a link is redefined such that 1) the cost of a link		The cost of a link is redefined such that 1) the cost of a link
	between A and Xi both surpport flooding reduction is much less		between A and Xi both support flooding reduction is much less
	than the cost of any link between A and Xk where Xk does not		than the cost of any link between A and Xk where Xk does not
	surpport flooding reduction; 2) the real metric of a link between		support flooding reduction; 2) the real metric of a link between
	A and Xi and the real metric of a link between A and Xk are used		A and Xi and the real metric of a link between A and Xk are used
	as their costs for determining the order of Xi and Xk if they all		as their costs for determining the order of Xi and Xk if they all
	(i.e., A, Xi and Xk) surpport flooding reduction or none of Xi		(i.e., A, Xi and Xk) support flooding reduction or none of Xi and
	and Xk supports flooding reduction.		Xk supports flooding reduction.
	4. Add Xi (i = 1, 2, ..., n) associated with previous hop PH=A into		4. Add Xi (i = 1, 2, ..., n) associated with previous hop PH=A into
	the front of the candidate queue Cq, and goto step 1.		the front of the candidate queue Cq, and goto step 1.
	A third algorithm for building a tree from node R as root with		A third algorithm for building a tree from node R as root with
	consideration of others' surpport for flooding reduction (using flag		consideration of others' support for flooding reduction (using flag F
	F = 1 for surpport, and F = 0 for not surpport in the following)		= 1 for support, and F = 0 for not support in the following) starts
	starts with a candidate list Cq containing R associated with low		with a candidate list Cq containing R associated with low order cost
	order cost Lc=0, high order cost Hc=0 and previous hop ID PH=0, and		Lc=0, high order cost Hc=0 and previous hop ID PH=0, and an empty
	an empty flooding topology Ft:		flooding topology Ft:
	1. Remove the first node A from Cq and add A into Ft.		1. Remove the first node A from Cq and add A into Ft.
	2. If all the nodes are on Ft, then return with Ft		2. If all the nodes are on Ft, then return with Ft
	3. Suppose that node A is associated with a cost Ca which is the		3. Suppose that node A is associated with a cost Ca which is the
	cost from root R to node A, node Xi (i = 1, 2, ..., n) is		cost from root R to node A, node Xi (i = 1, 2, ..., n) is
	connected to node A and not in Ft and the cost of the link		connected to node A and not in Ft and the cost of the link
	between A and Xi is LCi (i=1, 2, ..., n). Compute Ci = Ca + LCi,		between A and Xi is LCi (i=1, 2, ..., n). Compute Ci = Ca + LCi,
	check if Xi is in Cq and if Cxi (cost from R to Xi) < Ci. If Xi		check if Xi is in Cq and if Cxi (cost from R to Xi) < Ci. If Xi
End of changes. 55 change blocks.
	115 lines changed or deleted		263 lines changed or added
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