< draft-chen-bier-te-lan-01.txt		draft-chen-bier-te-lan-02.txt >
	Network Working Group H. Chen		Network Working Group H. Chen
	Internet-Draft M. McBride		Internet-Draft M. McBride
	Intended status: Standards Track Futurewei		Intended status: Standards Track Futurewei
	Expires: 17 May 2022 A. Wang		Expires: 26 August 2022 A. Wang
	China Telecom		China Telecom
	G. Mishra		G. Mishra
	Verizon Inc.		Verizon Inc.
	L. Liu		L. Liu
	Fujitsu		Fujitsu
	X. Liu		X. Liu
	Volta Networks		Volta Networks
	13 November 2021		22 February 2022
	BIER-TE for Broadcast Link		BIER-TE for Broadcast Link
	draft-chen-bier-te-lan-01		draft-chen-bier-te-lan-02
	Abstract		Abstract
	This document describes extensions to "Bit Index Explicit Replication		This document describes extensions to "Bit Index Explicit Replication
	Traffic Engineering" (BIER-TE) for supporting LANs (i.e., broadcast		Traffic Engineering" (BIER-TE) for supporting LANs (i.e., broadcast
	links). For a multicast packet with an explicit point-to-multipoint		links). For a multicast packet with an explicit point-to-multipoint
	(P2MP) path traversing LANs, the packet is replicated and forwarded		(P2MP) path traversing LANs, the packet is replicated and forwarded
	statelessly along the path.		statelessly along the path.
	Requirements Language		Requirements Language
	skipping to change at page 1, line 49 ¶		skipping to change at page 1, line 49 ¶
	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 17 May 2022.		This Internet-Draft will expire on 26 August 2022.
	Copyright Notice		Copyright Notice
	Copyright (c) 2021 IETF Trust and the persons identified as the		Copyright (c) 2022 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
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	license-info) in effect on the date of publication of this document.		license-info) in effect on the date of publication of this document.
	Please review these documents carefully, as they describe your rights		Please review these documents carefully, as they describe your rights
	and restrictions with respect to this document. Code Components		and restrictions with respect to this document. Code Components
	extracted from this document must include Simplified BSD License text		extracted from this document must include Revised BSD License text as
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	provided without warranty as described in the Simplified BSD License.		provided without warranty as described in the Revised BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Example Application of Current BIER-TE with LAN . . . . . . . 4		2. Example Application of Current BIER-TE with LAN . . . . . . . 4
	2.1. Example BIER-TE Topology with LAN . . . . . . . . . . . . 4		2.1. Example BIER-TE Topology with LAN . . . . . . . . . . . . 4
	2.2. BIER-TE BIFT on BFR . . . . . . . . . . . . . . . . . . . 5		2.2. BIER-TE BIFT on BFR . . . . . . . . . . . . . . . . . . . 5
	2.3. Example P2MP Path with LAN . . . . . . . . . . . . . . . 10		2.3. Example P2MP Path with LAN . . . . . . . . . . . . . . . 10
	3. Improved BIER-TE with LAN . . . . . . . . . . . . . . . . . . 11		3. Improved BIER-TE with LAN . . . . . . . . . . . . . . . . . . 12
	3.1. New BP Assignments for LAN . . . . . . . . . . . . . . . 11		3.1. New BP Assignments for LAN . . . . . . . . . . . . . . . 12
	3.2. Improved BIER-TE BIFT on BFR . . . . . . . . . . . . . . 13		3.2. Improved BIER-TE BIFT on BFR . . . . . . . . . . . . . . 13
	3.3. Updated Forwarding Procedure . . . . . . . . . . . . . . 17		3.3. Updated Forwarding Procedure . . . . . . . . . . . . . . 17
	4. Example Application of Improved BIER-TE . . . . . . . . . . . 18		4. Example Application of Improved BIER-TE . . . . . . . . . . . 18
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 19		5. Security Considerations . . . . . . . . . . . . . . . . . . . 19
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20		6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
	7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 20		7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 20
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . 20		8. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
	8.1. Normative References . . . . . . . . . . . . . . . . . . 20		8.1. Normative References . . . . . . . . . . . . . . . . . . 20
	8.2. Informative References . . . . . . . . . . . . . . . . . 21		8.2. Informative References . . . . . . . . . . . . . . . . . 21
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
	skipping to change at page 4, line 36 ¶		skipping to change at page 4, line 36 ¶
	6		6
	( K )		( K )
	/14'		/14'
	/		/
	4' /13' | 4		4' /13' | 4
	/-----------( G )--------+ ( H )		/-----------( G )--------+ ( H )
	/ 16' |________/		/ 16' |________/
	/ | 17'		/ | 17'
	/3' _________|		/3' _________|
	1' 2' / 6' /15' | 18'		5 1' 2' / 6' /15' | 18'
	( A )------------( B )--------------( C ) +--------( D )		( A )------------( B )--------------( C ) +--------( D )
	5 7'\ 5' \11' | 1		\10' 7'\ 5' \11' | 1
	\ \ LAN		\ \ \ LAN
	\ \		\ \ \
	\8' 10' \12'		\ 9' \8' \12'
	( E )--------------( F )		\--------------( E ) ( F )
	3 9' 2		3 2
	Figure 1: Example BIER-TE Topology with BP to BFR on LAN		Figure 1: Example BIER-TE Topology with BP to BFR on LAN
	The BitPositions for the forward connected adjacencies are		The BitPositions for the forward connected adjacencies are
	represented by i', where i is from 1 to 18. In one option, they are		represented by i', where i is from 1 to 18. In one option, they are
	encoded as (n+i), where n is a power of 2 such as 32768. For		encoded as (n+i), where n is a power of 2 such as 32768. For
	simplicity, these BitPositions are represented by (SI:BitString),		simplicity, these BitPositions are represented by (SI:BitString),
	where SI = (6 + (i-1)/8) and BitString is of 8 bits. BitPositions i'		where SI = (6 + (i-1)/8) and BitString is of 8 bits. BitPositions i'
	(i from 1 to 18) are represented by 1'(6:00000001), 2'(6:00000010),		(i from 1 to 18) are represented by 1'(6:00000001), 2'(6:00000010),
	3'(6:00000100), 4'(6:00001000), 5'(6:00010000), 6'(6:00100000),		3'(6:00000100), 4'(6:00001000), 5'(6:00010000), 6'(6:00100000),
	skipping to change at page 5, line 44 ¶		skipping to change at page 5, line 44 ¶
	Every BFR in a BIER-TE domain/topology has a BIER-TE BIFT. This		Every BFR in a BIER-TE domain/topology has a BIER-TE BIFT. This
	section shows the BIER-TE BIFT on every BFR/node of the BIER-TE		section shows the BIER-TE BIFT on every BFR/node of the BIER-TE
	topology with LAN in Figure 1.		topology with LAN in Figure 1.
	For the BIER-TE topology in Figure 1, each of 9 nodes/BFRs A, B, C,		For the BIER-TE topology in Figure 1, each of 9 nodes/BFRs A, B, C,
	D, E, F, G, H and K has its BIER-TE BIFT for the topology. The BIFT		D, E, F, G, H and K has its BIER-TE BIFT for the topology. The BIFT
	on a BFR comprises a forwarding entry for each of the adjacencies of		on a BFR comprises a forwarding entry for each of the adjacencies of
	the BFR.		the BFR.
	The BIER-TE BIFT on BFR A (i.e., node A) is shown in Figure 2. There		The BIER-TE BIFT on BFR A (i.e., node A) is shown in Figure 2. There
	are two adjacencies of A. One is the forward connected adjacency		are three adjacencies of A. The 1st one is the forward connected
	from A to B (represented by BP 2'); the other is the local decap		adjacency from A to B (represented by BP 2'); the 2nd is the forward
	adjacency (represented by BP 5) for BFER (i.e., egress) A. The BIFT		connected adjacency from A to E (represented by BP 9'); the 3rd is
	on A has two forwarding entries.		the local decap adjacency (represented by BP 5) for BFER (i.e.,
			egress) A. The BIFT on A has three forwarding entries.
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| Adjacency BP | Action | BFR-NBR |		| Adjacency BP | Action | BFR-NBR |
	| (SI:BitString) | | (Next Hop) |		| (SI:BitString) | | (Next Hop) |
	+=================+==============+============+		+=================+==============+============+
	| 2'(6:00000010) | fw-connected | B |		| 2'(6:00000010) | fw-connected | B |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
			| 9'(7:00000001) | fw-connected | E |
			+-----------------+--------------+------------+
	| 5 (0:00010000) | local-decap | |		| 5 (0:00010000) | local-decap | |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	Figure 2: BIER-TE BIFT on BFR A		Figure 2: BIER-TE BIFT on BFR A
	The 1st forwarding entry in the BIFT is for BitPosition 2', which is		The 1st forwarding entry in the BIFT is for BitPosition 2', which is
	the forward connected adjacency from A to B. For a multicast packet		the forward connected adjacency from A to B. For a multicast packet
	with BitPosition 2', which indicates that the P2MP path in the packet		with BitPosition 2', which indicates that the P2MP path in the packet
	traverses the adjacency from A to B, the forwarding entry forwards		traverses the adjacency from A to B, the forwarding entry forwards
	the packet to B along the link from A to B.		the packet to B along the link from A to B.
	The 2nd forwarding entry in the BIFT locally decapsulates a multicast		The 2nd forwarding entry in the BIFT is for BitPosition 9', which is
			the forward connected adjacency from A to E. For a multicast packet
			with BitPosition 9', which indicates that the P2MP path in the packet
			traverses the adjacency from A to E, the forwarding entry forwards
			the packet to E along the link from A to E.
			The 3rd forwarding entry in the BIFT locally decapsulates a multicast
	packet with BitPosition 5 and passes a copy of the payload of the		packet with BitPosition 5 and passes a copy of the payload of the
	packet to the packet's NextProto. It is for BitPosition 5, which is		packet to the packet's NextProto. It is for BitPosition 5, which is
	the local decap adjacency for BFER (i.e., egress) A. For a multicast		the local decap adjacency for BFER (i.e., egress) A. For a multicast
	packet with BitPosition 5, which indicates that the P2MP path in the		packet with BitPosition 5, which indicates that the P2MP path in the
	packet has node A as one of its destinations (i.e., egress nodes),		packet has node A as one of its destinations (i.e., egress nodes),
	the forwarding entry decapsulates the packet and passes a copy of the		the forwarding entry decapsulates the packet and passes a copy of the
	payload of the packet to the packet's NextProto within node A.		payload of the packet to the packet's NextProto within node A.
	The BIER-TE BIFT on BFR B (i.e., node B) is shown in Figure 3. There		The BIER-TE BIFT on BFR B (i.e., node B) is shown in Figure 3. There
	are four forward connected adjacencies of B. They are the forward		are four forward connected adjacencies of B. They are the forward
	skipping to change at page 8, line 31 ¶		skipping to change at page 8, line 47 ¶
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 17'(8:00000001) | fw-connected | H |		| 17'(8:00000001) | fw-connected | H |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 1 (0:00000001) | local-decap | |		| 1 (0:00000001) | local-decap | |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	Figure 5: BIER-TE BIFT on BFR D		Figure 5: BIER-TE BIFT on BFR D
	The BIER-TE BIFT on BFR E (i.e., node E) is shown in Figure 6. There		The BIER-TE BIFT on BFR E (i.e., node E) is shown in Figure 6. There
	are three adjacencies of E. Two of them are the forward connected		are three adjacencies of E. Two of them are the forward connected
	adjacencies from E to B (represented by BP 7') and E to F		adjacencies from E to B (represented by BP 7') and E to A
	(represented by BP 10') respectively; the other is the local decap		(represented by BP 10') respectively; the other is the local decap
	adjacency (represented by BP 3) for BFER (i.e., egress) E. The BIFT		adjacency (represented by BP 3) for BFER (i.e., egress) E. The BIFT
	on E has three forwarding entries for these adjacencies.		on E has three forwarding entries for these adjacencies.
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| Adjacency BP | Action | BFR-NBR |		| Adjacency BP | Action | BFR-NBR |
	| (SI:BitString) | | (Next Hop) |		| (SI:BitString) | | (Next Hop) |
	+=================+==============+============+		+=================+==============+============+
	| 7'(6:01000000) | fw-connected | B |		| 7'(6:01000000) | fw-connected | B |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 10'(7:00000010) | fw-connected | F |		| 10'(7:00000010) | fw-connected | A |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 3 (0:00000100) | local-decap | |		| 3 (0:00000100) | local-decap | |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	Figure 6: BIER-TE BIFT on BFR E		Figure 6: BIER-TE BIFT on BFR E
	The BIER-TE BIFT on BFR F (i.e., node F) is shown in Figure 7. There		The BIER-TE BIFT on BFR F (i.e., node F) is shown in Figure 7. There
	are three adjacencies of F. Two of them are the forward connected		are two adjacencies of F. The 1st one is the forward connected
	adjacencies from F to E (represented by BP 9') and F to C		adjacencies from F to C (represented by BP 11'); the 2nd is the local
	(represented by BP 11') respectively; the other is the local decap		decap adjacency (represented by BP 2) for BFER (i.e., egress) F. The
	adjacency (represented by BP 2) for BFER (i.e., egress) F. The BIFT		BIFT on F has two forwarding entries for these adjacencies.
	on F has three forwarding entries for these adjacencies.
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| Adjacency BP | Action | BFR-NBR |		| Adjacency BP | Action | BFR-NBR |
	| (SI:BitString) | | (Next Hop) |		| (SI:BitString) | | (Next Hop) |
	+=================+==============+============+		+=================+==============+============+
	| 9'(7:00000001) | fw-connected | E |
	+-----------------+--------------+------------+
	| 11'(7:00000100) | fw-connected | C |		| 11'(7:00000100) | fw-connected | C |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 2 (0:00000010) | local-decap | |		| 2 (0:00000010) | local-decap | |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	Figure 7: BIER-TE BIFT on BFR F		Figure 7: BIER-TE BIFT on BFR F
	The BIER-TE BIFT on BFR G (i.e., node G) is shown in Figure 8. There		The BIER-TE BIFT on BFR G (i.e., node G) is shown in Figure 8. There
	are four forward connected adjacencies of G. They are the		are four forward connected adjacencies of G. They are the
	adjacencies from G to B (represented by BP 3'), G to C (represented		adjacencies from G to B (represented by BP 3'), G to C (represented
	skipping to change at page 10, line 30 ¶		skipping to change at page 10, line 47 ¶
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 18'(8:00000010) | fw-connected | D |		| 18'(8:00000010) | fw-connected | D |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 4 (0:00001000) | local-decap | |		| 4 (0:00001000) | local-decap | |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	Figure 9: BIER-TE BIFT on BFR H		Figure 9: BIER-TE BIFT on BFR H
	2.3. Example P2MP Path with LAN		2.3. Example P2MP Path with LAN
	This section presents the forwarding behaviors along an explicit P2MP		This section presents the issue about receiving duplicated packets at
	path in Figure 1 going through the LAN in the figure. The path is		BFER H for any explicit P2MP path/tree from BFIR A to BFERs K, H and
	from BFIR A to BFERs K, H and F		F in Figure 1 with minimum height of the tree, which is 3 (hops).
			Any path will go through the LAN in order to reach BFER H.
	The explicit P2MP path traverses the link/adjacency from A to B		There are only following explicit P2MP paths from A to K, H and D.
	(indicated by BP 2'), the link/adjacency from B to G (indicated by BP
	4') and the link/adjacency from B to C (indicated by BP 6'), the		K K
	link/adjacency from G to K (indicated by BP 14'), the link/adjacency		/14' H /14'
	from G to H (indicated by BP 17'), and the link/adjacency from C to F		/ |___/17' / H
	(indicated by BP 12'). This path is represented by {2', 4', 6', 12',		G---------| G |____/17'
	14', 17', 2, 4, 6}. The packet at A has this path.		/4' LAN /4' _|
			2' / 6' 2' / 6' / |
			A--------B----------C A--------B----------C |
			\ \ LAN
			\8' \8'
			F F
			Path 1 from A to K, H and F Path 2 from A to K, H and F
			Figure 10: All explicit paths with height 3 from A to K,H and F
			Path 1 and path 2 are represented by {2', 4', 6', 12', 14', 17', 2,
			4, 6}. Path 1 traverses the link/adjacency from A to B (indicated by
			BP 2'), the link/adjacency from B to G (indicated by BP 4'), the
			link/adjacency from B to C (indicated by BP 6'), the link/adjacency
			from G to K (indicated by BP 14'), the link/adjacency from G to H
			(indicated by BP 17') [the link/adjacency from C to H (also indicated
			by BP 17') for Path 2], and the link/adjacency from C to F (indicated
			by BP 12'). Path 1 is represented by {2', 4', 6', 12', 14', 17', 2,
			4, 6}. Path 2 has the same representation. The packet at A has this
			representation.
	For the packet with the P2MP path, A forwards the packet to B		For the packet with the P2MP path, A forwards the packet to B
	according to the forwarding entry for BP 2' in its BIFT.		according to the forwarding entry for BP 2' in its BIFT.
	After receiving the packet from A, B forwards the packet to G and C		After receiving the packet from A, B forwards the packet to G and C
	according to the forwarding entries for BPs 4' and 6' in B's BIFT		according to the forwarding entries for BPs 4' and 6' in B's BIFT
	respectively. The packet received by G has path {12', 14', 17', 2,		respectively. The packet received by G has path {12', 14', 17', 2,
	4, 6}. The packet received by C has path {12', 14', 17', 2, 4, 6}.		4, 6}. The packet received by C has path {12', 14', 17', 2, 4, 6}.
	After receiving the packet from B, G sends a copy of the packet to K		After receiving the packet from B, G sends a copy of the packet to K
	skipping to change at page 11, line 44 ¶		skipping to change at page 12, line 32 ¶
	attached to a LAN, two BPs are assigned to it. One is for the		attached to a LAN, two BPs are assigned to it. One is for the
	adjacency from the BFR to the pseudo node, the other is for the		adjacency from the BFR to the pseudo node, the other is for the
	adjacency from the pseudo node to the BFR.		adjacency from the pseudo node to the BFR.
	The adjacency from a BFR to the pseudo node is called a LAN		The adjacency from a BFR to the pseudo node is called a LAN
	adjacency. The adjacency from the pseudo node to a BFR is a forward		adjacency. The adjacency from the pseudo node to a BFR is a forward
	connected adjacency.		connected adjacency.
	For example, suppose that the pseudo node for the LAN in Figure 1 is		For example, suppose that the pseudo node for the LAN in Figure 1 is
	Px. The BP assignments for the LAN (i.e., connections between Px and		Px. The BP assignments for the LAN (i.e., connections between Px and
	BFRs C, G, H and D) are illustrated in Figure 10.		BFRs C, G, H and D) are illustrated in Figure 11.
	6		6
	( K )		( K )
	/14'		/14'
	/		/
	4' /13' | 4		4' /13' | 4
	/-----------( G )---------+ ( H )		/-----------( G )---------+ ( H )
	/ 17' | ________/		/ 17' | ________/
	/ 18'| /20' 19'		/ 18'| /20' 19'
	/3' _________ Px		/3' _________ Px
	1' 2' / 6' /15' 16' |22' 21'		5 1' 2' / 6' /15' 16' |22' 21'
	( A )------------( B )--------------( C ) +---------( D )		( A )------------( B )--------------( C ) +---------( D )
	5 7'\ 5' \11' 1		\10' 7'\ 5' \11' 1
	\ \		\ \ \
	\ \		\ \ \
	\8' 10' \12'		\ 9' \8' \12'
	( E )--------------( F )		\--------------( E ) ( F )
	3 9' 2		3 2
	Figure 10: Example BIER-TE Topology with BPs for LAN		Figure 11: Example BIER-TE Topology with BPs for LAN
	The connection/adjacency from Px to C is assigned BP 15', and the		The connection/adjacency from Px to C is assigned BP 15', and the
	connection/adjacency from C to Px is assigned BP 16'.		connection/adjacency from C to Px is assigned BP 16'.
	The connection/adjacency from Px to G is assigned BP 17', and the		The connection/adjacency from Px to G is assigned BP 17', and the
	connection/adjacency from G to Px is assigned BP 18'.		connection/adjacency from G to Px is assigned BP 18'.
	The connection/adjacency from Px to H is assigned BP 19', and the		The connection/adjacency from Px to H is assigned BP 19', and the
	connection/adjacency from H to Px is assigned BP 20'.		connection/adjacency from H to Px is assigned BP 20'.
	skipping to change at page 13, line 14 ¶		skipping to change at page 13, line 45 ¶
	3.2. Improved BIER-TE BIFT on BFR		3.2. Improved BIER-TE BIFT on BFR
	Each BFR in a BIER-TE domain has a BIER-TE BIFT. For a BFR not		Each BFR in a BIER-TE domain has a BIER-TE BIFT. For a BFR not
	attached to any LAN, the BIER-TE BIFT on the BFR is the same as		attached to any LAN, the BIER-TE BIFT on the BFR is the same as
	before. For a BFR attached to a LAN, its BIER-TE BIFT is changed for		before. For a BFR attached to a LAN, its BIER-TE BIFT is changed for
	considering the LAN.		considering the LAN.
	For example, BFRs C, G, H and D are attached to a LAN in Figure 1.		For example, BFRs C, G, H and D are attached to a LAN in Figure 1.
	The BIER-TE BIFT on each of these four BFRs is changed for the new BP		The BIER-TE BIFT on each of these four BFRs is changed for the new BP
	assignments for the LAN in Figure 10.		assignments for the LAN in Figure 11.
	For a BFR attached to a LAN, suppose that the pseudo node for the LAN		For a BFR attached to a LAN, suppose that the pseudo node for the LAN
	is Px. The improved BIER-TE BIFT on the BFR comprises a forwarding		is Px. The improved BIER-TE BIFT on the BFR comprises a forwarding
	entry for the LAN adjacency from the BFR to Px and a secondary BIFT		entry for the LAN adjacency from the BFR to Px and a secondary BIFT
	for Px. The secondary BIFT for Px on the BFR contains a forwarding		for Px. The secondary BIFT for Px on the BFR contains a forwarding
	entry for each of the forward connected adjacencies from Px to the		entry for each of the forward connected adjacencies from Px to the
	BFRs attached to the LAN except for the adjacency from Px to the BFR.		BFRs attached to the LAN except for the adjacency from Px to the BFR.
	For example, the improved BIER-TE BIFT on BFR C is illustrated in		For example, the improved BIER-TE BIFT on BFR C is illustrated in
	Figure 11. It comprises the forwarding entry for the LAN adjacency		Figure 12. It comprises the forwarding entry for the LAN adjacency
	from C to Px (indicated by BP 16') and the secondary BIFT for Px on		from C to Px (indicated by BP 16') and the secondary BIFT for Px on
	BFR C. The secondary BIFT contains three forwarding entries for		BFR C. The secondary BIFT contains three forwarding entries for
	three forward connected adjacencies from Px to G (indicated by 17'),		three forward connected adjacencies from Px to G (indicated by 17'),
	Px to H (indicated by 19') and Px to D (indicated by 21')		Px to H (indicated by 19') and Px to D (indicated by 21')
	respectively.		respectively.
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| Adjacency BP | Action | BFR-NBR |		| Adjacency BP | Action | BFR-NBR |
	| (SI:BitString) | | (Next Hop) |		| (SI:BitString) | | (Next Hop) |
	+=================+==============+============+		+=================+==============+============+
	skipping to change at page 14, line 28 ¶		skipping to change at page 14, line 36 ¶
	| Adjacency BP | Action | BFR-NBR |		| Adjacency BP | Action | BFR-NBR |
	| (SI:BitString) | | (Next Hop) |		| (SI:BitString) | | (Next Hop) |
	+=================+==============+============+		+=================+==============+============+
	| 5'(6:00010000) | fw-connected | B |		| 5'(6:00010000) | fw-connected | B |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 12'(7:00001000) | fw-connected | F |		| 12'(7:00001000) | fw-connected | F |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 16'(7:10000000) |lan-connected | Px |		| 16'(7:10000000) |lan-connected | Px |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	Figure 11: Improved BIER-TE BIFT on BFR C		Figure 12: Improved BIER-TE BIFT on BFR C
	The improved BIER-TE BIFT on BFR G is illustrated in Figure 12. It		The improved BIER-TE BIFT on BFR G is illustrated in Figure 13. It
	comprises the forwarding entry for the LAN adjacency from G to Px		comprises the forwarding entry for the LAN adjacency from G to Px
	(indicated by BP 18') and the secondary BIFT for Px on BFR G. The		(indicated by BP 18') and the secondary BIFT for Px on BFR G. The
	secondary BIFT contains three forwarding entries for three forward		secondary BIFT contains three forwarding entries for three forward
	connected adjacencies from Px to C (indicated by 15'), Px to H		connected adjacencies from Px to C (indicated by 15'), Px to H
	(indicated by 19') and Px to D (indicated by 21') respectively.		(indicated by 19') and Px to D (indicated by 21') respectively.
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| Adjacency BP | Action | BFR-NBR |		| Adjacency BP | Action | BFR-NBR |
	| (SI:BitString) | | (Next Hop) |		| (SI:BitString) | | (Next Hop) |
	+=================+==============+============+		+=================+==============+============+
	skipping to change at page 15, line 28 ¶		skipping to change at page 15, line 28 ¶
	| Adjacency BP | Action | BFR-NBR |		| Adjacency BP | Action | BFR-NBR |
	| (SI:BitString) | | (Next Hop) |		| (SI:BitString) | | (Next Hop) |
	+=================+==============+============+		+=================+==============+============+
	| 3'(6:00000100) | fw-connected | B |		| 3'(6:00000100) | fw-connected | B |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 14'(7:00100000) | fw-connected | K |		| 14'(7:00100000) | fw-connected | K |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 18'(8:00000010) |lan-connected | Px |		| 18'(8:00000010) |lan-connected | Px |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	Figure 12: Improved BIER-TE BIFT on BFR G		Figure 13: Improved BIER-TE BIFT on BFR G
	The improved BIER-TE BIFT on BFR H is illustrated in Figure 13. It		The improved BIER-TE BIFT on BFR H is illustrated in Figure 14. It
	comprises the forwarding entry for the LAN adjacency from H to Px		comprises the forwarding entry for the LAN adjacency from H to Px
	(indicated by BP 20') and the secondary BIFT for Px on BFR H. The		(indicated by BP 20') and the secondary BIFT for Px on BFR H. The
	secondary BIFT contains three forwarding entries for three forward		secondary BIFT contains three forwarding entries for three forward
	connected adjacencies from Px to C (indicated by 15'), Px to G		connected adjacencies from Px to C (indicated by 15'), Px to G
	(indicated by 17') and Px to D (indicated by 21') respectively.		(indicated by 17') and Px to D (indicated by 21') respectively.
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| Adjacency BP | Action | BFR-NBR |		| Adjacency BP | Action | BFR-NBR |
	| (SI:BitString) | | (Next Hop) |		| (SI:BitString) | | (Next Hop) |
	+=================+==============+============+		+=================+==============+============+
	skipping to change at page 16, line 26 ¶		skipping to change at page 16, line 26 ¶
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| Adjacency BP | Action | BFR-NBR |		| Adjacency BP | Action | BFR-NBR |
	| (SI:BitString) | | (Next Hop) |		| (SI:BitString) | | (Next Hop) |
	+=================+==============+============+		+=================+==============+============+
	| 4 (0:00001000) | local-decap | |		| 4 (0:00001000) | local-decap | |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 20'(8:00001000) |lan-connected | Px |		| 20'(8:00001000) |lan-connected | Px |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	Figure 13: Improved BIER-TE BIFT on BFR H		Figure 14: Improved BIER-TE BIFT on BFR H
	The improved BIER-TE BIFT on BFR D is illustrated in Figure 14. It		The improved BIER-TE BIFT on BFR D is illustrated in Figure 15. It
	comprises the forwarding entry for the LAN adjacency from D to Px		comprises the forwarding entry for the LAN adjacency from D to Px
	(indicated by BP 22') and the secondary BIFT for Px on BFR D. The		(indicated by BP 22') and the secondary BIFT for Px on BFR D. The
	secondary BIFT contains three forwarding entries for three forward		secondary BIFT contains three forwarding entries for three forward
	connected adjacencies from Px to C (indicated by 15'), Px to G		connected adjacencies from Px to C (indicated by 15'), Px to G
	(indicated by 17') and Px to H (indicated by 19') respectively.		(indicated by 17') and Px to H (indicated by 19') respectively.
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| Adjacency BP | Action | BFR-NBR |		| Adjacency BP | Action | BFR-NBR |
	| (SI:BitString) | | (Next Hop) |		| (SI:BitString) | | (Next Hop) |
	+=================+==============+============+		+=================+==============+============+
	skipping to change at page 17, line 26 ¶		skipping to change at page 17, line 26 ¶
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| Adjacency BP | Action | BFR-NBR |		| Adjacency BP | Action | BFR-NBR |
	| (SI:BitString) | | (Next Hop) |		| (SI:BitString) | | (Next Hop) |
	+=================+==============+============+		+=================+==============+============+
	| 1 (0:00000001) | local-decap | |		| 1 (0:00000001) | local-decap | |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	| 22'(8:00000100) |lan-connected | Px |		| 22'(8:00000100) |lan-connected | Px |
	+-----------------+--------------+------------+		+-----------------+--------------+------------+
	Figure 14: Improved BIER-TE BIFT on BFR D		Figure 15: Improved BIER-TE BIFT on BFR D
	3.3. Updated Forwarding Procedure		3.3. Updated Forwarding Procedure
	The forwarding procedure defined in [I-D.ietf-bier-te-arch] is		The forwarding procedure defined in [I-D.ietf-bier-te-arch] is
	updated/enhanced for using an improved BIER-TE BIFT to support BIER-		updated/enhanced for using an improved BIER-TE BIFT to support BIER-
	TE with LAN.		TE with LAN.
	The updated procedure is described in Figure 15. For a multicast		The updated procedure is described in Figure 16. For a multicast
	packet containing the BitString encoding an explicit P2MP path, if		packet containing the BitString encoding an explicit P2MP path, if
	the BP in the BitString is for a LAN adjacency to pseudo node Px for		the BP in the BitString is for a LAN adjacency to pseudo node Px for
	the LAN, the updated forwarding procedure on a BFR sends the packet		the LAN, the updated forwarding procedure on a BFR sends the packet
	towards Px's next hop nodes on the P2MP path encoded in the packet.		towards Px's next hop nodes on the P2MP path encoded in the packet.
	The procedure on a BFR "sends" (i.e., works as sending) the packet		The procedure on a BFR "sends" (i.e., works as sending) the packet
	with the BP for the LAN adjacency to Px according to the forwarding		with the BP for the LAN adjacency to Px according to the forwarding
	entry for the BP in the improved BIER-TE BIFT on the BFR. And then		entry for the BP in the improved BIER-TE BIFT on the BFR. And then
	it acts on Px to "send" (i.e., works as sending) the packet to each		it acts on Px to "send" (i.e., works as sending) the packet to each
	of the Px's next hop nodes that are on the P2MP path using the		of the Px's next hop nodes that are on the P2MP path using the
	skipping to change at page 18, line 36 ¶		skipping to change at page 18, line 36 ¶
	Gets the forwarding entry for BP j in the		Gets the forwarding entry for BP j in the
	secondary BIFT for Px,		secondary BIFT for Px,
	Copies Packet, updates the copy's BitString by		Copies Packet, updates the copy's BitString by
	clearing all the BPs for Px's adjacencies,		clearing all the BPs for Px's adjacencies,
	and sends the updated copy to BFR-NBR		and sends the updated copy to BFR-NBR
	}		}
	}		}
	}		}
	}		}
	Figure 15: Updated Forwarding Procedure		Figure 16: Updated Forwarding Procedure
	4. Example Application of Improved BIER-TE		4. Example Application of Improved BIER-TE
	This section illustrates an example application of improved BIER-TE		This section illustrates an example application of improved BIER-TE
	to Figure 1. It shows the forwarding behaviors along an explicit		to Figure 1. It shows the forwarding behaviors along an explicit
	P2MP path in Figure 10 going through the LAN in the figure.		P2MP path in Figure 11 going through the LAN in the figure.
	The new BP assignments for the LAN in Figure 1 is shown in Figure 10.		The new BP assignments for the LAN in Figure 1 is shown in Figure 11.
	The improved BIER-TE BIFT on each of the BFRs attached to the LAN is		The improved BIER-TE BIFT on each of the BFRs attached to the LAN is
	given in Section 3.2.		given in Section 3.2.
	The explicit P2MP path traverses the link/adjacency from A to B		The explicit P2MP path traverses the link/adjacency from A to B
	(indicated by BP 2'), the link/adjacency from B to G (indicated by BP		(indicated by BP 2'), the link/adjacency from B to G (indicated by BP
	4') and the link/adjacency from B to C (indicated by BP 6'), the		4') and the link/adjacency from B to C (indicated by BP 6'), the
	link/adjacency from G to K (indicated by BP 14'), the link/adjacency		link/adjacency from G to K (indicated by BP 14'), the link/adjacency
	from G to Px (indicated by BP 18'), the link/adjacency from C to F		from G to Px (indicated by BP 18'), the link/adjacency from C to F
	(indicated by BP 12'), and the link/adjacency from Px to H (indicated		(indicated by BP 12'), and the link/adjacency from Px to H (indicated
	by BP 19'). This path is represented by {2', 4', 6', 12', 14', 18',		by BP 19'). This path is represented by {2', 4', 6', 12', 14', 18',
	skipping to change at page 20, line 19 ¶		skipping to change at page 20, line 19 ¶
	7. Acknowledgements		7. Acknowledgements
	The authors would like to thank people for their comments to this		The authors would like to thank people for their comments to this
	work.		work.
	8. References		8. References
	8.1. Normative References		8.1. Normative References
	[I-D.ietf-bier-te-arch]		[I-D.ietf-bier-te-arch]
	Eckert, T., Cauchie, G., and M. Menth, "Tree Engineering		Eckert, T., Menth, M., and G. Cauchie, "Tree Engineering
	for Bit Index Explicit Replication (BIER-TE)", Work in		for Bit Index Explicit Replication (BIER-TE)", Work in
	Progress, Internet-Draft, draft-ietf-bier-te-arch-10, 9		Progress, Internet-Draft, draft-ietf-bier-te-arch-12, 28
	July 2021, <https://www.ietf.org/archive/id/draft-ietf-		January 2022, <https://www.ietf.org/archive/id/draft-ietf-
	bier-te-arch-10.txt>.		bier-te-arch-12.txt>.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an		[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
	IANA Considerations Section in RFCs", RFC 5226,		IANA Considerations Section in RFCs", RFC 5226,
	DOI 10.17487/RFC5226, May 2008,		DOI 10.17487/RFC5226, May 2008,
	<https://www.rfc-editor.org/info/rfc5226>.		<https://www.rfc-editor.org/info/rfc5226>.
	skipping to change at page 22, line 5 ¶		skipping to change at page 22, line 5 ¶
	"Protection Methods for BIER-TE", Work in Progress,		"Protection Methods for BIER-TE", Work in Progress,
	Internet-Draft, draft-eckert-bier-te-frr-03, 5 March 2018,		Internet-Draft, draft-eckert-bier-te-frr-03, 5 March 2018,
	<https://www.ietf.org/archive/id/draft-eckert-bier-te-frr-		<https://www.ietf.org/archive/id/draft-eckert-bier-te-frr-
	03.txt>.		03.txt>.
	[I-D.ietf-rtgwg-segment-routing-ti-lfa]		[I-D.ietf-rtgwg-segment-routing-ti-lfa]
	Litkowski, S., Bashandy, A., Filsfils, C., Francois, P.,		Litkowski, S., Bashandy, A., Filsfils, C., Francois, P.,
	Decraene, B., and D. Voyer, "Topology Independent Fast		Decraene, B., and D. Voyer, "Topology Independent Fast
	Reroute using Segment Routing", Work in Progress,		Reroute using Segment Routing", Work in Progress,
	Internet-Draft, draft-ietf-rtgwg-segment-routing-ti-lfa-		Internet-Draft, draft-ietf-rtgwg-segment-routing-ti-lfa-
	07, 29 June 2021, <https://www.ietf.org/archive/id/draft-		08, 21 January 2022, <https://www.ietf.org/archive/id/
	ietf-rtgwg-segment-routing-ti-lfa-07.txt>.		draft-ietf-rtgwg-segment-routing-ti-lfa-08.txt>.
	[I-D.ietf-spring-segment-protection-sr-te-paths]		[I-D.ietf-spring-segment-protection-sr-te-paths]
	Hegde, S., Bowers, C., Litkowski, S., Xu, X., and F. Xu,		Hegde, S., Bowers, C., Litkowski, S., Xu, X., and F. Xu,
	"Segment Protection for SR-TE Paths", Work in Progress,		"Segment Protection for SR-TE Paths", Work in Progress,
	Internet-Draft, draft-ietf-spring-segment-protection-sr-		Internet-Draft, draft-ietf-spring-segment-protection-sr-
	te-paths-01, 11 July 2021,		te-paths-02, 21 January 2022,
	<https://www.ietf.org/archive/id/draft-ietf-spring-		<https://www.ietf.org/archive/id/draft-ietf-spring-
	segment-protection-sr-te-paths-01.txt>.		segment-protection-sr-te-paths-02.txt>.
	[RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,		[RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
	Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation		Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation
	for Bit Index Explicit Replication (BIER) in MPLS and Non-		for Bit Index Explicit Replication (BIER) in MPLS and Non-
	MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January		MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January
	2018, <https://www.rfc-editor.org/info/rfc8296>.		2018, <https://www.rfc-editor.org/info/rfc8296>.
	[RFC8401] Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z.		[RFC8401] Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z.
	Zhang, "Bit Index Explicit Replication (BIER) Support via		Zhang, "Bit Index Explicit Replication (BIER) Support via
	IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018,		IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018,
End of changes. 40 change blocks.
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