< draft-ietf-bier-php-00.txt		draft-ietf-bier-php-01.txt >
	BIER Z. Zhang		BIER Z. Zhang
	Internet-Draft Juniper Networks		Internet-Draft Juniper Networks
	Intended status: Standards Track November 16, 2018		Intended status: Standards Track November 28, 2018
	Expires: May 20, 2019		Expires: June 1, 2019
	BIER Penultimate Hop Popping		BIER Penultimate Hop Popping
	draft-ietf-bier-php-00		draft-ietf-bier-php-01
	Abstract		Abstract
	Bit Index Explicit Replication (BIER) can be used as provider tunnel		Bit Index Explicit Replication (BIER) can be used as provider tunnel
	for MVPN/GTM [RFC6514] [RFC7716] or EVPN BUM [RFC7432]. It is		for MVPN/GTM [RFC6514] [RFC7716] or EVPN BUM [RFC7432]. It is
	possible that not all routers in the provider network support BIER		possible that not all routers in the provider network support BIER
	and there are various methods to handle BIER incapable transit		and there are various methods to handle BIER incapable transit
	routers. However the MVPN/EVPN PEs are assumed to be BIER capable -		routers. However the MVPN/EVPN PEs are assumed to be BIER capable -
	they are BFIRs/BFERs. This document specifies a method to allow BIER		they are BFIRs/BFERs. This document specifies a method to allow BIER
	incapable routers to act as MVPN/EVPN PEs with BIER as the transport,		incapable routers to act as MVPN/EVPN PEs with BIER as the transport,
	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 May 20, 2019.		This Internet-Draft will expire on June 1, 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 26 ¶		skipping to change at page 2, line 26 ¶
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Terminologies . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Terminologies . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	3. Specifications . . . . . . . . . . . . . . . . . . . . . . . 3		3. Specifications . . . . . . . . . . . . . . . . . . . . . . . 3
	4. Security Considerations . . . . . . . . . . . . . . . . . . . 4		4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
	6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5		6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
	7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5		7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
	7.1. Normative References . . . . . . . . . . . . . . . . . . 5		7.1. Normative References . . . . . . . . . . . . . . . . . . 5
	7.2. Informative References . . . . . . . . . . . . . . . . . 6		7.2. Informative References . . . . . . . . . . . . . . . . . 6
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7		Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
	1. Terminologies		1. Terminologies
	Familiarity with BIER/MVPN/EVPN protocols and procedures is assumed.		Familiarity with BIER/MVPN/EVPN protocols and procedures is assumed.
	Some terminologies are listed below for convenience.		Some terminologies are listed below for convenience.
	skipping to change at page 3, line 27 ¶		skipping to change at page 3, line 27 ¶
	so that the upstream BFR can pop the BIER header and send the payload		so that the upstream BFR can pop the BIER header and send the payload
	"natively" (note that the upstream BFR can be connected directly or		"natively" (note that the upstream BFR can be connected directly or
	indiretly via a tunnel to the PE). This is similar to MPLS PHP		indiretly via a tunnel to the PE). This is similar to MPLS PHP
	though it is the BIER header that is popped. In case of MPLS		though it is the BIER header that is popped. In case of MPLS
	encapsulation, even the signaling is similar - a BIER incapable		encapsulation, even the signaling is similar - a BIER incapable
	router signals as if it supported BIER, but to request PHP at the		router signals as if it supported BIER, but to request PHP at the
	penultimate hop, it signals an Implicit Null label instead of a		penultimate hop, it signals an Implicit Null label instead of a
	regular BIER label as the Label Range Base in its BIER MPLS		regular BIER label as the Label Range Base in its BIER MPLS
	Encapsulation sub-TLV.		Encapsulation sub-TLV.
	In order for the PE to be able to correctly forward the packets		The transition of an existing MVPN/EVPN deployment with traditional
	resulting from the PHP, certain conditions must be met, as specified		provider tunnels to using BIER with some PEs not capable of receiving
	in Section 3.		BIER packets can be incremental. All PEs are first upgraded to
			support BIER at least in the control plane, with those not capable of
			BIER forwarding requesting PHP. Then BIER capable ingress PEs
			independently and incrementally switch to BIER transport.
	While the above text uses MVPN/EVPN as example, BIER PHP is		While the above text uses MVPN/EVPN as example, BIER PHP is
	applicable to any scenario where the multicast flow overlay edge		applicable to any scenario where the multicast flow overlay edge
	router does not support BIER.		router does not support BIER.
	This works well if a BIER incapable PE only needs to receive		This works well if a BIER incapable PE only needs to receive
	multicast traffic. If it needs to send multicast traffic as well,		multicast traffic. If it needs to send multicast traffic as well,
	then it must Ingress Replicate to a BIER capable helper PE, who will		then it must Ingress Replicate to a BIER capable helper PE, who will
	in turn relay the packet to other PEs. The helper PE is either a		in turn relay the packet to other PEs. The helper PE is either a
	Virtual Hub as specified in [RFC7024] for MVPN and [I-D.keyupate-		Virtual Hub as specified in [RFC7024] for MVPN and [I-D.keyupate-
	bess-evpn-virtual-hub] for EVPN, or an AR-Replicator as specified in		bess-evpn-virtual-hub] for EVPN, or an AR-Replicator as specified in
	[I-D.ietf-bess-evpn-optimized-ir] for EVPN.		[I-D.ietf-bess-evpn-optimized-ir] for EVPN.
	3. Specifications		3. Specifications
	The procedures in this section can be applied only if, by means		The procedures in this section apply only if, by means outside the
	outside the scope of this document, it is known that one of the		scope of this document, it is known that the payload after BIER
	following conditions is met.		header is MPLS packet with downstream-assigned label at top of stack
			(i.e., the Proto field in the BIER header is 1). For example, a
	o The payload after BIER header is IPv4 or IPv6 (i.e., the Proto		label from a Domain-wide Common Block (DCB) is used as specified in
	field in the BIER header is 4 or 6).		[I-D.ietf-bess-mvpn-evpn-aggregation-label].
	Notice that in this case the Destination Address in the IPv4/IPv6
	header must be in the address space for the BIER layer.
	o The payload after BIER header is MPLS packet with downstream-
	assigned label at top of stack (i.e., the Proto field in the BIER
	header is 1). For example, a label from a Domain-wide Common
	Block (DCB) is used as specified in [I-D.zzhang-bess-mvpn-evpn-
	aggregation-label].
	A BIER incapable router, if acting as a multicast flow overlay		A BIER incapable router, if acting as a multicast flow overlay
	router, MUST signal its BIER information as specified in [RFC8401] or		router, MUST signal its BIER information as specified in [RFC8401] or
	[I-D.ietf-bier-ospf-bier-extensions] or [I-D.ietf-bier-idr-		[I-D.ietf-bier-ospf-bier-extensions] or [I-D.ietf-bier-idr-
	extensions], with a PHP sub-sub-TLV included in the BIER sub-TLV		extensions], with a PHP sub-sub-TLV included in the BIER sub-TLV
	attached to the BIER incapable router's BIER prefix to request BIER		attached to the BIER incapable router's BIER prefix to request BIER
	PHP from other BFRs. The sub-sub-TLV's type is TBD, and the length		PHP from other BFRs. The sub-sub-TLV's type is TBD, and the length
	is 0.		is 0.
	With MPLS encapsulation, the BIER incapable multicast flow overlay		With MPLS encapsulation, the BIER incapable multicast flow overlay
	skipping to change at page 5, line 33 ¶		skipping to change at page 5, line 27 ¶
	The author wants to thank Eric Rosen and Antonie Przygienda for their		The author wants to thank Eric Rosen and Antonie Przygienda for their
	review, comments and suggestions. The author also wants to thank		review, comments and suggestions. The author also wants to thank
	Senthil Dhanaraj for his suggestion of requesting PHP if a BFER does		Senthil Dhanaraj for his suggestion of requesting PHP if a BFER does
	not support certain BSL.		not support certain BSL.
	7. References		7. References
	7.1. Normative References		7.1. Normative References
	[I-D.ietf-bess-evpn-optimized-ir]
	Rabadan, J., Sathappan, S., Lin, W., Katiyar, M., and A.
	Sajassi, "Optimized Ingress Replication solution for
	EVPN", draft-ietf-bess-evpn-optimized-ir-06 (work in
	progress), October 2018.
	[I-D.ietf-bier-idr-extensions]		[I-D.ietf-bier-idr-extensions]
	Xu, X., Chen, M., Patel, K., Wijnands, I., and T.		Xu, X., Chen, M., Patel, K., Wijnands, I., and T.
	Przygienda, "BGP Extensions for BIER", draft-ietf-bier-		Przygienda, "BGP Extensions for BIER", draft-ietf-bier-
	idr-extensions-05 (work in progress), March 2018.		idr-extensions-05 (work in progress), March 2018.
	[I-D.ietf-bier-ospf-bier-extensions]
	Psenak, P., Kumar, N., Wijnands, I., Dolganow, A.,
	Przygienda, T., Zhang, Z., and S. Aldrin, "OSPFv2
	Extensions for BIER", draft-ietf-bier-ospf-bier-
	extensions-18 (work in progress), June 2018.
	[I-D.keyupate-bess-evpn-virtual-hub]
	Patel, K., Sajassi, A., Drake, J., Zhang, Z., and W.
	Henderickx, "Virtual Hub-and-Spoke in BGP EVPNs", draft-
	keyupate-bess-evpn-virtual-hub-01 (work in progress),
	October 2018.
	[I-D.zzhang-bess-mvpn-evpn-aggregation-label]		[I-D.zzhang-bess-mvpn-evpn-aggregation-label]
	Zhang, Z., Rosen, E., Lin, W., Li, Z., and I. Wijnands,		Zhang, Z., Rosen, E., Lin, W., Li, Z., and I. Wijnands,
	"MVPN/EVPN Tunnel Aggregation with Common Labels", draft-		"MVPN/EVPN Tunnel Aggregation with Common Labels", draft-
	zzhang-bess-mvpn-evpn-aggregation-label-01 (work in		zzhang-bess-mvpn-evpn-aggregation-label-01 (work in
	progress), April 2018.		progress), April 2018.
	[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>.
	skipping to change at page 6, line 39 ¶		skipping to change at page 6, line 16 ¶
	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,
	<https://www.rfc-editor.org/info/rfc8401>.		<https://www.rfc-editor.org/info/rfc8401>.
			[RFC8444] Psenak, P., Ed., Kumar, N., Wijnands, IJ., Dolganow, A.,
			Przygienda, T., Zhang, J., and S. Aldrin, "OSPFv2
			Extensions for Bit Index Explicit Replication (BIER)",
			RFC 8444, DOI 10.17487/RFC8444, November 2018,
			<https://www.rfc-editor.org/info/rfc8444>.
	7.2. Informative References		7.2. Informative References
			[I-D.ietf-bess-evpn-optimized-ir]
			Rabadan, J., Sathappan, S., Lin, W., Katiyar, M., and A.
			Sajassi, "Optimized Ingress Replication solution for
			EVPN", draft-ietf-bess-evpn-optimized-ir-06 (work in
			progress), October 2018.
			[I-D.keyupate-bess-evpn-virtual-hub]
			Patel, K., Sajassi, A., Drake, J., Zhang, Z., and W.
			Henderickx, "Virtual Hub-and-Spoke in BGP EVPNs", draft-
			keyupate-bess-evpn-virtual-hub-01 (work in progress),
			October 2018.
	[RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/		[RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/
	BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February		BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February
	2012, <https://www.rfc-editor.org/info/rfc6513>.		2012, <https://www.rfc-editor.org/info/rfc6513>.
	[RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP		[RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP
	Encodings and Procedures for Multicast in MPLS/BGP IP		Encodings and Procedures for Multicast in MPLS/BGP IP
	VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012,		VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012,
	<https://www.rfc-editor.org/info/rfc6514>.		<https://www.rfc-editor.org/info/rfc6514>.
	[RFC7024] Jeng, H., Uttaro, J., Jalil, L., Decraene, B., Rekhter,		[RFC7024] Jeng, H., Uttaro, J., Jalil, L., Decraene, B., Rekhter,
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