< draft-chunduri-lsr-isis-mt-deployment-cons-02.txt		draft-chunduri-lsr-isis-mt-deployment-cons-03.txt >
	LSR Working Group U. Chunduri		LSR Working Group U. Chunduri
	Internet-Draft Huawei USA		Internet-Draft Futurewei USA
	Intended status: Informational J. Tantsura		Intended status: Informational J. Tantsura
	Expires: November 20, 2019 Apstra, Inc.		Expires: November 18, 2020 Apstra, Inc.
	S. Hegde		S. Hegde
	Juniper Networks		Juniper Networks
	May 19, 2019		May 17, 2020
	IS-IS Multi Topology Deployment Considerations		IS-IS Multi Topology Deployment Considerations
	draft-chunduri-lsr-isis-mt-deployment-cons-02		draft-chunduri-lsr-isis-mt-deployment-cons-03
	Abstract		Abstract
	This document analyzes IS-IS Multi Topology (MT) applicability in		This document analyzes IS-IS Multi Topology (MT) applicability in
	various deployments (Core/Mobile Backhaul/Data Center underlays).		various IS-IS deployments. This document explores the nuances around
	This document explores the nuances around the terminology and usage		the terminology and usage of various IS-IS address families,
	of various IS-IS address families, topologies with different		topologies with different considerations, for choosing the right
	considerations, for choosing the right combination for a specific		combination for a specific deployment scenario.
	deployment scenario.
	This document also discusses various ways one can deploy IPv6 only		This document also discusses various ways one can deploy IPv6 only
	IS-IS topology.		IS-IS topology.
	Requirements Language		Requirements Language
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in RFC2119 [RFC2119],		document are to be interpreted as described in RFC2119 [RFC2119],
	RFC8174 [RFC8174] when, and only when they appear in all capitals, as		RFC8174 [RFC8174] when, and only when they appear in all capitals, as
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	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 November 20, 2019.		This Internet-Draft will expire on November 18, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2020 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
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	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
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	4.2. Multiple Topology Mode and Multiple Address Families . . 5		4.2. Multiple Topology Mode and Multiple Address Families . . 5
	4.2.1. Transition Mode . . . . . . . . . . . . . . . . . . . 6		4.2.1. Transition Mode . . . . . . . . . . . . . . . . . . . 6
	4.3. IPv6 Only Topology . . . . . . . . . . . . . . . . . . . 6		4.3. IPv6 Only Topology . . . . . . . . . . . . . . . . . . . 6
	5. IS-IS MT and LFA . . . . . . . . . . . . . . . . . . . . . . 7		5. IS-IS MT and LFA . . . . . . . . . . . . . . . . . . . . . . 7
	6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7		6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
	7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7		7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
	8. Security Considerations . . . . . . . . . . . . . . . . . . . 7		8. Security Considerations . . . . . . . . . . . . . . . . . . . 7
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . 7		9. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
	9.1. Normative References . . . . . . . . . . . . . . . . . . 7		9.1. Normative References . . . . . . . . . . . . . . . . . . 7
	9.2. Informative References . . . . . . . . . . . . . . . . . 8		9.2. Informative References . . . . . . . . . . . . . . . . . 8
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
	1. Introduction		1. Introduction
	ISIS originally developed for OSI [ISO.10589.1992] and extensions		IS-IS originally developed for OSI [ISO.10589.1992] and extensions
	have been made available to support IPv4 [RFC1195]. A method for		have been made available to support IPv4 [RFC1195]. A method for
	exchanging IPv6 routing information using the IS-IS routing protocol		exchanging IPv6 routing information using the IS-IS routing protocol
	is specified in [RFC5308]. How to run a set of independent IP		is specified in [RFC5308]. How to run a set of independent IP
	topologies with topology specific adjacencies, within a single IS-IS		topologies with topology specific adjacencies, within a single IS-IS
	domain has been defined in IS-IS MT [RFC5120].		domain has been defined in IS-IS MT [RFC5120].
	Multiple mobile backhaul network user plane proposals like		There are number of networks, including mobile backhaul networks
	[I-D.ietf-dmm-srv6-mobile-uplane] and [I-D.herbert-ila-mobile] use		seeking to use IPv6 only solutions. It is possible to conceive,
	IPv6 only solution using source routing, address transformation		various parts of the backhaul networks use IPv4 and appropriate
	respectively. It is possible to conceive, various parts of the		migration strategy needed before eventually moving towards IPv6 only
	backhaul networks use IPv4 and appropriate migration strategy needed		network. While any IGP can be used in these networks, this document
	before eventually moving towards IPv6 only network. While any IGP		covers only IS-IS protocol aspects.
	can be used in these networks, this document covers only IS-IS
	protocol aspects.
	Various layer-3 DC fabric routing options (refs: openfabric, spine-		Various layer-3 DC fabric routing options (refs: openfabric, spine-
	leaf, controller-based) by changing or optimizing some aspects w.r.t		leaf, controller-based) by changing or optimizing some aspects w.r.t
	adjacency formation, flooding optimizations, or/and mechanisms to		adjacency formation, flooding optimizations, or/and mechanisms to
	automatically compute the location of the node in the fat tree		automatically compute the location of the node in the fat tree
	topology are proposed recently and this document brings some of the		topology are proposed recently and this document brings some of the
	multi topology deployment aspects relevant to these networks. Please		multi topology deployment aspects relevant to these networks. Please
	note, part of the discussion around IS-IS MT is not specific to DC or		note, part of the discussion around IS-IS MT is not specific to DC or
	CLOS fabrics and generally applicable to any IS-IS deployment but		CLOS fabrics and generally applicable to any IS-IS deployment but
	discussed here because of multiple proposals to use various forms of		discussed here because of multiple proposals to use various forms of
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	network can be built with multi topology adjacencies (TLV 222) and		network can be built with multi topology adjacencies (TLV 222) and
	reachability prefixes (TLV 237) with MT ID #2 as discussed above in		reachability prefixes (TLV 237) with MT ID #2 as discussed above in
	Section 4.2. With this, any other address family can be introduced		Section 4.2. With this, any other address family can be introduced
	including "standard" topology MT ID #0 (Single topology mode with		including "standard" topology MT ID #0 (Single topology mode with
	both address families) and there are no restrictions on which address		both address families) and there are no restrictions on which address
	family has to enable on which link as specified in Section 4.1.		family has to enable on which link as specified in Section 4.1.
	5. IS-IS MT and LFA		5. IS-IS MT and LFA
	IP Fast Reroute (FRR) or Loop Free Alternative (LFA) computation in		IP Fast Reroute (FRR) or Loop Free Alternative (LFA) computation in
	MT mode are described in detail in Section 5.2 of		MT mode are described in detail in Section 5.2 of [RFC5120].
	[I-D.ietf-rtgwg-multihomed-prefix-lfa].
	6. Acknowledgements		6. Acknowledgements
	Thanks to Acee Lindem, Chris Hopps, Michael Abramson and Les Ginsberg		Thanks to Acee Lindem, Chris Hopps, Michael Abramson and Les Ginsberg
	for various inputs on this work.		for various inputs on this work.
	7. IANA Considerations		7. IANA Considerations
	This document has no actions for IANA.		This document has no actions for IANA.
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	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>.
	[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC		[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
	2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,		2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
	May 2017, <https://www.rfc-editor.org/info/rfc8174>.		May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	9.2. Informative References		9.2. Informative References
	[I-D.herbert-ila-mobile]
	Herbert, T. and K. Bogineni, "Identifier Locator
	Addressing for Mobile User-Plane", draft-herbert-ila-
	mobile-01 (work in progress), March 2018.
	[I-D.ietf-dmm-srv6-mobile-uplane]
	Matsushima, S., Filsfils, C., Kohno, M., Camarillo, P.,
	daniel.voyer@bell.ca, d., and C. Perkins, "Segment Routing
	IPv6 for Mobile User Plane", draft-ietf-dmm-srv6-mobile-
	uplane-04 (work in progress), March 2019.
	[I-D.ietf-rtgwg-multihomed-prefix-lfa]
	Sarkar, P., Chunduri, U., Hegde, S., Tantsura, J., and H.
	Gredler, "Loop-Free Alternates selection for Multi-Homed
	Prefixes", draft-ietf-rtgwg-multihomed-prefix-lfa-09 (work
	in progress), November 2018.
	[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi		[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
	Topology (MT) Routing in Intermediate System to		Topology (MT) Routing in Intermediate System to
	Intermediate Systems (IS-ISs)", RFC 5120,		Intermediate Systems (IS-ISs)", RFC 5120,
	DOI 10.17487/RFC5120, February 2008,		DOI 10.17487/RFC5120, February 2008,
	<https://www.rfc-editor.org/info/rfc5120>.		<https://www.rfc-editor.org/info/rfc5120>.
	[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic		[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
	Authentication", RFC 5304, DOI 10.17487/RFC5304, October		Authentication", RFC 5304, DOI 10.17487/RFC5304, October
	2008, <https://www.rfc-editor.org/info/rfc5304>.		2008, <https://www.rfc-editor.org/info/rfc5304>.
	skipping to change at page 9, line 10 ¶		skipping to change at page 8, line 35 ¶
	[RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,		[RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
	and M. Fanto, "IS-IS Generic Cryptographic		and M. Fanto, "IS-IS Generic Cryptographic
	Authentication", RFC 5310, DOI 10.17487/RFC5310, February		Authentication", RFC 5310, DOI 10.17487/RFC5310, February
	2009, <https://www.rfc-editor.org/info/rfc5310>.		2009, <https://www.rfc-editor.org/info/rfc5310>.
	[RFC7645] Chunduri, U., Tian, A., and W. Lu, "The Keying and		[RFC7645] Chunduri, U., Tian, A., and W. Lu, "The Keying and
	Authentication for Routing Protocol (KARP) IS-IS Security		Authentication for Routing Protocol (KARP) IS-IS Security
	Analysis", RFC 7645, DOI 10.17487/RFC7645, September 2015,		Analysis", RFC 7645, DOI 10.17487/RFC7645, September 2015,
	<https://www.rfc-editor.org/info/rfc7645>.		<https://www.rfc-editor.org/info/rfc7645>.
			[RFC8518] Sarkar, P., Ed., Chunduri, U., Ed., Hegde, S., Tantsura,
			J., and H. Gredler, "Selection of Loop-Free Alternates for
			Multi-Homed Prefixes", RFC 8518, DOI 10.17487/RFC8518,
			March 2019, <https://www.rfc-editor.org/info/rfc8518>.
	Authors' Addresses		Authors' Addresses
	Uma Chunduri		Uma Chunduri
	Huawei USA		Futurewei USA
	2330 Central Expressway		2330 Central Expressway
	Santa Clara, CA 95050		Santa Clara, CA 95050
	USA		USA
	Email: uma.chunduri@huawei.com		Email: umac.ietf@gmail.com
	Jeff Tantsura		Jeff Tantsura
	Apstra, Inc.		Apstra, Inc.
	Email: jefftant.ietf@gmail.com		Email: jefftant.ietf@gmail.com
	Shraddha Hegde		Shraddha Hegde
	Juniper Networks		Juniper Networks
	Elnath-Exora Business Park Survey		Elnath-Exora Business Park Survey
	Bangalore, Karnataka 560103		Bangalore, Karnataka 560103
	USA		USA
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