draft-ietf-ospf-ospfv3-segment-routing-extensions-17.txt		draft-ietf-ospf-ospfv3-segment-routing-extensions-18.txt
	Open Shortest Path First IGP P. Psenak, Ed.		Open Shortest Path First IGP P. Psenak, Ed.
	Internet-Draft Cisco Systems, Inc.		Internet-Draft Cisco Systems, Inc.
	Intended status: Standards Track S. Previdi, Ed.		Intended status: Standards Track S. Previdi, Ed.
	Expires: May 9, 2019 Individual		Expires: May 20, 2019 Individual
	November 5, 2018		November 16, 2018
	OSPFv3 Extensions for Segment Routing		OSPFv3 Extensions for Segment Routing
	draft-ietf-ospf-ospfv3-segment-routing-extensions-17		draft-ietf-ospf-ospfv3-segment-routing-extensions-18
	Abstract		Abstract
	Segment Routing (SR) allows a flexible definition of end-to-end paths		Segment Routing (SR) allows a flexible definition of end-to-end paths
	within IGP topologies by encoding paths as sequences of topological		within IGP topologies by encoding paths as sequences of topological
	sub-paths, called "segments". These segments are advertised by the		sub-paths, called "segments". These segments are advertised by the
	link-state routing protocols (IS-IS and OSPF).		link-state routing protocols (IS-IS and OSPF).
	This draft describes the OSPFv3 extensions required for Segment		This draft describes the OSPFv3 extensions required for Segment
	Routing with MPLS data plane.		Routing with MPLS data plane.
	skipping to change at page 1, line 43 ¶		skipping to change at page 1, line 43 ¶
	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 9, 2019.		This Internet-Draft will expire on May 20, 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 27 ¶		skipping to change at page 2, line 27 ¶
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
	3. Segment Routing Identifiers . . . . . . . . . . . . . . . . . 4		3. Segment Routing Identifiers . . . . . . . . . . . . . . . . . 4
	3.1. SID/Label Sub-TLV . . . . . . . . . . . . . . . . . . . . 4		3.1. SID/Label Sub-TLV . . . . . . . . . . . . . . . . . . . . 4
	4. Segment Routing Capabilities . . . . . . . . . . . . . . . . 5		4. Segment Routing Capabilities . . . . . . . . . . . . . . . . 5
	4.1. SR-Algorithm TLV . . . . . . . . . . . . . . . . . . . . 5		4.1. SR-Algorithm TLV . . . . . . . . . . . . . . . . . . . . 5
	4.2. SID/Label Range TLV . . . . . . . . . . . . . . . . . . . 6		4.2. SID/Label Range TLV . . . . . . . . . . . . . . . . . . . 6
	4.3. SR Local Block TLV . . . . . . . . . . . . . . . . . . . 8		4.3. SR Local Block TLV . . . . . . . . . . . . . . . . . . . 8
	4.4. SRMS Preference TLV . . . . . . . . . . . . . . . . . . . 10		4.4. SRMS Preference TLV . . . . . . . . . . . . . . . . . . . 10
	5. OSPFv3 Extended Prefix Range TLV . . . . . . . . . . . . . . 11		5. OSPFv3 Extended Prefix Range TLV . . . . . . . . . . . . . . 11
	6. Prefix SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 14		6. Prefix SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 13
	7. Adjacency Segment Identifier (Adj-SID) . . . . . . . . . . . 17		7. Adjacency Segment Identifier (Adj-SID) . . . . . . . . . . . 17
	7.1. Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 18		7.1. Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 17
	7.2. LAN Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . 19		7.2. LAN Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . 19
	8. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 20		8. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 20
	8.1. Intra-area Segment routing in OSPFv3 . . . . . . . . . . 20		8.1. Intra-area Segment routing in OSPFv3 . . . . . . . . . . 20
	8.2. Inter-area Segment routing in OSPFv3 . . . . . . . . . . 21		8.2. Inter-area Segment routing in OSPFv3 . . . . . . . . . . 21
	8.3. Segment Routing for External Prefixes . . . . . . . . . . 22		8.3. Segment Routing for External Prefixes . . . . . . . . . . 22
	8.4. Advertisement of Adj-SID . . . . . . . . . . . . . . . . 23		8.4. Advertisement of Adj-SID . . . . . . . . . . . . . . . . 22
	8.4.1. Advertisement of Adj-SID on Point-to-Point Links . . 23		8.4.1. Advertisement of Adj-SID on Point-to-Point Links . . 22
	8.4.2. Adjacency SID on Broadcast or NBMA Interfaces . . . . 23		8.4.2. Adjacency SID on Broadcast or NBMA Interfaces . . . . 22
	9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23		9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
	9.1. OSPFv3 Extended-LSA TLV Registry . . . . . . . . . . . . 23		9.1. OSPFv3 Extended-LSA TLV Registry . . . . . . . . . . . . 23
	9.2. OSPFv3 Extended-LSA Sub-TLV registry . . . . . . . . . . 24		9.2. OSPFv3 Extended-LSA Sub-TLV registry . . . . . . . . . . 23
	10. Security Considerations . . . . . . . . . . . . . . . . . . . 24		10. Security Considerations . . . . . . . . . . . . . . . . . . . 23
	11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 24		11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 24
	12. References . . . . . . . . . . . . . . . . . . . . . . . . . 25		12. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
	12.1. Normative References . . . . . . . . . . . . . . . . . . 25		12.1. Normative References . . . . . . . . . . . . . . . . . . 25
	12.2. Informative References . . . . . . . . . . . . . . . . . 27		12.2. Informative References . . . . . . . . . . . . . . . . . 26
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
	1. Introduction		1. Introduction
	Segment Routing (SR) allows a flexible definition of end-to-end paths		Segment Routing (SR) allows a flexible definition of end-to-end paths
	within IGP topologies by encoding paths as sequences of topological		within IGP topologies by encoding paths as sequences of topological
	sub-paths, called "segments". These segments are advertised by the		sub-paths, called "segments". These segments are advertised by the
	link-state routing protocols (IS-IS and OSPF). Prefix segments		link-state routing protocols (IS-IS and OSPF). Prefix segments
	represent an ECMP-aware shortest-path to a prefix (or a node), as per		represent an ECMP-aware shortest-path to a prefix (or a node), as per
	the state of the IGP topology. Adjacency segments represent a hop		the state of the IGP topology. Adjacency segments represent a hop
	over a specific adjacency between two nodes in the IGP. A prefix		over a specific adjacency between two nodes in the IGP. A prefix
	skipping to change at page 6, line 19 ¶		skipping to change at page 6, line 19 ¶
	flooding scopes, the SR-Algorithm TLV in the OSPFv3 Router		flooding scopes, the SR-Algorithm TLV in the OSPFv3 Router
	Information Opaque LSA with the area-scoped flooding scope MUST be		Information Opaque LSA with the area-scoped flooding scope MUST be
	used. If the SR-Algorithm TLV appears in multiple OSPFv3 Router		used. If the SR-Algorithm TLV appears in multiple OSPFv3 Router
	Information Opaque LSAs that have the same flooding scope, the SR-		Information Opaque LSAs that have the same flooding scope, the SR-
	Algorithm TLV in the OSPFv3 Router Information Opaque LSA with the		Algorithm TLV in the OSPFv3 Router Information Opaque LSA with the
	numerically smallest Instance ID MUST be used and subsequent		numerically smallest Instance ID MUST be used and subsequent
	instances of the SR-Algorithm TLV MUST be ignored.		instances of the SR-Algorithm TLV MUST be ignored.
	The OSPFv3 Router Information Opaque LSA can be advertised at any of		The OSPFv3 Router Information Opaque LSA can be advertised at any of
	the defined opaque flooding scopes (link, area, or Autonomous System		the defined opaque flooding scopes (link, area, or Autonomous System
	(AS)). For the purpose of SR-Algorithm TLV advertisement, area-		(AS)). For the purpose of SR-Algorithm TLV advertisement, at least
	scoped flooding is REQUIRED.		area-scoped flooding is REQUIRED.
	4.2. SID/Label Range TLV		4.2. SID/Label Range TLV
	Prefix SIDs MAY be advertised in a form of an index as described in		Prefix SIDs MAY be advertised in a form of an index as described in
	Section 6. Such index defines the offset in the SID/Label space		Section 6. Such index defines the offset in the SID/Label space
	advertised by the router. The SID/Label Range TLV is used to		advertised by the router. The SID/Label Range TLV is used to
	advertise such SID/Label space.		advertise such SID/Label space.
	The SID/Label Range TLV is a top-level TLV of the OSPFv3 Router		The SID/Label Range TLV is a top-level TLV of the OSPFv3 Router
	Information Opaque LSA (defined in [RFC7770]).		Information Opaque LSA (defined in [RFC7770]).
	skipping to change at page 8, line 31 ¶		skipping to change at page 8, line 31 ¶
	...		...
	index 99 means label 199		index 99 means label 199
	index 100 means label 1000		index 100 means label 1000
	index 199 means label 1099		index 199 means label 1099
	...		...
	index 200 means label 500		index 200 means label 500
	...		...
	The OSPFv3 Router Information Opaque LSA can be advertised at any of		The OSPFv3 Router Information Opaque LSA can be advertised at any of
	the defined flooding scopes (link, area, or autonomous system (AS)).		the defined flooding scopes (link, area, or autonomous system (AS)).
	For the purpose of SID/Label Range TLV advertisement, area-scoped		For the purpose of SID/Label Range TLV advertisement, at least area-
	flooding is REQUIRED.		scoped flooding is REQUIRED.
	4.3. SR Local Block TLV		4.3. SR Local Block TLV
	The SR Local Block TLV (SRLB TLV) contains the range of labels the		The SR Local Block TLV (SRLB TLV) contains the range of labels the
	node has reserved for local SIDs. SIDs from the SRLB MAY be used for		node has reserved for local SIDs. SIDs from the SRLB MAY be used for
	Adjacency-SIDs, but also by components other than the OSPFv3		Adjacency-SIDs, but also by components other than the OSPFv3
	protocol. As an example, an application or a controller can instruct		protocol. As an example, an application or a controller can instruct
	the router to allocate a specific local SID. Some controllers or		the router to allocate a specific local SID. Some controllers or
	applications can use the control plane to discover the available set		applications can use the control plane to discover the available set
	of local SIDs on a particular router. In such cases, the SRLB is		of local SIDs on a particular router. In such cases, the SRLB is
	skipping to change at page 10, line 19 ¶		skipping to change at page 10, line 19 ¶
	document.		document.
	A router advertising the SRLB TLV MAY also have other label ranges,		A router advertising the SRLB TLV MAY also have other label ranges,
	outside of the SRLB, used for its local allocation purposes which are		outside of the SRLB, used for its local allocation purposes which are
	not advertised in the SRLB TLV. For example, it is possible that an		not advertised in the SRLB TLV. For example, it is possible that an
	Adjacency-SID is allocated using a local label that is not part of		Adjacency-SID is allocated using a local label that is not part of
	the SRLB.		the SRLB.
	The OSPFv3 Router Information Opaque LSA can be advertised at any of		The OSPFv3 Router Information Opaque LSA can be advertised at any of
	the defined flooding scopes (link, area, or autonomous system (AS)).		the defined flooding scopes (link, area, or autonomous system (AS)).
	For the purpose of SRLB TLV advertisement, area-scoped flooding is		For the purpose of SRLB TLV advertisement, at least area-scoped
	REQUIRED.		flooding is REQUIRED.
	4.4. SRMS Preference TLV		4.4. SRMS Preference TLV
	The Segment Routing Mapping Server Preference TLV (SRMS Preference		The Segment Routing Mapping Server Preference TLV (SRMS Preference
	TLV) is used to advertise a preference associated with a node that		TLV) is used to advertise a preference associated with a node that
	acts as an SR Mapping Server. The role of an SRMS is described in		acts as an SR Mapping Server. The role of an SRMS is described in
	[I-D.ietf-spring-segment-routing-ldp-interop]. SRMS preference is		[I-D.ietf-spring-segment-routing-ldp-interop]. SRMS preference is
	defined in [I-D.ietf-spring-segment-routing-ldp-interop].		defined in [I-D.ietf-spring-segment-routing-ldp-interop].
	The SRMS Preference TLV is a top-level TLV of the OSPFv3 Router		The SRMS Preference TLV is a top-level TLV of the OSPFv3 Router
	skipping to change at page 12, line 46 ¶		skipping to change at page 12, line 46 ¶
	the advertisement. The Range Size MUST NOT exceed the number of		the advertisement. The Range Size MUST NOT exceed the number of
	prefixes that could be satisfied by the prefix length without		prefixes that could be satisfied by the prefix length without
	including:		including:
	Addresses from the IPv4 multicast address range (224.0.0.0/3),		Addresses from the IPv4 multicast address range (224.0.0.0/3),
	if the AF is IPv4 unicast		if the AF is IPv4 unicast
	Addresses other than the IPv6 unicast addresses, if the AF is		Addresses other than the IPv6 unicast addresses, if the AF is
	IPv6 unicast		IPv6 unicast
	Flags: Single octet field. The following flags are defined:		Flags: Reserved. MUST be zero when sent and are ignored when
			received.
	0 1 2 3 4 5 6 7
	+--+--+--+--+--+--+--+--+
	|IA| | | | | | | |
	+--+--+--+--+--+--+--+--+
	where:
	IA-Flag: Inter-Area flag. If set, advertisement is of inter-
	area type. An Are Border Router (ABR) that is advertising the
	OSPFv3 Extended Prefix Range TLV between areas MUST set this
	bit.
	This bit is used to prevent redundant flooding of Prefix Range
	TLVs between areas as follows:
	An ABR only propagates an inter-area Prefix Range
	advertisement from the backbone area to connected non-
	backbone areas if the advertisement is considered to be the
	best one. The following rules are used to select the best
	range from the set of advertisements for the same Prefix
	Range:
	An ABR always prefers intra-area Prefix Range
	advertisements over inter-area advertisements.
	An ABR does not consider inter-area Prefix Range
	advertisements coming from non-backbone areas.
	Other bits: Reserved. These MUST be zero when sent and are
	ignored when received.
	Reserved: SHOULD be set to 0 on transmission and MUST be ignored		Reserved: SHOULD be set to 0 on transmission and MUST be ignored
	on reception.		on reception.
	Address Prefix:		Address Prefix:
	For the address family IPv4 unicast, the prefix itself is		For the address family IPv4 unicast, the prefix itself is
	encoded as a 32-bit value. The default route is represented by		encoded as a 32-bit value. The default route is represented by
	a prefix of length 0.		a prefix of length 0.
	skipping to change at page 19, line 18 ¶		skipping to change at page 18, line 27 ¶
	Other bits: Reserved. These MUST be zero when sent and are		Other bits: Reserved. These MUST be zero when sent and are
	ignored when received.		ignored when received.
	Reserved: SHOULD be set to 0 on transmission and MUST be ignored		Reserved: SHOULD be set to 0 on transmission and MUST be ignored
	on reception.		on reception.
	Weight: Weight used for load-balancing purposes. The use of the		Weight: Weight used for load-balancing purposes. The use of the
	weight is defined in [RFC8402].		weight is defined in [RFC8402].
	SID/Index/Label: According to the V and L flags, it contains		SID/Index/Label: According to the V-Flag, it contains either:
	either:
	A 32-bit index defining the offset in the SID/Label space		A 32-bit index defining the offset in the SID/Label space
	advertised by this router.		advertised by this router.
	A 24-bit label where the 20 rightmost bits are used for		A 24-bit label where the 20 rightmost bits are used for
	encoding the label value.		encoding the label value.
	An SR-capable router MAY allocate an Adj-SID for each of its		An SR-capable router MAY allocate an Adj-SID for each of its
	adjacencies and set the B-Flag when the adjacency is eligible for		adjacencies and set the B-Flag when the adjacency is eligible for
	protection by an FRR mechanism (IP or MPLS) as described in		protection by an FRR mechanism (IP or MPLS) as described in
End of changes. 13 change blocks.
	53 lines changed or deleted		22 lines changed or added
This html diff was produced by rfcdiff 1.47. The latest version is available from http://tools.ietf.org/tools/rfcdiff/