draft-ietf-ospf-ospfv3-segment-routing-extensions-20.txt   draft-ietf-ospf-ospfv3-segment-routing-extensions-21.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: June 6, 2019 Individual Expires: June 17, 2019 Individual
December 3, 2018 December 14, 2018
OSPFv3 Extensions for Segment Routing OSPFv3 Extensions for Segment Routing
draft-ietf-ospf-ospfv3-segment-routing-extensions-20 draft-ietf-ospf-ospfv3-segment-routing-extensions-21
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.
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", "NOT RECOMMENDED", "MAY", and
document are to be interpreted as described in [RFC2119]. "OPTIONAL" in this document are to be interpreted as described in
BCP14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 June 6, 2019. This Internet-Draft will expire on June 17, 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
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
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 . . . . . . . . . . . . . . . . 4 4. Segment Routing Capabilities . . . . . . . . . . . . . . . . 5
5. OSPFv3 Extended Prefix Range TLV . . . . . . . . . . . . . . 5 5. OSPFv3 Extended Prefix Range TLV . . . . . . . . . . . . . . 5
6. Prefix SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 7 6. Prefix SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 7
7. Adjacency Segment Identifier (Adj-SID) . . . . . . . . . . . 10 7. Adjacency Segment Identifier (Adj-SID) . . . . . . . . . . . 11
7.1. Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 11 7.1. Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 11
7.2. LAN Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . 12 7.2. LAN Adj-SID Sub-TLV . . . . . . . . . . . . . . . . . . . 13
8. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 13 8. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 14
8.1. Intra-area Segment routing in OSPFv3 . . . . . . . . . . 13 8.1. Intra-area Segment routing in OSPFv3 . . . . . . . . . . 14
8.2. Inter-area Segment routing in OSPFv3 . . . . . . . . . . 14 8.2. Inter-area Segment routing in OSPFv3 . . . . . . . . . . 15
8.3. Segment Routing for External Prefixes . . . . . . . . . . 15 8.3. Segment Routing for External Prefixes . . . . . . . . . . 16
8.4. Advertisement of Adj-SID . . . . . . . . . . . . . . . . 16 8.4. Advertisement of Adj-SID . . . . . . . . . . . . . . . . 16
8.4.1. Advertisement of Adj-SID on Point-to-Point Links . . 16 8.4.1. Advertisement of Adj-SID on Point-to-Point Links . . 16
8.4.2. Adjacency SID on Broadcast or NBMA Interfaces . . . . 16 8.4.2. Adjacency SID on Broadcast or NBMA Interfaces . . . . 16
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
9.1. OSPFv3 Extended-LSA TLV Registry . . . . . . . . . . . . 16 9.1. OSPFv3 Extended-LSA TLV Registry . . . . . . . . . . . . 17
9.2. OSPFv3 Extended-LSA Sub-TLV registry . . . . . . . . . . 16 9.2. OSPFv3 Extended-LSA Sub-TLV registry . . . . . . . . . . 17
10. Security Considerations . . . . . . . . . . . . . . . . . . . 17 10. Security Considerations . . . . . . . . . . . . . . . . . . . 17
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 17 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 18
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
12.1. Normative References . . . . . . . . . . . . . . . . . . 18 12.1. Normative References . . . . . . . . . . . . . . . . . . 19
12.2. Informative References . . . . . . . . . . . . . . . . . 20 12.2. Informative References . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
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
segment is typically a multi-hop path while an adjacency segment, in segment is typically a multi-hop path while an adjacency segment, in
most cases, is a one-hop path. SR's control-plane can be applied to most cases, is a one-hop path. SR's control-plane can be applied to
both IPv6 and MPLS data-planes, and does not require any additional both IPv6 and MPLS data-planes, and does not require any additional
signalling (other than IGP extensions). The IPv6 data plane is out signalling (other than IGP extensions). The IPv6 data plane is out
of the scope of this specification - OSPFv3 extension for SR with of the scope of this specification - OSPFv3 extension for SR with
IPv6 data plane will be specified in a separate document. When used IPv6 data plane will be specified in a separate document. When used
in MPLS networks, SR paths do not require any LDP or RSVP-TE in MPLS networks, SR paths do not require any LDP or RSVP-TE
signalling. However, SR can interoperate in the presence of LSPs signalling. However, SR can interoperate in the presence of LSPs
established with RSVP or LDP. established with RSVP or LDP.
There are additional segment types, e.g., Binding SID defined in
[RFC8402].
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.
Segment Routing architecture is described in [RFC8402]. Segment Routing architecture is described in [RFC8402].
Segment Routing use cases are described in [RFC7855]. Segment Routing use cases are described in [RFC7855].
2. Terminology 2. Terminology
This section lists some of the terminology used in this document: This section lists some of the terminology used in this document:
ABR - Area Border Router ABR - Area Border Router
Adj-SID - Adjacency Segment Identifier Adj-SID - Adjacency Segment Identifier
AS - Autonomous System AS - Autonomous System
ASBR - Autonomous System Boundary Router ASBR - Autonomous System Boundary Router
DR - Designated Router
IS-IS - Intermediate System to Intermediate System IS-IS - Intermediate System to Intermediate System
LDP - Label Distribution Protocol LDP - Label Distribution Protocol
LSP - Label Switched Path LSP - Label Switched Path
MPLS - Multi Protocol Label Switching MPLS - Multi Protocol Label Switching
OSPF - Open Shortest Path First OSPF - Open Shortest Path First
SPF - Shortest Path First SPF - Shortest Path First
RSVP - Resource Reservation Protocol RSVP - Resource Reservation Protocol
SID - Segment Identifier SID - Segment Identifier
SR - Segment Routing SR - Segment Routing
SRGB - Segment Routing Global Block SRGB - Segment Routing Global Block
SRLB - Segment Routing Local Block SRLB - Segment Routing Local Block
SRMS - Segment Routing Mapping Server SRMS - Segment Routing Mapping Server
TLV - Type Length Value TLV - Type Length Value
skipping to change at page 4, line 17 skipping to change at page 4, line 25
SRLB - Segment Routing Local Block SRLB - Segment Routing Local Block
SRMS - Segment Routing Mapping Server SRMS - Segment Routing Mapping Server
TLV - Type Length Value TLV - Type Length Value
3. Segment Routing Identifiers 3. Segment Routing Identifiers
Segment Routing defines various types of Segment Identifiers (SIDs): Segment Routing defines various types of Segment Identifiers (SIDs):
Prefix-SID, Adjacency-SID, LAN Adjacency SID, and Binding SID. Prefix-SID, Adjacency-SID, and LAN Adjacency SID.
3.1. SID/Label Sub-TLV 3.1. SID/Label Sub-TLV
The SID/Label Sub-TLV appears in multiple TLVs or Sub-TLVs defined The SID/Label Sub-TLV appears in multiple TLVs or Sub-TLVs defined
later in this document. It is used to advertise the SID or label later in this document. It is used to advertise the SID or label
associated with a prefix or adjacency. The SID/Label Sub-TLV has associated with a prefix or adjacency. The SID/Label Sub-TLV has
following format: following 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
skipping to change at page 6, line 45 skipping to change at page 7, line 17
a prefix of length 0. a prefix of length 0.
For the address family IPv6 unicast, the prefix, encoded as an For the address family IPv6 unicast, the prefix, encoded as an
even multiple of 32-bit words, padded with zeroed bits as even multiple of 32-bit words, padded with zeroed bits as
necessary. This encoding consumes ((PrefixLength + 31) / 32) necessary. This encoding consumes ((PrefixLength + 31) / 32)
32-bit words. 32-bit words.
Prefix encoding for other address families is beyond the scope Prefix encoding for other address families is beyond the scope
of this specification. of this specification.
The range represents the contiguous set of prefixes with the same
prefix length as specified by the Prefix Length field. The set
starts with the prefix that is specified by the Address Prefix field.
The number of prefixes in the range is equal to the Range size.
If the OSPFv3 Extended Prefix Range TLVs advertising the exact same If the OSPFv3 Extended Prefix Range TLVs advertising the exact same
range appears in multiple LSAs of the same type, originated by the range appears in multiple LSAs of the same type, originated by the
same OSPFv3 router, the LSA with the numerically smallest Instance ID same OSPFv3 router, the LSA with the numerically smallest Instance ID
MUST be used and subsequent instances of the OSPFv3 Extended Prefix MUST be used and subsequent instances of the OSPFv3 Extended Prefix
Range TLVs MUST be ignored. Range TLVs MUST be ignored.
6. Prefix SID Sub-TLV 6. Prefix SID Sub-TLV
The Prefix SID Sub-TLV is a Sub-TLV of the following OSPFv3 TLVs as The Prefix SID Sub-TLV is a Sub-TLV of the following OSPFv3 TLVs as
defined in [RFC8362] and in Section 5: defined in [RFC8362] and in Section 5:
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for the prefix. This MUST be done regardless of whether the next-hop for the prefix. This MUST be done regardless of whether the next-hop
router contributes to the best path to the prefix. router contributes to the best path to the prefix.
The NP-Flag (No-PHP) MUST be set and the E-flag MUST be clear for The NP-Flag (No-PHP) MUST be set and the E-flag MUST be clear for
Prefix-SIDs allocated to prefixes that are propagated between areas Prefix-SIDs allocated to prefixes that are propagated between areas
by an ABR based on intra-area or inter-area reachability, unless the by an ABR based on intra-area or inter-area reachability, unless the
advertised prefix is directly attached to such ABR. advertised prefix is directly attached to such ABR.
The NP-Flag (No-PHP) MUST be set and the E-flag MUST be clear for The NP-Flag (No-PHP) MUST be set and the E-flag MUST be clear for
Prefix-SIDs allocated to redistributed prefixes, unless the Prefix-SIDs allocated to redistributed prefixes, unless the
redistributed prefix is directly attached to the advertising redistributed prefix is directly attached to the advertising ASBR.
Autonomous System Boundary Router (ASBR).
If the NP-Flag is not set, then any upstream neighbor of the Prefix- If the NP-Flag is not set, then any upstream neighbor of the Prefix-
SID originator MUST pop the Prefix-SID. This is equivalent to the SID originator MUST pop the Prefix-SID. This is equivalent to the
penultimate hop popping mechanism used in the MPLS dataplane. If the penultimate hop popping mechanism used in the MPLS dataplane. If the
NP-flag is not set, then the received E-flag is ignored. NP-flag is not set, then the received E-flag is ignored.
If the NP-flag is set then: If the NP-flag is set then:
If the E-flag is not set, then any upstream neighbor of the If the E-flag is not set, then any upstream neighbor of the
Prefix-SID originator MUST keep the Prefix-SID on top of the Prefix-SID originator MUST keep the Prefix-SID on top of the
stack. This is useful when the originator of the Prefix-SID needs stack. This is useful when the originator of the Prefix-SID needs
to stitch the incoming packet into a continuing MPLS LSP to the to stitch the incoming packet into a continuing MPLS LSP to the
final destination. This could occur at an Area Border Router final destination. This could occur at an ABR (prefix propagation
(prefix propagation from one area to another) or at an AS Boundary from one area to another) or at an ASBR (prefix propagation from
Router (prefix propagation from one domain to another). one domain to another).
If the E-flag is set, then any upstream neighbor of the Prefix-SID If the E-flag is set, then any upstream neighbor of the Prefix-SID
originator MUST replace the Prefix-SID with an Explicit-NULL originator MUST replace the Prefix-SID with an Explicit-NULL
label. This is useful, e.g., when the originator of the Prefix- label. This is useful, e.g., when the originator of the Prefix-
SID is the final destination for the related prefix and the SID is the final destination for the related prefix and the
originator wishes to receive the packet with the original EXP originator wishes to receive the packet with the original Traffic
bits. Class field [RFC5462].
When the M-Flag is set, the NP-flag and the E-flag MUST be ignored on When the M-Flag is set, the NP-flag and the E-flag MUST be ignored on
reception. reception.
As the Mapping Server does not specify the originator of a prefix As the Mapping Server does not specify the originator of a prefix
advertisement, it is not possible to determine PHP behavior solely advertisement, it is not possible to determine PHP behavior solely
based on the Mapping Server advertisement. However, PHP behavior based on the Mapping Server advertisement. However, PHP behavior
SHOULD be done in following cases: SHOULD be done in following cases:
The Prefix is intra-area type and the downstream neighbor is the The Prefix is intra-area type and the downstream neighbor is the
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weight is defined in [RFC8402]. weight is defined in [RFC8402].
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.
Neighbor ID: The Router ID of the neighbor for which the LAN-Adj- Neighbor ID: The Router ID of the neighbor for which the LAN-Adj-
SID is advertised. SID is advertised.
SID/Index/Label: as described in Section 6. SID/Index/Label: as described in Section 6.
When the P-flag is not set, the Adj-SID MAY be persistent. When When the P-flag is not set, the LAN Adj-SID MAY be persistent.
the P-flag is set, the Adj-SID MUST be persistent. When the P-flag is set, the LAN Adj-SID MUST be persistent.
8. Elements of Procedure 8. Elements of Procedure
8.1. Intra-area Segment routing in OSPFv3 8.1. Intra-area Segment routing in OSPFv3
An OSPFv3 router that supports segment routing MAY advertise Prefix- An OSPFv3 router that supports segment routing MAY advertise Prefix-
SIDs for any prefix to which it is advertising reachability (e.g., a SIDs for any prefix to which it is advertising reachability (e.g., a
loopback IP address as described in Section 6). loopback IP address as described in Section 6).
A Prefix-SID can also be advertised by SR Mapping Servers (as A Prefix-SID can also be advertised by SR Mapping Servers (as
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External-LSA [RFC8362] is used. External-LSA [RFC8362] is used.
When a Prefix-SID is advertised by the Mapping Server, which is When a Prefix-SID is advertised by the Mapping Server, which is
indicated by the M-flag in the Prefix-SID Sub-TLV (Section 6), the indicated by the M-flag in the Prefix-SID Sub-TLV (Section 6), the
route type as implied by the LSA type is ignored and the Prefix-SID route type as implied by the LSA type is ignored and the Prefix-SID
is bound to the corresponding prefix independent of the route type. is bound to the corresponding prefix independent of the route type.
Advertisement of the Prefix-SID by the Mapping Server using an Inter- Advertisement of the Prefix-SID by the Mapping Server using an Inter-
Area Prefix TLV, External-Prefix TLV, or Intra-Area-Prefix TLV Area Prefix TLV, External-Prefix TLV, or Intra-Area-Prefix TLV
[RFC8362] does not itself contribute to the prefix reachability. The [RFC8362] does not itself contribute to the prefix reachability. The
NU-bit MUST be set in the PrefixOptions field of the LSA which is NU-bit [RFC5340] MUST be set in the PrefixOptions field of the LSA
used by the Mapping Server to advertise SID or SID Range, which which is used by the Mapping Server to advertise SID or SID Range,
prevents the advertisement from contributing to prefix reachability. which prevents the advertisement from contributing to prefix
reachability.
An SR Mapping Server MUST use the OSPFv3 Extended Prefix Range TLVs An SR Mapping Server MUST use the OSPFv3 Extended Prefix Range TLVs
when advertising SIDs for prefixes. Prefixes of different route- when advertising SIDs for prefixes. Prefixes of different route-
types can be combined in a single OSPFv3 Extended Prefix Range TLV types can be combined in a single OSPFv3 Extended Prefix Range TLV
advertised by an SR Mapping Server. advertised by an SR Mapping Server.
Area-scoped OSPFv3 Extended Prefix Range TLVs are propagated between Area-scoped OSPFv3 Extended Prefix Range TLVs are propagated between
areas. Similar to propagation of prefixes between areas, an ABR only areas, similar to propagation of prefixes between areas. Same rules
propagates the OSPFv3 Extended Prefix Range TLV that it considers to that are used for propagating prefixes between areas [RFC5340] are
be the best from the set it received. The rules used to pick the used for the propagation of the prefix ranges.
best OSPFv3 Extended Prefix Range TLV are described in Section 5.
8.2. Inter-area Segment routing in OSPFv3 8.2. Inter-area Segment routing in OSPFv3
In order to support SR in a multi-area environment, OSPFv3 MUST In order to support SR in a multi-area environment, OSPFv3 MUST
propagate Prefix-SID information between areas. The following propagate Prefix-SID information between areas. The following
procedure is used to propagate Prefix SIDs between areas. procedure is used to propagate Prefix SIDs between areas.
When an OSPFv3 ABR advertises an Inter-Area-Prefix-LSA from an intra- When an OSPFv3 ABR advertises an Inter-Area-Prefix-LSA from an intra-
area prefix to all its connected areas, it will also include the area prefix to all its connected areas, it will also include the
Prefix-SID Sub-TLV, as described in Section 6. The Prefix-SID value Prefix-SID Sub-TLV, as described in Section 6. The Prefix-SID value
skipping to change at page 16, line 22 skipping to change at page 16, line 38
An Adj-SID MAY be advertised for any adjacency on a P2P link that is An Adj-SID MAY be advertised for any adjacency on a P2P link that is
in neighbor state 2-Way or higher. If the adjacency on a P2P link in neighbor state 2-Way or higher. If the adjacency on a P2P link
transitions from the FULL state, then the Adj-SID for that adjacency transitions from the FULL state, then the Adj-SID for that adjacency
MAY be removed from the area. If the adjacency transitions to a MAY be removed from the area. If the adjacency transitions to a
state lower than 2-Way, then the Adj-SID advertisement MUST be state lower than 2-Way, then the Adj-SID advertisement MUST be
withdrawn from the area. withdrawn from the area.
8.4.2. Adjacency SID on Broadcast or NBMA Interfaces 8.4.2. Adjacency SID on Broadcast or NBMA Interfaces
Broadcast, NBMA, or hybrid [RFC6845] networks in OSPFv3 are Broadcast, NBMA, or hybrid [RFC6845] networks in OSPFv3 are
represented by a star topology where the Designated Router (DR) is represented by a star topology where the DR is the central point to
the central point to which all other routers on the broadcast, NBMA, which all other routers on the broadcast, NBMA, or hybrid network
or hybrid network connect. As a result, routers on the broadcast, connect. As a result, routers on the broadcast, NBMA, or hybrid
NBMA, or hybrid network advertise only their adjacency to the DR. network advertise only their adjacency to the DR. Routers that do
Routers that do not act as DR do not form or advertise adjacencies not act as DR do not form or advertise adjacencies with each other.
with each other. They do, however, maintain 2-Way adjacency state They do, however, maintain 2-Way adjacency state with each other and
with each other and are directly reachable. are directly reachable.
When Segment Routing is used, each router on the broadcast, NBMA, or When Segment Routing is used, each router on the broadcast, NBMA, or
hybrid network MAY advertise the Adj-SID for its adjacency to the DR hybrid network MAY advertise the Adj-SID for its adjacency to the DR
using the Adj-SID Sub-TLV as described in Section 7.1. using the Adj-SID Sub-TLV as described in Section 7.1.
SR-capable routers MAY also advertise a LAN-Adj-SID for other SR-capable routers MAY also advertise a LAN-Adj-SID for other
neighbors (e.g., BDR, DR-OTHER) on the broadcast, NBMA, or hybrid neighbors (e.g., BDR, DR-OTHER) on the broadcast, NBMA, or hybrid
network using the LAN-Adj-SID Sub-TLV as described in Section 7.2. network using the LAN-Adj-SID Sub-TLV as described in Section 7.2.
9. IANA Considerations 9. IANA Considerations
skipping to change at page 19, line 9 skipping to change at page 19, line 16
12.1. Normative References 12.1. Normative References
[ALGOREG] "IGP Algorithm Types", <https://www.iana.org/assignments/ [ALGOREG] "IGP Algorithm Types", <https://www.iana.org/assignments/
igp-parameters/igp-parameters.xhtml#igp-algorithm-types>. igp-parameters/igp-parameters.xhtml#igp-algorithm-types>.
[I-D.ietf-ospf-segment-routing-extensions] [I-D.ietf-ospf-segment-routing-extensions]
Psenak, P., Previdi, S., Filsfils, C., Gredler, H., Psenak, P., Previdi, S., Filsfils, C., Gredler, H.,
Shakir, R., Henderickx, W., and J. Tantsura, "OSPF Shakir, R., Henderickx, W., and J. Tantsura, "OSPF
Extensions for Segment Routing", draft-ietf-ospf-segment- Extensions for Segment Routing", draft-ietf-ospf-segment-
routing-extensions-26 (work in progress), November 2018. routing-extensions-27 (work in progress), December 2018.
[I-D.ietf-spring-segment-routing-ldp-interop] [I-D.ietf-spring-segment-routing-ldp-interop]
Bashandy, A., Filsfils, C., Previdi, S., Decraene, B., and Bashandy, A., Filsfils, C., Previdi, S., Decraene, B., and
S. Litkowski, "Segment Routing interworking with LDP", S. Litkowski, "Segment Routing interworking with LDP",
draft-ietf-spring-segment-routing-ldp-interop-15 (work in draft-ietf-spring-segment-routing-ldp-interop-15 (work in
progress), September 2018. progress), September 2018.
[I-D.ietf-spring-segment-routing-mpls] [I-D.ietf-spring-segment-routing-mpls]
Bashandy, A., Filsfils, C., Previdi, S., Decraene, B., Bashandy, A., Filsfils, C., Previdi, S., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing with MPLS Litkowski, S., and R. Shakir, "Segment Routing with MPLS
data plane", draft-ietf-spring-segment-routing-mpls-16 data plane", draft-ietf-spring-segment-routing-mpls-18
(work in progress), November 2018. (work in progress), December 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>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001, DOI 10.17487/RFC3031, January 2001,
<https://www.rfc-editor.org/info/rfc3031>. <https://www.rfc-editor.org/info/rfc3031>.
skipping to change at page 19, line 45 skipping to change at page 20, line 5
<https://www.rfc-editor.org/info/rfc3101>. <https://www.rfc-editor.org/info/rfc3101>.
[RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed., [RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
"LDP Specification", RFC 5036, DOI 10.17487/RFC5036, "LDP Specification", RFC 5036, DOI 10.17487/RFC5036,
October 2007, <https://www.rfc-editor.org/info/rfc5036>. October 2007, <https://www.rfc-editor.org/info/rfc5036>.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>. <https://www.rfc-editor.org/info/rfc5340>.
[RFC5462] Andersson, L. and R. Asati, "Multiprotocol Label Switching
(MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic
Class" Field", RFC 5462, DOI 10.17487/RFC5462, February
2009, <https://www.rfc-editor.org/info/rfc5462>.
[RFC6845] Sheth, N., Wang, L., and J. Zhang, "OSPF Hybrid Broadcast [RFC6845] Sheth, N., Wang, L., and J. Zhang, "OSPF Hybrid Broadcast
and Point-to-Multipoint Interface Type", RFC 6845, and Point-to-Multipoint Interface Type", RFC 6845,
DOI 10.17487/RFC6845, January 2013, DOI 10.17487/RFC6845, January 2013,
<https://www.rfc-editor.org/info/rfc6845>. <https://www.rfc-editor.org/info/rfc6845>.
[RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and [RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
S. Shaffer, "Extensions to OSPF for Advertising Optional S. Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 7770, DOI 10.17487/RFC7770, Router Capabilities", RFC 7770, DOI 10.17487/RFC7770,
February 2016, <https://www.rfc-editor.org/info/rfc7770>. February 2016, <https://www.rfc-editor.org/info/rfc7770>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and [RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and
F. Baker, "OSPFv3 Link State Advertisement (LSA) F. Baker, "OSPFv3 Link State Advertisement (LSA)
Extensibility", RFC 8362, DOI 10.17487/RFC8362, April Extensibility", RFC 8362, DOI 10.17487/RFC8362, April
2018, <https://www.rfc-editor.org/info/rfc8362>. 2018, <https://www.rfc-editor.org/info/rfc8362>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>. July 2018, <https://www.rfc-editor.org/info/rfc8402>.
 End of changes. 28 change blocks. 
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