< draft-ietf-ospf-te-link-attr-reuse-14.txt   draft-ietf-ospf-te-link-attr-reuse-15.txt >
LSR Working Group P. Psenak, Ed. LSR Working Group P. Psenak, Ed.
Internet-Draft L. Ginsberg Internet-Draft L. Ginsberg
Intended status: Standards Track Cisco Systems Intended status: Standards Track Cisco Systems
Expires: December 9, 2020 W. Henderickx Expires: December 24, 2020 W. Henderickx
Nokia Nokia
J. Tantsura J. Tantsura
Apstra Apstra
J. Drake J. Drake
Juniper Networks Juniper Networks
June 7, 2020 June 22, 2020
OSPF Link Traffic Engineering Attribute Reuse OSPF Application-Specific Link Attributes
draft-ietf-ospf-te-link-attr-reuse-14.txt draft-ietf-ospf-te-link-attr-reuse-15.txt
Abstract Abstract
Existing traffic engineering related link attribute advertisements Existing traffic engineering related link attribute advertisements
have been defined and are used in RSVP-TE deployments. Since the have been defined and are used in RSVP-TE deployments. Since the
original RSVP-TE use case was defined, additional applications (e.g., original RSVP-TE use case was defined, additional applications (e.g.,
Segment Routing Traffic Engineering, Loop Free Alternate) have been Segment Routing Policy, Loop Free Alternate) have been defined that
defined which also make use of the link attribute advertisements. In also make use of the link attribute advertisements. In cases where
cases where multiple applications wish to make use of these link multiple applications wish to make use of these link attributes the
attributes the current advertisements do not support application current advertisements do not support application specific values for
specific values for a given attribute nor do they support indication a given attribute nor do they support indication of which
of which applications are using the advertised value for a given applications are using the advertised value for a given link. This
link. This document introduces new link attribute advertisements in document introduces new link attribute advertisements in OSPFv2 and
OSPFv2 and OSPFv3 which address both of these shortcomings. OSPFv3 that address both of these shortcomings.
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 December 9, 2020. This Internet-Draft will expire on December 24, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2020 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
skipping to change at page 2, line 27 skipping to change at page 2, line 27
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. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
3. Existing Advertisement of Link Attributes . . . . . . . . . . 4 3. Existing Advertisement of Link Attributes . . . . . . . . . . 4
4. Advertisement of Link Attributes . . . . . . . . . . . . . . 4 4. Advertisement of Link Attributes . . . . . . . . . . . . . . 4
4.1. OSPFv2 Extended Link Opaque LSA and OSPFv3 E-Router-LSA . 4 4.1. OSPFv2 Extended Link Opaque LSA and OSPFv3 E-Router-LSA . 4
5. Advertisement of Application Specific Values . . . . . . . . 5 5. Advertisement of Application-Specific Values . . . . . . . . 5
6. Reused TE link attributes . . . . . . . . . . . . . . . . . . 8 6. Reused TE link attributes . . . . . . . . . . . . . . . . . . 9
6.1. Shared Risk Link Group (SRLG) . . . . . . . . . . . . . . 8 6.1. Shared Risk Link Group (SRLG) . . . . . . . . . . . . . . 9
6.2. Extended Metrics . . . . . . . . . . . . . . . . . . . . 8 6.2. Extended Metrics . . . . . . . . . . . . . . . . . . . . 9
6.3. Administrative Group . . . . . . . . . . . . . . . . . . 9 6.3. Administrative Group . . . . . . . . . . . . . . . . . . 10
6.4. Traffic Engineering Metric . . . . . . . . . . . . . . . 10 6.4. Traffic Engineering Metric . . . . . . . . . . . . . . . 10
7. Maximum Link Bandwidth . . . . . . . . . . . . . . . . . . . 10 7. Maximum Link Bandwidth . . . . . . . . . . . . . . . . . . . 11
8. Considerations for Extended TE Metrics . . . . . . . . . . . 10 8. Considerations for Extended TE Metrics . . . . . . . . . . . 11
9. Local Interface IPv6 Address Sub-TLV . . . . . . . . . . . . 11 9. Local Interface IPv6 Address Sub-TLV . . . . . . . . . . . . 11
10. Remote Interface IPv6 Address Sub-TLV . . . . . . . . . . . . 11 10. Remote Interface IPv6 Address Sub-TLV . . . . . . . . . . . . 12
11. Attribute Advertisements and Enablement . . . . . . . . . . . 11 11. Attribute Advertisements and Enablement . . . . . . . . . . . 12
12. Deployment Considerations . . . . . . . . . . . . . . . . . . 12 12. Deployment Considerations . . . . . . . . . . . . . . . . . . 13
12.1. Use of Legacy RSVP-TE LSA Advertisements . . . . . . . . 12 12.1. Use of Legacy RSVP-TE LSA Advertisements . . . . . . . . 13
12.2. Use of Zero Length Application Identifier Bit Masks . . 13 12.2. Interoperability, Backwards Compatibility and Migration
12.3. Interoperability, Backwards Compatibility and Migration
Concerns . . . . . . . . . . . . . . . . . . . . . . . . 14 Concerns . . . . . . . . . . . . . . . . . . . . . . . . 14
12.3.1. Multiple Applications: Common Attributes with RSVP- 12.2.1. Multiple Applications: Common Attributes with RSVP-
TE . . . . . . . . . . . . . . . . . . . . . . . . . 14 TE . . . . . . . . . . . . . . . . . . . . . . . . . 14
12.3.2. Multiple Applications: Some Attributes Not Shared 12.2.2. Multiple Applications: Some Attributes Not Shared
with RSVP-TE . . . . . . . . . . . . . . . . . . . . 14 with RSVP-TE . . . . . . . . . . . . . . . . . . . . 14
12.3.3. Interoperability with Legacy Routers . . . . . . . . 14 12.2.3. Interoperability with Legacy Routers . . . . . . . . 15
12.3.4. Use of Application Specific Advertisements for RSVP- 12.2.4. Use of Application-Specific Advertisements for RSVP-
TE . . . . . . . . . . . . . . . . . . . . . . . . . 15 TE . . . . . . . . . . . . . . . . . . . . . . . . . 15
13. Security Considerations . . . . . . . . . . . . . . . . . . . 15 13. Security Considerations . . . . . . . . . . . . . . . . . . . 16
14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
14.1. OSPFv2 . . . . . . . . . . . . . . . . . . . . . . . . . 16 14.1. OSPFv2 . . . . . . . . . . . . . . . . . . . . . . . . . 16
14.2. OSPFv3 . . . . . . . . . . . . . . . . . . . . . . . . . 17 14.2. OSPFv3 . . . . . . . . . . . . . . . . . . . . . . . . . 17
15. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 18 15. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 18
16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18
17. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 17. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
17.1. Normative References . . . . . . . . . . . . . . . . . . 18 17.1. Normative References . . . . . . . . . . . . . . . . . . 19
17.2. Informative References . . . . . . . . . . . . . . . . . 20 17.2. Informative References . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
1. Introduction 1. Introduction
Advertisement of link attributes by the OSPFv2 [RFC2328] and OSPFv3 Advertisement of link attributes by the OSPFv2 [RFC2328] and OSPFv3
[RFC5340] protocols in support of traffic engineering (TE) was [RFC5340] protocols in support of traffic engineering (TE) was
introduced by [RFC3630] and [RFC5329] respectively. It has been introduced by [RFC3630] and [RFC5329] respectively. It has been
extended by [RFC4203], [RFC7308] and [RFC7471]. Use of these extended by [RFC4203], [RFC7308] and [RFC7471]. Use of these
extensions has been associated with deployments supporting Traffic extensions has been associated with deployments supporting Traffic
Engineering over Multiprotocol Label Switching (MPLS) in the presence Engineering over Multiprotocol Label Switching (MPLS) in the presence
of the Resource Reservation Protocol (RSVP) - more succinctly of the Resource Reservation Protocol (RSVP) - more succinctly
referred to as RSVP-TE [RFC3209]. referred to as RSVP-TE [RFC3209].
For the purposes of this document an application is a technology For the purposes of this document an application is a technology that
which makes use of link attribute advertisements - examples of which makes use of link attribute advertisements, examples of which are
are listed in Section 5. listed in Section 5.
In recent years new applications have been introduced which have use In recent years new applications have been introduced that have use
cases for many of the link attributes historically used by RSVP-TE. cases for many of the link attributes historically used by RSVP-TE.
Such applications include Segment Routing Traffic Engineering (SRTE) Such applications include Segment Routing (SR) Policy
[I-D.ietf-spring-segment-routing-policy] and Loop Free Alternates [I-D.ietf-spring-segment-routing-policy] and Loop Free Alternates
(LFA) [RFC5286]. This has introduced ambiguity in that if a (LFA) [RFC5286]. This has introduced ambiguity in that if a
deployment includes a mix of RSVP-TE support and SRTE support (for deployment includes a mix of RSVP-TE support and SR Policy support
example) it is not possible to unambiguously indicate which (for example) it is not possible to unambiguously indicate which
advertisements are to be used by RSVP-TE and which advertisements are advertisements are to be used by RSVP-TE and which advertisements are
to be used by SRTE. If the topologies are fully congruent this may to be used by SR Policy. If the topologies are fully congruent this
not be an issue, but any incongruence leads to ambiguity. may not be an issue, but any incongruence leads to ambiguity.
An example where this ambiguity causes a problem is a network in An example where this ambiguity causes a problem is a network in that
which RSVP-TE is enabled only on a subset of its links. A link RSVP-TE is enabled only on a subset of its links. A link attribute
attribute is advertised for the purpose of another application (e.g. is advertised for the purpose of another application (e.g. SR
SRTE) for a link that is not enabled for RSV-TE. As soon as the Policy) for a link that is not enabled for RSVP-TE. As soon as the
router that is an RSVP-TE head-end sees the link attribute being router that is an RSVP-TE head-end sees the link attribute being
advertised for that link, it assumes RSVP-TE is enabled on that link, advertised for that link, it assumes RSVP-TE is enabled on that link,
even though it is not. If such RSVP-TE head-end router tries to even though it is not. If such RSVP-TE head-end router tries to
setup an RSVP-TE path via that link it will result in the path setup setup an RSVP-TE path via that link, it will result in the path setup
failure. failure.
An additional issue arises in cases where both applications are An additional issue arises in cases where both applications are
supported on a link but the link attribute values associated with supported on a link but the link attribute values associated with
each application differ. Current advertisements do not support each application differ. Current advertisements do not support
advertising application specific values for the same attribute on a advertising application-specific values for the same attribute on a
specific link. specific link.
This document defines extensions which address these issues. Also, This document defines extensions that address these issues. Also, as
as evolution of use cases for link attributes can be expected to evolution of use cases for link attributes can be expected to
continue in the years to come, this document defines a solution which continue in the years to come, this document defines a solution that
is easily extensible for the introduction of new applications and new is easily extensible for the introduction of new applications and new
use cases. use cases.
2. Requirements Language 2. 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", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Existing Advertisement of Link Attributes 3. Existing Advertisement of Link Attributes
There are existing advertisements used in support of RSVP-TE. These There are existing advertisements used in support of RSVP-TE. These
advertisements are carried in the OSPFv2 TE Opaque LSA [RFC3630] and advertisements are carried in the OSPFv2 TE Opaque LSA [RFC3630] and
OSPFv3 Intra-Area-TE-LSA [RFC5329]. Additional RSVP-TE link OSPFv3 Intra-Area-TE-LSA [RFC5329]. Additional RSVP-TE link
attributes have been defined by [RFC4203], [RFC7308] and [RFC7471]. attributes have been defined by [RFC4203], [RFC7308] and [RFC7471].
Extended Link Opaque LSAs as defined in [RFC7684] for OSPFv2 and Extended Link Opaque LSAs as defined in [RFC7684] for OSPFv2 and
Extended Router-LSAs [RFC8362] for OSPFv3 are used to advertise link Extended Router-LSAs [RFC8362] for OSPFv3 are used to advertise link
attributes that are used by applications other then RSVP-TE or GMPLS. attributes that are used by applications other than RSVP-TE or GMPLS
These LSAs were defined as a generic containers for distribution of [RFC4203]. These LSAs were defined as a generic containers for
the extended link attributes. distribution of the extended link attributes.
4. Advertisement of Link Attributes 4. Advertisement of Link Attributes
This section outlines the solution for advertising link attributes This section outlines the solution for advertising link attributes
originally defined for RSVP-TE or GMPLS when they are used for other originally defined for RSVP-TE or GMPLS when they are used for other
applications. applications.
4.1. OSPFv2 Extended Link Opaque LSA and OSPFv3 E-Router-LSA 4.1. OSPFv2 Extended Link Opaque LSA and OSPFv3 E-Router-LSA
Advantages of Extended Link Opaque LSAs as defined in [RFC7684] for Advantages of Extended Link Opaque LSAs as defined in [RFC7684] for
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advertisement of link attributes originally defined for RSVP-TE when advertisement of link attributes originally defined for RSVP-TE when
used in packet networks and in GMPLS: used in packet networks and in GMPLS:
1. Advertisement of the link attributes does not make the link part 1. Advertisement of the link attributes does not make the link part
of the RSVP-TE topology. It avoids any conflicts and is fully of the RSVP-TE topology. It avoids any conflicts and is fully
compatible with [RFC3630] and [RFC5329]. compatible with [RFC3630] and [RFC5329].
2. The OSPFv2 TE Opaque LSA and OSPFv3 Intra-Area-TE-LSA remains 2. The OSPFv2 TE Opaque LSA and OSPFv3 Intra-Area-TE-LSA remains
truly opaque to OSPFv2 and OSPFv3 as originally defined in truly opaque to OSPFv2 and OSPFv3 as originally defined in
[RFC3630] and [RFC5329] respectively. Their contents are not [RFC3630] and [RFC5329] respectively. Their contents are not
inspected by OSPF, that acts as a pure transport. inspected by OSPF, which instead acts as a pure transport.
3. There is a clear distinction between link attributes used by 3. There is a clear distinction between link attributes used by
RSVP-TE and link attributes used by other OSPFv2 or OSPFv3 RSVP-TE and link attributes used by other OSPFv2 or OSPFv3
applications. applications.
4. All link attributes that are used by other applications are 4. All link attributes that are used by other applications are
advertised in a single LSA, the Extended Link Opaque LSA in advertised in a single LSA, the Extended Link Opaque LSA in
OSPFv2 or the OSPFv3 E-Router-LSA [RFC8362] in OSPFv3. OSPFv2 or the OSPFv3 E-Router-LSA [RFC8362] in OSPFv3.
The disadvantage of this approach is that in rare cases, the same The disadvantage of this approach is that in rare cases, the same
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TE link attributes used for RSVP-TE/GMPLS continue to use OSPFv2 TE TE link attributes used for RSVP-TE/GMPLS continue to use OSPFv2 TE
Opaque LSA [RFC3630] and OSPFv3 Intra-Area-TE-LSA [RFC5329]. Opaque LSA [RFC3630] and OSPFv3 Intra-Area-TE-LSA [RFC5329].
The format of the link attribute TLVs that have been defined for The format of the link attribute TLVs that have been defined for
RSVP-TE applications will be kept unchanged even when they are used RSVP-TE applications will be kept unchanged even when they are used
for non-RSVP-TE applications. Unique code points are allocated for for non-RSVP-TE applications. Unique code points are allocated for
these link attribute TLVs from the OSPFv2 Extended Link TLV Sub-TLV these link attribute TLVs from the OSPFv2 Extended Link TLV Sub-TLV
Registry [RFC7684] and from the OSPFv3 Extended-LSA Sub-TLV Registry Registry [RFC7684] and from the OSPFv3 Extended-LSA Sub-TLV Registry
[RFC8362], as specified in Section 14. [RFC8362], as specified in Section 14.
5. Advertisement of Application Specific Values 5. Advertisement of Application-Specific Values
To allow advertisement of the application specific values of the link To allow advertisement of the application-specific values of the link
attribute, a new Application Specific Link Attributes (ASLA) sub-TLV attribute, a new Application-Specific Link Attributes (ASLA) sub-TLV
is defined. The ASLA sub-TLV is a sub-TLV of the OSPFv2 Extended is defined. The ASLA sub-TLV is a sub-TLV of the OSPFv2 Extended
Link TLV [RFC7684] and OSPFv3 Router-Link TLV [RFC8362]. Link TLV [RFC7684] and OSPFv3 Router-Link TLV [RFC8362].
On top of advertising the link attributes for standardized On top of advertising the link attributes for standardized
applications, link attributes can be advertised for the purpose of applications, link attributes can be advertised for the purpose of
application that is not defined as standardized one. We call such applications that are not standardized. We call such an application
application a user defined application. What such application might a "User Defined Application" or "UDA". These applications are not
be is not subject to the standardization and is outside of the scope subject to standardization and are outside of the scope of this
of this specification. specification.
The ASLA sub-TLV is an optional sub-TLV and can appear multiple times The ASLA sub-TLV is an optional sub-TLV of OSPFv2 Extended Link TLV
in the OSPFv2 Extended Link TLV and OSPFv3 Router-Link TLV. The ASLA and OSPFv3 Router-Link TLV. Multiple ASLA sub-TLVs can be present in
sub-TLV MUST be used for advertisement of the link attributes listed its parent TLV when different applications want to control different
at the end on this section if these are advertised inside OSPFv2 link attributes or when different value of the same attribute needs
Extended Link TLV and OSPFv3 Router-Link TLV. It has the following to be advertised by multiple applications. The ASLA sub-TLV MUST be
format: used for advertisement of the link attributes listed at the end on
this section if these are advertised inside OSPFv2 Extended Link TLV
and OSPFv3 Router-Link TLV. It has the 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SABM Length | UDABM Length | Reserved | | SABM Length | UDABM Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Standard Application Identifier Bit Mask | | Standard Application Identifier Bit Mask |
+- -+ +- -+
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in octets. The value MUST be 0, 4 or 8. If the User Defined in octets. The value MUST be 0, 4 or 8. If the User Defined
Application Bit Mask is not present, the User Defined Application Application Bit Mask is not present, the User Defined Application
Bit Mask Length MUST be set to 0. Bit Mask Length MUST be set to 0.
Standard Application Identifier Bit Mask: Optional set of bits, Standard Application Identifier Bit Mask: Optional set of bits,
where each bit represents a single standard application. Bits are where each bit represents a single standard application. Bits are
defined in the Link Attribute Application Identifier Registry, defined in the Link Attribute Application Identifier Registry,
which has been defined in [I-D.ietf-isis-te-app]. Current which has been defined in [I-D.ietf-isis-te-app]. Current
assignments are repeated here for informational purpose: assignments are repeated here for informational purpose:
0 1 2 3 4 5 6 7 ...
+-+-+-+-+-+-+-+-+...
|R|S|F| ...
+-+-+-+-+-+-+-+-+...
Bit-0 (R-bit): RSVP-TE Bit-0 (R-bit): RSVP-TE
Bit-1 (S-bit): Segment Routing TE Bit-1 (S-bit): Segment Routing Policy
Bit-2 (F-bit): Loop Free Alternate (LFA). Includes all LFA Bit-2 (F-bit): Loop Free Alternate (LFA). Includes all LFA
types types
User Defined Application Identifier Bit Mask: Optional set of User Defined Application Identifier Bit Mask: Optional set of
bits, where each bit represents a single user defined application. bits, where each bit represents a single user defined application.
If the SABM or UDABM length is other than 0, 4, or 8, the ASLA sub- If the SABM or UDABM length is other than 0, 4, or 8, the ASLA sub-
TLV MUST be ignored by the receiver. TLV MUST be ignored by the receiver.
Standard Application Identifier Bits are defined/sent starting with Standard Application Identifier Bits are defined/sent starting with
Bit 0. Undefined bits which are transmitted MUST be transmitted as 0 Bit 0. Undefined bits that are transmitted MUST be transmitted as 0
and MUST be ignored on receipt. Bits that are not transmitted MUST and MUST be ignored on receipt. Bits that are not transmitted MUST
be treated as if they are set to 0 on receipt. Bits that are not be treated as if they are set to 0 on receipt. Bits that are not
supported by an implementation MUST be ignored on receipt. supported by an implementation MUST be ignored on receipt.
User Defined Application Identifier Bits have no relationship to User Defined Application Identifier Bits have no relationship to
Standard Application Identifier Bits and are not managed by IANA or Standard Application Identifier Bits and are not managed by IANA or
any other standards body. It is recommended that bits are used any other standards body. It is recommended that bits are used
starting with Bit 0 so as to minimize the number of octets required starting with Bit 0 so as to minimize the number of octets required
to advertise all UDAs. to advertise all UDAs. Undefined bits which are transmitted MUST be
transmitted as 0 and MUST be ignored on receipt. Bits that are not
transmitted MUST be treated as if they are set to 0 on receipt. Bits
that are not supported by an implementation MUST be ignored on
receipt.
If the link attribute advertisement is intended to be only used by a If the link attribute advertisement is intended to be only used by a
specific set of applications, corresponding Bit Masks MUST be present specific set of applications, corresponding Bit Masks MUST be present
and application specific bit(s) MUST be set for all applications that and application-specific bit(s) MUST be set for all applications that
use the link attributes advertised in the ASLA sub-TLV. use the link attributes advertised in the ASLA sub-TLV.
Application Bit Masks apply to all link attributes that support Application Bit Masks apply to all link attributes that support
application specific values and are advertised in the ASLA sub-TLV. application-specific values and are advertised in the ASLA sub-TLV.
The advantage of not making the Application Bit Masks part of the The advantage of not making the Application Bit Masks part of the
attribute advertisement itself is that the format of any previously attribute advertisement itself is that the format of any previously
defined link attributes can be kept and reused when advertising them defined link attributes can be kept and reused when advertising them
in the ASLA sub-TLV. in the ASLA sub-TLV.
If the same attribute is advertised in more than single ASLA sub-TLVs If the same attribute is advertised in more than single ASLA sub-TLVs
with the application listed in the Application Bit Masks, the with the application listed in the Application Bit Masks, the
application SHOULD use the first instance of advertisement and ignore application SHOULD use the first instance of advertisement and ignore
any subsequent advertisements of that attribute. any subsequent advertisements of that attribute.
If link attributes are advertised associated with zero length
Application Identifier Bit Masks for both standard applications and
user defined applications, then any Standard Application and/or any
User Defined Application is permitted to use that set of link
attributes. If support for a new application is introduced on any
node in a network in the presence of such advertisements, these
advertisements are permitted to be used by the new application. If
this is not what is intended, then existing advertisements MUST be
readvertised with an explicit set of applications specified before a
new application is introduced.
An application-specific advertisement (Application Identifier Bit
Mask with a matching Application Identifier Bit set) for an attribute
MUST always be preferred over the advertisement of the same attribute
with the zero length Application Identifier Bit Masks for both
standard applications and user defined applications on the same link.
This document defines the initial set of link attributes that MUST This document defines the initial set of link attributes that MUST
use the ASLA sub-TLV if advertised in the OSPFv2 Extended Link TLV or use the ASLA sub-TLV if advertised in the OSPFv2 Extended Link TLV or
in the OSPFv3 Router-Link TLV. Documents which define new link in the OSPFv3 Router-Link TLV. Documents which define new link
attributes MUST state whether the new attributes support application attributes MUST state whether the new attributes support application-
specific values and as such MUST be advertised in an ASLA sub-TLV. specific values and as such are advertised in an ASLA sub-TLV. The
The link attributes that MUST be advertised in ASLA sub-TLVs are: standard link attributes that are advertised in ASLA sub-TLVs are:
- Shared Risk Link Group [RFC4203] - Shared Risk Link Group [RFC4203]
- Unidirectional Link Delay [RFC7471] - Unidirectional Link Delay [RFC7471]
- Min/Max Unidirectional Link Delay [RFC7471] - Min/Max Unidirectional Link Delay [RFC7471]
- Unidirectional Delay Variation [RFC7471] - Unidirectional Delay Variation [RFC7471]
- Unidirectional Link Loss [RFC7471] - Unidirectional Link Loss [RFC7471]
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- Unidirectional Residual Bandwidth [RFC7471] - Unidirectional Residual Bandwidth [RFC7471]
- Unidirectional Available Bandwidth [RFC7471] - Unidirectional Available Bandwidth [RFC7471]
- Unidirectional Utilized Bandwidth [RFC7471] - Unidirectional Utilized Bandwidth [RFC7471]
- Administrative Group [RFC3630] - Administrative Group [RFC3630]
- Extended Administrative Group [RFC7308] - Extended Administrative Group [RFC7308]
- TE Metric [RFC3630] - TE Metric [RFC3630]
6. Reused TE link attributes 6. Reused TE link attributes
This section defines the use case and indicates the code points This section defines the use case and indicates the code points
(Section 14) from the OSPFv2 Extended Link TLV Sub-TLV Registry and (Section 14) from the OSPFv2 Extended Link TLV Sub-TLV Registry and
OSPFv3 Extended-LSA Sub-TLV Registry for some of the link attributes OSPFv3 Extended-LSA Sub-TLV Registry for some of the link attributes
that have been originally defined for RSVP-TE or GMPLS. that have been originally defined for RSVP-TE or GMPLS.
6.1. Shared Risk Link Group (SRLG) 6.1. Shared Risk Link Group (SRLG)
The SRLG of a link can be used in OSPF calculated IPFRR [RFC5714] to The SRLG of a link can be used in OSPF calculated IPFRR (IP Fast
compute a backup path that does not share any SRLG group with the Reroute) [RFC5714] to compute a backup path that does not share any
protected link. SRLG group with the protected link.
To advertise the SRLG of the link in the OSPFv2 Extended Link TLV, To advertise the SRLG of the link in the OSPFv2 Extended Link TLV,
the same format for the sub-TLV defined in section 1.3 of [RFC4203] the same format for the sub-TLV defined in section 1.3 of [RFC4203]
is used and TLV type 11 is used. Similarly, for OSPFv3 to advertise is used and TLV type 11 is used. Similarly, for OSPFv3 to advertise
the SRLG in the OSPFv3 Router-Link TLV, TLV type 12 is used. the SRLG in the OSPFv3 Router-Link TLV, TLV type 12 is used.
6.2. Extended Metrics 6.2. Extended Metrics
[RFC3630] defines several link bandwidth types. [RFC7471] defines [RFC3630] defines several link bandwidth types. [RFC7471] defines
extended link metrics that are based on link bandwidth, delay and extended link metrics that are based on link bandwidth, delay and
loss characteristics. All these can be used to compute primary and loss characteristics. All of these can be used to compute primary
backup paths within an OSPF area to satisfy requirements for and backup paths within an OSPF area to satisfy requirements for
bandwidth, delay (nominal or worst case) or loss. bandwidth, delay (nominal or worst case) or loss.
To advertise extended link metrics in the OSPFv2 Extended Link TLV, To advertise extended link metrics in the OSPFv2 Extended Link TLV,
the same format for the sub-TLVs defined in [RFC7471] is used with the same format for the sub-TLVs defined in [RFC7471] is used with
the following TLV types: the following TLV types:
12 - Unidirectional Link Delay 12 - Unidirectional Link Delay
13 - Min/Max Unidirectional Link Delay 13 - Min/Max Unidirectional Link Delay
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advertised in the ASLA sub-TLV. Instead, it MAY be advertised as a advertised in the ASLA sub-TLV. Instead, it MAY be advertised as a
sub-TLV of the OSPFv3 E-Router-LSA Router-Link TLV [RFC8362]. sub-TLV of the OSPFv3 E-Router-LSA Router-Link TLV [RFC8362].
To advertise the Remote Interface IPv6 Address Sub-TLV in the OSPFv3 To advertise the Remote Interface IPv6 Address Sub-TLV in the OSPFv3
Router-Link TLV, the same format for sub-TLV defined in [RFC5329] is Router-Link TLV, the same format for sub-TLV defined in [RFC5329] is
used with TLV type 25. used with TLV type 25.
11. Attribute Advertisements and Enablement 11. Attribute Advertisements and Enablement
This document defines extensions to support the advertisement of This document defines extensions to support the advertisement of
application specific link attributes. application-specific link attributes.
There are applications where the application enablement on the link There are applications where the application enablement on the link
is relevant - e.g. RSVP-TE - one need to make sure that RSVP is is relevant - e.g., RSVP-TE - one needs to make sure that RSVP is
enabled on the link before sending a RSVP-TE signaling message over enabled on the link before sending a RSVP-TE signaling message over
it. it.
There are applications, where the enablement of the application on There are applications where the enablement of the application on the
the link is irrelevant and has nothing to do with the fact that some link is irrelevant and has nothing to do with the fact that some link
link attributes are advertised for the purpose of such application - attributes are advertised for the purpose of such application. An
e.g. LFA. example of this is LFA.
Whether the presence of link attribute advertisements for a given Whether the presence of link attribute advertisements for a given
application indicates that the application is enabled on that link application indicates that the application is enabled on that link
depends upon the application. Similarly, whether the absence of link depends upon the application. Similarly, whether the absence of link
attribute advertisements indicates that the application is not attribute advertisements indicates that the application is not
enabled depends upon the application. enabled depends upon the application.
In the case of RSVP-TE, the advertisement of application specific In the case of RSVP-TE, the advertisement of application-specific
link attributes has no implication of RSVP-TE being enabled on that link attributes has no implication of RSVP-TE being enabled on that
link. The RSVP-TE enablement is solely derived from the information link. The RSVP-TE enablement is solely derived from the information
carried in the OSPFv2 TE Opaque LSA [RFC3630] and OSPFv3 Intra-Area- carried in the OSPFv2 TE Opaque LSA [RFC3630] and OSPFv3 Intra-Area-
TE-LSA [RFC5329]. TE-LSA [RFC5329].
In the case of SRTE, advertisement of application specific link In the case of SR Policy, advertisement of application-specific link
attributes does not indicate enablement of SRTE. The advertisements attributes does not indicate enablement of SR Policy. The
are only used to support constraints which may be applied when advertisements are only used to support constraints that may be
specifying an explicit path. SRTE is implicitly enabled on all links applied when specifying an explicit path. SR Policy is implicitly
which are part of the Segment Routing enabled topology independent of enabled on all links that are part of the Segment Routing enabled
the existence of link attribute advertisements topology independent of the existence of link attribute
advertisements
In the case of LFA, advertisement of application specific link In the case of LFA, advertisement of application-specific link
attributes does not indicate enablement of LFA on that link. attributes does not indicate enablement of LFA on that link.
Enablement is controlled by local configuration. Enablement is controlled by local configuration.
If, in the future, additional standard applications are defined to If, in the future, additional standard applications are defined to
use this mechanism, the specification defining this use MUST define use this mechanism, the specification defining this use MUST define
the relationship between application specific link attribute the relationship between application-specific link attribute
advertisements and enablement for that application. advertisements and enablement for that application.
This document allows the advertisement of application specific link This document allows the advertisement of application-specific link
attributes with no application identifiers i.e., both the Standard attributes with no application identifiers i.e., both the Standard
Application Identifier Bit Mask and the User Defined Application Application Identifier Bit Mask and the User Defined Application
Identifier Bit Mask are not present (See Section 5). This supports Identifier Bit Mask are not present (See Section 5). This supports
the use of the link attribute by any application. In the presence of the use of the link attribute by any application. In the presence of
an application where the advertisement of link attribute an application where the advertisement of link attribute
advertisements is used to infer the enablement of an application on advertisements is used to infer the enablement of an application on
that link (e.g., RSVP-TE), the absence of the application identifier that link (e.g., RSVP-TE), the absence of the application identifier
leaves ambiguous whether that application is enabled on such a link. leaves ambiguous whether that application is enabled on such a link.
This needs to be considered when making use of the "any application" This needs to be considered when making use of the "any application"
encoding. encoding.
12. Deployment Considerations 12. Deployment Considerations
12.1. Use of Legacy RSVP-TE LSA Advertisements 12.1. Use of Legacy RSVP-TE LSA Advertisements
Bit Identifiers for Standard Applications are defined in Section 5. Bit Identifiers for Standard Applications are defined in Section 5.
All of the identifiers defined in this document are associated with All of the identifiers defined in this document are associated with
applications which were already deployed in some networks prior to applications that were already deployed in some networks prior to the
the writing of this document. Therefore, such applications have been writing of this document. Therefore, such applications have been
deployed using the RSVP-TE LSA advertisements. The Standard deployed using the RSVP-TE LSA advertisements. The Standard
Applications defined in this document may continue to use RSVP-TE LSA Applications defined in this document may continue to use RSVP-TE LSA
advertisements for a given link so long as at least one of the advertisements for a given link so long as at least one of the
following conditions is true: following conditions is true:
The application is RSVP-TE The application is RSVP-TE
The application is SRTE or LFA and RSVP-TE is not deployed The application is SR Policy or LFA and RSVP-TE is not deployed
anywhere in the network anywhere in the network
The application is SRTE or LFA, RSVP-TE is deployed in the The application is SR Policy or LFA, RSVP-TE is deployed in the
network, and both the set of links on which SRTE and/or LFA network, and both the set of links on which SR Policy and/or LFA
advertisements are required and the attribute values used by SRTE advertisements are required and the attribute values used by SR
and/or LFA on all such links is fully congruent with the links and Policy and/or LFA on all such links is fully congruent with the
attribute values used by RSVP-TE links and attribute values used by RSVP-TE
Under the conditions defined above, implementations which support the Under the conditions defined above, implementations that support the
extensions defined in this document have the choice of using RSVP-TE extensions defined in this document have the choice of using RSVP-TE
LSA advertisements or application specific advertisements in support LSA advertisements or application-specific advertisements in support
of SRTE and/or LFA. This will require implementations to provide of SR Policy and/or LFA. This will require implementations to
controls specifying which type of advertisements are to be sent/ provide controls specifying which type of advertisements are to be
processed on receive for these applications. Further discussion of sent/ processed on receive for these applications. Further
the associated issues can be found in Section 12.3. discussion of the associated issues can be found in Section 12.2.
New applications which future documents define to make use of the New applications that future documents define to make use of the
advertisements defined in this document MUST NOT make use of RSVP-TE advertisements defined in this document MUST NOT make use of RSVP-TE
LSA advertisements. This simplifies deployment of new applications LSA advertisements. This simplifies deployment of new applications
by eliminating the need to support multiple ways to advertise by eliminating the need to support multiple ways to advertise
attributes for the new applications. attributes for the new applications.
12.2. Use of Zero Length Application Identifier Bit Masks 12.2. Interoperability, Backwards Compatibility and Migration Concerns
If link attributes are advertised associated with zero length
Application Identifier Bit Masks for both standard applications and
user defined applications, then any Standard Application and/or any
User Defined Application is permitted to use that set of link
attributes so long as there is not another set of attributes
advertised on that same link which is associated with a non-zero
length Application Identifier Bit Mask with a matching Application
Identifier Bit set. If support for a new application is introduced
on any node in a network in the presence of such advertisements,
these advertisements are permitted to be used by the new application.
If this is not what is intended, then existing advertisements MUST be
readvertised with an explicit set of applications specified before a
new application is introduced.
12.3. Interoperability, Backwards Compatibility and Migration Concerns
Existing deployments of RSVP-TE, SRTE, and/or LFA utilize the legacy Existing deployments of RSVP-TE, SR Policy, and/or LFA utilize the
advertisements listed in Section 3. Routers which do not support the legacy advertisements listed in Section 3. Routers which do not
extensions defined in this document will only process legacy support the extensions defined in this document will only process
advertisements and are likely to infer that RSVP-TE is enabled on the legacy advertisements and are likely to infer that RSVP-TE is enabled
links for which legacy advertisements exist. It is expected that on the links for which legacy advertisements exist. It is expected
deployments using the legacy advertisements will persist for a that deployments using the legacy advertisements will persist for a
significant period of time. Therefore deployments using the significant period of time. Therefore deployments using the
extensions defined in this document in the presence of routers which extensions defined in this document in the presence of routers that
do not support these extensions need to be able to interoperate with do not support these extensions need to be able to interoperate with
the use of legacy advertisements by the legacy routers. The the use of legacy advertisements by the legacy routers. The
following sub-sections discuss interoperability and backwards following sub-sections discuss interoperability and backwards
compatibility concerns for a number of deployment scenarios. compatibility concerns for a number of deployment scenarios.
12.3.1. Multiple Applications: Common Attributes with RSVP-TE 12.2.1. Multiple Applications: Common Attributes with RSVP-TE
In cases where multiple applications are utilizing a given link, one In cases where multiple applications are utilizing a given link, one
of the applications is RSVP-TE, and all link attributes for a given of the applications is RSVP-TE, and all link attributes for a given
link are common to the set of applications utilizing that link, link are common to the set of applications utilizing that link,
interoperability is achieved by using legacy advertisements for RSVP- interoperability is achieved by using legacy advertisements for RSVP-
TE. Attributes for applications other than RSVP-TE MUST be TE. Attributes for applications other than RSVP-TE MUST be
advertised using application specific advertisements. This results advertised using application-specific advertisements. This results
in duplicate advertisements for those attributes. in duplicate advertisements for those attributes.
12.3.2. Multiple Applications: Some Attributes Not Shared with RSVP-TE 12.2.2. Multiple Applications: Some Attributes Not Shared with RSVP-TE
In cases where one or more applications other than RSVP-TE are In cases where one or more applications other than RSVP-TE are
utilizing a given link and one or more link attribute values are not utilizing a given link and one or more link attribute values are not
shared with RSVP-TE, interoperability is achieved by using legacy shared with RSVP-TE, interoperability is achieved by using legacy
advertisements for RSVP-TE. Attributes for applications other than advertisements for RSVP-TE. Attributes for applications other than
RSVP-TE MUST be advertised using application specific advertisements. RSVP-TE MUST be advertised using application-specific advertisements.
In cases where some link attributes are shared with RSVP-TE, this In cases where some link attributes are shared with RSVP-TE, this
requires duplicate advertisements for those attributes requires duplicate advertisements for those attributes
12.3.3. Interoperability with Legacy Routers 12.2.3. Interoperability with Legacy Routers
For the applications defined in this document, routers which do not For the applications defined in this document, routers that do not
support the extensions defined in this document will send and receive support the extensions defined in this document will send and receive
only legacy link attribute advertisements. So long as there is any only legacy link attribute advertisements. So long as there is any
legacy router in the network which has any of the applications legacy router in the network that has any of the applications
enabled, all routers MUST continue to advertise link attributes using enabled, all routers MUST continue to advertise link attributes using
legacy advertisements. In addition, the link attribute values legacy advertisements. In addition, the link attribute values
associated with the set of applications supported by legacy routers associated with the set of applications supported by legacy routers
(RSVP-TE, SRTE, and/or LFA) are always shared since legacy routers (RSVP-TE, SR Policy, and/or LFA) are always shared since legacy
have no way of advertising or processing application specific values. routers have no way of advertising or processing application-specific
Once all legacy routers have been upgraded, migration from legacy values. Once all legacy routers have been upgraded, migration from
advertisements to application specific advertisements can be achieved legacy advertisements to application specific advertisements can be
via the following steps: achieved via the following steps:
1)Send new application specific advertisements while continuing to 1)Send new application-specific advertisements while continuing to
advertise using the legacy advertisement (all advertisements are then advertise using the legacy advertisement (all advertisements are then
duplicated). Receiving routers continue to use legacy duplicated). Receiving routers continue to use legacy
advertisements. advertisements.
2)Enable the use of the application specific advertisements on all 2)Enable the use of the application-specific advertisements on all
routers routers
3)Keep legacy advertisements if needed for RSVP-TE purposes. 3)Keep legacy advertisements if needed for RSVP-TE purposes.
When the migration is complete, it then becomes possible to advertise When the migration is complete, it then becomes possible to advertise
incongruent values per application on a given link. incongruent values per application on a given link.
Documents defining new applications which make use of the application Documents defining new applications that make use of the application-
specific advertisements defined in this document MUST discuss specific advertisements defined in this document MUST discuss
interoperability and backwards compatibility issues that could occur interoperability and backwards compatibility issues that could occur
in the presence of routers which do not support the new application. in the presence of routers that do not support the new application.
12.3.4. Use of Application Specific Advertisements for RSVP-TE 12.2.4. Use of Application-Specific Advertisements for RSVP-TE
The extensions defined in this document support RSVP-TE as one of the The extensions defined in this document support RSVP-TE as one of the
supported applications. It is however RECOMMENDED to advertise all supported applications. It is however RECOMMENDED to advertise all
link-attributes for RSVP-TE in the existing OSPFv2 TE Opaque LSA link-attributes for RSVP-TE in the existing OSPFv2 TE Opaque LSA
[RFC3630] and OSPFv3 Intra-Area-TE-LSA [RFC5329] to maintain backward [RFC3630] and OSPFv3 Intra-Area-TE-LSA [RFC5329] to maintain backward
compatibility. RSVP-TE can eventually utilize the application compatibility. RSVP-TE can eventually utilize the application-
specific advertisements for newly defined link attributes, which are specific advertisements for newly defined link attributes, that are
defined as application specific. defined as application-specific.
Link attributes that are NOT allowed to be advertised in the ASLA Link attributes that are not allowed to be advertised in the ASLA
Sub-TLV, such as Maximum Reservable Link Bandwidth and Unreserved Sub-TLV, such as Maximum Reservable Link Bandwidth and Unreserved
Bandwidth MUST use the OSPFv2 TE Opaque LSA [RFC3630] and OSPFv3 Bandwidth MUST use the OSPFv2 TE Opaque LSA [RFC3630] and OSPFv3
Intra-Area-TE-LSA [RFC5329] and MUST NOT be advertised in ASLA Sub- Intra-Area-TE-LSA [RFC5329] and MUST NOT be advertised in ASLA Sub-
TLV. TLV.
13. Security Considerations 13. Security Considerations
Existing security extensions as described in [RFC2328], [RFC5340] and Existing security extensions as described in [RFC2328], [RFC5340] and
[RFC8362] apply to extensions defined in this document. While OSPF [RFC8362] apply to extensions defined in this document. While OSPF
is under a single administrative domain, there can be deployments is under a single administrative domain, there can be deployments
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this document are detected and do not provide a vulnerability for this document are detected and do not provide a vulnerability for
attackers to crash the OSPF router or routing process. Reception of attackers to crash the OSPF router or routing process. Reception of
a malformed TLV or Sub-TLV SHOULD be counted and/or logged for a malformed TLV or Sub-TLV SHOULD be counted and/or logged for
further analysis. Logging of malformed TLVs and Sub-TLVs SHOULD be further analysis. Logging of malformed TLVs and Sub-TLVs SHOULD be
rate-limited to prevent a Denial of Service (DoS) attack (distributed rate-limited to prevent a Denial of Service (DoS) attack (distributed
or otherwise) from overloading the OSPF control plane. or otherwise) from overloading the OSPF control plane.
This document defines a new way to advertise link attributes. This document defines a new way to advertise link attributes.
Tampering with the information defined in this document may have an Tampering with the information defined in this document may have an
effect on applications using it, including impacting Traffic effect on applications using it, including impacting Traffic
Engineering. This is similar in nature to the impacts associated Engineering that uses various link attributes for its path
computation. This is similar in nature to the impacts associated
with (for example) [RFC3630]. As the advertisements defined in this with (for example) [RFC3630]. As the advertisements defined in this
document limit the scope to specific applications, the impact of document limit the scope to specific applications, the impact of
tampering is similarly limited in scope. tampering is similarly limited in scope.
14. IANA Considerations 14. IANA Considerations
This specifications updates two existing registries: This specifications updates two existing registries:
- OSPFv2 Extended Link TLV Sub-TLVs Registry - OSPFv2 Extended Link TLV Sub-TLVs Registry
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New values are allocated using the IETF Review procedure as described New values are allocated using the IETF Review procedure as described
in [RFC5226]. in [RFC5226].
14.1. OSPFv2 14.1. OSPFv2
The OSPFv2 Extended Link TLV Sub-TLVs Registry [RFC7684] defines sub- The OSPFv2 Extended Link TLV Sub-TLVs Registry [RFC7684] defines sub-
TLVs at any level of nesting for OSPFv2 Extended Link TLVs. IANA has TLVs at any level of nesting for OSPFv2 Extended Link TLVs. IANA has
assigned the following Sub-TLV types from the OSPFv2 Extended Link assigned the following Sub-TLV types from the OSPFv2 Extended Link
TLV Sub-TLVs Registry: TLV Sub-TLVs Registry:
10 - Application Specific Link Attributes 10 - Application-Specific Link Attributes
11 - Shared Risk Link Group 11 - Shared Risk Link Group
12 - Unidirectional Link Delay 12 - Unidirectional Link Delay
13 - Min/Max Unidirectional Link Delay 13 - Min/Max Unidirectional Link Delay
14 - Unidirectional Delay Variation 14 - Unidirectional Delay Variation
15 - Unidirectional Link Loss 15 - Unidirectional Link Loss
16 - Unidirectional Residual Bandwidth 16 - Unidirectional Residual Bandwidth
17 - Unidirectional Available Bandwidth 17 - Unidirectional Available Bandwidth
18 - Unidirectional Utilized Bandwidth 18 - Unidirectional Utilized Bandwidth
19 - Administrative Group 19 - Administrative Group
20 - Extended Administrative Group 20 - Extended Administrative Group
22 - TE Metric 22 - TE Metric
23 - Maximum Link Bandwidth 23 - Maximum Link Bandwidth
14.2. OSPFv3 14.2. OSPFv3
The OSPFv3 Extended-LSA Sub-TLV Registry [RFC8362] defines sub-TLVs The OSPFv3 Extended-LSA Sub-TLV Registry [RFC8362] defines sub-TLVs
at any level of nesting for OSPFv3 Extended LSAs. IANA has assigned at any level of nesting for OSPFv3 Extended LSAs. IANA has assigned
the following Sub-TLV types from the OSPFv3 Extended-LSA Sub-TLV the following Sub-TLV types from the OSPFv3 Extended-LSA Sub-TLV
Registry: Registry:
11 - Application Specific Link Attributes 11 - Application-Specific Link Attributes
12 - Shared Risk Link Group 12 - Shared Risk Link Group
13 - Unidirectional Link Delay 13 - Unidirectional Link Delay
14 - Min/Max Unidirectional Link Delay 14 - Min/Max Unidirectional Link Delay
15 - Unidirectional Delay Variation 15 - Unidirectional Delay Variation
16 - Unidirectional Link Loss 16 - Unidirectional Link Loss
skipping to change at page 18, line 43 skipping to change at page 19, line 12
Thanks to Alvaro Retana for his detailed review and comments. Thanks to Alvaro Retana for his detailed review and comments.
17. References 17. References
17.1. Normative References 17.1. Normative References
[I-D.ietf-isis-te-app] [I-D.ietf-isis-te-app]
Ginsberg, L., Psenak, P., Previdi, S., Henderickx, W., and Ginsberg, L., Psenak, P., Previdi, S., Henderickx, W., and
J. Drake, "IS-IS TE Attributes per application", draft- J. Drake, "IS-IS TE Attributes per application", draft-
ietf-isis-te-app-14 (work in progress), June 2020. ietf-isis-te-app-17 (work in progress), June 2020.
[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>.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998, DOI 10.17487/RFC2328, April 1998,
<https://www.rfc-editor.org/info/rfc2328>. <https://www.rfc-editor.org/info/rfc2328>.
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