< draft-ietf-ospf-te-link-attr-reuse-12.txt   draft-ietf-ospf-te-link-attr-reuse-13.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: November 20, 2020 W. Henderickx Expires: December 7, 2020 W. Henderickx
Nokia Nokia
J. Tantsura J. Tantsura
Apstra Apstra
J. Drake J. Drake
Juniper Networks Juniper Networks
May 19, 2020 June 5, 2020
OSPF Link Traffic Engineering Attribute Reuse OSPF Link Traffic Engineering Attribute Reuse
draft-ietf-ospf-te-link-attr-reuse-12.txt draft-ietf-ospf-te-link-attr-reuse-13.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 Traffic Engineering, Loop Free Alternate) have been
defined which also make use of the link attribute advertisements. In defined which also make use of the link attribute advertisements. In
cases where multiple applications wish to make use of these link cases where multiple applications wish to make use of these link
attributes the current advertisements do not support application attributes the current advertisements do not support application
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 20, 2020. This Internet-Draft will expire on December 7, 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 42 skipping to change at page 2, line 42
6.4. Traffic Engineering Metric . . . . . . . . . . . . . . . 10 6.4. Traffic Engineering Metric . . . . . . . . . . . . . . . 10
7. Maximum Link Bandwidth . . . . . . . . . . . . . . . . . . . 10 7. Maximum Link Bandwidth . . . . . . . . . . . . . . . . . . . 10
8. Considerations for Extended TE Metrics . . . . . . . . . . . 10 8. Considerations for Extended TE Metrics . . . . . . . . . . . 10
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 . . . . . . . . . . . . 11
11. Attribute Advertisements and Enablement . . . . . . . . . . . 11 11. Attribute Advertisements and Enablement . . . . . . . . . . . 11
12. Deployment Considerations . . . . . . . . . . . . . . . . . . 12 12. Deployment Considerations . . . . . . . . . . . . . . . . . . 12
12.1. Use of Legacy RSVP-TE LSA Advertisements . . . . . . . . 12 12.1. Use of Legacy RSVP-TE LSA Advertisements . . . . . . . . 12
12.2. Use of Zero Length Application Identifier Bit Masks . . 13 12.2. Use of Zero Length Application Identifier Bit Masks . . 13
12.3. Interoperability, Backwards Compatibility and Migration 12.3. Interoperability, Backwards Compatibility and Migration
Concerns . . . . . . . . . . . . . . . . . . . . . . . . 13 Concerns . . . . . . . . . . . . . . . . . . . . . . . . 14
12.3.1. Multiple Applications: Common Attributes with RSVP- 12.3.1. Multiple Applications: Common Attributes with RSVP-
TE . . . . . . . . . . . . . . . . . . . . . . . . . 13 TE . . . . . . . . . . . . . . . . . . . . . . . . . 14
12.3.2. Multiple Applications: Some Attributes Not Shared 12.3.2. Multiple Applications: Some Attributes Not Shared
with RSVP-TE . . . . . . . . . . . . . . . . . . . . 14 with RSVP-TE . . . . . . . . . . . . . . . . . . . . 14
12.3.3. Interoperability with Legacy Routers . . . . . . . . 14 12.3.3. Interoperability with Legacy Routers . . . . . . . . 14
12.3.4. Use of Application Specific Advertisements for RSVP- 12.3.4. Use of Application Specific Advertisements for RSVP-
TE . . . . . . . . . . . . . . . . . . . . . . . . . 15 TE . . . . . . . . . . . . . . . . . . . . . . . . . 15
13. Security Considerations . . . . . . . . . . . . . . . . . . . 15 13. Security Considerations . . . . . . . . . . . . . . . . . . . 15
14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
14.1. OSPFv2 . . . . . . . . . . . . . . . . . . . . . . . . . 16 14.1. OSPFv2 . . . . . . . . . . . . . . . . . . . . . . . . . 16
14.2. OSPFv3 . . . . . . . . . . . . . . . . . . . . . . . . . 16 14.2. OSPFv3 . . . . . . . . . . . . . . . . . . . . . . . . . 17
15. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 17 15. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 18
16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18
17. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 17. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
17.1. Normative References . . . . . . . . . . . . . . . . . . 18 17.1. Normative References . . . . . . . . . . . . . . . . . . 18
17.2. Informative References . . . . . . . . . . . . . . . . . 19 17.2. Informative References . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 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
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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 Traffic Engineering (SRTE)
[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 SRTE support (for
example) it is not possible to unambiguously indicate which 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 SRTE. If the topologies are fully congruent this may
not be an issue, but any incongruence leads to ambiguity. not be an issue, but any incongruence leads to ambiguity.
An example where this ambiguity causes a problem is a network in
which RSVP-TE is enabled only on a subset of its links. A link
attribute is advertised for the purpose of another application (e.g.
SRTE) for a link that is not enabled for RSV-TE. As soon as the
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,
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
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 which address these issues. Also,
as evolution of use cases for link attributes can be expected to as 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 which
is easily extensible for the introduction of new applications and new is easily extensible for the introduction of new applications and new
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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
OSPFv2 and Extended Router-LSAs [RFC8362] for OSPFv3 when used for OSPFv2 and Extended Router-LSAs [RFC8362] for OSPFv3 with respect to
advertisement of link attributes originally defined for RSVP-TE or advertisement of link attributes originally defined for RSVP-TE when
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, that acts as a pure transport.
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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
applications, link attributes can be advertised for the purpose of
application that is not defined as standardized one. We call such
application a user defined application. What such application might
be is not subject to the standardization and is outside of the scope
of this specification.
The ASLA sub-TLV is an optional sub-TLV and can appear multiple times The ASLA sub-TLV is an optional sub-TLV and can appear multiple times
in the OSPFv2 Extended Link TLV and OSPFv3 Router-Link TLV. The ASLA in the OSPFv2 Extended Link TLV and OSPFv3 Router-Link TLV. The ASLA
sub-TLV MUST be used for advertisement of the link attributes listed sub-TLV MUST be used for advertisement of the link attributes listed
at the end on this section if these are advertised inside OSPFv2 at the end on this section if these are advertised inside OSPFv2
Extended Link TLV and OSPFv3 Router-Link TLV. It has the following Extended Link TLV and OSPFv3 Router-Link TLV. It has the following
format: 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Type: 10 (OSPFv2), 11 (OSPFv3) Type: 10 (OSPFv2), 11 (OSPFv3)
Length: variable Length: variable
SABM Length: Standard Application Identifier Bit Mask Length in SABM Length: Standard Application Identifier Bit Mask Length in
octets. The value MUST be 0, 4 or 8. If the Standard Application octets. The value MUST be 0, 4 or 8. If the Standard Application
Bit Mask is not present, the Standard Application Bit Mask Length Bit Mask is not present, the Standard Application Bit Mask Length
MUST be set to 0. MUST be set to 0.
UDABM Length: User Defined Application Identifier Bit Mask Length UDABM Length: User Defined Application Identifier Bit Mask Length
in octets. The legal values are 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 [I-D.ietf-isis-te-app]. The bits are repeated here for defined in the Link Attribute Application Identifier Registry,
informational purpose: which has been defined in [I-D.ietf-isis-te-app]. Current
assignments are repeated here for informational purpose:
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 TE
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 MUST be transmitted as 0 and MUST be ignored Bit 0. Undefined bits which are transmitted MUST be transmitted as 0
on receipt. Bits that are NOT transmitted MUST be treated as if they and MUST be ignored on receipt. Bits that are not transmitted MUST
are set to 0 on receipt. Bits that are not supported by an be treated as if they are set to 0 on receipt. Bits that are not
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.
If the link attribute advertisement is limited to be 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
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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 MUST be advertised in an ASLA sub-TLV.
The link attributes that MUST be advertised in ASLA sub-TLVs are: The link attributes that MUST be advertised in ASLA sub-TLVs are:
- Shared Risk Link Group [RFC4203] - Shared Risk Link Group [RFC4203]
- Unidirectional Link Dela [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]
- Unidirectional Residual Bandwidth [RFC7471] - Unidirectional Residual Bandwidth [RFC7471]
- Unidirectional Available Bandwidth [RFC7471] - Unidirectional Available Bandwidth [RFC7471]
- Unidirectional Utilized Bandwidth [RFC7471] - Unidirectional Utilized Bandwidth [RFC7471]
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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
is relevant - e.g. RSVP-TE - one need to make sure that RSVP is
enabled on the link before sending a RSVP-TE signaling message over
it.
There are applications, where the enablement of the application on
the link is irrelevant and has nothing to do with the fact that some
link attributes are advertised for the purpose of such application -
e.g. 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 SRTE, advertisement of application specific link
attributes does NOT indicate enablement of SRTE. The advertisements attributes does not indicate enablement of SRTE. The advertisements
are only used to support constraints which may be applied when are only used to support constraints which may be applied when
specifying an explicit path. SRTE is implicitly enabled on all links specifying an explicit path. SRTE is implicitly enabled on all links
which are part of the Segment Routing enabled topology independent of which are part of the Segment Routing enabled topology independent of
the existence of link attribute advertisements 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
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12.3. Interoperability, Backwards Compatibility and Migration Concerns 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, SRTE, and/or LFA utilize the legacy
advertisements listed in Section 3. Routers which do not support the advertisements listed in Section 3. Routers which do not support the
extensions defined in this document will only process legacy extensions defined in this document will only process legacy
advertisements and are likely to infer that RSVP-TE is enabled on the advertisements and are likely to infer that RSVP-TE is enabled on the
links for which legacy advertisements exist. It is expected that links for which legacy advertisements exist. It is expected that
deployments using the legacy advertisements will persist for a 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 must be able to co-exist with use extensions defined in this document in the presence of routers which
of the legacy advertisements by routers which do not support the do not support these extensions need to be able to interoperate with
extensions defined in this document. The following sub-sections the use of legacy advertisements by the legacy routers. The
discuss interoperability and backwards compatibility concerns for a following sub-sections discuss interoperability and backwards
number of deployment scenarios. compatibility concerns for a number of deployment scenarios.
12.3.1. Multiple Applications: Common Attributes with RSVP-TE 12.3.1. 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 12.3.2. 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 12.3.3. Interoperability with Legacy Routers
For the applications defined in this document, routers which do not For the applications defined in this document, routers which do not
support the extensions defined in this document will send and receive support the extensions defined in this document will send and receive
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legacy router in the network which has any of the applications legacy router in the network which 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, SRTE, and/or LFA) are always shared since legacy routers
have no way of advertising or processing application specific values. have no way of advertising or processing application specific values.
Once all legacy routers have been upgraded, migration from legacy Once all legacy routers have been upgraded, migration from legacy
advertisements to application specific advertisements can be achieved advertisements to application specific advertisements can be achieved
via the following steps: via the following steps:
1)Send application specific advertisements while continuing to 1)Send new application specific advertisements while continuing to
advertise using legacy (all advertisements are then duplicated). advertise using the legacy advertisement (all advertisements are then
Receiving routers continue to use legacy advertisements. duplicated). Receiving routers continue to use legacy
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 which make use of the application
skipping to change at page 16, line 4 skipping to change at page 16, line 22
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. 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:
- OSPFv2 Extended Link TLV Sub-TLVs Registry
- OSPFv3 Extended LSA Sub-TLV Registry
New values are allocated using the IETF Review procedure as described
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
skipping to change at page 18, line 38 skipping to change at page 18, line 43
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-13 (work in progress), May 2020. ietf-isis-te-app-14 (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>.
skipping to change at page 20, line 20 skipping to change at page 20, line 22
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<https://www.rfc-editor.org/info/rfc3209>. <https://www.rfc-editor.org/info/rfc3209>.
[RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality [RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality
for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006, for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006,
<https://www.rfc-editor.org/info/rfc4552>. <https://www.rfc-editor.org/info/rfc4552>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<https://www.rfc-editor.org/info/rfc5226>.
[RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for [RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for
IP Fast Reroute: Loop-Free Alternates", RFC 5286, IP Fast Reroute: Loop-Free Alternates", RFC 5286,
DOI 10.17487/RFC5286, September 2008, DOI 10.17487/RFC5286, September 2008,
<https://www.rfc-editor.org/info/rfc5286>. <https://www.rfc-editor.org/info/rfc5286>.
[RFC5709] Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, M., [RFC5709] Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, M.,
Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA Cryptographic Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA Cryptographic
Authentication", RFC 5709, DOI 10.17487/RFC5709, October Authentication", RFC 5709, DOI 10.17487/RFC5709, October
2009, <https://www.rfc-editor.org/info/rfc5709>. 2009, <https://www.rfc-editor.org/info/rfc5709>.
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