draft-ietf-isis-te-app-10.txt   draft-ietf-isis-te-app-11.txt 
Networking Working Group L. Ginsberg Networking Working Group L. Ginsberg
Internet-Draft P. Psenak Internet-Draft P. Psenak
Intended status: Standards Track Cisco Systems Intended status: Standards Track Cisco Systems
Expires: August 9, 2020 S. Previdi Expires: August 30, 2020 S. Previdi
Huawei Huawei
W. Henderickx W. Henderickx
Nokia Nokia
J. Drake J. Drake
Juniper Networks Juniper Networks
February 6, 2020 February 27, 2020
IS-IS TE Attributes per application IS-IS TE Attributes per application
draft-ietf-isis-te-app-10 draft-ietf-isis-te-app-11
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 August 9, 2020. This Internet-Draft will expire on August 30, 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
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Discussion . . . . . . . . . . . . . . . . . . . 4 2. Requirements Discussion . . . . . . . . . . . . . . . . . . . 4
3. Legacy Advertisements . . . . . . . . . . . . . . . . . . . . 4 3. Legacy Advertisements . . . . . . . . . . . . . . . . . . . . 4
3.1. Legacy sub-TLVs . . . . . . . . . . . . . . . . . . . . . 5 3.1. Legacy sub-TLVs . . . . . . . . . . . . . . . . . . . . . 5
3.2. Legacy SRLG Advertisements . . . . . . . . . . . . . . . 5 3.2. Legacy SRLG Advertisements . . . . . . . . . . . . . . . 5
4. Advertising Application Specific Link Attributes . . . . . . 6 4. Advertising Application Specific Link Attributes . . . . . . 6
4.1. Application Identifier Bit Mask . . . . . . . . . . . . . 6 4.1. Application Identifier Bit Mask . . . . . . . . . . . . . 6
4.2. Application Specific Link Attributes sub-TLV . . . . . . 8 4.2. Application Specific Link Attributes sub-TLV . . . . . . 8
4.2.1. Special Considerations for Maximum Link Bandwidth . . 9 4.2.1. Special Considerations for Maximum Link Bandwidth . . 9
4.2.2. Special Considerations for Reservable/Unreserved 4.2.2. Special Considerations for Reservable/Unreserved
Bandwidth . . . . . . . . . . . . . . . . . . . . . . 9 Bandwidth . . . . . . . . . . . . . . . . . . . . . . 10
4.2.3. Considerations for Extended TE Metrics . . . . . . . 10 4.2.3. Considerations for Extended TE Metrics . . . . . . . 10
4.3. Application Specific SRLG TLV . . . . . . . . . . . . . . 10 4.3. Application Specific SRLG TLV . . . . . . . . . . . . . . 10
5. Attribute Advertisements and Enablement . . . . . . . . . . . 11 5. Attribute Advertisements and Enablement . . . . . . . . . . . 11
6. Deployment Considerations . . . . . . . . . . . . . . . . . . 12 6. Deployment Considerations . . . . . . . . . . . . . . . . . . 12
6.1. Use of Legacy Advertisements . . . . . . . . . . . . . . 12 6.1. Use of Legacy Advertisements . . . . . . . . . . . . . . 12
6.2. Use of Zero Length Application Identifier Bit Masks . . . 13 6.2. Use of Zero Length Application Identifier Bit Masks . . . 13
6.3. Interoperability, Backwards Compatibility and Migration 6.3. Interoperability, Backwards Compatibility and Migration
Concerns . . . . . . . . . . . . . . . . . . . . . . . . 13 Concerns . . . . . . . . . . . . . . . . . . . . . . . . 14
6.3.1. Multiple Applications: Common Attributes with RSVP- 6.3.1. Multiple Applications: Common Attributes with RSVP-
TE . . . . . . . . . . . . . . . . . . . . . . . . . 13 TE . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.3.2. Multiple Applications: All Attributes Not Shared with 6.3.2. Multiple Applications: All Attributes Not Shared with
RSVP-TE . . . . . . . . . . . . . . . . . . . . . . . 14 RSVP-TE . . . . . . . . . . . . . . . . . . . . . . . 14
6.3.3. Interoperability with Legacy Routers . . . . . . . . 14 6.3.3. Interoperability with Legacy Routers . . . . . . . . 15
6.3.4. Use of Application Specific Advertisements for RSVP- 6.3.4. Use of Application Specific Advertisements for RSVP-
TE . . . . . . . . . . . . . . . . . . . . . . . . . 14 TE . . . . . . . . . . . . . . . . . . . . . . . . . 15
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
8. Security Considerations . . . . . . . . . . . . . . . . . . . 17 7.1. Application Specific Link Attributes sub-TLV . . . . . . 15
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17 7.2. Application Specific SRLG TLV . . . . . . . . . . . . . . 16
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 17 7.3. Application Specific Link Attributes sub-sub-TLV Registry 16
10.1. Normative References . . . . . . . . . . . . . . . . . . 17 7.4. Link Attribute Application Identifier Registry . . . . . 17
10.2. Informative References . . . . . . . . . . . . . . . . . 18 7.5. SRLG sub-TLVs . . . . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19 8. Security Considerations . . . . . . . . . . . . . . . . . . . 18
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 18
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
10.1. Normative References . . . . . . . . . . . . . . . . . . 18
10.2. Informative References . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction 1. Introduction
Advertisement of link attributes by the Intermediate-System-to- Advertisement of link attributes by the Intermediate-System-to-
Intermediate-System (IS-IS) protocol in support of traffic Intermediate-System (IS-IS) protocol in support of traffic
engineering (TE) was introduced by [RFC5305] and extended by engineering (TE) was introduced by [RFC5305] and extended by
[RFC5307], [RFC6119], and [RFC8570]. Use of these extensions has [RFC5307], [RFC6119], and [RFC8570]. Use of these extensions has
been associated with deployments supporting Traffic Engineering over been associated with deployments supporting Traffic Engineering over
Multiprotocol Label Switching (MPLS) in the presence of the Resource Multiprotocol Label Switching (MPLS) in the presence of the Resource
Reservation Protocol (RSVP) - more succinctly referred to as RSVP-TE Reservation Protocol (RSVP) - more succinctly referred to as RSVP-TE
[RFC3209]. [RFC3209].
For the purposes of this document an application is a technology For the purposes of this document an application is a technology
which makes use of link attribute advertisements - examples of which which makes use of link attribute advertisements - examples of which
are listed in Section 3. are listed in Section 3.
In recent years new applications have been introduced which have use In recent years new applications have been introduced which 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 Traffic Engineering (SRTE)
[RFC8402] and Loop Free Alternates (LFA) [RFC5286]. This has [I-D.ietf-spring-segment-routing-policy] and Loop Free Alternates
introduced ambiguity in that if a deployment includes a mix of RSVP- (LFA) [RFC5286]. This has introduced ambiguity in that if a
TE support and SRTE support (for example) it is not possible to deployment includes a mix of RSVP-TE support and SRTE support (for
unambiguously indicate which advertisements are to be used by RSVP-TE example) it is not possible to unambiguously indicate which
and which advertisements are to be used by SRTE. If the topologies advertisements are to be used by RSVP-TE and which advertisements are
are fully congruent this may not be an issue, but any incongruence to be used by SRTE. If the topologies are fully congruent this may
leads to ambiguity. not be an issue, but any incongruence leads to ambiguity.
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
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utilize the application specific advertisements. This can be done in utilize the application specific advertisements. This can be done in
the following step-wise manner: the following step-wise manner:
1)Upgrade all routers to support the extensions in this document 1)Upgrade all routers to support the extensions in this document
2)Advertise all legacy link attributes using application specific 2)Advertise all legacy link attributes using application specific
advertisements with L-flag clear and R-bit set. advertisements with L-flag clear and R-bit set.
3)Remove legacy advertisements 3)Remove legacy advertisements
Migrating RSVP-TE away from legacy advertisements could result in
some implementation simplification as it allows the removal of code
which encodes/decodes the legacy advertisements. Whether this is
seen as desirable is something for the marketplace to determine.
7. IANA Considerations 7. IANA Considerations
This document defines a new sub-TLV for TLVs 22, 23, 25, 141, 222, This section lists the protocol code point changes introduced by this
and 223. document and the related IANA changes required.
For new registries defined under IS-IS TLV Codepoints Registry with
registration procedure "Expert Review", guidance for designated
experts can be found in [RFC7370].
7.1. Application Specific Link Attributes sub-TLV
This document defines a new sub-TLV in the Sub-TLVs for TLVs 22, 23,
25, 141, 222, and 223 registry.
Type Description 22 23 25 141 222 223 Type Description 22 23 25 141 222 223
---- --------------------- ---- ---- ---- ---- ---- ---- ---- --------------------- ---- ---- ---- ---- ---- ----
16 Application Specific y y y(s) y y y 16 Application Specific y y y(s) y y y
Link Attributes Link Attributes
This document defines one new TLV: 7.2. Application Specific SRLG TLV
This document defines one new TLV in the IS-IS TLV Codepoints
Registry.
Type Description IIH LSP SNP Purge Type Description IIH LSP SNP Purge
---- --------------------- --- --- --- ----- ---- --------------------- --- --- --- -----
238 Application Specific n y n n 238 Application Specific n y n n
SRLG SRLG
This document requests a new IANA registry be created to control the 7.3. Application Specific Link Attributes sub-sub-TLV Registry
assignment of sub-sub-TLV codepoints for the Application Specific
Link Attributes sub-TLV. The suggested name of the new registry is This document requests a new IANA registry under the IS-IS TLV
Codepoints Registry be created to control the assignment of sub-sub-
TLV codepoints for the Application Specific Link Attributes sub-TLV
defined in Section 7.1. The suggested name of the new registry is
"sub-sub-TLV code points for application specific link attributes". "sub-sub-TLV code points for application specific link attributes".
The registration procedure is "Expert Review" as defined in The registration procedure is "Expert Review" as defined in
[RFC8126]. The following assignments are made by this document: [RFC8126]. The following assignments are made by this document:
Type Description Type Description
--------------------------------------------------------- ---------------------------------------------------------
0-2 Unassigned 0-2 Unassigned
3 Administrative group (color) 3 Administrative group (color)
4-8 Unassigned 4-8 Unassigned
9 Maximum link bandwidth 9 Maximum link bandwidth
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18 TE Default Metric 18 TE Default Metric
19-32 Unassigned 19-32 Unassigned
33 Unidirectional Link Delay 33 Unidirectional Link Delay
34 Min/Max Unidirectional Link Delay 34 Min/Max Unidirectional Link Delay
35 Unidirectional Delay Variation 35 Unidirectional Delay Variation
36 Unidirectional Link Loss 36 Unidirectional Link Loss
37 Unidirectional Residual Bandwidth 37 Unidirectional Residual Bandwidth
38 Unidirectional Available Bandwidth 38 Unidirectional Available Bandwidth
39 Unidirectional Utilized Bandwidth 39 Unidirectional Utilized Bandwidth
40-255 Unassigned 40-255 Unassigned
Note to designated experts: If a link attribute can be advertised Note to designated experts: If a link attribute can be advertised
both as a sub-TLV of TLVs 22, 23, 25, 141, 222, and 223 and as a sub- both as a sub-TLV of TLVs 22, 23, 25, 141, 222, and 223 and as a sub-
sub-TLV of the Application Specific Link Attributes sub-TLV defined sub-TLV of the Application Specific Link Attributes sub-TLV defined
in this document, then the same numerical code should be assigned to in this document, then the same numerical code should be assigned to
the link attribute whenever possible. the link attribute whenever possible.
7.4. Link Attribute Application Identifier Registry
This document requests a new IANA registry be created, under the This document requests a new IANA registry be created, under the
category of "Interior Gateway Protocol (IGP) Parameters", to control category of "Interior Gateway Protocol (IGP) Parameters", to control
the assignment of Application Identifier Bits. The suggested name of the assignment of Application Identifier Bits. The suggested name of
the new registry is "Link Attribute Applications". The registration the new registry is "Link Attribute Applications". The registration
policy for this registry is "Standards Action" ([RFC8126] and policy for this registry is "Standards Action" ([RFC8126] and
[RFC7120]). Bit definitions SHOULD be assigned in ascending bit [RFC7120]). Bit definitions SHOULD be assigned in ascending bit
order beginning with Bit 0 so as to minimize the number of octets order beginning with Bit 0 so as to minimize the number of octets
that will need to be transmitted. The following assignments are made that will need to be transmitted. The following assignments are made
by this document: by this document:
Bit # Name Bit # Name
--------------------------------------------------------- ---------------------------------------------------------
0 RSVP-TE (R-bit) 0 RSVP-TE (R-bit)
1 Segment Routing Traffic Engineering (S-bit) 1 Segment Routing Traffic Engineering (S-bit)
2 Loop Free Alternate (F-bit) 2 Loop Free Alternate (F-bit)
Additional bits are undefined
7.5. SRLG sub-TLVs
This document requests a new IANA registry be created to control the This document requests a new IANA registry be created to control the
assignment of sub-TLV types for the application specific SRLG TLV. assignment of sub-TLV types for the application specific SRLG TLV.
The suggested name of the new registry is "Sub-TLVs for TLV 238". The suggested name of the new registry is "Sub-TLVs for TLV 238".
The registration procedure is "Expert Review" as defined in The registration procedure is "Expert Review" as defined in
[RFC8126]. The following assignments are made by this document: [RFC8126]. The following assignments are made by this document:
Value Description Value Description Encoding
Reference
--------------------------------------------------------- ---------------------------------------------------------
0-3 Unassigned 0-3 Unassigned
4 Link Local/Remote Identifiers (see [RFC5307]) 4 Link Local/Remote Identifiers [RFC5307]
5 Unassigned 5 Unassigned
6 IPv4 interface address (see [RFC5305]) 6 IPv4 interface address [RFC5305]
7 Unassigned 7 Unassigned
8 IPv4 neighbor address (see [RFC5305]) 8 IPv4 neighbor address [RFC5305]
9-11 Unassigned 9-11 Unassigned
12 IPv6 Interface Address (see [RFC6119]) 12 IPv6 Interface Address [RFC6119]
13 IPv6 Neighbor Address (see [RFC6119]) 13 IPv6 Neighbor Address [RFC6119]
14-255 Unassigned 14-255 Unassigned
8. Security Considerations 8. Security Considerations
Security concerns for IS-IS are addressed in [ISO10589, [RFC5304], Security concerns for IS-IS are addressed in [ISO10589], [RFC5304],
and [RFC5310]. and [RFC5310].
This document defines a new way to advertise link attributes.
Tampering with the information defined in this document may have an
effect on applications using it, including impacting Traffic
Engineering. This is similar in nature to the impacts associated
with (for example) [RFC5305].
9. Acknowledgements 9. Acknowledgements
The authors would like to thank Eric Rosen and Acee Lindem for their The authors would like to thank Eric Rosen and Acee Lindem for their
careful review and content suggestions. careful review and content suggestions.
10. References 10. References
10.1. Normative References 10.1. Normative References
[ISO10589]
International Organization for Standardization,
"Intermediate system to Intermediate system intra-domain
routeing information exchange protocol for use in
conjunction with the protocol for providing the
connectionless-mode Network Service (ISO 8473)", ISO/
IEC 10589:2002, Second Edition, Nov 2002.
[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>.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic [RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, DOI 10.17487/RFC5304, October Authentication", RFC 5304, DOI 10.17487/RFC5304, October
2008, <https://www.rfc-editor.org/info/rfc5304>. 2008, <https://www.rfc-editor.org/info/rfc5304>.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
skipping to change at page 18, line 18 skipping to change at page 19, line 18
2009, <https://www.rfc-editor.org/info/rfc5310>. 2009, <https://www.rfc-editor.org/info/rfc5310>.
[RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic [RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic
Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119, Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119,
February 2011, <https://www.rfc-editor.org/info/rfc6119>. February 2011, <https://www.rfc-editor.org/info/rfc6119>.
[RFC7120] Cotton, M., "Early IANA Allocation of Standards Track Code [RFC7120] Cotton, M., "Early IANA Allocation of Standards Track Code
Points", BCP 100, RFC 7120, DOI 10.17487/RFC7120, January Points", BCP 100, RFC 7120, DOI 10.17487/RFC7120, January
2014, <https://www.rfc-editor.org/info/rfc7120>. 2014, <https://www.rfc-editor.org/info/rfc7120>.
[RFC7370] Ginsberg, L., "Updates to the IS-IS TLV Codepoints
Registry", RFC 7370, DOI 10.17487/RFC7370, September 2014,
<https://www.rfc-editor.org/info/rfc7370>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8570] Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward, [RFC8570] Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward,
skipping to change at page 19, line 11 skipping to change at page 20, line 11
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>.
[RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B., [RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B.,
Litkowski, S., Horneffer, M., and R. Shakir, "Source Litkowski, S., Horneffer, M., and R. Shakir, "Source
Packet Routing in Networking (SPRING) Problem Statement Packet Routing in Networking (SPRING) Problem Statement
and Requirements", RFC 7855, DOI 10.17487/RFC7855, May and Requirements", RFC 7855, DOI 10.17487/RFC7855, May
2016, <https://www.rfc-editor.org/info/rfc7855>. 2016, <https://www.rfc-editor.org/info/rfc7855>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
Authors' Addresses Authors' Addresses
Les Ginsberg Les Ginsberg
Cisco Systems Cisco Systems
821 Alder Drive 821 Alder Drive
Milpitas, CA 95035 Milpitas, CA 95035
USA USA
Email: ginsberg@cisco.com Email: ginsberg@cisco.com
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