Internet DRAFT - draft-filsfils-spring-srv6-net-pgm-insertion
draft-filsfils-spring-srv6-net-pgm-insertion
SPRING C. Filsfils
Internet-Draft P. Camarillo, Ed.
Intended status: Standards Track Cisco Systems, Inc.
Expires: 17 February 2024 J. Leddy
Individual Contributor
D. Voyer
Bell Canada
S. Matsushima
SoftBank
Z. Li
Huawei Technologies
16 August 2023
SRv6 NET-PGM extension: Insertion
draft-filsfils-spring-srv6-net-pgm-insertion-09
Abstract
Traffic traversing an SR domain is encapsulated in an outer IPv6
header for its journey through the SR domain.
To implement transport services strictly within the SR domain, the SR
domain may require insertion or deletion of an SRH after the outer
IPv6 header of the SR domain. Any segment within the SRH is strictly
contained within the SR domain.
This document extends SRv6 Network Programming [RFC8986] with new SR
endpoint and transit behaviors to be performed only within the SR
domain in any packet owned by the domain.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 17 February 2024.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. SRv6 endpoint behaviors . . . . . . . . . . . . . . . . . . . 3
2.1. End.B6.Insert: Endpoint bound to an SRv6 policy . . . . . 3
2.2. End.B6.Insert.Red: [...] with reduced SRH . . . . . . . . 4
3. SR Policy Headend Behaviors . . . . . . . . . . . . . . . . . 5
3.1. H.Insert: SR Headend with insertion of an SRv6 Policy . . 5
3.2. H.Insert.Red: H.Insert with reduced insertion . . . . . . 5
4. Maximum H.Insert MSD Type . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5.1. SRv6 Endpoint Behaviors . . . . . . . . . . . . . . . . . 6
5.2. MSD Types . . . . . . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
Packets transiting an SR Domain may be steered into an SR Policy for
a variety of reasons. For example, a PLR router reroutes traffic on
a TI-LFA repair path [I-D.ietf-rtgwg-segment-routing-ti-lfa] or when
a Binding-SID is expanded [I-D.ietf-spring-segment-routing-policy].
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This document extends the SRv6 Network Programming [RFC8986] model
with new endpoint and transit behaviors enabling the insertion of an
SRH after the outer IPv6 header of the SR domain. The operations
described in this document must take into account the considerations
described in [I-D.voyer-6man-extension-header-insertion].
2. SRv6 endpoint behaviors
SRv6 Network Programming Section 4 defines a base set of SRv6
endpoint behaviors. This is extended with the behaviors described in
this section.
2.1. End.B6.Insert: Endpoint bound to an SRv6 policy
The "Endpoint bound to an SRv6 Policy" is a variant of the End
behavior.
One of its applications is to express scalable traffic-engineering
policies across multiple domains. It is the one of the SRv6
instantiations of a Binding SID [RFC8402].
An End.B6.Insert SID is never the last segment in a SID list, and any
SID instantiation must be associated with an SR Policy
B[I-D.ietf-spring-segment-routing-policy].
When N receives a packet whose IPv6 DA is S and S is a local
End.B6.Insert SID, does:
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S01. When an SRH is processed {
S02. If (Segments Left == 0) {
S03. Send an ICMP Parameter Problem message to the Source Address
Code TBD-SRH (SR Upper-layer Header Error),
Pointer set to the offset of the upper-layer header,
interrupt packet processing and discard the packet
S04. }
S04. If (IPv6 Hop Limit <= 1) {
S05. Send an ICMP Time Exceeded message to the Source Address,
Code 0 (Hop limit exceeded in transit),
interrupt packet processing and discard the packet
S06. }
S07. max_LE = (Hdr Ext Len / 2) - 1
S08. If ((Last Entry > max_LE) or (Segments Left > (Last Entry+1)){
S09. Send an ICMP Parameter Problem to the Source Address,
Code 0 (Erroneous header field encountered),
Pointer set to the Segments Left field,
interrupt packet processing and discard the packet
S11. }
S12. Decrement Hop Limit by 1
S13. Insert a new SRH in between the IPv6 Header and the received
SRH containing the list of segments of B
S14. Set the IPv6 DA to the first segment of B
S15. Resubmit the packet to the egress IPv6 FIB lookup and
transmission to the new destination
S16. }
When processing the Upper-layer header of a packet matching a FIB
entry locally instantiated as an SRv6 End.B6.Insert SID, send an ICMP
parameter problem message to the Source Address and discard the
packet. Error code "SR Upper-layer Header Error", Pointer set to the
offset of the upper-layer header.
2.2. End.B6.Insert.Red: [...] with reduced SRH
This is an optimization of the End.B6.Insert behavior.
End.B6.Insert.Red reduces the size of the new SRH by one SID by
avoiding the insertion of the first SID in the pushed SRH. In this
way, the first SID is only written in the DA and the packet is
forwarded according to it.
The new SRH is created as described in Section 4.1.1 of [RFC8754].
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3. SR Policy Headend Behaviors
SRv6 Network Programming defines in Section 5 a set of SR Policy
Headend Behaviors. This is extended with the following behaviors
defined in this section.
3.1. H.Insert: SR Headend with insertion of an SRv6 Policy
Node N receives two packets P1=(A, B2) and P2=(A,B2)(B3, B2, B1;
SL=1). B2 is neither a local address nor SID of N.
N steers the transit packets P1 and P2 into an SRv6 Policy with one
SID list <S1, S2, S3>.
The "H.Insert" transit insertion behavior is defined as follows:
1. insert the SRH (B2, S3, S2, S1; SL=3) ;; Ref1, Ref1bis
2. set the IPv6 DA = S1
3. forward along the shortest path to S1
Ref1: The received IPv6 DA is placed as last SID of the inserted SRH.
Ref1bis: The SRH is inserted
[I-D.voyer-6man-extension-header-insertion] before any other IPv6
Routing Extension Header.
After the H.Insert behavior, P1 and P2 respectively look like:
1. (A, S1) (B2, S3, S2, S1; SL=3)
2. (A, S1) (B2, S3, S2, S1; SL=3) (B3, B2, B1; SL=1)
3.2. H.Insert.Red: H.Insert with reduced insertion
The H.Insert.Red behavior is an optimization of the H.Insert
behavior. It is defined as follows:
1. insert the SRH (B2, S3, S2; SL=3)
2. set the IPv6 DA = S1
3. forward along the shortest path to S1
H.Insert.Red will reduce the size of the SRH by one segment by
avoiding the insertion of the first SID in the pushed SRH. In this
way, the first segment is only introduced in the DA and the packet is
forwarded according to it.
After the H.Insert.Red behavior, P1 and P2 respectively look like:
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1. (A, S1) (B2, S3, S2; SL=3)
2. (A, S1) (B2, S3, S2; SL=3) (B3, B2, B1; SL=1)
4. Maximum H.Insert MSD Type
This document defines the MSD (Maximum SID Depth) for H.Insert
behavior and requests the MSD type assignment from the IGP MSD-Types
registry created by [RFC8491].
The Maximum H.Insert MSD Type specifies the maximum number of SIDs
that can be inserted as part of the "H.insert" behavior:
1. Max H.insert Type: 43 (Suggested value - to be assigned by IANA)
If the advertised value is zero or no value is advertised then the
router is assumed not to support any variation of the "H.insert"
behavior.
5. IANA Considerations
5.1. SRv6 Endpoint Behaviors
This document requests IANA to allocate the following codepoints
within the "SRv6 Endpoint Behaviors" sub-registry under the top-level
"Segment Routing Parameters" registry.
+=======+========+===================+===========+
| Value | Hex | Endpoint behavior | Reference |
+=======+========+===================+===========+
| 13 | 0x000D | End.B6.Insert | [This.ID] |
+-------+--------+-------------------+-----------+
| 26 | 0x001A | End.B6.Insert.Red | [This.ID] |
+-------+--------+-------------------+-----------+
Table 1: IETF - SRv6 Endpoint Behaviors
5.2. MSD Types
This document requests IANA to allocate the following codepoint
within the "IGP MSD-Types" sub-registry under the top-level "IGP
Parameters" registry.
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+=======+======+===================+===========+
| Value | Hex | Endpoint behavior | Reference |
+=======+======+===================+===========+
| 43 | 0x2B | Max H.Insert | [This.ID] |
+-------+------+-------------------+-----------+
Table 2: IETF - MSD Types
6. Acknowledgements
The authors would like to acknowledge Stefano Previdi, Dave Barach,
Mark Townsley, Peter Psenak, Thierry Couture, Kris Michielsen, Paul
Wells, Robert Hanzl, Dan Ye, Gaurav Dawra, Faisal Iqbal, Jaganbabu
Rajamanickam, David Toscano, Asif Islam, Jianda Liu, Yunpeng Zhang,
Jiaoming Li, Narendra A.K, Mike Mc Gourty, Bhupendra Yadav, Sherif
Toulan, Satish Damodaran, John Bettink, Kishore Nandyala Veera Venk,
Jisu Bhattacharya and Saleem Hafeez.
7. Contributors
Daniel Bernier
Bell Canada
Canada
Email: daniel.bernier@bell.ca
Dirk Steinberg
Lapishills Consulting Limited
Cyprus
Email: dirk@lapishills.com
Robert Raszuk
Bloomberg LP
United States of America
Email: robert@raszuk.net
Bart Peirens
Proximus
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Belgium
Email: bart.peirens@proximus.com
Hani Elmalky
Ericsson
United States of America
Email: hani.elmalky@gmail.com
Prem Jonnalagadda
Barefoot Networks
United States of America
Email: prem@barefootnetworks.com
Milad Sharif
Barefoot Networks
United States of America
Email: msharif@barefootnetworks.com
David Lebrun
Google
Belgium
Email: dlebrun@google.com
Stefano Salsano
Universita di Roma "Tor Vergata"
Italy
Email: stefano.salsano@uniroma2.it
Ahmed AbdelSalam
Gran Sasso Science Institute
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Italy
Email: ahmed.abdelsalam@gssi.it
Gaurav Naik
Drexel University
United States of America
Email: gn@drexel.edu
Arthi Ayyangar
Arista
United States of America
Email: arthi@arista.com
Satish Mynam
Innovium Inc.
United States of America
Email: smynam@innovium.com
Wim Henderickx
Nokia
Belgium
Email: wim.henderickx@nokia.com
Shaowen Ma
Juniper
Singapore
Email: mashao@juniper.net
Ahmed Bashandy
Individual
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United States of America
Email: abashandy.ietf@gmail.com
Francois Clad
Cisco Systems, Inc.
France
Email: fclad@cisco.com
Kamran Raza
Cisco Systems, Inc.
Canada
Email: skraza@cisco.com
Darren Dukes
Cisco Systems, Inc.
Canada
Email: ddukes@cisco.com
Patrice Brissete
Cisco Systems, Inc.
Canada
Email: pbrisset@cisco.com
Zafar Ali
Cisco Systems, Inc.
United States of America
Email: zali@cisco.com
8. References
8.1. Normative References
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[I-D.voyer-6man-extension-header-insertion]
Voyer, D., Filsfils, C., Dukes, D., Matsushima, S., Leddy,
J., Li, Z., and J. Guichard, "Deployments With Insertion
of IPv6 Segment Routing Headers", Work in Progress,
Internet-Draft, draft-voyer-6man-extension-header-
insertion-10, 20 November 2020,
<https://www.ietf.org/archive/id/draft-voyer-6man-
extension-header-insertion-10.txt>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[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>.
[RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
"Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491,
DOI 10.17487/RFC8491, November 2018,
<https://www.rfc-editor.org/info/rfc8491>.
[RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
<https://www.rfc-editor.org/info/rfc8754>.
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021,
<https://www.rfc-editor.org/info/rfc8986>.
8.2. Informative References
[I-D.ietf-rtgwg-segment-routing-ti-lfa]
Litkowski, S., Bashandy, A., Filsfils, C., Francois, P.,
Decraene, B., and D. Voyer, "Topology Independent Fast
Reroute using Segment Routing", Work in Progress,
Internet-Draft, draft-ietf-rtgwg-segment-routing-ti-lfa-
08, 21 January 2022, <https://www.ietf.org/archive/id/
draft-ietf-rtgwg-segment-routing-ti-lfa-08.txt>.
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[I-D.ietf-spring-segment-routing-policy]
Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and
P. Mattes, "Segment Routing Policy Architecture", Work in
Progress, Internet-Draft, draft-ietf-spring-segment-
routing-policy-18, 17 February 2022,
<https://www.ietf.org/archive/id/draft-ietf-spring-
segment-routing-policy-18.txt>.
Authors' Addresses
Clarence Filsfils
Cisco Systems, Inc.
Belgium
Email: cf@cisco.com
Pablo Camarillo Garvia (editor)
Cisco Systems, Inc.
Spain
Email: pcamaril@cisco.com
John Leddy
Individual Contributor
United States of America
Email: john@leddy.net
Daniel Voyer
Bell Canada
Canada
Email: daniel.voyer@bell.ca
Satoru Matsushima
SoftBank
1-9-1,Higashi-Shimbashi,Minato-Ku, Tokyo 105-7322
Japan
Email: satoru.matsushima@g.softbank.co.jp
Zhenbin Li
Huawei Technologies
China
Email: lizhenbin@huawei.com
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