| < draft-ietf-spring-segment-routing-policy-21.txt | draft-ietf-spring-segment-routing-policy-22.txt > | |||
|---|---|---|---|---|
| SPRING Working Group C. Filsfils | SPRING Working Group C. Filsfils | |||
| Internet-Draft K. Talaulikar, Ed. | Internet-Draft K. Talaulikar, Ed. | |||
| Updates: 8402 (if approved) Cisco Systems, Inc. | Updates: 8402 (if approved) Cisco Systems, Inc. | |||
| Intended status: Standards Track D. Voyer | Intended status: Standards Track D. Voyer | |||
| Expires: September 20, 2022 Bell Canada | Expires: September 23, 2022 Bell Canada | |||
| A. Bogdanov | A. Bogdanov | |||
| British Telecom | British Telecom | |||
| P. Mattes | P. Mattes | |||
| Microsoft | Microsoft | |||
| March 19, 2022 | March 22, 2022 | |||
| Segment Routing Policy Architecture | Segment Routing Policy Architecture | |||
| draft-ietf-spring-segment-routing-policy-21 | draft-ietf-spring-segment-routing-policy-22 | |||
| Abstract | Abstract | |||
| Segment Routing (SR) allows a node to steer a packet flow along any | Segment Routing (SR) allows a node to steer a packet flow along any | |||
| path. Intermediate per-path states are eliminated thanks to source | path. Intermediate per-path states are eliminated thanks to source | |||
| routing. SR Policy is an ordered list of segments (i.e., | routing. SR Policy is an ordered list of segments (i.e., | |||
| instructions) that represent a source-routed policy. Packet flows | instructions) that represent a source-routed policy. Packet flows | |||
| are steered into a SR Policy on a node where it is instantiated | are steered into a SR Policy on a node where it is instantiated | |||
| called a headend node. The packets steered into an SR Policy carry | called a headend node. The packets steered into an SR Policy carry | |||
| an ordered list of segments associated with that SR Policy. | an ordered list of segments associated with that SR Policy. | |||
| skipping to change at page 1, line 45 ¶ | skipping to change at page 1, line 45 ¶ | |||
| 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 September 20, 2022. | This Internet-Draft will expire on September 23, 2022. | |||
| Copyright Notice | Copyright Notice | |||
| Copyright (c) 2022 IETF Trust and the persons identified as the | Copyright (c) 2022 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 3, line 18 ¶ | skipping to change at page 3, line 18 ¶ | |||
| 8.6. Per-Flow Steering . . . . . . . . . . . . . . . . . . . . 26 | 8.6. Per-Flow Steering . . . . . . . . . . . . . . . . . . . . 26 | |||
| 8.7. Policy-based Routing . . . . . . . . . . . . . . . . . . 28 | 8.7. Policy-based Routing . . . . . . . . . . . . . . . . . . 28 | |||
| 8.8. Optional Steering Modes for BGP Destinations . . . . . . 28 | 8.8. Optional Steering Modes for BGP Destinations . . . . . . 28 | |||
| 9. Recovering from Network Failures . . . . . . . . . . . . . . 30 | 9. Recovering from Network Failures . . . . . . . . . . . . . . 30 | |||
| 9.1. Leveraging TI-LFA local protection of the constituent IGP | 9.1. Leveraging TI-LFA local protection of the constituent IGP | |||
| segments . . . . . . . . . . . . . . . . . . . . . . . . 30 | segments . . . . . . . . . . . . . . . . . . . . . . . . 30 | |||
| 9.2. Using an SR Policy to locally protect a link . . . . . . 30 | 9.2. Using an SR Policy to locally protect a link . . . . . . 30 | |||
| 9.3. Using a Candidate Path for Path Protection . . . . . . . 31 | 9.3. Using a Candidate Path for Path Protection . . . . . . . 31 | |||
| 10. Security Considerations . . . . . . . . . . . . . . . . . . . 31 | 10. Security Considerations . . . . . . . . . . . . . . . . . . . 31 | |||
| 11. Manageability Considerations . . . . . . . . . . . . . . . . 32 | 11. Manageability Considerations . . . . . . . . . . . . . . . . 32 | |||
| 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32 | 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33 | |||
| 12.1. Guidance for Designated Experts . . . . . . . . . . . . 33 | 12.1. Guidance for Designated Experts . . . . . . . . . . . . 33 | |||
| 13. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 33 | 13. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 34 | |||
| 14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 34 | 14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 34 | |||
| 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 35 | 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 35 | |||
| 15.1. Normative References . . . . . . . . . . . . . . . . . . 35 | 15.1. Normative References . . . . . . . . . . . . . . . . . . 35 | |||
| 15.2. Informative References . . . . . . . . . . . . . . . . . 36 | 15.2. Informative References . . . . . . . . . . . . . . . . . 36 | |||
| Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 39 | Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40 | |||
| 1. Introduction | 1. Introduction | |||
| Segment Routing (SR) [RFC8402] allows a node to steer a packet flow | Segment Routing (SR) [RFC8402] allows a node to steer a packet flow | |||
| along any path. The headend is a node where the instructions for | along any path. The headend is a node where the instructions for | |||
| source routing (i.e., segments) are written into the packet and hence | source routing (i.e., segments) are written into the packet and hence | |||
| becomes the starting node for a specific segment routing path. | becomes the starting node for a specific segment routing path. | |||
| Intermediate per-path states are eliminated thanks to source routing. | Intermediate per-path states are eliminated thanks to source routing. | |||
| A Segment Routing Policy (SR Policy) [RFC8402] is an ordered list of | A Segment Routing Policy (SR Policy) [RFC8402] is an ordered list of | |||
| skipping to change at page 32, line 26 ¶ | skipping to change at page 32, line 26 ¶ | |||
| scenarios. The details of these mechanisms are outside the scope of | scenarios. The details of these mechanisms are outside the scope of | |||
| this document. | this document. | |||
| The Section 8 specifies mechanism for steering of traffic flows | The Section 8 specifies mechanism for steering of traffic flows | |||
| corresponding to BGP routes over SR Policies matching the color value | corresponding to BGP routes over SR Policies matching the color value | |||
| signaled via the BGP Color Extended Community attached with the BGP | signaled via the BGP Color Extended Community attached with the BGP | |||
| routes. Misconfiguration or error in setting of the Color Extended | routes. Misconfiguration or error in setting of the Color Extended | |||
| Community with the BGP routes can result in forwarding of packets for | Community with the BGP routes can result in forwarding of packets for | |||
| those routes along undesired paths. | those routes along undesired paths. | |||
| In Section 2.1 and Section 2.6, the document mentions that a symbolic | ||||
| name MAY be signaled along with a candidate path for the SR Policy | ||||
| and for the SR Policy Candidate Path respectively. While the value | ||||
| of symbolic names for display clarity is indisputable, as with any | ||||
| unrestricted freeform text received from external parties, there can | ||||
| be no absolute assurance that the information the text purports to | ||||
| show is accurate or even truthful. For this reason, users of | ||||
| implementations that display such information would be well-advised | ||||
| not to rely on it without question and to use the specific | ||||
| identifiers of the SR Policy and SR Policy Candidate Path for | ||||
| validation. Furthermore, implementations that display such | ||||
| information might wish to display it in such a fashion as to | ||||
| differentiate it from known-good information. (Such display | ||||
| conventions are inherently implementation-specific; one example might | ||||
| be use of a distinguished text color or style for information that | ||||
| should be treated with caution.) | ||||
| This document does not define any new protocol extensions and does | This document does not define any new protocol extensions and does | |||
| not introduce any further security considerations. | not introduce any further security considerations. | |||
| 11. Manageability Considerations | 11. Manageability Considerations | |||
| This document specifies in detail the SR Policy construct introduced | This document specifies in detail the SR Policy construct introduced | |||
| in [RFC8402] and its instantiation on a router supporting SR along | in [RFC8402] and its instantiation on a router supporting SR along | |||
| with descriptions of mechanisms for steering of traffic flows over | with descriptions of mechanisms for steering of traffic flows over | |||
| it. Therefore, the manageability considerations of [RFC8402] apply. | it. Therefore, the manageability considerations of [RFC8402] apply. | |||
| skipping to change at page 37, line 20 ¶ | skipping to change at page 37, line 44 ¶ | |||
| [I-D.ietf-lsr-flex-algo] | [I-D.ietf-lsr-flex-algo] | |||
| Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and | Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and | |||
| A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex- | A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex- | |||
| algo-18 (work in progress), October 2021. | algo-18 (work in progress), October 2021. | |||
| [I-D.ietf-pce-binding-label-sid] | [I-D.ietf-pce-binding-label-sid] | |||
| Sivabalan, S., Filsfils, C., Tantsura, J., Previdi, S., | Sivabalan, S., Filsfils, C., Tantsura, J., Previdi, S., | |||
| and C. L. (editor), "Carrying Binding Label/Segment | and C. L. (editor), "Carrying Binding Label/Segment | |||
| Identifier (SID) in PCE-based Networks.", draft-ietf-pce- | Identifier (SID) in PCE-based Networks.", draft-ietf-pce- | |||
| binding-label-sid-14 (work in progress), March 2022. | binding-label-sid-15 (work in progress), March 2022. | |||
| [I-D.ietf-pce-segment-routing-policy-cp] | [I-D.ietf-pce-segment-routing-policy-cp] | |||
| Koldychev, M., Sivabalan, S., Barth, C., Peng, S., and H. | Koldychev, M., Sivabalan, S., Barth, C., Peng, S., and H. | |||
| Bidgoli, "PCEP extension to support Segment Routing Policy | Bidgoli, "PCEP extension to support Segment Routing Policy | |||
| Candidate Paths", draft-ietf-pce-segment-routing-policy- | Candidate Paths", draft-ietf-pce-segment-routing-policy- | |||
| cp-06 (work in progress), October 2021. | cp-06 (work in progress), October 2021. | |||
| [I-D.ietf-rtgwg-segment-routing-ti-lfa] | [I-D.ietf-rtgwg-segment-routing-ti-lfa] | |||
| Litkowski, S., Bashandy, A., Filsfils, C., Francois, P., | Litkowski, S., Bashandy, A., Filsfils, C., Francois, P., | |||
| Decraene, B., and D. Voyer, "Topology Independent Fast | Decraene, B., and D. Voyer, "Topology Independent Fast | |||
| End of changes. 9 change blocks. | ||||
| 8 lines changed or deleted | 25 lines changed or added | |||
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