SR Policy Implementation and Deployment Considerations
draft-filsfils-spring-sr-policy-considerations-03

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SPRING Working Group                                         C. Filsfils
Internet-Draft                                        K. Talaulikar, Ed.
Intended status: Informational                       Cisco Systems, Inc.
Expires: October 17, 2019                                        P. Krol
                                                            Google, Inc.
                                                            M. Horneffer
                                                        Deutsche Telekom
                                                               P. Mattes
                                                               Microsoft
                                                          April 15, 2019

         SR Policy Implementation and Deployment Considerations
         draft-filsfils-spring-sr-policy-considerations-03.txt

Abstract

   Segment Routing (SR) allows a headend node to steer a packet flow
   along any path.  Intermediate per-flow states are eliminated thanks
   to source routing.  SR Policy framework enables the instantiation and
   the management of necessary state on the headend node for flows along
   a source routed paths using an ordered list of segments associated
   with their specific SR Policies.  This document describes some of the
   implementation and deployment aspects that are useful for
   operationalizing the SR Policy architecture.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on October 17, 2019.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Filsfils, et al.        Expires October 17, 2019                [Page 1]
Internet-Draft          SR Policy Considerations              April 2019

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  SR Policy Headend Architecture  . . . . . . . . . . . . . . .   3
   3.  Dynamic Path Computation  . . . . . . . . . . . . . . . . . .   4
     3.1.  Optimization Objective  . . . . . . . . . . . . . . . . .   4
     3.2.  Constraints . . . . . . . . . . . . . . . . . . . . . . .   5
     3.3.  SR Native Algorithm . . . . . . . . . . . . . . . . . . .   6
     3.4.  Path to SID . . . . . . . . . . . . . . . . . . . . . . .   7
   4.  Candidate Path Selection  . . . . . . . . . . . . . . . . . .   7
   5.  Distributed and/or Centralized Control Plane  . . . . . . . .  11
     5.1.  Distributed Control Plane within a single Link-State IGP
           area  . . . . . . . . . . . . . . . . . . . . . . . . . .  11
     5.2.  Distributed Control Plane across several Link-State IGP
           areas . . . . . . . . . . . . . . . . . . . . . . . . . .  11
     5.3.  Centralized Control Plane . . . . . . . . . . . . . . . .  12
     5.4.  Distributed and Centralized Control Plane . . . . . . . .  12
   6.  Binding SID Aspects . . . . . . . . . . . . . . . . . . . . .  13
     6.1.  Benefits of Binding SID . . . . . . . . . . . . . . . . .  13
     6.2.  Centralized Discovery of available BSID . . . . . . . . .  14
   7.  Flex-Algorithm Based SR Policies  . . . . . . . . . . . . . .  16
   8.  Layer 2 and Optical Transport . . . . . . . . . . . . . . . .  17
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  18
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  18
   11. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .  18
   12. Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  18
   13. References  . . . . . . . . . . . . . . . . . . . . . . . . .  20
     13.1.  Normative References . . . . . . . . . . . . . . . . . .  20
     13.2.  Informative References . . . . . . . . . . . . . . . . .  20
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  22