IGP Flexible Algorithm
draft-ietf-lsr-flex-algo-01

Document Type Active Internet-Draft (lsr WG)
Last updated 2018-11-12
Replaces draft-hegdeppsenak-isis-sr-flex-algo, draft-ppsenak-ospf-sr-flex-algo
Stream IETF
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Network Working Group                                     P. Psenak, Ed.
Internet-Draft                                             Cisco Systems
Intended status: Standards Track                                S. Hegde
Expires: May 16, 2019                             Juniper Networks, Inc.
                                                             C. Filsfils
                                                           K. Talaulikar
                                                     Cisco Systems, Inc.
                                                                A. Gulko
                                                         Thomson Reuters
                                                       November 12, 2018

                         IGP Flexible Algorithm
                    draft-ietf-lsr-flex-algo-01.txt

Abstract

   IGP protocols traditionally compute best paths over the network based
   on the IGP metric assigned to the links.  Many network deployments
   use RSVP-TE based or Segment Routing based Traffic Engineering to
   enforce traffic over a path that is computed using different metrics
   or constraints than the shortest IGP path.  This document proposes a
   solution that allows IGPs themselves to compute constraint based
   paths over the network.  This document also specifies a way of using
   Segment Routing Prefix-SIDs to steer packets along the constraint-
   based paths.

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
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   This Internet-Draft will expire on May 16, 2019.

Psenak, et al.            Expires May 16, 2019                  [Page 1]
Internet-Draft           IGP Flexible Algorithm            November 2018

Copyright Notice

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   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Requirements notation . . . . . . . . . . . . . . . . . . . .   4
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Flexible Algorithm  . . . . . . . . . . . . . . . . . . . . .   4
   5.  Flexible Algorithm Definition Advertisement . . . . . . . . .   5
     5.1.  ISIS Flexible Algorithm Definition Sub-TLV  . . . . . . .   5
     5.2.  OSPF Flexible Algorithm Definition TLV  . . . . . . . . .   7
     5.3.  Common Handling of Flexible Algorithm Definition TLV  . .   8
   6.  Sub-TLVs of ISIS FAD Sub-TLV  . . . . . . . . . . . . . . . .   9
     6.1.  ISIS Flexible Algorithm Exclude Admin Group Sub-TLV . . .   9
     6.2.  ISIS Flexible Algorithm Include-Any Admin Group Sub-TLV .  10
     6.3.  ISIS Flexible Algorithm Include-All Admin Group Sub-TLV .  10
   7.  Sub-TLVs of OSPF FAD TLV  . . . . . . . . . . . . . . . . . .  10
     7.1.  OSPF Flexible Algorithm Exclude Admin Group Sub-TLV . . .  11
     7.2.  OSPF Flexible Algorithm Include-Any Admin Group Sub-TLV .  11
     7.3.  OSPF Flexible Algorithm Include-All Admin Group Sub-TLV .  11
   8.  Advertisement of Node Participation in a Flex-Algorithm . . .  12
     8.1.  Advertisement of Node Participation for Segment Routing .  12
     8.2.  Advertisement of Node Participation for Other
           Applications  . . . . . . . . . . . . . . . . . . . . . .  12
   9.  Advertisement of Link Attributes for Flex-Algorithm . . . . .  13
   10. Calculation of Flexible Algorithm Paths . . . . . . . . . . .  13
   11. Flex-Algorithm and Forwarding Plane . . . . . . . . . . . . .  15
     11.1.  Segment Routing MPLS Forwarding for Flex-Algorithm . . .  15
     11.2.  Other Applications' Forwarding for Flex-Algorithm  . . .  15
   12. Backward Compatibility  . . . . . . . . . . . . . . . . . . .  16
   13. Security Considerations . . . . . . . . . . . . . . . . . . .  16
   14. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  16
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