RIFT: Routing in Fat Trees
draft-ietf-rift-rift-09

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Last updated 2019-11-04
Replaces draft-przygienda-rift
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RIFT Working Group                                    A. Przygienda, Ed.
Internet-Draft                                                   Juniper
Intended status: Standards Track                               A. Sharma
Expires: May 7, 2020                                             Comcast
                                                              P. Thubert
                                                                   Cisco
                                                          Bruno. Rijsman
                                                              Individual
                                                       Dmitry. Afanasiev
                                                                  Yandex
                                                        November 4, 2019

                       RIFT: Routing in Fat Trees
                        draft-ietf-rift-rift-09

Abstract

   This document defines a specialized, dynamic routing protocol for
   Clos and fat-tree network topologies optimized towards minimization
   of configuration and operational complexity.  The protocol

      deals with no configuration, fully automated construction of fat-
      tree topologies based on detection of links,

      minimizes the amount of routing state held at each level,

      automatically prunes and load balances topology flooding exchanges
      over a sufficient subset of links,

      supports automatic disaggregation of prefixes on link and node
      failures to prevent black-holing and suboptimal routing,

      allows traffic steering and re-routing policies,

      allows loop-free non-ECMP forwarding,

      automatically re-balances traffic towards the spines based on
      bandwidth available and finally

      provides mechanisms to synchronize a limited key-value data-store
      that can be used after protocol convergence to e.g.  bootstrap
      higher levels of functionality on nodes.

Przygienda, et al.         Expires May 7, 2020                  [Page 1]
Internet-Draft                    RIFT                     November 2019

Status of This Memo

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Table of Contents

   1.  Authors . . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   6
     2.1.  Requirements Language . . . . . . . . . . . . . . . . . .   8
   3.  Reference Frame . . . . . . . . . . . . . . . . . . . . . . .   8
     3.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   8
     3.2.  Topology  . . . . . . . . . . . . . . . . . . . . . . . .  13
   4.  RIFT: Routing in Fat Trees  . . . . . . . . . . . . . . . . .  14
     4.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .  15
       4.1.1.  Properties  . . . . . . . . . . . . . . . . . . . . .  15
       4.1.2.  Generalized Topology View . . . . . . . . . . . . . .  16
         4.1.2.1.  Terminology . . . . . . . . . . . . . . . . . . .  16
         4.1.2.2.  Clos as Crossed Crossbars . . . . . . . . . . . .  17
       4.1.3.  Fallen Leaf Problem . . . . . . . . . . . . . . . . .  26
       4.1.4.  Discovering Fallen Leaves . . . . . . . . . . . . . .  28

Przygienda, et al.         Expires May 7, 2020                  [Page 2]
Internet-Draft                    RIFT                     November 2019

       4.1.5.  Addressing the Fallen Leaves Problem  . . . . . . . .  29
     4.2.  Specification . . . . . . . . . . . . . . . . . . . . . .  30
       4.2.1.  Transport . . . . . . . . . . . . . . . . . . . . . .  31
       4.2.2.  Link (Neighbor) Discovery (LIE Exchange)  . . . . . .  31
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