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

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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

   This Internet-Draft is submitted in full conformance with the
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   This Internet-Draft will expire on May 7, 2020.

Copyright Notice

   Copyright (c) 2019 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
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   (https://trustee.ietf.org/license-info) in effect on the date of
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   described in the Simplified BSD License.

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