RIFT: Routing in Fat Trees
draft-ietf-rift-rift-08

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RIFT Working Group                                    A. Przygienda, Ed.
Internet-Draft                                                   Juniper
Intended status: Standards Track                               A. Sharma
Expires: March 11, 2020                                          Comcast
                                                              P. Thubert
                                                                   Cisco
                                                          Bruno. Rijsman
                                                              Individual
                                                       Dmitry. Afanasiev
                                                                  Yandex
                                                       September 8, 2019

                       RIFT: Routing in Fat Trees
                        draft-ietf-rift-rift-08

Abstract

   This document outlines a specialized, dynamic routing protocol for
   Clos and fat-tree network topologies.  The protocol (1) deals with
   fully automated construction of fat-tree topologies based on
   detection of links, (2) minimizes the amount of routing state held at
   each level, (3) automatically prunes and load balances topology
   flooding exchanges over a sufficient subset of links, (4) supports
   automatic disaggregation of prefixes on link and node failures to
   prevent black-holing and suboptimal routing, (5) allows traffic
   steering and re-routing policies, (6) allows loop-free non-ECMP
   forwarding, (7) automatically re-balances traffic towards the spines
   based on bandwidth available and finally (8) 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.

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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Przygienda, et al.       Expires March 11, 2020                 [Page 1]
Internet-Draft                    RIFT                    September 2019

   This Internet-Draft will expire on March 11, 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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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  . . . . . . . . . . . . . . . . . . . . . . . .  12
   4.  Requirement Considerations  . . . . . . . . . . . . . . . . .  14
   5.  RIFT: Routing in Fat Trees  . . . . . . . . . . . . . . . . .  17
     5.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .  18
       5.1.1.  Properties  . . . . . . . . . . . . . . . . . . . . .  18
       5.1.2.  Generalized Topology View . . . . . . . . . . . . . .  18
       5.1.3.  Fallen Leaf Problem . . . . . . . . . . . . . . . . .  28
       5.1.4.  Discovering Fallen Leaves . . . . . . . . . . . . . .  30
       5.1.5.  Addressing the Fallen Leaves Problem  . . . . . . . .  31
     5.2.  Specification . . . . . . . . . . . . . . . . . . . . . .  32
       5.2.1.  Transport . . . . . . . . . . . . . . . . . . . . . .  32
       5.2.2.  Link (Neighbor) Discovery (LIE Exchange)  . . . . . .  33
       5.2.3.  Topology Exchange (TIE Exchange)  . . . . . . . . . .  35
         5.2.3.1.  Topology Information Elements . . . . . . . . . .  35
         5.2.3.2.  South- and Northbound Representation  . . . . . .  36
         5.2.3.3.  Flooding  . . . . . . . . . . . . . . . . . . . .  38
         5.2.3.4.  TIE Flooding Scopes . . . . . . . . . . . . . . .  39