RIFT: Routing in Fat Trees
draft-ietf-rift-rift-12
RIFT Working Group A. Przygienda, Ed.
Internet-Draft Juniper
Intended status: Standards Track A. Sharma
Expires: November 27, 2020 Comcast
P. Thubert
Cisco
Bruno. Rijsman
Individual
Dmitry. Afanasiev
Yandex
May 26, 2020
RIFT: Routing in Fat Trees
draft-ietf-rift-rift-12
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
o deals with no configuration, fully automated construction of fat-
tree topologies based on detection of links,
o minimizes the amount of routing state held at each level,
o automatically prunes and load balances topology flooding exchanges
over a sufficient subset of links,
o supports automatic disaggregation of prefixes on link and node
failures to prevent black-holing and suboptimal routing,
o allows traffic steering and re-routing policies,
o allows loop-free non-ECMP forwarding,
o automatically re-balances traffic towards the spines based on
bandwidth available and finally
o 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 November 27, 2020 [Page 1]
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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 . . . . . . . . . . . . . . . . . 15
4.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1.1. Properties . . . . . . . . . . . . . . . . . . . . . 16
4.1.2. Generalized Topology View . . . . . . . . . . . . . . 17
4.1.2.1. Terminology . . . . . . . . . . . . . . . . . . . 17
4.1.2.2. Clos as Crossed Crossbars . . . . . . . . . . . . 18
4.1.3. Fallen Leaf Problem . . . . . . . . . . . . . . . . . 28
4.1.4. Discovering Fallen Leaves . . . . . . . . . . . . . . 30
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4.1.5. Addressing the Fallen Leaves Problem . . . . . . . . 31
4.2. Specification . . . . . . . . . . . . . . . . . . . . . . 32
4.2.1. Transport . . . . . . . . . . . . . . . . . . . . . . 33
4.2.2. Link (Neighbor) Discovery (LIE Exchange) . . . . . . 33
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