IS-IS Optimal Distributed Flooding for Dense Topologies
draft-white-distoptflood-01

Document Type Active Internet-Draft (individual)
Last updated 2019-09-30
Replaces draft-white-openfabric
Stream (None)
Intended RFC status (None)
Formats plain text xml pdf htmlized bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
Network Working Group                                           R. White
Internet-Draft                                                  S. Hegde
Intended status: Informational                          Juniper Networks
Expires: April 2, 2020                                          S. Zandi
                                                                LinkedIn
                                                      September 30, 2019

        IS-IS Optimal Distributed Flooding for Dense Topologies
                      draft-white-distoptflood-01

Abstract

   In dense topologies, such as data center fabrics based on the Clos
   and butterfly fabric topologies, flooding mechanisms designed for
   sparse topologies, when used in these dense topologies, can
   "overflood," or carry too many copies of topology and reachability to
   fabric devices.  This results in slower convergence times and higher
   resource utilization.  The modifications to the flooding mechanism in
   the Intermediate System to Intermediate System (IS-IS) link state
   protocol described in this document reduce resource utilization to a
   minimum, while increaseing convergence performance in dense
   topologies.

   Note that a Clos fabric is used as the primary example of a desne
   flooding topology throughout this document.  However, the flooding
   optimizations described in this document apply to any dense topology.

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 2, 2020.

White, et al.             Expires April 2, 2020                 [Page 1]
Internet-DraftIS-IS Optimal Distributed Flooding for DenseSeptember 2019

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
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Goals . . . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.2.  Contributors  . . . . . . . . . . . . . . . . . . . . . .   3
     1.3.  Experience  . . . . . . . . . . . . . . . . . . . . . . .   3
     1.4.  Sample Network  . . . . . . . . . . . . . . . . . . . . .   3
   2.  Flooding Modifications  . . . . . . . . . . . . . . . . . . .   5
     2.1.  Optimizing Flooding . . . . . . . . . . . . . . . . . . .   5
     2.2.  Flooding Failures . . . . . . . . . . . . . . . . . . . .   6
   3.  Use of Flooding Leaders and Flooding Mechanism Advertisements   6
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Appendix A.  Flooding Optimization Operation  . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

1.1.  Goals

   The goal of this draft is to solve one specific set of problems
   involved in operating a link state protocol in a dense mesh topology.
   The problem with such topologies is the connectivity density, which
   causes too much information to be flooded (or too much repeated state
   to be flooded).  Analysis and experiment show, for instance, that in
   a butterfly fabric of around 2500 intermediate systems, each
   intermediate system will receive 40+ copies of any changed LSP
   fragment.  This not only wastes bandwidth and processor time, this
   dramatically slows convergence speed.

White, et al.             Expires April 2, 2020                 [Page 2]
Internet-DraftIS-IS Optimal Distributed Flooding for DenseSeptember 2019
Show full document text