IS-IS Optimal Distributed Flooding for Dense Topologies
draft-white-distoptflood-00

Document Type Active Internet-Draft (individual)
Last updated 2019-03-31
Replaces draft-white-openfabric
Stream (None)
Intended RFC status (None)
Formats plain text xml pdf html 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, Ed.
Internet-Draft                                             S. Zandi, Ed.
Intended status: Informational                                  LinkedIn
Expires: October 2, 2019                                  March 31, 2019

        IS-IS Optimal Distributed Flooding for Dense Topologies
                      draft-white-distoptflood-00

Abstract

   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 result 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 October 2, 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

White & Zandi            Expires October 2, 2019                [Page 1]
Internet-DraIS-IS Optimal Distributed Flooding for Dense Top  March 2019

   (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.  Additions . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.5.  Sample Network  . . . . . . . . . . . . . . . . . . . . .   4
   2.  Adjacency Formation Optimization  . . . . . . . . . . . . . .   5
   3.  Flooding Modifications  . . . . . . . . . . . . . . . . . . .   6
     3.1.  Optimizing Flooding . . . . . . . . . . . . . . . . . . .   6
     3.2.  Flooding Failures . . . . . . . . . . . . . . . . . . . .   7
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Appendix A.  Flooding Optimization Operation  . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

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 butterfyl 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.

   While there are a number of centralized flooding reduction mechanisms
   designed specifically for data center fabrics available, a
   distributed flooding reduction mechanism will be more widely
   applicable to dense topologies.  Modifying existing distributed
   flooding mechanisms for efficiency is also simpler than creating
   entirely new flooding mechanisms.  Experience with the existing
Show full document text