Applicability of the Babel routing protocol
draft-ietf-babel-applicability-04

Document Type Active Internet-Draft (babel WG)
Last updated 2018-10-23
Replaces draft-chroboczek-babel-applicability
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Network Working Group                                      J. Chroboczek
Internet-Draft                         IRIF, University of Paris-Diderot
Intended status: Informational                          October 23, 2018
Expires: April 26, 2019

              Applicability of the Babel routing protocol
                   draft-ietf-babel-applicability-04

Abstract

   Babel is a routing protocol based on the distance-vector algorithm
   augmented with mechanisms for loop avoidance and starvation
   avoidance.  In this document, we argue that there exist niches where
   Babel is useful and that are not adequately served by more mature
   protocols.

Status of This Memo

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   This Internet-Draft will expire on April 26, 2019.

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   Copyright (c) 2018 IETF Trust and the persons identified as the
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Table of Contents

   1.  Introduction and background . . . . . . . . . . . . . . . . .   2
     1.1.  Technical overview of the Babel protocol  . . . . . . . .   2
   2.  Properties of the Babel protocol  . . . . . . . . . . . . . .   3
     2.1.  Simplicity and implementability . . . . . . . . . . . . .   3
     2.2.  Robustness  . . . . . . . . . . . . . . . . . . . . . . .   3
     2.3.  Extensibility . . . . . . . . . . . . . . . . . . . . . .   4
     2.4.  Limitations . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Successful deployments of Babel . . . . . . . . . . . . . . .   6
     3.1.  Hybrid networks . . . . . . . . . . . . . . . . . . . . .   6
     3.2.  Large scale overlay networks  . . . . . . . . . . . . . .   6
     3.3.  Pure mesh networks  . . . . . . . . . . . . . . . . . . .   7
     3.4.  Small unmanaged networks  . . . . . . . . . . . . . . . .   7
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     6.2.  Informational References  . . . . . . . . . . . . . . . .   8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction and background

   Babel [RFC6126bis] is a routing protocol based on the familiar
   distance-vector algorithm (sometimes known as distributed Bellman-
   Ford) augmented with mechanisms for loop avoidance (there is no
   "counting to infinity") and starvation avoidance.  In this document,
   we argue that there exist niches where Babel is useful and that are
   not adequately served by more mature protocols such as OSPF [RFC5340]
   and IS-IS [RFC1195].

1.1.  Technical overview of the Babel protocol

   At its core, Babel is a distance-vector protocol based on the
   distributed Bellman-Ford algorithm, similar in principle to RIP
   [RFC2453], but with two important extensions: provisions for sensing
   of neighbour reachability, bidirectional reachability and link
   quality, and support for multiple address families (e.g., IPv6 and
   IPv4) in a single protocol instance.

   Algorithms of this class are simple to understand and simple to
   implement, but unfortunately they do not work very well -- they
   suffer from "counting to infinity", a case of pathologically slow
   convergence in some topologies after a link failure.  Babel uses a
   mechanism pioneered by EIGRP [DUAL] [RFC7868], known as
   "feasibility", which avoids routing loops and therefore makes
   counting to infinity impossible.

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