Network Working Group                                      J. Chroboczek
Internet-Draft                         IRIF, University of Paris-Diderot
Intended status: Informational                         February 29, 2016
Expires: September 1, 2016


              Applicability of the Babel routing protocol
                draft-chroboczek-babel-applicability-01

Abstract

   This document describes some application areas where the Babel
   routing protocol [RFC6126] has been found to be useful.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Existing successful deployments of Babel  . . . . . . . . . .   2
     2.1.  Hybrid networks . . . . . . . . . . . . . . . . . . . . .   2
     2.2.  Large scale overlay networks  . . . . . . . . . . . . . .   2
     2.3.  Small unmanaged networks  . . . . . . . . . . . . . . . .   3
   3.  Potential deployments of Babel  . . . . . . . . . . . . . . .   3
     3.1.  Pure mesh networks  . . . . . . . . . . . . . . . . . . .   3
   4.  Application Areas where Babel is not recommended  . . . . . .   3
     4.1.  Large, stable networks  . . . . . . . . . . . . . . . . .   3
     4.2.  Low-power networks  . . . . . . . . . . . . . . . . . . .   3
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   Babel [RFC6126] is a loop-avoiding distance-vector routing protocol
   that aims to be robust in a variety of environments.

   This document describes a few areas where Babel has been found to be
   useful.  It is structured as follows.  In Section 2, we describe
   application areas where Babel has been successfully deployed.  In
   Section 3, we describe application areas where Babel works well, but
   has not been widely deployed yet.  In Section 4, we describe
   application areas where deployment of Babel is not encouraged because
   better alternatives are available.

2.  Existing successful deployments of Babel

2.1.  Hybrid networks

   Babel is able to deal with both classical, prefix-based ("Internet-
   style") routing and flat ("mesh-style") over non-transitive link
   technologies.  Because of that, it has seen a number of succesful
   deployments in medium-sized hybrid networks, networks that combine a
   wired, aggregated backbone with meshy wireless bits at the edges.  No
   other routing protocol known to us is similarly robust and efficient
   in this particular type of network.

2.2.  Large scale overlay networks

   The algorithms used by Babel (loop avoidance, hysteresis, delayed
   updates) allow it to remain stable and efficient in the presence of
   unstable metrics, even in the presence of a feedback loop.  For this
   reason, it has been successfully deployed in large scale overlay
   networks, built out of thousands of tunnels spanning continents,




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   where it is used with a metric computed from links' latencies
   [DELAY-BASED].

2.3.  Small unmanaged networks

   Because of its small size and simple configuration, Babel has been
   deployed in small, unmanaged networks (three to five routers), where
   it serves as a more efficient replacement for RIP [RFC2453], albeit
   with good support for wireless links.

3.  Potential deployments of Babel

   There are application areas for which Babel is a good fit, but where
   it has not seen major deployments yet.

3.1.  Pure mesh networks

   Babel has been repeatedly shown to be competitive with dedicated
   routing protocols for wireless mesh networks [REAL-WORLD]
   [BRIDGING-LAYERS].  However, this particular niche is already served
   by a number of mature protocols, notably OLSR-ETX as well as OLSRv2
   [RFC7181] equipped with the DAT metric [DAT], so Babel has not seen
   major deployments in pure meshes yet.

4.  Application Areas where Babel is not recommended

   There are a number of application areas where Babel is a poor fit.

4.1.  Large, stable networks

   Babel relies on periodic updates, and even in a stable network, it
   generates a constant amount of background traffic.  In large, stable,
   well-administered networks, it is preferable to use protocols layered
   above a reliable transport mechanism, such as OSPF [RFC5340], EIGRP
   [EIGRP] or IS-IS [RFC1195].

4.2.  Low-power networks

   Babel relies on periodic updates and maintains within each node an
   amount of state that is proportional to the number of reachable
   destinations.  In networks containing resource-constrained or
   exteremely low-power nodes, it may be preferable to use a protocol
   that limits the amount of state maintained and propagated; we have
   heard of AODVv2 [AODVv2], RPL [RFC6550] and LOADng [LOADng].







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5.  References

   [AODVv2]   Perkins, C., Ratliff, S., Dowdell, J., Steenbrink, L., and
              V. Mercieca, "Ad Hoc On-demand Distance Vector Version 2
              (AODVv2) Routing", draft-ietf-manet-aodvv2-13 (work in
              progress), January 2016.

   [BRIDGING-LAYERS]
              Murray, D., Dixon, M., and T. Koziniec, "An Experimental
              Comparison of Routing Protocols in Multi Hop Ad Hoc
              Networks", Proc. ATNAC 2010, 2010.

   [DAT]      Rogge, H. and E. Baccelli, "Packet Sequence Number based
              directional airtime metric for OLSRv2", draft-ietf-manet-
              olsrv2-dat-metric-12 (work in progress), December 2015.

   [DELAY-BASED]
              Jonglez, B. and J. Chroboczek, "A delay-based routing
              metric", March 2014, <http://arxiv.org/abs/1403.3488>.

   [EIGRP]    Savage, D., Ng, J., Moore, S., Slice, D., Paluch, P., and
              R. White, "Enhanced Interior Gateway Routing Protocol",
              draft-savage-eigrp-04 (work in progress), August 2015.

   [LOADng]   Clausen, T., Verdiere, A., Yi, J., Niktash, A., Igarashi,
              Y., Satoh, H., Herberg, U., Lavenu, C., Lys, T., and J.
              Dean, "The Lightweight On-demand Ad hoc Distance-vector
              Routing Protocol - Next Generation (LOADng)", draft-
              clausen-lln-loadng-14 (work in progress), January 2016.

   [REAL-WORLD]
              Abolhasan, M., Hagelstein, B., and J. Wang, "Real-world
              performance of current proactive multi-hop mesh
              protocols", Asia-Pacific Conference on Communication 2009,
              2009.

   [RFC1195]  Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
              dual environments", RFC 1195, December 1990.

   [RFC2453]  Malkin, G., "RIP Version 2", STD 56, RFC 2453, November
              1998.

   [RFC5340]  Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
              for IPv6", RFC 5340, July 2008.

   [RFC6126]  Chroboczek, J., "The Babel Routing Protocol", RFC 6126,
              February 2011.




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   [RFC6550]  Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J.,
              Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur,
              JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
              Low-Power and Lossy Networks", RFC 6550, March 2012.

   [RFC7181]  Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg,
              "The Optimized Link State Routing Protocol Version 2", RFC
              7181, April 2014.

Author's Address

   Juliusz Chroboczek
   IRIF, University of Paris-Diderot
   Case 7014
   75205 Paris Cedex 13
   France

   Email: jch@pps.univ-paris-diderot.fr

































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