The contents of this legacy page are no longer maintained nor supported, and are made available only for historical purposes.

Atomized Routing

CAIDA is researching and implementing modifications to BGP routing that aggregate prefixes into equivalence classes (policy atoms) based on common AS path from a given topological location. The motivation behind development of BGP atomization mechanisms is to achieve potential savings in computation and communication costs (by absorbing routing dynamics of prefixes into coarser grained atoms), as well as reduction in BGP table size (there will be far fewer atoms than prefixes). Supported by RIPE NCC.

Sponsored by:
NLNet Labs Foundation (NLNet Labs) RIPE Network Coordination Centre (RIPE NCC)

Principal Investigators: kc claffyPatrick VerkaikAndre Broido

Funding source:  NLNet Labs Foundation RIPE Network Coordination Centre Period of performance: October 1, 2002 - October 31, 2003.


Atoms software (and its bundled component script, straightenRV) is available for download, but is no longer supported.

Router Development Tasks

  • Develop an atomized router, a BGP router with extensions for atoms. The router should be deployable in the Internet without breaking BGP or forwarding. The router is based on Zebra BGP router code base.
  • Test atomized routing in a confined deployment scenario using vimage.
  • Simulate and measure atomized routing performance in BGP++.

Analysis Tasks

  • Analyse number and stability of (hypothetical) declared atoms based on observed BGP table snapshots and BGP updates of prefixes.
  • Transform observed BGP updates on prefixes to an equivalent stream of updates on (hypothetical) declared atoms. Analyse the the resulting atom update stream.
  • Repeat the above analysis under provider-declared atoms, i.e. under the assumption that providers are able to aggregate prefixes originated by stub customers into atoms.
  • Determine properties and dynamics of atoms with respect to BGP attributes other than AS path.


  • Andre Broido
  • k claffy
  • Christos Xenofontas Dimitropoulos
  • Ruomei Gao
  • Bradley Huffaker
  • Young Hyun
  • Ronald van der Pol
  • Patrick Verkaik (primary contact)



  • BGP++ - a BGP/Zebra/C++ extension to the ns-2 simulator
  • vimage - FreeBSD network stack cloning

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