Parallel Simulations

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Project Background

This approach analyses the current NS3 architecture, spot areas of parallelization and build the fundamentals algorithms to achieve performance gains! Main goal is a CPU local parallelization but an powerful architecture on the other hand should also scale in large (in a distributed environments).

The approach should be universal and transparent for all major subsystems withing the simulator. Therefore an additional abstraction layer should be introduced to hide all implementation issues and enable the possibility to disable the parallelization completely, substitute or enhance the algorithms. The additional layer is an increment, the first usable results should illume where an interface is suitable. Focus is still an working implementation!

Project Plan

  • Literature study
  • Basic parallelization and packet serialization/serialization
  • Synchronization approach
    • Node local (CMP/SMP)
    • Distributed (MPI)
  • Balance subsystem isolation (WHERE to split the NS3 system for parallelization)
  • Clean parallelization layer with the following characteristics
    • as few as possible interaction with other subsystems
    • minimal overhead
    • new technologies should be implemented without knownledge of the underlying algorithm (e.g. interference calculation for wireless nodes)
    • last but not least: the introduced algorithm should scale well for uniprocessor systems as same as clusters! ;)


Current approach and fundamental algorithm is based on a space parallel paradigm. Nodes are merged into subsets where each subset represent a working thread (consider this as a thread, local process or distributed working task).


  • Decision how to parallelize the simulator - currently a strict space parallel approach is selected.
    • Not sure if this approach scale well for communication channels (MAC/PHY) with a large set of interferences (this leads to a large set of inter-node communication). To be discussed with George ... ;)
  • Packets are transmitted and received via vanilla socket communication to test the serialization/deserialization behavior. Especially attention must consider the Packet meta data (e.g. tags).

Suggestions from Mathieu Lacage

These were posted on the ns-developers mailing-list:


Parallelization Approaches

  • omnet++ [1]
  • The Georgia Tech Network Simulator [2]
  • Dartmouth SSF [3]


  • MPI


  • GloMoSim: A Library for Parallel Simulation of Large-scale Wireless Networks [5]
  • Space-parallel network simulations using ghosts [6]
  • Lock-free Scheduling of Logical Processes in Parallel Simulation [7]
  • Learning Not to Share [8]
  • Towards Realistic Million-Node Internet Simulations [9]
  • A Generic Framework for Parallelization of Network Simulations [10]