SimGrid  3.13
Versatile Simulation of Distributed Systems
Packet level simulation

It is possible to use a packet-level network simulator instead of the default flow-based models. You may want to use this feature if you have doubts about the validity of the default model or want to perform some validation experiments.

At the moment, we support the well-known ns-3 packet-level simulator. Earlier releases of SimGrid did support the GTNetS simulator. Its support could possibly be revived by someone who would need it.

ns-3 as a SimGrid model

This section explains how to replace the SimGrid network models by those of the well-known ns-3 packet-level network simulator.

Installing ns-3

The easiest is to install it with the package manager. Under Debian/Ubuntu, simply type as root:

apt-get install libns3-dev ns3

You can also install it from scratch with the following commands:

# Download the source
wget http://www.nsnam.org/release/ns-allinone-3.25.tar.bz2
tar -xf ns-allinone-3.25.tar.bz2
cd ns-allinone-3.25/ns-3.25/
# Configure, build and install
./waf configure --prefix="/opt/ns3" # or give another path if you prefer
./waf
./waf install

For more information, please refer to the ns-3 documentation.

Enabling SimGrid's support for ns-3

Normally, you just have to enable ns-3 in ccmake or cmake as follows. If you installed ns-3 in a regular path, just drop the ns3_path configuration item.

cmake . -Denable_ns3=ON -DNS3_HINT=/opt/ns3 # or change the path if needed

By the end of the configuration, cmake reports whether ns-3 was found. You can also double-check by executing the tests after the compilation.

$ ctest -R ns3
(test(s) should be run)

If you have a ns-3 version that is not known to SimGrid (yet), the detection may fail. In that case, edit the tools/cmake/Modules/FindNS3.cmake file in your SimGrid tree. The required changes are very easy, and documented in the file header.

If the compilation fails when linking the library because of some .a file that cannot be used dynamically, this is probably because you only installed the libns3-dev library on your Debian, where you also need libns3-3. This is probably a bug of the libns3-dev package that should depend on the dynamic libraries corresponding to its .so files.

Using ns-3 from SimGrid

A working example of ns-3/SimGrid interactions can be found in examples/msg/network-ns3/. Basically, you just have to run your SimGrid simulation with the configuration option "network/model" set to "NS3". The rest remains unchanged.

The following should work from the examples/msg/network-ns3 folder (network-ns3 is the name of our example binary).

./network-ns3 ./3hosts_2links_p.xml 3hosts_2links_d.xml --cfg=network/model:NS3 --log=root.threshold:info

A ns-3 platform is automatically created from the provided SimGrid platform file. However, there are some known caveats:

  • The default values (e.g., TCP parameters) are the ns3 values. Don't blame us for them.

  • ns-3 networks are routed using the shortest path algorithm, using ns3::Ipv4GlobalRoutingHelper::PopulateRoutingTables.

  • End hosts cannot have more than one interface card (so, only one <link> in your SimGrid platform should link an end host to the platform ; if not, your end host will be considered as a router.

More about ns-3 simulator (Official website)

Examples

There is an example in the examples/ folder, that shows how to use the bindings. See also the documentation for this example.