Kodo NS3 Examples

The kodo-ns3-examples repository demonstrates how to use the Kodo erasure coding library (http://kodo.steinwurf.com) in various ns-3 examples.

ns-3 (http://nsnam.org) is a discrete-event network simulator, targeted primarily for research and educational use. ns-3 is licensed under the GNU GPLv2 license.

The kodo-ns3-examples repository: https://github.com/steinwurf/kodo-ns3-examples

If you have any questions or suggestions about this library, please contact us at our developer mailing list (hosted at Google Groups):

• http://groups.google.com/group/steinwurf-dev

Important: Before asking any questions, please try to precisely follow the instructions here and read the guidelines of our mailing list!

If you have a technical issue with ns-3 itself, then please ask around on the ns-3 mailing list.

License

A valid Kodo license is required if you wish to use this project. Please request a license by filling out the license request form.

If you try to configure without a valid license, then you will get an error!

Using Kodo in an ns-3 example

The examples in this repository will be installed to the examples/kodo subfolder of your ns-3 folder. We will also build the Kodo static libraries which will be installed in the same folder together with the required header files. The examples will be linked with the required static libraries.

Getting Started

As a first step, you need ns-3 installed on your development machine. You may find lots of information about this on the ns-3 webpage:

http://www.nsnam.org/wiki/index.php/Installation

On Ubuntu/Debian, you need to install the following packages:

sudo apt-get install g++ python3 git

In the following, we will clone ns-3 to the ~/ns-3-dev folder and we will clone the kodo-ns3-examples to the ~/kodo-ns3-examples folder. You may use different folders, but the two folders must be separate, i.e. one cannot be the subfolder of the other.

Installing ns-3

First clone the ns-3 repository (we start from the home folder, so it will be cloned to ~/ns-3-dev):

cd ~
git clone https://gitlab.com/nsnam/ns-3-dev.git

This command will download the ns-3 simulator to your computer into the ns-3-dev folder (this may take a few minutes).

Go to this freshly cloned folder:

cd ns-3-dev

Our aim is to make the examples compatible with the latest ns-3 revision. If you experience any issues with the latest revision, then you can switch to the latest stable release (this step is optional):

git checkout ns-3.35

Configure the ns-3 project (it is important to also enable the examples):

python3 waf configure --enable-examples

This will output a whole bunch of information about the enabled modules based on the availability of tools and libraries installed on your computer.

Now we build the ns-3 libraries and examples:

python3 waf build

Installing the Kodo examples to ns-3

After building ns-3, you can switch to the kodo-ns3-examples repository. We will clone this repository to the ~/kodo-ns3-examples folder:

cd ~
git clone git@github.com:steinwurf/kodo-ns3-examples.git

Configure this project:

cd kodo-ns3-examples
python3 waf configure

The waf configure command ensures that all dependencies are downloaded (by default, waf will create a folder called bundle_dependencies to store these libraries).

Now we build the kodo-rlnc static library and we install the examples and all the required files to the ~/ns-3-dev/examples/kodo folder:

python3 waf build install --destdir ~/ns-3-dev/examples/kodo

The --destdir option is used to specify the target folder (you can change the kodo subfolder name to something else if you like).

Building the Kodo examples in ns-3

After the install step, you can switch back to your ns-3 folder:

cd ~/ns-3-dev

You can follow the normal ns-3 workflow to build our examples. The ns-3 waf will automatically find the new examples in ~/ns-3-dev/examples/kodo:

python3 waf build

We have the following examples:

• kodo-wired-broadcast: This example demonstrates broadcasting packets with RLNC from a transmitter to N receivers with the same erasure channel.
• kodo-wifi-broadcast: This example demonstrates broadcasting packets with RLNC to N receivers over an IEEE 802.11b WiFi channel.
• kodo-recoders: This example shows the gain of RLNC with recoding in a 2-hop line network consisting of an encoder, N recoders and a decoder with different erasure rates. Recoding can be turned on or off and the erasure rates can be modified by command-line options.

You can find more details about each example in their respective source files. There you can also check how to change the simulation parameters like the packet-, field- and generation sizes.

You can run the examples with the usual ns-3 run commands:

python3 waf --run kodo-wired-broadcast
python3 waf --run kodo-wifi-broadcast
python3 waf --run kodo-recoders

Most of the examples will print out how the decoding matrix changes with each combination packet. You will see if a received packet is linearly dependent or not. You will also see when the decoding process is completed and how many transmissions were required.

Adding your own simulation

At this point, you might want to add your own simulation that uses kodo.

It is recommended to create a separate folder (e.g. ~/ns-3-dev/examples/my-simulation) for your custom simulation and copy all the necessary files from ~/ns-3-dev/examples/kodo (most importantly the include and lib folders).

If you copy the wscript file, then please delete or comment out the parts where we call bld.create_ns3_program. We cannot have multiple programs with the same name (e.g. kodo-recoders).

When you create a new program, you can start by copying one of the kodo examples. If you have a source file called my-simulation.cc, then you can define a new program in ~/ns-3-dev/examples/my-simulation/wscript. like this:

obj = bld.create_ns3_program('my-simulation',
                             ['core', 'applications', 'point-to-point',
                              'point-to-point-layout', 'internet', 'wifi'])
obj.source = 'my-simulation.cc'
set_properties(obj)

After this change, the ns-3 waf will detect the new example and you will be able to run it from the ~/ns-3-dev folder as usual:

cd ~/ns-3-dev
python3 waf --run my-simulation

Now you can expand your custom simulation as you like. If you use additional ns-3 modules, then you need to add them in the wscript (most likely, you will get a build error if you are missing a module).

If your simulation has multiple source files (.cc files), then you can add these in the wscript like this:

obj.source = ['my-simulation.cc', 'source2.cc', 'source3.cc']

Warning: If you install the kodo ns-3 examples again with this command:

cd ~/kodo-ns3-examples
python3 waf build install --destdir="~/ns-3-dev/examples/kodo"

then the example source files and the wscript will be overwritten in the ~/ns-3-dev/examples/kodo folder, so it is recommended to create a backup if you modified any of these files.