Lace

A network simulator designed for teaching networks. Uses modern Linux features such as namespaces and caps (so only works on Linux, unfortunately).

Building and Setup

The program is split into three components: nsrun, vsetup and lace. nsrun is a C program which needs to be built, using the provided makefile. However, libcap-dev needs to be installed first:

sudo apt install libcap-dev
make

The makefile will also require admin access to grant the necessary caps to nsrun, and so will also run sudo.

Python 3, and xterm are also required to run lace, but these should already be installed on most Linux systems.

Usage

First you'll need to setup a network config file, a sample config file config.json is provided which sets up three hosts.

Each host should at least be given an IP address with the block (this is passed directly into ip addr), and exactly one host should be marked as the switch host. The switch host will have a bridge interface connecting the veth devices in the other hosts.

Once the config file is created, you can run Lace like so:

./lace.py (config file)

This spawns several xterm windows running a bash shell in the new network namespace, with the network interfaces setup already. If you used the sample config file, you can try something like ping 192.168.5.2, or using nc on two of the hosts.

Because of the way the caps are set, each shell has control over its own network namespace, so you can run more network setup commands (e.g. ip addr to configure more IP addresses).