Plugins

A number of plugins are available for olsrd. Check out the olsr.org website for a complete list. Here a little HOWTO for the network topology visualization plugin olsrd_dot_draw.

Figure 3.8: An automatically generated OLSR network topology.

Often it is very good for the understanding of a mesh network to have the ability to show the network topology graphically. Olsrd_dot_draw outputs the topology in the dot file format on TCP port 2004. The graphviz tools can then be used to draw the graphs.

Installing the dot_draw Plugin

Compile the olsr plugins separately and install them. To load the plugin add the following lines to /etc/olsrd.conf

LoadPlugin "olsrd_dot_draw.so.0.3"
{
PlParam "accept" "192.168.0.5"
PlParam "port" "2004"
}

The parameter "accept" specifies which host is accepted to view the Topology Information (currently only one) and is "localhost" by default. The parameter "port" specifies the TCP port.

Then restart olsr and check if you get output on TCP Port 2004

telnet localhost 2004

After a while you should get some text output.

Now you can save the output graph descriptions and run the tools dot or neato form the graphviz package to get images.

Bruno Randolf has written a small perl script which continuously gets the topology information from olsrd and displays it using the graphviz and ImageMagick tools.

First install the following packages on your workstation:

• graphviz,
• ImageMagick,

Download the script at: meshcube.org/nylon/utils/olsr-topology-view.pl

Now you can start the script with ./olsr-topology-view.pl and view the topology updates in near-realtime.