Having modified my ipcop over the years I have learned to appreciate the open nature of GPL software and the power and flexibility of Linux and the various tools that complement it. rrd-tool is one such tool and is used to produce the system and network graphs in ipcop.
Exploring and experimenting with rrd-tool can be fun and the internet will reveal some imaginative uses of it. Once I'd mastered its basics by tweaking the provided graphs, I wanted to start from scratch and my link quality modification was the drive for that.
I began with a straightforward 'ping time' graph (details here):
I moved on, with a change of ISP, to a line speed and noise graph (details here):
and more recently, a graph that combines the above two (my latest version is here):