How to graph RRD data from DEVMON

I would like to create graphs from the devmon output of cisco switches. For this, I found a document "How to if_* grpah from Devmon to Hobbit". However I can't find the extra-rrd.pl program

Is there anyone outthere who is able to tell me how to use the data from devmon to create a rrd graph ?

Regards,

Bert Klomp NLR