staying online with a dialup connection

I have a linux server machine with an internal Fritz! DSL card installed providing internet access to my windows boxes, with dial-on-demand activated. that works fine. but I need to ensure that my linux box stays online because there's also a CVS server running on it which needs to be accessed by a fellow.

So when the connection is terminated once daily by the provider (I don't know when, as it's at different times), it shall come up again automatically and promptly.

Of course I could setup a cron job every 5 minutes or so which either pings another server or requests an internet-page in order to re-establish the connection. Does anybody know a more efficient way to do that? I am thinking of some sort of daemon program that watches the connection a automatically reconnects if necessary..?