Restarting network

Every two or three weeks, my network (DSL) goes down. "rcnetwork start" brings it right back up, but that's a nuisance. I want it to restart automatically, if possible. If all else fails, I can write a short script that checks every five minutes or so and restarts it if it's down. But I'd much rather have a configuration in the distribution that I can set for auto-restart. Is there such a thing?