Do you mean you lose your cable connection once a day, and you need to re-obtain it by powering off and on?
If so, it's because your DHCP lease might be expiring. To solve the problem, get into your web-based router config, go to the "Setup" menu and check the "Renew IP forever" box. Then power off the router, and turn it on again.
I too have this problem with my linksys router. I didn't have this problem until recently when AT&T was taken over by Comcast. I have to cycle the router and occasionally do the release and renew via the cmd window so everything is sync'd up. I don't have any option in my setup or advanced selections that would enable me to always maintain my IP. I thought the router would automatically renew the IP upon expiration, guess I thought wrong. It's a little annoying but easy to fix.
If anyone can shed some light on my rather dark mind, I'd really appreciated it.
Thanks in advance