Issue with Internet Connectivity

I am running Fedora 18 on my HP laptop. When I first start the machine up it connects to the internet fine. It gets assigned an IP address and everything however; when I close my laptop and put it to sleep, then wake it up and log back in it never connects to the internet. The only way I ever get it to connect back to the internet is if I restart it.
Any advice on what might be the cause and how I can go about fixing the problem would be appreciated.