coax cable -> cable modem -> ethernet cable -> into WAN port of (wireless) router -> from LAN port of (wireless) router -> to 24 port gigabit switch
GAH!
Um, yeah, I see now.
Just plug the cable modem into the gigabit switch directly. In fact, everything will be faster that way. You're probably throttling your whole house's bandwidth by trying to go through the (likely inferior) switch in the wireless router.
Think of the wireless router as just another "device" that hangs off your network, not as an integral part of its main backbone.
Oh wait. Unless you're using the wireless router for your NAT firewall. The cable modem doesn't have that built-in already?