It's not really an issue with the modem, but one with the ISP. If you can grab a second public IP address a switch work just fine, but most ISPs won't let you do that. Since a switch is fairly hard to find (relatively speaking) and about the same price as a router, the router is an easier solution. The downside being it will be a little more difficult to access the computer (or the Stoker) from the Internet, but often that's a good thing since it's also more difficult for hackers to access it.