This happened to me recently, and I really wanted to keep using the old router (BT Home Hub 3), as it had a natty power save feature (it switches off WiFi) that I could use to prevent the children accessing the Internet from any of their devices outside of the hours we had agreed. Having the WiFi just switch off automatically and on again at preset times seems much easier than trying to setup firewalls and VLANs to try and limit their access.
Also, with the BT Home Hub 3 it's very easy to bypass the power save feature and extend their access time, so the kids can watch movies, for example, at weekends and sleep overs. So, the challenge was to re-use the BT Hub as a dedicated access point (AP) for the kids PCs, phones and iPods.
A quick bit of 'research' (aka google) revealed that this should be relatively simple, but I thought it worth documenting the simple steps required. Below is what I did (the order is important!). I've assumed that you haven't re-configured the old router too much, but you could always factory-reset it before starting (which I would recommend if you customised it's setup a lot):
- Firstly, disconnect your computer from any networks (wireless and wired).
- Attach the old router to your computer using an ethernet patch cable.
- Login by browsing to the old router's address (usually 192.168.0.1 or 192.168.1.1, but often printed on a label underneath).
- The username and password are usually on the label to, but you should change these to something more secure.
- Go to the WiFi settings page and configure the access point's SSID as you want it (I took the option here to restrict this network to the slower b/g standards as a way of throttling the bandwidth being 'hogged' for Skype etc.!).
- Next, change your old routers IP address to something that is in the range used by your new router, you'll probably find this setting on the 'LAN' settings page. In my case, the new router was 192.168.1.1, so I chose to set the old router to 192.168.1.2. Just make sure you're not selecting an address already in use - you'll need to login to your new router to check, or download fing.
- Next, again usually in 'LAN' settings, disable DHCP (this is the service that issues out IP addresses, and you only want one device on your network doing this, and your new router is doing this and will continue to do so).
- Disconnect your old router from your computer, and instead connect it to a spare ethernet port on the back of your new router.
- Now, logon to your new router and in the LAN settings, look for a setting called 'reserve addresses' or similar, and reserve the address you selected in step 6. This ensures that the address will not be dynamically allocated to another device, for example if the old router (which is now just an AP) is switched off.
Finally, logon to the new SSID and check that it connects to the Internet. That's it, and for no extra cost I have a separate access point for the kids, time-limited and restricted to the theoretical 54Mbps of wireless 'g', while the adults and the Apple TV get to connect to the new router by wireless 'n', which theoretically offers 6 times the bandwidth (300Mbps). In practice, real throughputs will be a lot lower so this is a crude way of carving up the 25Mbps or so we have from our fibre broadband.