In short, at BT, no way. Your IP is your LAN. Other users get different IPs. BT runs three SSIDs. Your network, BT-Wifi (FKA OpenZone), and BT-FON. Your netwo

In short, at BT, no way. Your IP is your LAN. Other users get different IPs. BT runs three SSIDs. Your network, BT-Wifi (FKA OpenZone), and BT-FON. Your network is your network. Private IP, different encryption. The packets leave your house, travel over the ADSL, exit the DSLAM, into a BRAS. There (more or less) it exits onto the "internet" connectivity of BT, with the IP of your ADSL modem. FON and BT-WiFi leave your house, travel over the ADSL, exit the DSLAM, into a BRAS, but there's a difference now. Instead of exiting onto the "internet", it is stuck in a channel that goes to a different part of the network. This part hosts the server where you login/etc. and where your traffic eventually leaves, with a different IP address than the home network, to the internet. I'm fairly sure the IP is a proxy address, assigned to the logged in user's session, and not tied to the specific router. That channel used to be 256kbps reserved. I think it is now 512kbps. This channel has lower priority than your normal internet traffic. There is also another channel for BT Vision, that IIRC has 2Mbps reserved for their video. I assume this never leaves the BT network for the internet :-) This has a higher priority than your normal internet traffic (for obvious reasons). AFAIK the BRAS is where the quality of service is enforced. The router is requesting the different classes of service though, and is tagging the packets. (And I think it's also running a tunnel for the FON and BT WiFi). EDIT: Corrected a mistake, added some clarity for other q's raised elsewhere.