Just a heads up that the Arris DG860 Gateway I received from Time Warner works with multiple consoles on one connection.
We both have open NAT and have been able to play in the same lobby together.
Both Xbox consoles are set to get their IP automatically and the UPnP in the gateway seems to be handling the traffic quite well. I noticed an improvement in game play over our previous gateway as well, that was a Motorola Surfboard SBG6580.
Thank you for sharing this lelady! :)