Our team has not personally tested this with Xbox Live, but we have tested a few cellular routers with gaming consoles. In our personal experience, as well as working with customers, we've found NAT types to be rather hit or miss. In most cases, the best NAT type you can get over a cellular Internet connection is a moderate NAT type 2. However, we have seen an Open NAT in some cases. We recommend following the steps on our gaming tip sheet, which can help, and the only other thing that MAY work is to pay the cellular provider for a static IP address. In any case, we can't guarantee what NAT type you'll receive.