I am using an AT&T Microcell. I need to prioritize the packets, or else I get calls that cuts in and out. Unfortunately there is very to little information on the TCP/UDP it uses to communicate from the Microcell back to AT&T center. When I was using another brand's router with DD-WRT I was able to just tell DD-WRT what MAC address the Microcell was and set the priority, but with this Buffalo firmware you can only assign UDP/TCP packets.
Buffalo Employee: PLEASE ADD MAC/IP QoS priority options! OR GET DD-WRT WORKING FOR THIS ROUTER!