Software-Defined Radio (SDR) describes radio transceivers implemented in software that executes on general-purpose hardware. SDR combined with cloud computing technology will reshape the wireless access infrastructure, enabling computing resource sharing and centralized Digital-Signal Processing (DSP). SDR clouds have different constraints than general-purpose grids or clouds: real-time response to user session requests and real-time execution of the corresponding DSP chains. This paper addresses the SDR cloud computing resource management problem. The authors show that the maximum traffic load that a single Resource Allocator (RA) can handle is limited.