A method of processing a frame of a CPU intensive communications protocol includes disabling per frame interrupts of a CPU; enabling a periodic interrupt handler to interrupt the CPU upon an interrupt period; and upon an interrupt of the periodic interrupt handler, determining and processing a frame received in the interrupt period. Further, a frame sent acknowledgment stored in the interrupt period may be processed during the interrupt. A method of processing the transmission of frames of a CPU intensive communications protocol includes, when no MSU frame is queued for transmission, sending FISU frames that each point to itself; and if a MSU frame is queued for transmission, updating the MSU frame to point to a new FISU frame, updating a current FISU frame to point to the MSU frame, and sending the current FISU frame, the MSU frame and the new FISU frame.