Soliton transmission control techniques in both the time and frequency domains designed to enable ultralong distance soliton transmission is described in detail. Soliton transmission control in the time domain, which can be realized by synchronous modulation, is a retiming technique which removes jitter and nonlinear interaction between adjacent solitons. In addition, a transfer function reduces noise and the noise power eventually converges to a low level for any transmission distance. Soliton transmission control in the frequency domain, which can be realized with a band pass optical filter, stabilizes the soliton pulse. One millon km transmission experiment confirms the usefulness of these techniques.