In this paper, we propose a new OBS scheme, named Fixed Burst Length OBS. The FBL-OBS networks, combined with the extra-offset time scheme, can guarantee the QoS of OBS networks in a more efficient way. In this paper, we propose a new OBS scheme, named Fixed Burst Length OBS. The FBL-OBS networks, combined with the extra-offset time scheme, can guarantee the QoS of OBS networks in a more efficient way.