The Optical Burst Switching (OBS) paradigm allows statistical multiplexing directly at the optical layer. Thus, OBS networks are suited to carry traffic demands varying in either the short or long term. Due to the lack of buffering, burst contention due to short term variations can only be mitigated through deflection routing. For longer term variations, higher order mechanisms such as dynamic flow-balancing or flow shaping are generally proposed. In this paper, a unified scheme, based on a feedback mechanism combined with deflection routing and admission control is introduced to handle all types of traffic variations. The use of only one single scheme simplifies the architecture of OBS networks and enhances its flexibility. The validity of our technique is supported by simulation results.