In this study, we examine control-plane throughput in optical burst switching (OBS) networks with electronic header processing. In a large-scale OBS network, headers arrive to the burst scheduler at a very high rate. This can potentially cause overloading of the core-node control-processor and lead to data loss if headers are not processed in a timely manner. In this work, we examine the effect of control-plane congestion on the overall loss performance of OBS networks. We present preliminary results that show how this congestion can become the primary source of loss and can ultimately limit the throughput and the scalability of the OBS system if not properly accounted for when designing the OBS network.