The prospects of Optical Burst Switching (OBS) as a cost-effective optical networking paradigm are related with the capability (and the associated complexity) of resolving contention in these networks. The lack of RAM-like optical buffers greatly limits the effectiveness of contention resolution in OBS networks. However, the electronic buffers available at the ingress edge nodes can be exploited, not only for shaping burst traffic using appropriate burst assembly strategies, but also for minimizing/resolving contention by adjusting the bursts departure time from these nodes. This paper describes OBS network architectures which benefit from this flexible ingress burst scheduling and compares their performance and complexity. It is shown that JET-based OBS networks using traffic engineering in the wavelength domain achieve a comparable burst loss to that of centralized scheduling.