In this paper we discussed different switch architectures. We focus mainly on optical buffering. We investigate an all-optical buffer architecture comprising of cascaded stages of quantum-dot semiconductor optical amplifier-based tunable wavelength converters, at 160 Gb/s. We also propose the optical buffer with multi-wavelength converters based on quantum-dot semiconductor optical amplifiers. We present multistage switching fabrics with optical buffers, where optical buffers are based on fibre delay lines and are located in the first stage. Finally, we describe a photonic asynchronous packet switch and show that the employment of a few optical buffer stages to complement the electronic ones significantly improves the switch performance. We also propose two asynchronous optical packet switching node architectures, where an efficient contention resolution is based on controllable optical buffers and tunable wavelength converters TWCs.