Future Internet infrastructure will require the utiliza-tion of new all-optical devices able to enhance the use of fiber ca-pacity. Nevertheless, before deploying such devices, it is necessary to test them under conditions similar to the ones of commercial net-works and to evaluate their impact on real-world applications. In this work we investigate the performance of a tunable fiber four-wave mixing all-optical wavelength converter (AOWC) on a video-streaming carried through a field-trial network. This analysis is performed by measuring the packet-error rate (PER) degradation caused by the AOWC for different wavelength separations between the input and output optical carriers. To the best of our knowl-edge, this is the first time that such a cross-layer effect is systemat-ically evaluated for an AOWC. A dynamic polarization controller was successfully used to prevent the FWM efficiency variations that were caused by the changes in the state-of-polarization of the video signal. Our results show that the AOWC introduced a max-imum power penalty of 2.5 dB for wavelength separations of up to 12 nm. We also find that such a penalty is related to the optical signal-to-noise ratio degradation induced by the converter. Index Terms—All-optical wavelength converters (AOWC), cross-layer effect, transparent optical network (TON), wavelength division multiplexing (WDM).