In this paper we present a performance evaluation of two distributed channel assignment algorithms in a large-scale wireless multi-radio testbed. We compare the performance of a link-based approach, in which channels are assigned to existing links in the network, with an interface-based approach, in which channels are assigned to the network interfaces. Both algorithms have significantly increased the network capacity in small wireless testbeds with less than 15 nodes. In this study, we investigate if the performance gain scales to large-scale wireless mesh networks. We evaluate the performance of the algorithms in the DES-Testbed, a multi-radio wireless mesh network with 126 nodes at Freie Universität Berlin. We compare the results to a single channel network and a randomized strategy. Additionally, we analyze the impact of the algorithms on the network connectivity and the spectral diversity. The results show, that compared to the single channel network, both algorithms increase the network capacity by a factor of three.