Multi-detector analysis, involving a world-wide network of detectors, offers the best prospects for the detection of g.w. events. The crucial aspect of this analysis is a reliable estimate of the background, despite the presence of non-modellable environmental artifacts such as clustered event arrival times. As a by-product of the multi-detector analysis, one also estimates the direction of propagation and polarization of candidate gw events. In order to exploit the full capabilities of a detector network, we study the performances of two strategies devised to combine the data acquired by the network, namely the "AND" and "OR" network logics. In particular, we compare the False Dismissals of the two logics (at a given false alarm rate) as a function of the search thresholds of each detector and the search threshold of the network.