Abstract: A station used as a node in a peer-to-peer communications system keeps a list of stations to which requests for resources may be sent. The list includes for each member a performance parameter. When a station receives a request for resources it selects at least one station from the list and sends a resource request message to it. The selection of the station from the list may be performed by a random or pseudo-random process such that the probability of selection of any station is a function of the stored parameter. A station receiving such a request, for resources that it can itself supply, sends a reply to the originator. When the originator receives a reply it updates the respective performance parameter: the degree of adjustment may vary according to the quality of reply received.