Methods and systems for discovering object-exchange resources on a network

A method for an object-exchange client device to discover network resources is disclosed. Clients listen on well-known communications channels of routable network protocols for advertisements identifying accessible resources. Clients use the information in the advertisements to determine which resources are available and when they become unavailable. In addition, clients send discovery requests over well-known communications channels requesting accessible resources to respond by identifying themselves. When a new resource becomes available, it advertises itself on a common communications channel. The client can specify criteria in its discovery request and only resources meeting those criteria are expected to respond. In particular, the client can limit the scope of dispersion of a discovery request to one network hop or to a certain geographical or network topological region. The scope can be expanded by propagating the request to other networks by means of a bridging protocol.