Abstract: The present invention concerns packet-based communications networks in which gateways are used to direct communications between terminals. For example, H.323 based communications networks are one example of this type of communications network. One problem relates to how such gateways can be enabled to direct communications between terminals in such a way that takes into account cost information and/or the fact that telephone numbers (or other identifiers) are repeated in different parts of the communications network. This is addressed by providing a gatekeeper with cost information associated with each gateway. An originating gateway sends a request to the gatekeeper comprising a unique identifier of that originating gateway and an identifier for a destination terminal. The gatekeeper uses this information to provide a reply comprising a list of all possible gateways that can be used to contact the destination terminal or a single preferred gateway.