The invention relates to Internet telephony, and in particular an arrangement of gatekeepers in a H.323 network to reduce signalling during call set-up procedures. This is achieved by arranging the gatekeepers hierarchically, that is each gatekeeper knows a number of lower level gatekeepers (except the "bottom" nodes) and a higher level gatekeeper (except the "top" node). During set-up of a call, the gatekeeper connected to the calling user performs a user location algorithm on its attached users and lower level gatekeepers. If this procedure fails, it will proceed to its higher level gatekeeper.