An approach for providing telephony services over a data network is disclosed. A communications system includes a location server that receives a request from a calling station to establish a call with a station associated with a called party. The location server generates a message specifying a set of addresses relating to the called party and context information. A proxy server communicates with the location server and is configured to receive the message and to attempt to establish the call based on the set of addresses. The proxy server iteratively queries the location server to obtain another set of addresses if no prior address results in establishment of the call.