16. The device of claim 15 , wherein the call session comprises a packet-switched communication session.
15. A mobile communication device, comprising: a memory storing executable instructions; and a processor coupled to the memory, wherein the executable instructions facilitate performance of operations comprising: transmitting a request to an originating call session control function server for a call session with a terminating device over a communication network, wherein the request comprises a fully qualified domain name for identifying the mobile communication device, and wherein a notification is sent from the originating call session control function server to a termination call session control function server responsive to the request; and receiving, from an terminating call session control function server, a response message via an internet protocol version 4 address or an internet protocol version 6 address according to an answer combination, wherein a query is transmitted from the terminating call session control function server to a domain naming server according to the fully qualified domain name, wherein an answer from the domain naming server is received by the terminating call session control function server, wherein the answer is analyzed by the terminating call session control function server to determine an answer combination according to the answer.