At least one telephone network element receives an attempt by a caller to
place a telephone call to a telephone number of a callee. The telephone
number is registered in a telephone number mapping (ENUM) database to
receive incoming telephone calls via a Voice over Internet Protocol
(VoIP) network. The at least one telephone network element determines a
preference to carry the telephone call via a public switched telephone
network (PSTN) or a public land mobile network (PLMN) instead of the VoIP
network. Based on the preference, the telephone call is forwarded to a
gateway to carry the telephone call to the callee via the PSTN or the
PLMN instead of the VoIP network.