A method of routing a message in a network includes transmitting by a mobile station ( 105 ) a signaling connection establishment message ( 308 ) on a radio connection to a radio network controller ( 102 ) though a base station ( 104 ). The signaling connection establishment message can include a registration request message. Next the mobile station can receive a registration accept message ( 310 ) on the radio connection and can subsequently transmit an uplink signaling message ( 312 ) on the radio connection. The uplink signaling message from the mobile station can include a core network operator identifier ( 604 ).