Call transfer determination based on a geographic area served by a communication network

1. A call control system to route a voice over internet protocol call between a wireless communication device and a destination communication device, wherein the destination communication device is located in a geographic area served by a communication network, the call control system comprising:

a communication interface configured to receive an authorization response from an authorization system located in a home wireless network of the wireless communication device, wherein the authorization response includes a destination identifier of the destination communication device and a location identifier of the wireless communication device;

a processing system configured to process the destination identifier and the location identifier to determine if the wireless communication device is located in the geographic area served by the communication network; and

if the wireless communication device is located in the geographic area served by the communication network, the processing system configured to direct the communication interface to transfer the voice over internet protocol call over a source port associated with the geographic area served by the communication network.

2. The system of claim 1 wherein, if the wireless communication device is located in the geographic area served by the communication network, the processing system is configured to include the location identifier in a carrier identification code associated with the voice over internet protocol call.

3. The system of claim 1 further comprising the communication interface configured to receive a call request from a media gateway controller in a session initiation protocol (SIP) call invite message and transfer an authorization request to the authorization system in response to the call request.

4. The system of claim 3 wherein the call request from the media gateway controller comprises the location identifier of the wireless communication device, and wherein the processing system is configured to include the location identifier of the wireless communication device in the authorization request transferred to the authorization system.

5. The system of claim 1 wherein the destination identifier comprises a called number associated with the voice over internet protocol call and wherein the location identifier comprises an identifier of a mobile switching center (MSC) serving the wireless communication device.

6. The system of claim 5 wherein the processing system configured to process the destination identifier and the location identifier to determine if the wireless communication device is located in the geographic area served by the communication network comprises the processing system configured to process the called number and the identifier of the MSC to determine if the MSC serving the wireless communication device is associated with the geographic area served by the communication network.

7. The system of claim 1 wherein the destination identifier comprises a network address of the destination communication device and wherein the location identifier comprises an identifier of a wireless access node serving the wireless communication device.

8. The system of claim 7 wherein the processing system configured to process the destination identifier and the location identifier to determine if the wireless communication device is located in the geographic area served by the communication network comprises the processing system configured to process the network address and the identifier of the wireless access node to determine if the wireless access node serving the wireless communication device is associated with the geographic area served by the communication network.

9. The system of claim 1 wherein the wireless communication device is located outside of a geographic area served by the home wireless network of the wireless communication device when the voice over internet protocol call is initiated.

10. The system of claim 1 wherein the call control system comprises a session border controller.

11. A method of operating a call control system to route a voice over internet protocol call between a wireless communication device and a destination communication device, wherein the destination communication device is located in a geographic area served by a communication network, the method comprising:

receiving an authorization response from an authorization system located in a home wireless network of the wireless communication device, wherein the authorization response includes a destination identifier of the destination communication device and a location identifier of the wireless communication device;

processing the destination identifier and the location identifier to determine if the wireless communication device is located in the geographic area served by the communication network; and

if the wireless communication device is located in the geographic area served by the communication network, transferring the voice over internet protocol call over a source port associated with the geographic area served by the communication network.

12. The method of claim 11 further comprising, if the wireless communication device is located in the geographic area served by the communication network, including the location identifier in a carrier identification code associated with the voice over internet protocol call.

13. The method of claim 11 further comprising receiving a call request from a media gateway controller in a session initiation protocol (SIP) call invite message and transferring an authorization request to the authorization system in response to the call request.

14. The method of claim 13 wherein the call request from the media gateway controller comprises the location identifier of the wireless communication device, and further comprising including the location identifier of the wireless communication device in the authorization request transferred to the authorization system.

15. The method of claim 11 wherein the destination identifier comprises a called number associated with the voice over internet protocol call and wherein the location identifier comprises an identifier of a mobile switching center (MSC) serving the wireless communication device.

16. The method of claim 15 wherein processing the destination identifier and the location identifier to determine if the wireless communication device is located in the geographic area served by the communication network comprises processing the called number and the identifier of the MSC to determine if the MSC serving the wireless communication device is associated with the geographic area served by the communication network.

17. The method of claim 11 wherein the destination identifier comprises a network address of the destination communication device and wherein the location identifier comprises an identifier of a wireless access node serving the wireless communication device.

18. The method of claim 17 wherein processing the destination identifier and the location identifier to determine if the wireless communication device is located in the geographic area served by the communication network comprises processing the network address and the identifier of the wireless access node to determine if the wireless access node serving the wireless communication device is associated with the geographic area served by the communication network.

19. The method of claim 11 wherein the wireless communication device is located outside of a geographic area served by the home wireless network of the wireless communication device when the voice over internet protocol call is initiated.

20. A call control system to route a voice over internet protocol call between a wireless communication device and a destination communication device, wherein the destination communication device is located in a geographic area served by a communication network, the call control system comprising:

a communication interface configured to receive a call request from a media gateway controller and, in response to the call request, transfer an authorization request to an authorization system located in a home wireless network of the wireless communication device, wherein the call request and the authorization request include a location identifier of the wireless communication device;

the communication interface configured to receive an authorization response from the authorization system, wherein the authorization response includes a destination identifier of the destination communication device and the location identifier of the wireless communication device, and wherein the destination identifier includes a called number associated with the voice over internet protocol call;

a processing system configured to process the destination identifier and the location identifier to determine if the wireless communication device is located in the geographic area served by the communication network; and

if the wireless communication device is located in the geographic area served by the communication network, the processing system configured to direct the communication interface to transfer the voice over internet protocol call over a source port associated with the geographic area served by the communication network.