Methods and apparatus to enable call completion in internet protocol communication networks

1. A method to process a voice over Internet protocol call, the method comprising:

sending a first query to a telephone number mapping server to obtain a session initiation protocol uniform resource identifier associated with a destination device with which the voice over Internet protocol call is to be established;

in response to the voice over Internet protocol call failing to be established using the session initiation protocol uniform resource identifier obtained from the first query, sending a second query to the telephone number mapping server to obtain a numeric Internet protocol address associated with the destination device; and

using the numeric Internet protocol address obtained from the second query to establish the voice over Internet protocol call with the destination device.

2. The method of claim 1 , wherein the second query includes a value to request a particular one of a plurality of stored numeric Internet protocol addresses associated with the destination device.

3. The method of claim 2 , wherein the value is based on a chronological ordering of the plurality of stored numeric Internet protocol addresses associated with the destination device.

4. The method of claim 1 , further comprising determining whether a response to a third query sent to a domain name server to obtain numeric Internet protocol address information for the destination device has not been received within a timeout period, the third query including the session initiation protocol uniform resource identifier obtained from the first query, the voice over Internet protocol call being determined to have failed to be established using the session initiation protocol uniform resource identifier obtained from the first query when the response has not been received within the timeout period.

5. The method of claim 1 , wherein the numeric Internet protocol address associated with the destination device is a first numeric Internet protocol address, and further comprising:

in response to the voice over Internet protocol call failing to be established using the first numeric Internet protocol address obtained from the second query, sending a third query to the telephone number mapping server to obtain a second numeric Internet protocol address associated with the destination device; and

using the second numeric Internet protocol address obtained from the third query to establish the voice over Internet protocol call with the destination device.

6. The method of claim 5 , wherein the first numeric Internet protocol address was associated with the destination device more recently than the second numeric Internet protocol address.

7. The method of claim 5 , wherein the first and second numeric Internet protocol addresses are based on addresses dynamically assigned to a call server associated with the destination device.

8. A machine readable storage device comprising machine readable instructions which, when executed, cause a machine to perform operations comprising:

sending a first query to a telephone number mapping server to obtain a session initiation protocol uniform resource identifier associated with a destination device with which a voice over Internet protocol call is to be established;

in response to the voice over Internet protocol call failing to be established using the session initiation protocol uniform resource identifier obtained from the first query, sending a second query to the telephone number mapping server to obtain a numeric Internet protocol address associated with the destination device; and

using the numeric Internet protocol address obtained from the second query to establish the voice over Internet protocol call with the destination device.

9. The storage device of claim 8 , wherein the second query includes a value to request a particular one of a plurality of stored numeric Internet protocol addresses associated with the destination device.

10. The storage device of in claim 9 , wherein the value is based on a chronological ordering of the plurality of stored numeric Internet protocol addresses associated with the destination device.

11. The storage device of claim 8 , wherein the operations further comprise determining whether a response to a third query sent to a domain name server to obtain numeric Internet protocol address information for the destination device has not been received within a timeout period, the third query including the session initiation protocol uniform resource identifier obtained from the first query, the voice over Internet protocol call being determined to have failed to be established using the session initiation protocol uniform resource identifier obtained from the first query when the response has not been received within the timeout period.

12. The storage device of claim 8 , wherein the numeric Internet protocol address associated with the destination device is a first numeric Internet protocol address, and the operations further comprise:

in response to the voice over Internet protocol call failing to be established using the first numeric Internet protocol address obtained from the second query, sending a third query to the telephone number mapping server to obtain a second numeric Internet protocol address associated with the destination device; and

using the second numeric Internet protocol address obtained from the third query to establish the voice over Internet protocol call with the destination device.

13. The storage device of claim 12 , wherein the first numeric Internet protocol address has been associated with the destination device more recently than the second numeric Internet protocol address.

14. The storage device of claim 12 , wherein the first and second numeric Internet protocol addresses are based on addresses dynamically assigned to a call server associated with the destination device.

15. An apparatus to process a voice over Internet protocol call, the apparatus comprising:

memory to store machine readable instructions; and

a processor to execute the machine readable instructions to perform operations comprising:

sending a first query to a telephone number mapping server to obtain a session initiation protocol uniform resource identifier associated with a destination device with which the voice over Internet protocol call is to be established;

in response to the voice over Internet protocol call failing to be established using the session initiation protocol uniform resource identifier obtained from the first query, sending a second query to the telephone number mapping server to obtain a numeric Internet protocol address associated with the destination device; and

using the numeric Internet protocol address obtained from the second query to establish the voice over Internet protocol call with the destination device.

16. The apparatus of claim 15 , wherein the second query includes a value to request a particular one of a plurality of stored numeric Internet protocol addresses associated with the destination device.

17. The apparatus of claim 16 , wherein the value is based on a chronological ordering of the plurality of stored numeric Internet protocol addresses associated with the destination device.

18. The apparatus of claim 15 , wherein the operations further comprise determining whether a response to a third query sent to a domain name server to obtain numeric Internet protocol address information for the destination device has not been received within a timeout period, the third query including the session initiation protocol uniform resource identifier obtained from the first query, the voice over Internet protocol call being determined to have failed to be established using the session initiation protocol uniform resource identifier obtained from the first query when the response has not been received within the timeout period.

19. The apparatus of claim 15 , wherein the numeric Internet protocol address associated with the destination device is a first numeric Internet protocol address, and the operations further comprise:

in response to the voice over Internet protocol call failing to be established using the first numeric Internet protocol address obtained from the second query, sending a third query to the telephone number mapping server to obtain a second numeric Internet protocol address associated with the destination device; and

using the second numeric Internet protocol address obtained from the third query to establish the voice over Internet protocol call with the destination device.

20. The apparatus of claim 19 , wherein the first and second numeric Internet protocol addresses are based on addresses dynamically assigned to a call server associated with the destination device, and the first numeric Internet protocol address was associated with the destination device more recently than the second numeric Internet protocol address.