Call prioritization in a communication network

1. A method of operating a call control system, the method comprising:

receiving a first access request from a communication system requesting access to a voice service, wherein the first access request comprises an off-hook notify message;

in response to receiving the first access request, transferring a rejection to the communication system that indicates that the voice service is not available;

in response to transferring the rejection, receiving a first call request for a priority service from the communication system;

processing the first call request to determine if the first call request indicates the priority service;

if the first call request indicates the priority service, then transferring a second access request to a communication network in response to the first call request, wherein the second access request comprises an out-of-sequence off-hook notify message representing a high priority call request;

in response to transferring the second access request to the communication network, receiving a first successful response from the communication network; and

in response to receiving the first successful response, transferring a second call request to the communication network.

2. The method of claim 1 further comprising:

in response to transferring the second call request to the communication network, receiving a second successful response from the communication network;

in response to receiving the second successful response from the communication network, transferring a third successful response to the communication system; and

connecting the communication system to the priority service.

3. The method of claim 1 wherein the first successful response comprises a request for dialed digits, wherein the request for dialed digits comprises a request identifier.

4. The method of claim 3 wherein transferring the second call request comprises transferring dialed digits to the communication network, wherein the second call request includes the request identifier.

5. The method of claim 1 wherein the first call request for the priority service comprises a priority bit.

6. The method of claim 5 wherein processing the first call request to determine if the first call request indicates the priority service comprises processing the first call request to determine if the first call request comprises the priority bit.

7. The method of claim 1 wherein receiving the first call request comprises receiving dialed digits from the communication system.

8. The method of claim 7 wherein processing the first call request to determine if the first call request indicates the priority service comprises processing the first call request to determine if the dialed digits are equal to 9-1-1.

9. A call control system comprising:

a communication interface configured to receive a first access request from a communication system requesting access to a voice service, wherein the first access request comprises an off-hook notify message;

the communication interface configured to, in response to receiving the first access request, transfer a rejection to the communication system that indicates that the voice service is not available;

the communication interface configured to, in response to transferring the rejection, receive a first call request for a priority service from the communication system;

a processing system configured to process the first call request to determine if the first call request indicates the priority service;

if the first call request indicates the priority service, then the communication interface configured to transfer a second access request to a communication network in response to the first call request, wherein the second access request comprises an out-of-sequence off-hook notify message representing a high priority call request;

the communication interface configured to, in response to transferring the second access request to the communication network, receive a first successful response from the communication network; and

the communication interface configured to, in response to receiving the first successful response, transfer a second call request to the communication network.

10. The system of claim 9 further comprising:

the communication interface configured to, in response to transferring the second call request to the communication network, receive a second successful response from the communication network, and in response to receiving the second successful response from the communication network, transfer a third successful response to the communication system; and

the processing system configured to connect the communication system to the priority service.

11. The system of claim 9 wherein the first successful response comprises a request for dialed digits, wherein the request for dialed digits comprises a request identifier.

12. The system of claim 11 wherein the communication interface configured to transfer the second call request comprises the communication interface configured to transfer dialed digits to the communication network, wherein the second call request includes the request identifier.

13. The system of claim 9 wherein the first call request for the priority service comprises a priority bit.

14. The system of claim 13 wherein the processing system configured to process the first call request to determine if the first call request indicates the priority service comprises the processing system configured to process the first call request to determine if the first call request comprises the priority bit.

15. The system of claim 9 wherein the communication interface configured to receive the first call request comprises the communication interface configured to receive dialed digits from the communication system.

16. The system of claim 15 wherein the processing system configured to process the first call request to determine if the first call request indicates the priority service comprises the processing system configured to process the first call request to determine if the dialed digits are equal to 9-1-1.