Using Registration State to Determine Potential Change in User Location

1 . A method for determining potential relocation of an Internet Protocol (IP)-enabled telephony device, the method comprising:

subscribing to a registration events package of a Voice over IP (VoIP) network to which at least the IP-enabled telephony device is communicably connected;

receiving one or more notifications indicating a registration state of the IP-enabled telephony device; and

based on one or more registration state changes, determining that the IP-enabled telephony device has potentially relocated.

2 . The method as recited in claim 1 , further comprising determining the location of the IP-enabled device only if the registration state indicates that the device has potentially relocated.

3 . The method as recited in claim 1 , wherein the receiving operation comprises:

receiving a notify message indicating that the IP-enabled telephony device is in an active registration state.

4 . The method as recited in claim 3 , wherein the receiving operation further comprises:

receiving a notify message indicating that the IP-enabled telephony device is in a terminated registration state; and

receiving another notify message indicating that the IP-enabled telephony device is in the active registration state.

5 . The method as recited in claim 4 , wherein the determining operation comprises determining that a transition from the terminated registration state to the active registration state indicates that the IP-enabled telephony device has potentially relocated.

6 . The method as recited in claim 1 , further comprising:

receiving a notify message indicating that the IP-enabled telephony device has entered an active registration state; and

determining that a billing process should begin based on the IP-enabled telephony device's entry into the active registration state for an initial time.

7 . The method as recited in claim 1 , further comprising initiating a process to determine the location of the IP-enabled telephony device based on an indication that the IP-enabled telephony device has potentially relocated.

8 . A system for determining potential relocation of a user of a Voice over Internet Protocol (VoIP)-enabled device, the system comprising:

an application server comprising a user relocation determination application operable to subscribe to a VoIP registration events package and determine whether the user has potentially relocated based on a change in registration state of the user's VoIP-enabled device.

9 . The system as recited in claim 8 wherein the application server is further operable to determine that the VoIP-enabled device has potentially relocated based on a change in registration state from a terminated registration state to an active registration state.

10 . The system as recited in claim 8 wherein the application server is further operable to initiate a billing process based on a notification that the VoIP-enabled device has entered an active registration state for an initial time.

11 . The system as recited in claim 8 wherein the application server is further operable to initiate a location determination process that determines a new location of the VoIP-enabled device.

12 . A computer-readable medium having computer-executable instructions, which, when executed, cause a computer to implement a process, the process comprising:

subscribing to a registrar of a VoIP network associated with a customer VoIP-enabled device before said device has been activated for an initial time;

receiving a first message from the registrar indicating that the customer VoIP-enabled device has entered an active state;

based on the first message indicating that the VoIP-enabled device has entered the active state, beginning a billing process to bill the customer for use of the VoIP-enabled device;

receiving one or more other messages from the registrar indicating that the VoIP-enabled device has re-entered the active state from a terminated state; and

based on the message indicating that the VoIP-enabled device has re-entered the active state from the terminated state, determining that the VoIP-enabled device has potentially relocated.

13 . The computer-readable medium as recited in claim 12 , the process further comprising, initiating a process for determining a potentially new location of the VoIP-enabled device based on the determination that the VoIP-enabled device has potentially relocated.

14 . The computer-readable medium as recited in claim 12 , the process further comprising, automatically notifying an Enhanced 911 service of the determined new location.

15 . The computer-readable medium as recited in claim 12 , wherein receiving one or more other messages comprises:

receiving a message indicating that the VoIP-enabled device has entered the terminated state;

waiting for a message indicating that the VoIP-enabled device has re-entered the active state; and

receiving the message indicating that the VoIP-enabled device has re-entered the active state.