Method and system for providing call-forwarding status indications in a packet-switched network

1. A method, comprising:

sending a first subscription message over a packet-switched network, using Session Initiation Protocol (SIP) event notification, to receive a call forwarding status notification associated with a call forwarding service of a user when a state associated with the call forwarding service changes;

receiving a call forwarding status notification when a state associated with the call forwarding service changes;

sending a second subscription message over the packet-switched network, using Session Initiation Protocol (SIP) event notification, to receive a call redirection notification associated with the call forwarding service of the user when a call has been forwarded; and

interpreting the call forwarding status notification at a device locally coupled to a user interface of the user, wherein the device is capable of notifying the user when the call has been forwarded; wherein the first subscription message comprises a first field identifying the call forwarding service and a second field defining the format of the call forwarding status notification.

2. The method according to claim 1 , wherein the packet-switched network comprises an Internet Protocol (IP) network.

3. The method according to claim 2 , wherein the IP network implements Session Initiation Protocol (SIP), the subscribe request is a SIP SUBSCRIBE message, and the call forwarding status notification is a SIP NOTIFY message.

4. The method according to claim 1 , wherein the receiving comprises receiving a notify request from a server in the packet-switched network, the notify request indicating the state associated with call forwarding service.

5. The message according to claim 4 , wherein the notify request comprises a first field identifying the call forwarding service.

6. A method, comprising:

receiving a first subscription message over a packet-switched network, using Session Initiation Protocol (SIP) event notification, to provide a call forwarding status notification associated with a call forwarding service of a user;

determining a change in a state associated with the call forwarding service;

providing a call forwarding status notification to a device locally coupled to a user interface of the user when the state associated with the call forwarding service changes;

receiving a second subscription message over a packet-switched network, using Session Initiation Protocol (SIP) event notification, to provide a call redirection notification associated with the call forwarding service of the user when a call has been forwarded; and

providing the call redirection notification to the device locally coupled to a user interface of the user when the call has been forwarded, wherein the device is capable of notifying the user when the call has been forwarded; wherein the first subscription message comprises a first field identifying the call forwarding service and a second field defining the format of the call forwarding status notification.

7. The method according to claim 6 , wherein the packet-switched network comprises an Internet Protocol (IP) network.

8. The method according to claim 7 , wherein the IP network implements Session Initiation Protocol (SIP), the subscription is a SIP SUBSCRIBE message, and the call forwarding status notification is a SIP NOTIFY message.

9. The method according to claim 6 , wherein the providing comprises providing a notify request from a server in the packet-switched network, the notify request indicating the state associated with call forwarding service.

10. The method according to claim 9 , wherein the notify request comprises a first field identifying the call forwarding service.

11. A system comprising:

a subscriber module, using Session Initiation Protocol (SIP) event notification, to subscribe to and receive a call forwarding status notification associated with a call forwarding service of a user and to subscribe to and receive a call redirection notification associated with the call forwarding service of the user and the subscriber module transmits a subscribe message over a packet switched network, the subscribe message comprising a first field identifying the call forwarding service and a second field defining the format of the call forwarding status notification; and

an interpreter module at a device locally coupled to a user interface of the user to interpret the received call forwarding status notification and to interpret the received call redirection notification, wherein the device is capable of notifying the user when a call has been forwarded.

12. The system according to claim 11 , wherein the subscriber module receives a notify request from a server in the packet-switched network, the notify request indicating a state associated with call forwarding service.

13. A system, comprising:

a subscribe module, using Session Initiation Protocol (SIP) event notification, to receive a subscription to provide a call forwarding status notification associated with a call forwarding service of a user and to receive a subscription to provide a forwarded call notification for one or more calls forwarded for the user and the subscribe module receives a subscribe message over a packet-switched network, the subscribe message comprising a first field identifying the call forwarding service and a second field defining the format of the call forwarding status notification;

a notify module to determine a change in a state associated with the call forwarding service and provide a call forwarding status notification to a device locally coupled to a user interface of the user when the state associated with the call forwarding service changes and to identify a forwarded call and provide a call redirection notification to the device when a call associated with the call forwarding service is forwarded, wherein the device is capable of notifying the user when the call has been forwarded.

14. The system according to claim 13 , wherein the notify module transmits a notify request from a server in the packet-switched network, the notify request indicating a state associated with call forwarding service.