Granted Patent B2

US 7,453,876 · App. 10/956,858 · Granted Nov 18, 2008

Abstract

Claims (40)

1. A method for routing in an internet protocol (IP) multimedia subsystem (IMS) incorporating a distributed subscriber locator function, the method comprising:

determining by a first network element whether a private user identification including a realm name is available for use in routing using a Diameter Protocol;

populating by the first network element a destination-realm attribute value pair of a first Diameter Protocol message with the private user identification if the private user identification is available;

performing a subscriber locator function by a first network element to determine a first home subscriber service (HSS) element to which to send the first Diameter Protocol message based on the destination realm attribute value pair;

transmitting the first Diameter Protocol message from the first network element to the first home subscriber service (HSS) element;

populating by the first network element the destination-realm attribute value pair of a second Diameter Protocol message with a whole network realm if the private user identification is not available;

transmitting the second Diameter Protocol message from the first network element to a second network element;

performing a second subscriber locator function by the second network element to determine a second home subscriber service (HSS) element to which the second Diameter Protocol message should be sent;

populating by the second network element a Redirect-Host attribute value pair with information relating to the second home subscriber service (HSS) element; and,

transmitting the second message back to the first network element and to the second home subscriber service (HSS) element if the second home subscriber service (HSS) element is not the second network element.

2. The method as set forth in claim 1 further comprising receiving a response to one of the first and second Diameter Protocol messages by the first network element.

3. The method as set forth in claim 1 wherein the determining whether a private user identification is available is responsive to a service request message.

4. The method as set forth in claim 1 wherein the first network element is a call service control function (CSCF) module.

5. The method as set forth in claim 1 wherein the first network element is an application server.

6. The method as set forth in claim 1 wherein the second network element is the second home subscriber service (HSS) element and the method further comprises responding to the second message by the second network element.

7. The method as set forth in claim 1 wherein performing the second subscriber locator function comprises accessing at least one of a realm routing table and a peer table.

8. A system for routing in an internet multimedia subsystem (IMS) incorporating a distributed subscriber locator function, the method comprising:

means for determining by a first network element whether a private user identification including a realm name is available for use in routing using a Diameter Protocol;

means for populating by the first network element a destination-realm attribute value pair of a first Diameter Protocol message with the private user identification if the private user identification is available;

means for performing a subscriber locator function by a first network element to determine a first home subscriber service (HSS) element to which to send the first Diameter Protocol message based on the destination-realm attribute value pair;

means for transmitting the first Diameter Protocol message from the first network element to the first home subscriber service (HSS) element;

means for populating by the first network element the destination-realm attribute value pair of a second Diameter Protocol message with a whole network realm if the private user identification is not available;

means for transmitting the second Diameter Protocol message from the first network element to a second network element;

means for performing a second subscriber locator function by the second network element to determine a second home subscriber service (HSS) element to which the second Diameter Protocol message should be sent;

means for populating by the second network element a Redirect-Host attribute value pair with information relating to the second home subscriber service (HSS) element; and,

means for transmitting the second message back to the first network element and to the second home subscriber service (HSS) element if the second home subscriber service (HSS) element is not the second network element.

9. The system as set forth in claim 8 further comprising means for receiving a response to one of the first and second Diameter Protocol messages by the first network element.

10. The system as set forth in claim 8 wherein the means for determining whether a private user identification is available is responsive to a service request message.

11. The system as set forth in claim 8 wherein the means for the first network element is a call service control function (CSCF) module.

12. The system as set forth in claim 8 wherein the means for the first network element is an application server.

13. The system as set forth in claim 8 wherein the means for the second network element is the second home subscriber service (HSS) element and the system further comprises means for responding to the second message.

14. The system as set forth in claim 8 wherein the means for performing the second subscriber locator function comprises accessing at least one of a realm routing table and a peer table.

15. A system for implementing an internet multimedia subsystem (IMS) incorporating a distributed subscriber location function, the system comprising:

a first network element operative to determine whether a private user identification including a realm name is available for use in routing using a Diameter Protocol, perform a first subscriber locator function to determine a first home subscriber service (HSS) element to which to send a first Diameter Protocol message based on the availability of the private user identification, populate by the first network element a destination-realm attribute value pair of a first Diameter Protocol message with the private user identification if the private user identification is available, transmit the first Diameter Protocol message to the first home subscriber service (HSS) element, populate by the first network element the destination-realm attribute value pair of a second Diameter Protocol message with a whole network realm if the private user identification is not available, and transmit a second Diameter Protocol message to a second network element if the private user identification is not available; and,

the second network element operative to perform a second subscriber locator function to determine a second home subscriber (HSS) element to which the second Diameter Protocol message should be sent and transmit the second Diameter Protocol message back to the first network element if the second home subscriber service (HSS) element is not the second network element.

16. The system as set forth in claim 15 further comprising tables stored in the second network element, the tables having stored therein peer information and realm routing information.

17. The system as set forth in claim 15 wherein the first network element is responsive to a service request message.

18. The system as set forth in claim 15 wherein the first network element is a call service control function (CSCF) module.

19. The system as set forth in claim 15 wherein the first network element is an application server.

20. The system as set forth in claim 15 wherein the second network element is a home subscriber service (HSS) element.

Assignments (10)