IP multimedia subsystem virtual call/session control functions

• US 20080254795A1
• Filed: 04/11/2007
• Published: 10/16/2008
• Est. Priority Date: 04/11/2007
• Status: Active Grant

• Current Assignee: AT&T Knowledge Ventures, L.P. (AT&T, Inc.)
• Original Assignee: AT&T Knowledge Ventures, L.P. (AT&T, Inc.)
• Inventors: Lu, Min, Ratcliffe, Mark, Hoover, Gerald L.
• Granted Patent: US 8,533,340 B2
• Time in Patent Office: Days
• US Class Current: 455/435.1
• CPC Class Codes: H04L 65/1016 IP multimedia subsystem [IMS]
• CPC Class Codes: H04L 65/1045 Proxies, e.g. for session initiation protocol [SIP]
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes

Abstract

Systems and methods provide virtual CSCFs in an IMS system. The Virtual CSCFs may be virtual S-CSCFs or virtual P-CSCFs. A master virtual CSCF may be used to distribute subscriber data and initial filter criteria to the virtual CSCFs in a group. Thus one of multiple servers may be used for processing call sessions for the same subscriber, thereby avoiding overloading a particular CSCF in an IMS system.

Claims

1. A method comprising:

configuring one or more virtual call session/control function (CSCF) groups, each of the groups having a plurality of virtual CSCF servers;

determining a master virtual CSCF server from the plurality of virtual CSCF servers; and

downloading subscriber or registration data to the plurality of virtual CSCF servers.

2. The method of claim 1, wherein the virtual CSCF servers are virtual serving CSCF servers.

3. The method of claim 1, wherein the virtual CSCF servers are virtual proxy CSCF servers.

4. The method of claim 1, further comprising receiving a first registration request and wherein determining the master virtual CSCF server includes selecting one of the plurality of virtual CSCF servers to be the master virtual CSCF server in response to receiving the first registration request.

5. The method of claim 1, wherein downloading subscriber data to the plurality of virtual CSCF servers includes receiving the subscriber or registration data by the master virtual CSCF server and downloading the subscriber or registration data by the master virtual CSCF server to the plurality of virtual CSCF servers.

6. The method of claim 1, wherein the plurality of virtual CSCF servers comprise virtual S-CSCF servers and wherein downloading subscriber data to the plurality of virtual CSCF servers includes broadcasting the subscriber data by a home subscriber server (HSS) to the plurality of virtual S-CSCF servers.

7. The method of claim 1, further comprising:

initiating a call session;

selecting one of the virtual CSCF servers in the plurality of virtual CSCF servers to handle the call session.

8. The method of claim 7, wherein selecting one of the virtual CSCF servers includes utilizing a round-robin scheduler to select one of the virtual CSCF servers.

9. The method of claim 8, wherein selecting one of the virtual CSCF servers includes utilizing a priority to select one of the virtual CSCF servers.

10. The method of claim 8, wherein selecting one of the virtual CSCFs includes utilizing a utilization percentage to select one of the virtual CSCFs.

11. An IP Multimedia system (IMS) comprising:

a home subscriber server (HSS) to maintain subscriber data and initial filter criteria; and

at least one virtual S-CSCF group, the virtual S-CSCF group including a plurality of virtual S-CSCF servers, the plurality of virtual S-CSCF servers including a master virtual S-CSCF server;

wherein the subscriber data and initial filter criteria are downloaded to the plurality of virtual S-CSCF servers.

12. The system of claim 11, further comprising at least one virtual P-CSCF group, the virtual P-CSCF group including a plurality of virtual proxy CSCF (VP-CSCF) servers, the plurality of VP-CSCF servers including a master virtual P-CSCF server;

wherein registration data is distributed to the plurality of VP-CSCF servers.

13. The system of claim 11, wherein the master virtual S-CSCF server is determined by selection of one of the plurality of virtual S-CSCF servers in response to receiving a first registration request.

14. The system of claim 11, wherein the master virtual S-CSCF is operable to receive the subscriber data from the HSS and to download subscriber data to the plurality of virtual S-CSCF servers.

15. The system of claim 11, wherein the HSS is operable to download the subscriber data to the plurality of virtual S-CSCF servers.

16. A machine-readable medium having machine-executable instructions, that when executed, cause the machine to perform a method, the method comprising:

receiving a configuration for one or more virtual call session/control function (CSCF) groups, each of the groups having a plurality of virtual CSCF servers;

determining a master virtual CSCF server from the plurality of virtual CSCF servers; and

downloading subscriber or registration data to the plurality of virtual CSCF servers.

17. The machine-readable medium of claim 16, wherein the method further comprises receiving a first registration request and wherein determining the master virtual CSCF server includes selecting one of the plurality of virtual CSCF servers to be the master virtual CSCF server in response to receiving the first registration request.

18. The machine-readable medium of claim 16, wherein downloading subscriber data to the plurality of virtual CSCF servers includes receiving the subscriber data by the master virtual CSCF server and downloading the subscriber data by the master virtual CSCF server to the plurality of virtual CSCF servers.

19. The machine-readable medium of claim 16, wherein the plurality of virtual CSCF servers comprise virtual S-CSCF servers, and wherein downloading subscriber data to the plurality of virtual S-CSCF servers includes broadcasting the subscriber data by a home subscriber server (HSS) to the plurality of virtual S-CSCF servers.

20. The machine-readable medium of claim 16, wherein the method further comprises:

initiating a call session;

selecting one of the virtual CSCF servers in the plurality of virtual CSCF servers to handle the call session.

21. An apparatus comprising a virtual CSCF server operable to provide call session and control functions and further operable to share data with one or more alternative virtual CSCF servers.

22. The apparatus of claim 21, wherein the virtual CSCF server and the alternative virtual CSCF servers comprise virtual S-CSCF servers and wherein the data includes subscriber data and further wherein the subscriber data or initial filter criteria.

23. The apparatus of claim 21, wherein the virtual CSCF server and the alternative virtual CSCF servers comprise virtual P-CSCF servers and wherein the data includes registration data.