IMS and Method of Multiple S-CSCF Operation in Support of Single PUID

• US 20100150137A1
• Filed: 12/17/2008
• Published: 06/17/2010
• Est. Priority Date: 12/17/2008
• Status: Active Grant

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Inventors: Lu, Min, Ratcliffe, Mark
• Granted Patent: US 8,369,313 B2
• Time in Patent Office: Days
• US Class Current: 370/352
• CPC Class Codes: H04L 65/1016 IP multimedia subsystem [IMS]
• CPC Class Codes: H04L 65/1073 Registration or de-registration
• CPC Class Codes: H04L 65/1094 Inter-user-equipment sessions transfer or sharing

Abstract

A method for providing multimedia services to subscriber user equipment (UE) within an IP multimedia subsystem network (IMS) may include configuring the IMS to enable a single UE to fork register and cooperate with multiple serving-call session control functions (S-CSCFs). After obtaining IP connectivity, the single UE signals to register with the IMS and the IMS determines whether the UE is configured to fork register with multiple S-CSCFs. If the UE is configured, the IMS determines which S-CSCFs are eligible for the UE registration and fork registers the UE to multiple S-CSCFs of the eligible S-CSCFs. Consequently, incoming and outgoing calls to/from the UE are routed by the IMS to any of the multiple registered S-CSCFs.

Claims

1. A method for providing multimedia services to subscriber user equipment (UE) within an IP multimedia subsystem network (IMS), comprising:

configuring the IMS to provide a single UE with a capability of fork registering with multiple serving-call session control functions (S-CSCFs).

2. The method as set forth in claim 1, further comprising:

after obtaining IP connectivity, the single UE signalling to register onto the IMS; and

the IMS responding by fork registering the single UE to multiple eligible S-CSCFs.

3. The method as set forth in claim 1, wherein the configuring includes setting a multiple S-CSCF forking data field for the single UE maintained by a home subscriber server (HSS).

4. The method as set forth in claim 3, wherein:

the single UE signals to fork register with a proxy-CSCF (P-CSCF);

the P-CSCF signals to register with an interrogating-CSCF (I-CSCF); and

the I-CSCF signals the HSS.

5. The method as set forth in claim 4, further comprising:

the HSS responding by determining whether the single UE is already registered, and whether the single UE is enabled to fork register to multiple S-CSCFs, and signalling the I-CSCF with eligible S-CSCF capabilities if the multiple S-CSCF forking data field is set; and

the I-CSCF responding by choosing the multiple S-CSCFs from the eligible S-CSCFs, and register signalling the chosen, eligible multiple S-CSCFs.

6. The method as set forth in claim 5, further comprising:

the chosen multiple S-CSCFs exchange signalling with the HSS;

the HSS recording a binding fork registration and sending UE profile information to each of the multiple fork registered multiple S-CSCFs;

each of the multiple S-CSCFs responding by signalling the I-CSCF;

the I-CSCF responding by signalling the P-CSCF with registration information, and

the P-CSCF responding by creating security associations (SA) and storing a list of the multiple S-CSCFs.

7. The method as set forth in claim 6, further comprising:

the UE using an algorithm to choose one of security associations with the P-CSCF and its associated registered S-CSCFs in response to an outgoing call from the UE.

8. The method as set forth in claim 6, further comprising:

I-CSCF using an algorithm to choose one of the multiple registered S-CSCFs in response to an incoming call to the UE.

9. The method as set forth in claim 8, further comprising:

if one of the multiple fork registered S-CSCFs is determined by the IMS to be unavailable for an incoming call, the I-CSCF choosing an alternative one of the multiple registered S-CSCFs.

10. The method as set forth in claim 7, further comprising:

if one of the multiple fork registered S-CSCFs is determined by the UE/P-CSCF to be unavailable for an outgoing call, the UE choosing an alternative one of security associations to reach an alternate registered S-CSCFs.

11. A computer readable medium encoded with computer program instructions for providing multimedia services to subscriber user equipment (UE) within an IP multimedia subsystem network (IMS), the computer program instructions comprising:

configuring the IMS to provide a single UE with a capability of fork registering with multiple serving-call session control functions (S-CSCFs).

12. The computer readable medium as set forth in claim 11, the computer program instructions further comprising:

after obtaining IP connectivity, the single UE register signalling the IMS; and

the IMS fork registering the single UE to multiple S-CSCFs.

13. The computer readable medium as set forth in claim 12, the computer program instructions further comprising;

setting a multiple S-CSCF forking data field and eligible S-CSCFs maintained by a home subscriber server (HSS) for the single UE.

14. The computer readable medium as set forth in claim 13, the computer program instructions further comprising:

the UE signalling to register with a proxy CSCF (P-CSCF), the P-CSCF register signalling an interrogating CSCF (I-CSCF).

15. The computer readable medium as set forth in claim 14, the computer program instructions further comprising:

the HSS determining whether the single UE is already registered, and whether the single UE is enabled to fork register;

the HSS signalling the I-CSCF with eligible S-CSCF capabilities if the UE is fork register enabled; and

the I-CSCF selecting the multiple CSCFs from the eligible S-CSCFs and register signalling the chosen, eligible multiple S-CSCFs.

16. The computer readable medium as set forth in claim 15, the computer program instructions further comprising:

the multiple S-CSCFs responding by exchanging signals with the HSS;

the HSS responding by recording the binding forking registration in the HSS and sending UE profile information to each multiple S-CSCF;

each multiple S-CSCFs responding by signalling the I-CSCF;

the I-CSCF responding by signalling the P-CSCF and releasing registration information; and

the P-CSCF responding by creating security associations (SA) and storing a list of the multiple S-CSCFs.

17. The computer readable medium as set forth in claim 16, the computer program instructions further comprising:

the UE using an algorithm to choose one of the security associations (SA) with P-CSCF and the registered S-CSCF in response to an outgoing call from the UE.

18. The computer readable medium as set forth in claim 16, the computer program instructions further comprising:

the I-CSCF using an algorithm to choose one of the multiple registered S-CSCFs in response to an incoming call to the UE.

19. The computer readable medium as set forth in claim 17, the computer program instructions further comprising:

if one of the multiple fork registered S-CSCFs is determined by the UE/P-CSCF to be unavailable for an outgoing call;

the UE choosing an alternative one of the security associations to reach an alternate forked registered S-CSCFs.

20. The computer readable medium as set forth in claim 18, the computer program instructions further comprising:

if one of the multiple fork registered S-CSCFs is determined by the I-CSCF to be unavailable for an incoming or outgoing call;

the I-CSCF choosing an alternative one of the multiple registered S-CSCFs.

21. An Internet Protocol multimedia subsystem network (IMS) for managing multimedia services that enables single subscriber user equipment (UE) to fork register with multiple serving-call session control functions (S-CSCF), the IMS comprising:

a single UE;

a home subscriber server (HSS) for managing operation of the single UE including a field indicating whether the single UE is enabled for multiple S-CSCF operation; and

multiple S-CSCFs adapted to accept, in cooperation with the HSS, fork registration from a single UE.

22. The IMS as set forth in claim 21, wherein the IMS is adapted to respond to incoming and outgoing calls to/from the single UE, upon the single UE fork registering with the multiple S-CSCFs, by choosing one of the multiple registered S-CSCFs in cooperation with the stored fork registration information associated with the UE.

23. The IMS as set forth in claim 21, wherein the IMS is adapted to use an alternative one of the multiple S-CSCFs if one of the multiple S-CSCFs is unavailable for an incoming or outgoing call.

24. The IMS as set forth in claim 21, further comprising a proxy CSCF (P-CSCF) and an interrogating CSCF (I-CSCF), wherein the HSS is adapted to return eligible S-CSCFs to the I-CSCF which chooses the eligible S-CSCFs for registration as the multiple S-CSCFs.

25. The IMS as set forth in claim 24, wherein the UE is adapted to choose one of the security associations with P-CSCF to utilize for an outgoing call using a process from a group consisting of:

a random choosing process, prioritized or weighted process and a process based on S-CSCF capacity.

26. The IMS as set forth in claim 24, wherein the I-CSCF is adapted to choose which of multiple S-CSCFs to utilize for an incoming call using a process from a group consisting of:

a random choosing process, a prioritized or weighted process and a process based on S-CSCF capacity.