Restoration of serving call session control and application server function

Patent metadata

Field	Value
Publication number	US-2018007612-A1
Application number	US-201615198510-A
Country	US
Kind code	A1
Filing date	Jun 30, 2016
Priority date	Jun 30, 2016
Publication date	Jan 4, 2018
Grant date	—

Abstract

A communication session for a UE can be restored in the event of serving call session control function (S-CSCF) node unavailability and/or application server (AS) unavailability by storing, prior to IMS unavailability, attribute-value pairs (AVPs) at a home subscriber server (HSS). These AVPs can be used independently by individual IMS nodes to restore a communication session for a UE due to an unavailable IMS node. When a first S-CSCF node becomes unavailable, a proxy CSCF (P-CSCF) node can send a SIP request originating from the UE to a second S-CSCF node. The second S-CSCF node can then send a request to the HSS for an identifier of an AS associated with the UE. Upon receipt of the AS identifier (e.g., an active AS name AVP) from the HSS, the second S-CSCF node can send the SIP request to the AS in order to restore the communication session for the UE.

First claim

We claim:

1 . A method comprising:
sending, from an application server (AS) as part of a registration procedure for a user equipment (UE), a value for an active AS name attribute-value pair (AVP) to a home subscriber server (HSS) for storage at the HSS, the value for the active AS name AVP identifying the AS as a serving AS for the UE; receiving, at a proxy call session control function (P-CSCF) node, a Session Initiation Protocol (SIP) request originating from the UE as part of a communication session; determining, by the P-CSCF node in response to making an attempt to contact a first serving call session control function (S-CSCF) node that was assigned to the UE as part of the registration procedure, that the first S-CSCF node is unavailable; selecting, by the P-CSCF node, a second S-CSCF node; sending, by the P-CSCF node, the SIP request to the second S-CSCF node; sending, by the second S-CSCF node, and to the HSS, a request for the value for the active AS name AVP associated with the UE; receiving, at the second S-CSCF node, and from the HSS, a response including the value for the active AS name AVP; and sending, by the second S-CSCF node, the SIP request to the AS identified by the value for the active AS name AVP.

2 . The method of claim 1 , wherein the request for the value for the active AS name AVP is sent by the second S-CSCF node to the HSS using Diameter protocol.

3 . The method of claim 1 , further comprising, prior to the second S-CSCF node sending the request for the value for the active AS name AVP:
sending, by the second S-CSCF node, and to the HSS, an initial request for restoration information; and at least partly in response to the initial request, overwriting, at the HSS, a first identifier of the first S-CSCF node in an S-CSCF binding with a second identifier of the second S-CSCF node.

4 . The method of claim 3 , further comprising:
receiving, at the AS, the SIP request; and contacting, by the AS, the HSS to confirm that the S-CSCF binding includes the second identifier of the second S-CSCF node.

5 . The method of claim 4 , further comprising updating, at the AS, a user profile, stored locally at the AS for the UE, with a mapping between the UE and the second S-CSCF node.

6 . The method of claim 1 , wherein the AS is a first AS, the method further comprising:
sending, from the AS as part of the registration procedure for the UE, and prior to the P-CSCF node receiving the SIP request, a second value for a user registration data AVP to the HSS for storage at the HSS; receiving, at the second S-CSCF node, an additional SIP request originating from the UE as part of the communication session; determining, by the second S-CSCF node in response to making an attempt to contact the first AS, that the first AS is unavailable; selecting, by the second S-CSCF node, a second AS; sending, by the second S-CSCF node, the additional SIP message to the second AS; sending, by the second AS, and to the HSS, a request for the second value for the user registration data AVP associated with the UE; receiving, at the second AS, and from the HSS, a response including the second value for the user registration data AVP; and creating, at the second AS and based at least in part on the second value for the user registration data AVP, a user profile associated with the UE specifying an association between the UE and the second AS.

7 . The method of claim 6 , further comprising sending, from the second AS, an updated value for the active AS name AVP to the HSS for storage at the HSS, the updated value for the active AS name AVP identifying the second AS as the serving AS for the UE.

8 . The method of claim 7 , further comprising sending, from the HSS to the first AS, an instruction to delete a local user profile at the first AS, the local user profile at the first AS specifying an association between the UE and the first AS.

9 . A system comprising:
a proxy call session control function (P-CSCF) node configured to:
receive, via a communications interface of the P-CSCF node, a Session Initiation Protocol (SIP) request originating from a user equipment (UE);
determine, based at least in part on a lack of response, or a negative response, from a first serving call session control function (S-CSCF) node to an attempt to contact the first S-CSCF node, that the first S-CSCF node is unavailable;
select, by executing computer-executable instructions stored in memory of the P-CSCF node, a second S-CSCF node; and
send, via the communications interface of the P-CSCF node, the SIP request to the second S-CSCF node; and
the second S-CSCF node configured to:
send, via a communications interface of the second S-CSCF node, and to a home subscriber server (HSS), a request for an identifier of an application server (AS) associated with the UE;
receive, via the communications interface of the second S-CSCF node, a response from the HSS that includes the identifier of the AS; and
send, via the communications interface of the second S-CSCF node, the SIP request to the AS.

10 . The system of claim 9 , wherein the second S-CSCF node is configured to send the request for the identifier of the AS to the HSS using Diameter protocol.

11 . The system of claim 9 , wherein the request for the identifier of the AS comprises a user data request (UDR) message.

12 . The system of claim 9 , wherein the identifier of the AS comprises a SIP Uniform Resource Identifier (URI).

13 . The system of claim 9 , wherein:
the AS is a first AS that is configured to forward the SIP request as part of a communication session for the UE served by the second S-CSCF node and the first AS; and the second S-CSCF node is further configured to:
receive an additional SIP request originating from the UE as part of the communication session;
determine, in response to making an attempt to contact the first AS, that the first AS is unavailable;
select, by executing computer-executable instructions stored in memory of the second S-CSCF node, a second AS; and
send, via the communications interface of the second S-CSCF node, the additional SIP request to the second AS;
the system further comprising the second AS, the second AS being configured to:
send, via a communications interface of the second AS, and to the HSS, a request for a value for a user registration data attribute-value pair (AVP) associated with the UE;
receive, via the communications interface of the second AS, and from the HSS, a response including the value for the user registration data AVP; and
create, by executing computer-executable instructions stored in memory of the second AS, and based at least in part on the value for the user registration data AVP, a user profile associated with the UE that specifies an association between the UE and the second AS.

14 . The system of claim 13 , wherein the second AS is further configured to send, via the communications interface of the second AS, and to the HSS, a second identifier of the second AS for storage at the HSS in association with the UE.

15 . A method comprising:
receiving, via a communications interface of a proxy call session control function (P-CSCF) node, a Session Initiation Protocol (SIP) request originating from a UE as part of a communication session; determining, by the P-CSCF node in response to making an attempt to contact a first serving call session control function (S-CSCF) node that was assigned to the UE as part of a registration procedure, that the first S-CSCF node is unavailable; selecting, by the P-CSCF node, a second S-CSCF node; sending, via the communic

Assignees

• T Mobile Usa Inc

Inventors

• Jahangir Zeeshan
• Mufti Shujaur

Classifications

• H04L65/1073

  Registration or de-registration · CPC title

• H04L65/1016

  IP multimedia subsystem [IMS] · CPC title

• H04W60/04

  using triggered events · CPC title

• H04W80/10

  adapted for {application} session management, e.g. SIP [Session Initiation Protocol] {(connection management H04W76/00; arrangements for session management H04L67/14)} · CPC title

• H04W8/005

  Discovery of network devices, e.g. terminals · CPC title