# US 12,192,251 B2 · Proxy-call session control function (P-CSCF) > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,192,251 B2 - Document ID: US12192251B2 - Status: Granted - Kind: B2 - Application number: 17/500,845 - Filed: 2021-10-13 - Published: 2023-04-13 - Granted: 2025-01-07 - Earliest claimed: 2021-10-13 - Assignees: T-Mobile USA, Inc. - Applicants: T-Mobile USA, Inc. - Inventors: Nassereddine Sabeur; Saqib Badar; Shujaur Mufti; Joel Arends; Subramania Kaushik - Web page: https://patentgrep.com/patent/US12192251B2 ## CPC - H04L 65/1016: IP multimedia subsystem [IMS] - H04L 65/1069: Session establishment or de-establishment - H04L 41/0654: using network fault recovery (ring fault isolation or reconfiguration in loop networks without recovery actions by a network management system H04L12/437) - H04L 65/1045: Proxies, e.g. for session initiation protocol [SIP] - H04L 65/1073: Registration or de-registration - H04L 65/1104: Session initiation protocol [SIP] - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Solutions for providing a data traffic session with proxy-call session control function (P-CSCF) restoration include: receiving an indication, by an application server (AS), that a user equipment (UE) is registered with a first proxy node; receiving, at a subscriber information node, from a call session control function (e.g., over an N70 interface), a first message triggering proxy node restoration; based on at least receiving the first message triggering proxy node restoration, transmitting, by the subscriber information node, to a management node, a second message triggering proxy node restoration; receiving an indication, by the AS, that the UE is registered with a second proxy node different than the first proxy node; and based on at least receiving a session initiation message, establishing the data traffic session for the UE with the second proxy node. ## Claims ### Claim 1 A method of providing a data traffic session, the method comprising: receiving, by a unified data management function (UDM), a proxy-call session control function (P-CSCF) restoration indication over a single N70 interface extending directly between the UDM and a serving-call session control function (S-CSCF); based on at least receiving the SIP message, transmitting, by the UDM, the P-CSCF restoration indication to a session management function (SMF) responsive to receiving the P-CSCF restoration indication over the single N70 interface; based on at least receiving the P-CSCF restoration indication, sending, from the SMF to a user equipment (UE), an internet protocol (IP) messaging system (IMS) Packet Data Network (PDN) connection release message instructing the UE to release registration with a first P-CSCF and re-register with a second P-CSCF that is different than the first P-CSCF; receiving an indication, by an application server (AS), that the UE is registered with the second P-CSCF; and based on at least receiving a session initiation message, establishing the data traffic session for the UE with the second P-CSCF. ### Claim 2 (depends on 1) The method of claim 1, wherein the AS comprises a telephony application server (TAS). ### Claim 3 (depends on 1) The method of claim 1, further comprising: based on at least receiving an indication that the first P-CSCF is unavailable, transmitting, by the S-CSCF, the P-CSCF restoration indication over the single N70 interface to the UDM. ### Claim 4 (depends on 3) The method of claim 3, wherein the indication that the first P-CSCF is unavailable comprises a time-out without a response from the first P-CSCF. ### Claim 5 (depends on 3) The method of claim 3, wherein the indication that the first P-CSCF is unavailable comprises a message from the first P-CSCF. ### Claim 6 (depends on 1) The method of claim 1, further comprising: releasing, by the UE, a connection to the first P-CSCF; performing, by the UE, a proxy node discovery with a status repository; and registering, by the UE, with the second P-CSCF. ### Claim 7 (depends on 6) The method of claim 6, wherein the status repository comprises a network repository function (NRF). ### Claim 8 A system comprising: processor(s); and computer-readable medium storing programming instructions that, when executed by the processor(s), cause the processor(s) to: receive, by a unified data management function (UDM), a proxy-call session control function (P-CSCF) restoration indication over a single N70 interface extending directly between the UDM and a serving-call session control function (S-CSCF); transmit, by the UDM, the P-CSCF restoration indication to a session management function (SMF) responsive to receiving the P-CSCF restoration indication over the single N70 interface; based on at least receiving the P-CSCF restoration indication, send, from the SMF to a user equipment (UE), an internet protocol (IP) messaging system (IMS) Packet Data Network (PDN) connection release message instructing the UE to release registration with a first P-CSCF and re-register with a second P-CSCF that is different than the first P-CSCF; receive an indication, by an application server (AS), that the UE is registered with the second P-CSCF; and based on at least receiving a session initiation message, establish a data traffic session for the UE with the second P-CSCF. ### Claim 9 (depends on 8) The system of claim 8, wherein the AS comprises a telephony application server (TAS). ### Claim 10 (depends on 8) The system of claim 8, wherein the programming instructions for cause the processor(s) to transmit by the S-CSCF, P-CSCF restoration indication over the single N70 interface to the UDM based at least on receiving an indication that the first P-CSCF is unavailable. ### Claim 11 (depends on 10) The system of claim 10, wherein the indication that the first P-CSCF is unavailable comprises a time-out without a response from the first P-CSCF. ### Claim 12 (depends on 10) The system of claim 10, wherein the indication that the first P-CSCF is unavailable comprises a message from the first P-CSCF. ### Claim 13 (depends on 10) The system of claim 10, wherein the programming instructions further cause the processor(s) to: release, by the UE, a connection to the first P-CSCF; perform, by the UE, a proxy node discovery with a status repository; and register, by the UE, with the second P-CSCF. ### Claim 14 (depends on 13) The system of claim 13, wherein the status repository comprises a network repository function (NRF). ### Claim 15 A method of providing a data traffic session, the method comprising: receiving, by a unified data management function (UDM), a proxy-call session control function (P-CSCF) restoration indication over a single N70 interface extending directly between the UDM and a serving-call session control function (S-CSCF); and transmitting, by the UDM, the P-CSCF restoration indication to a session management function (SMF) responsive to receiving the P-CSCF restoration indication over the single N70 interface, wherein the P-CSCF restoration indication prompts the SMF to send an internet protocol (IP) messaging system (IMS) Packet Data Network (PDN) connection release message instructing a user equipment (UE) to release registration with a first P-CSCF, to re-register with a second P-CSCF that is different than the first P-CSCF, and to notify an application server (AS) that the UE is registered with the second P-CSCF, and wherein notifying the AS that the UE is registered with the second P-CSCF triggers establishment of the data traffic session for the UE with the second P-CSCF. ### Claim 16 (depends on 15) The method of claim 15, wherein the AS comprises a telephony application server (TAS). ### Claim 17 (depends on 15) The method of claim 15, wherein the S-CSCF transmits the P-CSCF restoration indication over the single N70 interface in response to receiving an indication that the first P-CSCF is unavailable. ### Claim 18 (depends on 15) The method of claim 15, wherein the indication that the first P-CSCF is unavailable comprises a time-out without a response from the first P-CSCF. ### Claim 19 (depends on 15) The method of claim 15, wherein the indication that the first P-CSCF is unavailable comprises a message from the first P-CSCF.