Proactive P-CSCF Restoration via NRF Heartbeats
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Solution Overview
Problem
Existing P-CSCF restoration procedures are passive, leading to session termination and revenue loss, as they only detect failed P-CSCF when a terminating session occurs, and do not proactively manage failures across all UEs registered via the failed P-CSCF.
Innovation Solution
A proactive P-CSCF restoration method that involves P-CSCFs registering with the NRF, S-CSCFs maintaining lists of associated P-CSCFs and UEs, and upon detection of a failed P-CSCF, initiating a restoration process that includes communicating with the HSS and policy servers to tear down sessions and re-register UEs with a different P-CSCF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive P-CSCF restoration procedure is used, then detection of failed P-CSCF occurs only when terminating session happens, but session termination is lost and revenue is lost for all sessions that could not be established
Solution Approach 1:
The patent implements proactive P-CSCF failure detection by having the P-CSCF send periodic heartbeats to the NRF before actual failures occur. This preliminary action allows the network to detect and respond to P-CSCF failures before they impact ongoing or new sessions, thus preventing session termination and revenue loss while maintaining reliable detection
2Reliability
If passive P-CSCF restoration procedure is used, then IMS network can detect failed P-CSCF, but IMS network is not able to benefit from the knowledge that a P-CSCF is down
Solution Approach 1:
The patent establishes a feedback mechanism where the P-CSCF sends periodic status updates (heartbeats) to the NRF, and the NRF maintains current status information about all P-CSCFs. When a P-CSCF fails, the NRF immediately knows and can notify affected S-CSCFs and HSS, ensuring the network benefits from real-time knowledge of P-CSCF status rather than learning only through session termination
Solution Approach 2:
The NRF acts as an intermediary between P-CSCFs and other network elements. It collects status information from P-CSCFs via heartbeats and distributes relevant failure information to S-CSCFs and HSS, enabling the network to efficiently utilize P-CSCF status knowledge without requiring direct communication between all network elements
3Reliability
If proactive P-CSCF restoration procedure is implemented, then IMS network can benefit from P-CSCF failure knowledge for all UEs, but device complexity and network complexity increase
Solution Approach 1:
The patent reduces complexity by implementing preliminary failure detection through simple periodic heartbeats from P-CSCF to NRF, rather than complex monitoring of all UEs. The NRF pre-processes failure information and determines which UEs are affected, eliminating the need for complex queries across the entire network when failures occur
Solution Approach 2:
The NRF serves as a centralized intermediary that simplifies the system by consolidating P-CSCF status management. Instead of each S-CSCF and HSS independently monitoring all P-CSCFs (which would create exponential complexity), the NRF centralizes this function and provides targeted notifications only to affected elements, dramatically reducing overall system complexity while maintaining service continuity
Data Source
AI summary
Apparatuses and methods are disclosed for P-CSCF restoration. In one embodiment, a method includes receiving a P-CSCF restoration message, the P-CSCF restoration message including an indication of a failed P-CSCF server; as a result of the received P-CSCF restoration message, identifying at least one Session Management Function, SMF, server associated with the failed P-CSCF server; and communicating, to the identified at least one SMF server, a restoration message for tearing down at least one session for at least one user equipment, UE, associated with the failed P-CSCF server. In another embodiment, a method includes as a result of a received restoration message, at least one of: tearing down at least one session for at least one user equipment, UE, associated with the failed P-CSCF server; and notifying the at least one UE of the failed P-CSCF server.