CU-UP Failover State Synchronization for Service Continuity
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Solution Overview
Problem
Existing techniques for handling CU-UP failure in communication networks result in undesirable service disruption and degradation due to the inability to synchronize user plane protocol state parameters efficiently, leading to service continuity issues when a redundant CU-UP takes over from a failed active CU-UP.
Innovation Solution
A node manager component synchronizes the operational states of a standby CU-UP with a failed active CU-UP, including user plane protocol state parameters, to enable seamless transition without requiring resets that release the device from the DU or core network, thereby maintaining service continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standby CU-UP takes over from a failed active CU-UP without synchronization, then service continuity is disrupted, but synchronization increases system complexity and resource overhead
Solution Approach 1:
The patent implements preliminary synchronization of user plane protocol state parameters from the active CU-UP to the standby CU-UP before failure occurs. This advance preparation ensures that when the active CU-UP fails, the standby can immediately take over without service disruption, resolving the contradiction between reliability and complexity by performing the synchronization work in advance rather than during failure recovery
Solution Approach 2:
The patent creates a copy of the user plane protocol state parameters from the active CU-UP and stores them in the standby CU-UP. This copying mechanism allows the standby to assume the exact state of the active node, ensuring seamless service continuity while maintaining a relatively simple synchronization approach that only involves parameter replication rather than complex state management
2Reliability
If user plane protocol state parameters are synchronized during failure recovery, then service continuity can be maintained, but the recovery time is extended
Solution Approach 1:
The synchronization of user plane protocol state parameters is performed as a preliminary action during normal operation, continuously or periodically updating the standby CU-UP with the current state of the active CU-UP. This eliminates the need for time-consuming synchronization during failure recovery, as the standby already possesses up-to-date parameters, thus maintaining both service continuity and fast recovery
Solution Approach 2:
The patent maintains continuous synchronization of user plane protocol state parameters from the active to the standby CU-UP during normal operation. This continuous update ensures that the standby is always prepared to take over immediately upon failure, eliminating gaps in service and reducing recovery time while maintaining reliable service continuity
3Ease of repair
If reset procedures are executed to release device from DU or core network during CU-UP failure, then the failed node can be recovered, but service disruption occurs
Solution Approach 1:
The patent extracts the user plane protocol state parameters from the failed CU-UP and transfers them to the standby CU-UP, allowing the standby to assume the service without requiring reset procedures that would release the device from the network. This parameter extraction and transfer approach enables node recovery while maintaining service continuity, avoiding the need to disrupt the device connection
4Reliability
If comprehensive user plane protocol state parameters are synchronized, then service continuity is improved, but the amount of data to be synchronized and processed increases
Solution Approach 1:
The patent applies local quality by selectively synchronizing only the specific user plane protocol state parameters that are essential for service continuity, rather than synchronizing all possible parameters. This targeted approach includes parameters such as PDCP state, QoS configurations, and bearer information, which are the critical local qualities needed for seamless failover, while excluding unnecessary data to minimize synchronization overhead
Data Source
AI summary
Failure of an active CU-UP can be managed and mitigated. In connection with an active CU-UP serving a device using a service, CU-CP can employ a node manager component (NMC) that, in connection with failure of active CU-UP, can synchronize operational state parameters, including user plane protocol state parameters, associated with active CU-UP with standby CU-UP, and transition from active CU-UP to standby CU-UP to become an active CU-UP that can serve the device, to maintain service continuity for the device. NMC can inform RAN SMO to reconfigure transport network to switch downlink data and uplink data to standby CU-UP. Standby CU-UP can buffer downlink data and uplink data in buffer memory until the synchronization is completed, after which the formerly standby, now active, CU-UP can communicate buffered downlink data to DU for communication to the device, and buffered uplink data to UPF for communication to a desired destination.