Distributed CU-CP Failover Using Replicated Session State
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Solution Overview
Problem
The 5G RAN architecture, specifically the CU-CP, faces challenges in maintaining high availability due to potential failures in nodes, interfaces, and microservices, leading to downtime and service disruptions.
Innovation Solution
A method is disclosed to configure a single CU-CP instance across two nodes, maintaining session information on both nodes, and enabling failover in case of failure, utilizing core microservices and protocol-specific microservices, with database redundancy and failover capabilities, ensuring no single point of failure and geographical redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single CU-CP instance is deployed on a single node, then device complexity is reduced and ease of operation is improved, but reliability deteriorates due to single point of failure
Solution Approach 1:
The CU-CP instance is segmented across multiple nodes (first node and second node), with each node hosting a portion of the CU-CP functionality. This segmentation eliminates the single point of failure while distributing the system across geographically separated locations for enhanced reliability.
Solution Approach 2:
Session information is replicated and kept at both the first node and the second node. This copying mechanism ensures that if one node fails, the other node has the necessary session information to take over calls, thereby maintaining service continuity without requiring complex real-time synchronization protocols.
2Reliability
If session information is replicated across multiple nodes, then reliability is improved through failover capability, but loss of information increases due to synchronization challenges
Solution Approach 1:
Session information is pre-replicated to both nodes before any failure occurs. This preliminary action ensures that both nodes have the necessary information ready in advance, eliminating the need for complex real-time synchronization during failure events and preventing information loss.
3Reliability
If geographical redundancy is implemented, then reliability is improved against regional disruptions, but device complexity and infrastructure requirements worsen
Solution Approach 1:
The second node is configured to perform multiple functions: it operates as a standalone CU-CP instance during normal conditions and automatically takes over calls from the first node upon failure. This multi-functionality reduces the need for specialized components and simplifies the overall distributed system architecture.
Data Source
AI summary
A method of providing CU-CP high availability is disclosed, comprising: configuring a single CU-CP instance across a first node and a second node, The single CU-CP instance appears as a single node having multiple IPs to all its peer nodes; keeping session information of the single CU-CP instance at the first node and at the second node; and wherein if the first node fails, the second node may be configured to take up calls from the first node.