PFCP Association Recovery for Session Status Synchronization
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Solution Overview
Problem
Conventional PFCP session management in cellular communications networks faces issues such as immediate loss of sessions upon PFCP entity failure, leading to session status mismatches and unpredictable problems due to resource reuse, and unclear handling of PFCP sessions during SMF set failures, resulting in potential loss of sessions.
Innovation Solution
Implementing an enhanced PFCP association procedure that includes sending node-level messages to delete associated sessions, negotiating session retention information, and using PFCP Association Setup Requests to manage session setup and deletion, ensuring synchronized session status across CP and UP entities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PFCP entity fails without restart, then the PFCP sessions associated with that PFCP entity are immediately lost, but a peer entity of the PFCP entity cannot detect the failure until the failure of the path is detected, resulting in session status mismatch
Solution Approach 1:
The patent applies preliminary action by having the failed PFCP entity proactively notify its peer entity of the failure before the peer entity can detect it through path failure detection. The PFCP entity sends a notification message to the peer entity immediately upon failure, allowing the peer entity to delete associated sessions in advance, thus eliminating the detection delay and maintaining session status consistency.
2Reliability
If a PFCP entity deletes PFCP sessions associated with a failed PFCP path upon detection, then session status is updated, but a peer entity may not have detected the path failure yet, causing session status mismatch
Solution Approach 1:
The patent implements feedback by establishing a notification mechanism where the detecting PFCP entity immediately informs the peer entity of the path failure. This feedback loop ensures both entities have consistent session status information, preventing the mismatch that would occur if one entity deleted sessions while the other remained unaware of the failure.
3Adaptability or versatility
If a CP function initiates a new PFCP association setup procedure when dealing with SMF sets, then session management is updated, but a corresponding UP function cannot determine whether PFCP sessions should be deleted or kept, resulting in potential loss of sessions
Solution Approach 1:
The patent applies preliminary action by having the CP function include session retention indication information in the PFCP Association Setup Request message sent to the UP function. This allows the UP function to determine in advance whether to delete or retain PFCP sessions before the association setup is completed, preventing accidental session loss while maintaining SMF set management flexibility.
Data Source
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AI summary
Systems and methods are disclosed for providing an enhanced Packet Forwarding Control Protocol (PFCP) association procedure for session restoration. In this regard, a method performed by a PFCP node comprises deleting one or more PFCP sessions of the PFCP node that are associated with a failed PFCP entity or with a failed PFCP path. The method further comprises sending, to a PFCP peer node, a node level message to request that the PFCP peer node delete a corresponding one or more PFCP sessions of the PFCP peer node that are associated with the failed PFCP entity or with the failed PFCP path, wherein the node level message comprises an indication of the corresponding one or more PFCP sessions. Some embodiments provide that the node level message comprises a PFCP Association Setup Request including sessions retention information to indicate whether to retain PFCP sessions associated with the PFCP Association Setup Request.