SDCI PFD Update Synchronization for Signaling Reduction
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Solution Overview
Problem
The existing methods for managing Packet Flow Descriptions (PFDs) in SDCI systems face issues with immediate application in pull mode and high workload/storage in push mode, leading to inefficient signaling and storage usage, particularly due to the lack of synchronization between caching timers and allowed delays.
Innovation Solution
Synchronizing the caching timer and allowed delay between the Policy and Charging Enforcement Function (PCEF) and the Packet Flow Description Function (PFDF), and comparing these values to determine when to push updated PFDs to the PCEF, ensuring only valid PFDs are transferred based on live sessions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pull mode is used alone, then the PCEF/TDF can retrieve PFDs when needed, but the PFDs cannot be applied immediately when modified by the ASP until the caching timer expires
Solution Approach 1:
The PCEF/TDF sends a notification to the PFDF when a PFD is successfully cached, creating a feedback mechanism. This allows the PFDF to know which PFDs are already cached and avoid pushing duplicate or unnecessary updates, enabling timely PFD application when modifications occur by synchronizing the caching timer with the allowed delay parameter.
2Reliability
If push mode is used alone, then the PFDF can distribute PFDs to PCEF/TDF, but it leads to high workload and storage in the PCEF/TDF even for inactive application sessions
Solution Approach 1:
Instead of pushing all PFDs unconditionally, the system uses partial action by comparing the caching timer with the allowed delay parameter. The PFDF only pushes updated PFDs when necessary (when the caching timer indicates the PCEF/TDF needs fresh data), avoiding the excessive action of pushing all PFDs regardless of actual need, thus reducing storage workload while maintaining completeness for active sessions.
3Reliability
If the caching timer is set very short to capture PFD changes immediately, then PFD updates can be applied quickly, but it increases the signaling between PFDF and PCEF/TDF
Solution Approach 1:
The notification mechanism from PCEF/TDF to PFDF provides feedback about caching status. Combined with comparing the caching timer and allowed delay, this feedback system allows the PFDF to intelligently determine when pushing is necessary, achieving responsive PFD updates without continuously polling or setting excessively short timers, thus reducing signaling overhead while maintaining update responsiveness.
4Ease of operation
If the push mode is requested with an allowed delay larger than the pull mode time interval, then some unnecessary signaling is introduced as PFDs are already fetched within the allowed delay
Solution Approach 1:
The PCEF/TDF's feedback notification to the PFDF about caching status enables the PFDF to compare the caching timer with the allowed delay parameter. When the caching timer indicates PFDs are already fresh (fetched within the allowed delay), the PFDF can skip the push operation, thus maintaining ASP flexibility in specifying delay parameters while eliminating redundant signaling through intelligent comparison and conditional pushing.
Data Source
AI summary
A method, apparatus, and machine readable non-transitory storage medium for a SDCI pull and push mode optimization are provided, which comprise synchronizing a caching timer and an allowed delay between a Policy and Charging Enforcement Function (PCEF) and a Packet Flow Description Function (PFDF); comparing the caching timer and the allowed delay; and pushing an updated Packet Flow Description (PFD) from the PFDF to the PCEF based on a result of the comparing.