Binding Support Function Timestamp Validation for Stale Bindings
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Solution Overview
Problem
In 5G telecommunications networks, binding requests can become out-of-date due to race conditions when a requesting node times out and re-tries a PDU session request, leading to stale bindings that may result in application functions reaching the wrong Policy Control Function (PCF) instance.
Innovation Solution
The Policy Control Function (PCF) adds a custom header with a session acceptance timestamp to binding request messages, which the Binding Support Function (BSF) uses to determine whether to accept or reject subsequent binding requests based on the freshness of the timestamp, ensuring that only the latest binding is maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a binding request is created without timestamp validation, then the binding creation process is simple and fast, but stale bindings may occur when race conditions happen and lead to incorrect PCF instance references
Solution Approach 1:
The PCF adds a session acceptance timestamp to the binding request message before sending it to the BSF. This preliminary action enables the BSF to later validate the freshness of binding requests by comparing timestamps, preventing stale bindings without requiring complex validation logic at the BSF side.
Solution Approach 2:
The BSF compares the timestamp in the incoming binding request with the stored timestamp of existing bindings and provides feedback by accepting or rejecting the request based on this comparison. This feedback mechanism ensures that only the most recent binding request is accepted, maintaining binding accuracy while using a simple timestamp comparison logic.
2Reliability
If the BSF accepts all binding requests without timestamp comparison, then the binding update process is fast and simple, but out-of-date bindings are created leading to failed Rx/PA flows
Solution Approach 1:
The patent replaces complex validation mechanisms with a simple timestamp comparison approach. Instead of implementing sophisticated logic to detect stale bindings, the system uses timestamp metadata and numerical comparison, which is computationally simple and easy to implement while effectively ensuring binding freshness.
3Reliability
If timestamp validation is implemented in the BSF, then stale bindings are prevented, but the processing complexity and computational overhead increase
Solution Approach 1:
The patent uses lightweight timestamp values (simple numerical data) instead of complex validation objects or mechanisms. The timestamp comparison is a fast, inexpensive operation that can be performed quickly without significant computational overhead, minimizing the time loss while ensuring binding request validity.
Data Source
AI summary
Methods, systems, and computer readable media for processing binding requests in a telecommunications network. A method includes receiving, at a binding support function (BSF), a first request to create a first binding between a protocol data unit (PDU) session and a first policy and control function (PCF). The method includes creating, at the BSF, the first binding between the PDU session and the first PCF and storing, with the first binding, a first PCF session acceptance timestamp from a first header of the first request. The method includes receiving, at the BSF, a second request to create a second binding between the PDU session and a second PCF. The method includes determining, at the BSF, whether to accept or reject the second request based on a difference between the first PCF session acceptance timestamp and a second PCF session acceptance timestamp from a second header of the second request.