CTF Node Buffering for IMS Online Charging Availability
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Solution Overview
Problem
In IP Multimedia Subsystem (IMS) networks, the unreliable communication link between Charging Triggering Function (CTF) and Online Charging Service (OCS) nodes leads to unsatisfactory behavior, either resulting in poor service availability or revenue loss, as there is no easy way to configure nodes to handle credit status uncertainties during session requests.
Innovation Solution
The method involves buffering Credit Control Requests (CCR) at the CTF node when the OCS is unavailable, with a CONTINUE_BUFFER indication, allowing the CTF to assume granted requests and transmit them later when the OCS is available, and the OCS processes these buffered requests, enabling retroactive credit balance updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the CTF node terminates the session when OCS is unavailable (default behavior), then revenue loss is prevented, but service availability deteriorates
Solution Approach 1:
The CTF node performs preliminary actions by buffering CCR requests and maintaining session state before the OCS becomes available again. This allows the session to be granted proactively when OCS is unavailable, and the buffered requests are processed later when OCS recovers, thus preventing both revenue loss and service unavailability
Solution Approach 2:
The invention introduces an intermediary buffering mechanism at the CTF node that temporarily stores CCR requests when OCS is unavailable. This intermediary buffer acts as a mediator between the CTF and OCS, allowing session granting to proceed without immediate OCS involvement while ensuring revenue accounting is eventually performed
2Reliability
If the CTF node grants the session when OCS is unavailable, then service availability is improved, but revenue loss occurs due to inability to verify credit status
Solution Approach 1:
The invention implements a feedback mechanism where the CTF node sends buffered CCR requests to the OCS once it becomes available again. The OCS responds with credit status information, allowing the CTF to retroactively verify whether the granted session should have been allowed or terminated, thus recovering potential revenue losses through feedback-based correction
Solution Approach 2:
The CTF node performs preliminary session granting without OCS involvement, then performs preliminary accounting actions by buffering the CCR requests for later processing. This two-stage approach (grantee first, account later) maintains service availability while ensuring revenue protection through subsequent OCS verification
3Reliability
If the CTF node buffers CCR requests when OCS is unavailable, then service availability is maintained, but device complexity increases due to buffering and state management requirements
Solution Approach 1:
The CTF node provides self-service functionality by autonomously buffering CCR requests and maintaining session state without requiring complex external coordination. The node serves itself by managing its own buffer and state, reducing the need for complex configuration and external control mechanisms
Data Source
AI summary
A method of communication between two nodes providing online charging functionalities in an IP Multimedia Subsystem (IMS) network is described, wherein a first node is configured to operate as a Charging Triggering Function (CTF) and wherein a second node is configured to operate as an Online Charging Service (OCS). The method may alleviate drawbacks stemming from low availability of the OCS.