IMS Concurrent Call Handling for Abnormal Connection Termination
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Solution Overview
Problem
Communication networks wrongly decline communication requests from terminal devices due to abnormal termination of connections, leading to inefficient use of simultaneous communication connections.
Innovation Solution
A stateless application server (AS) in the IP multimedia subsystem (IMS) checks the status of previous communication connections via an alive request to confirm termination, ensuring that communication requests are not declined when the central concurrent calls counter reaches its maximum, even if previous connections have abnormally terminated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stateless AS uses the central concurrent calls counter to manage simultaneous communication connections, then the network can control the maximum number of allowed connections, but the system wrongly declines communication requests when connections terminate abnormally without updating the counter
Solution Approach 1:
The system performs preliminary actions by sending alive requests to check if previous communication connections are still active before accepting new requests. This prevents the counter from being incorrectly incremented when connections have already terminated, ensuring accurate tracking of actual simultaneous connections.
Solution Approach 2:
The system implements feedback mechanisms by monitoring the status of previous communication connections through alive requests. When a connection is found to have terminated abnormally, the system receives feedback and updates the central concurrent calls counter accordingly, preventing wrongful declines of new communication requests.
2Reliability
If the stateless AS strictly enforces the maximum number of simultaneous connections based on the counter value, then the network policy is maintained, but legitimate communication requests are declined when the counter does not reflect actual active connections
Solution Approach 1:
Before enforcing the maximum connection limit, the system performs preliminary verification by sending alive requests to confirm whether previous connections are truly active. This preliminary action ensures that the counter accurately reflects actual simultaneous connections before denying new requests, improving user experience by allowing legitimate connections.
3Device complexity
If the system allows the central concurrent calls counter to be updated only on normal connection termination, then connection management is simplified, but abnormal terminations cause the counter to retain incorrect values
Solution Approach 1:
The system maintains simplicity by not requiring complex exception handling for abnormal terminations. Instead, it uses feedback from alive requests sent before new connection attempts to detect and correct counter inaccuracies caused by abnormal terminations, preserving both simplicity and accuracy.
Solution Approach 2:
The system employs self-service mechanisms where the network entity automatically detects abnormal connection terminations through alive requests and self-corrects the counter values without requiring complex external intervention or manual management, maintaining simplicity while ensuring accuracy.
Data Source
AI summary
A method for operating an IP multimedia subsystem (IMS) of a communication network includes: a stateless application server (AS) of the IMS of the communication network receives a communication request from a terminal device relayed by a communication network entity of the IMS; the stateless AS provides the terminal device with a requested communication connection and increases a current value of a central concurrent calls counter associated with the terminal device and stored by a database of the communication network when the current value of the central concurrent calls counter is smaller than a maximum number of simultaneous communications allowed for the terminal device by the communication network; and the stateless AS provides the terminal device with the requested communication connection when the current value of the central concurrent calls counter equals the defined maximum number.