SIP Server Polling Based on Subscribe Expiration
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Solution Overview
Problem
In SIP-based networks, persistent subscription sessions often waste resources when client devices end subscriptions after receiving initial state information, and short-lived sessions miss updates due to their limited duration, leading to inefficient resource utilization and missed updates.
Innovation Solution
Implementing backend SIP polling sessions instead of persistent subscriptions, where the decision to poll is based on criteria such as expiration duration, client device characteristics, and behavior, allowing for quicker state information provision and reduced resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If persistent subscription sessions are used, then state information can be provided to client devices, but resources are wasted when client devices end subscriptions after receiving initial state information
Solution Approach 1:
The system dynamically selects between persistent subscription sessions and polling sessions based on the expiration value in the SUBSCRIBE request. When the expiration value indicates a short duration, the system switches to polling mode; when it indicates a long duration, the system uses persistent subscription mode. This dynamic adaptation resolves the contradiction by matching the session type to the actual usage pattern.
Solution Approach 2:
The system changes the operational parameter (session type) based on the expiration value parameter. By monitoring the expiration value in the SUBSCRIBE request, the system adjusts its behavior to use either persistent subscriptions or polling, thereby optimizing resource usage while ensuring reliable state information delivery.
2Loss of energy
If short-lived subscription sessions are used, then resource utilization is reduced, but updates are missed due to limited duration
Solution Approach 1:
Instead of using short-lived persistent subscriptions that may miss updates, the system implements periodic polling sessions. The polling mechanism actively queries the presence server at regular intervals, ensuring that state updates are captured even though the client device does not maintain a long-lived subscription session. This periodic action resolves the contradiction between resource utilization and information completeness.
3Reliability
If persistent subscription sessions are used for short expiration durations, then client devices can receive updates, but backend server resources are inefficiently allocated
Solution Approach 1:
The system dynamically determines the appropriate session type based on the expiration value. When the expiration value indicates a short duration (e.g., less than a threshold), the system switches to polling mode, which is more efficient for short-term information retrieval. This dynamic decision-making process resolves the contradiction by optimizing resource allocation efficiency while still ensuring reliable update delivery for the actual subscription duration.
Data Source
AI summary
Methods and computing systems may cause SIP backend polling based on nonzero SIP subscribe expiration. A SIP server receives from a SIP client a Session Initiation Protocol (SIP) subscribe message indicating a nonzero expiration time. Based at least on receipt of the subscribe message indicating a nonzero expiration time, the SIP server initiates a backend polling session to a backend server. The SIP server receives, via the backend polling session, state information and provides the state information to the SIP client.