Event State Compositor SIP REFER Update Enforcement
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Solution Overview
Problem
There is currently no mechanism for an Event State Compositor (ESC) to force an Event Publication Agent (EPA) to provide updates to published information, leading to outdated information being provided to watchers, especially in scenarios where predefined conditions such as new subscriptions or subscription refreshes occur.
Innovation Solution
The ESC can send a republication request to the EPA prior to the expiration of the agreed-upon expiration interval, using SIP REFER requests and specific header fields like SIP-If-Match and Allow:REFER, to ensure updated information is provided, such as location or contact information, when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ESC relies on the EPA to refresh information at regular intervals based on agreed expiration intervals, then the system operates with simple automated periodic updates, but the information may become outdated when the EPA fails to refresh at the expected intervals
Solution Approach 1:
The ESC monitors the expiration intervals of published information and compares them against expected values. When a discrepancy is detected (indicating the EPA may have failed to refresh), the ESC generates a feedback signal in the form of a republication request to prompt the EPA to update the information, ensuring accuracy without requiring constant active monitoring
Solution Approach 2:
The system allows the ESC to serve itself by automatically detecting when information may be outdated and autonomously initiating republication requests to the EPA. This self-service mechanism eliminates the need for external monitoring systems or manual intervention to maintain information freshness
2Reliability
If the ESC sends frequent republication requests to ensure updated information, then information accuracy is maintained, but network traffic and system resource consumption increase
Solution Approach 1:
Instead of sending republication requests at every expiration interval or continuously, the ESC applies partial action by sending requests only when necessary - specifically when expiration interval discrepancies indicate potential information staleness. This avoids excessive updating while maintaining sufficient information freshness
Solution Approach 2:
The system dynamically adjusts the timing and frequency of republication requests based on the expiration interval parameters observed in published information. By changing the update frequency parameter adaptively rather than using a fixed schedule, the system optimizes the balance between information freshness and network resource consumption
3Adaptability or versatility
If the system uses a standardized SIP PUBLISH subscription mechanism for information updates, then the communication protocol remains simple and widely compatible, but there is no mechanism for the ESC to force updates when needed
Solution Approach 1:
Instead of the traditional model where the subscriber (ESC) passively waits for the publisher (EPA) to initiate updates, the invention inverts the control relationship by enabling the ESC to actively request updates through republication requests. This reversal gives the ESC enforcement capability while maintaining SIP protocol compatibility
Solution Approach 2:
The republication request mechanism acts as an intermediary between the ESC and EPA, enabling the ESC to indirectly control the EPA's update behavior without directly modifying the EPA's internal logic or requiring changes to the EPA's core publishing functionality. This intermediary approach maintains protocol compatibility while adding enforcement capability
Data Source
AI summary
Methods, devices, and computer program products facilitate communications between two or more network entities that utilize Session Initiation Protocol. To this end, an Event State Compositor may force an Event Publication Agent to provide update information as deemed necessary by the Event State Compositor. The update of the publication information may be carried out by initiating an update triggering mechanism that is addressed to the Event State Compositor and comprises information that specifically identifies a particular publication. Such a triggering mechanism may be initiated when a predefined condition associated with the Event State Compositor's local policies is satisfied.