Call-Processing Event Notification Server for SIP Networks
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Solution Overview
Problem
In decentralized distributed communications networks, existing technologies face challenges in providing a unified view of the system and scalability due to the lack of a central call-processing entity, leading to inefficiencies in call-control and event monitoring.
Innovation Solution
An entity, such as an application server, dynamically subscribes to event notices of specific devices involved in a communication session, interacting directly with endpoints to provide a unified view to client applications while minimizing unnecessary monitoring, thus maintaining scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a central call-processing entity (PBX) is used to provide a unified view of all endpoints, then applications can easily monitor all devices and receive call progress events, but the system lacks scalability and creates a single point of failure in decentralized SIP networks
Solution Approach 1:
The patent introduces an application server as an intermediary between SIP endpoints and client applications. This server subscribes to event notifications from specific devices dynamically, aggregating event data from multiple distributed sources to provide a unified view to applications without requiring a central PBX or having all devices communicate directly with a central entity
Solution Approach 2:
The system segments the monitoring function by having the application server selectively subscribe to events from specific devices based on client application requests, rather than requiring all devices to connect to a central entity. This divides the monitoring task into targeted, on-demand subscriptions
2Ease of operation
If back-to-back user agent (B2BUA) style call control is used to handle all SIP signaling, then a unified view can be provided, but scalability is compromised as every message must be routed through the B2BUA
Solution Approach 1:
The patent extracts the event aggregation and subscription management functions from the SIP signaling path itself. Instead of routing all SIP messages through a B2BUA, the application server selectively subscribes to event notifications from specific devices, taking only the necessary event data out of the distributed SIP network without intercepting or routing all signaling traffic
Solution Approach 2:
The system dynamically subscribes to device events based on real-time client application requests and session state. The application server adjusts its subscriptions automatically - subscribing when a device becomes relevant to a monitored session and unsubscribing when no longer needed - rather than maintaining static, comprehensive subscriptions to all devices
3Loss of information
If static monitoring of all devices is implemented, then a complete unified view is achieved, but the system becomes less scalable as all devices must send control signals to a central entity
Solution Approach 1:
The patent implements partial monitoring by having the application server subscribe to events from only those devices that are currently involved in sessions relevant to the client application. Rather than monitoring all devices continuously, it performs selective, on-demand monitoring that provides sufficient information for the application's needs without the overhead of comprehensive static monitoring
Data Source
AI summary
In a distributed communications network without a central call-processing controller, such as a SIP-based network, an application server collects and reports call-processing events to a client application by dynamically subscribing to events on devices specified by the client application and other devices that enter into communication sessions with those specified devices, and dynamically unsubscribes to events on devices with which the communications sessions have ended.