PBX Integration with IMS via SIP Core Routing

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Solution Overview

Problem

Conventional enterprise communication systems, such as PBX, do not support IMS collaborative call processing, limiting the migration to IMS architecture and failing to provide IMS services for local calls, with existing solutions being complex, resource-intensive, and not scalable.

Innovation Solution

Implementing a method and system that routes calls through a SIP core for users with an Exposed Local Call (ELC) class of service, enabling IMS services by using dedicated virtual ELC line pairs and minimizing PBX configuration changes, allowing IMS services to be provided for local calls without controlling the call phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional PBX systems use full-call model processing, then local calls can be processed efficiently within the PBX, but IMS services cannot be provided to these local calls

Engineering Contradiction:

Improvelocal call processing efficiencyVSAvoidIMS service capability

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The call processing is segmented into two independent paths: traditional full-call model processing for local calls and half-call model processing for IMS services. The system segments the call handling based on user class (ELC vs non-ELC), allowing simultaneous support for both legacy PBX efficiency and new IMS service capabilities without forcing complete system redesign

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different processing qualities are applied to different user groups: ELC users receive IMS service quality with half-call processing, while non-ELC users continue with traditional full-call processing. This local differentiation allows the system to maintain backward compatibility while introducing forward-looking IMS services to specific segments

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If all PBX calls are routed via SIP core to expose them to IMS applications, then IMS services become accessible, but system complexity and configuration difficulty increase

Engineering Contradiction:

ImproveIMS service accessibilityVSAvoidPBX configuration complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of changing the fundamental routing architecture, the system changes the classification parameter (user class assignment) to determine routing behavior. By assigning users to ELC or non-ELC classes, the system achieves IMS service exposure without requiring complex universal routing changes, maintaining simplicity while enabling service differentiation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The call routing is segmented based on user class attributes rather than implementing a unified complex routing strategy. ELC users are routed to SIP core for IMS services, while non-ELC users continue with traditional PBX processing, simplifying the overall configuration by applying rules only where needed

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If digit manipulation and special routing rules are applied to route all PBX calls via SIP core, then IMS services are exposed, but routing loops and information display issues occur

Engineering Contradiction:

ImproveIMS service exposureVSAvoidrouting reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Different routing qualities are applied locally based on user class: ELC users receive SIP core routing for IMS services, while non-ELC users maintain traditional direct PBX routing. This local differentiation prevents routing loops by ensuring only appropriate calls are routed through the SIP core, maintaining routing reliability while enabling IMS service exposure

Inventive Principle:

Principle #3Local quality

4Adaptability or versatility

If ELC line pairs are created for each PBX user to enable IMS services, then scalable integration is achieved, but resource consumption increases

Engineering Contradiction:

Improveintegration scalabilityVSAvoidvirtual trunk resources

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

Instead of creating dedicated line pairs for all users, the system changes the allocation parameter to create ELC line pairs only when needed (per user class assignment). This on-demand allocation model enables scalable integration while minimizing resource consumption by avoiding unnecessary dedicated line pairs for users who don't require IMS services

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8917720B2System and method for integrating conventional enterprise communication systems into an IP multimedia subsystem-based services environment

Publication Date: 2014.12.23 AVAYA INC

AI summary

A system and method for integrating conventional enterprise communication systems into an IMS-based services environment are disclosed. In one embodiment, when a call request is received for a call between first and second local users of a PBX, the PBX determines whether a class of service for either the first or second local user is for Exposed Local Call (ELC) processing. If so, then call information is routed through a Session Initiation Protocol (SIP) core network that is coupled to an Internet Protocol Multimedia Subsystem (IMS) server to provide IMS services to the call.