Emergency Service in IMS Network via Local Application Server Function
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Solution Overview
Problem
In the IMS communication network, emergency service requests often require special handling to prioritize calls and route them correctly, but existing systems involve unnecessary steps and entities, such as the S-CSCF, which can complicate and delay emergency service provisioning.
Innovation Solution
Implementing an emergency-related local service function (ERLSF) co-located at the application server (AS) to determine if a session is an emergency session and route requests directly to the E-CSCF, bypassing the S-CSCF, allowing for click-to-dial services and location-based checks to ensure appropriate emergency service delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If emergency service requests are routed through the S-CSCF in the IMS network, then network protocol compliance and service handling are ensured, but routing delays and system complexity increase
Solution Approach 1:
The invention segments the emergency service handling process by separating the detection function (P-CSCF) from the service provision function (local service function co-located at AS). This allows emergency requests to be identified and routed directly to the appropriate emergency center without passing through the S-CSCF, reducing routing time while maintaining protocol compliance through the P-CSCF's initial involvement.
Solution Approach 2:
The local service function acts as an intermediary between the P-CSCF and the emergency center. It receives emergency service requests from the P-CSCF, determines whether they are emergency sessions, and routes them directly to the appropriate emergency center, thereby eliminating the need for S-CSCF involvement in the routing path and reducing delays.
2Reliability
If the P-CSCF detects all emergency service requests and routes them through the home network's S-CSCF, then proper IMS protocol handling is maintained, but visited network services cannot be applied and routing efficiency decreases
Solution Approach 1:
The invention segments the service handling responsibilities by keeping the P-CSCF for protocol compliance and detection, while introducing a local service function for service-specific handling. This segmentation allows visited network services to be applied at the local service function level without requiring home network S-CSCF involvement, thus maintaining both protocol compliance and service adaptability.
Solution Approach 2:
The local service function serves as an intermediary that enables visited network services to be applied to emergency requests. It receives requests from the P-CSCF, applies local service logic and visited network service rules, and routes requests appropriately, thereby enabling service versatility without compromising IMS protocol compliance enforced by the P-CSCF.
3Adaptability or versatility
If an application server implements click-to-dial service with location-based emergency checks, then user service capability is enhanced, but additional location verification steps increase processing time
Solution Approach 1:
The application server performs location-based emergency checks as a preliminary action before initiating the full emergency call setup. By checking location information and determining emergency session applicability in advance, the system can quickly route eligible requests through the optimized path via P-CSCF and local service function, minimizing actual call setup time while maintaining service capability.
Data Source
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AI summary
The invention relates to an apparatus, method and a computer program product for establishing a request for a session by an application server (AS), determining by an emergency related local service function that the session comprises an emergency session, wherein the emergency related local service function is co-located at the application server (AS), and, transmitting the request for the session to an emergency call state control function (E-CSCF) of the internet protocol multimedia subsystem (IMS) based on the determination.