Serving Entity Selection in IMS Networks
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Solution Overview
Problem
Current serving entity selection procedures in IMS networks fail to efficiently reassign users to the most preferred S-CSCF after it becomes available again, leading to suboptimal resource utilization and service continuity issues when the preferred S-CSCF is temporarily or permanently unavailable.
Innovation Solution
A method that involves receiving an indication from a serving entity if it is not the most preferred, storing this indication, and including information about server capabilities to select an alternative S-CSCF, allowing for re-selection based on availability and load, and transmitting this information through Diameter signals to ensure optimal S-CSCF assignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the current serving entity selection procedure is used, then the network can handle basic user registration and service requests, but it cannot efficiently reassign users to the most preferred S-CSCF when it becomes available again, leading to suboptimal resource utilization
Solution Approach 1:
The patent implements a feedback mechanism where the subscription entity stores an indication from the serving entity about whether it is the most preferred serving entity. When a user requests service, the subscription entity retrieves this stored indication and provides it to the control entity, enabling the control entity to make informed decisions about S-CSCF selection based on feedback about preference status and availability
Solution Approach 2:
The subscription entity performs preliminary action by storing the indication about preferred serving entity status in advance, before a user service request occurs. This pre-stored information allows the control entity to quickly determine whether to reassign users to the most preferred S-CSCF without requiring real-time queries, thus improving resource utilization while maintaining service continuity
2Reliability
If the network always selects the most preferred S-CSCF, then optimal service quality is achieved, but the system cannot handle scenarios where the preferred S-CSCF is temporarily or permanently unavailable
Solution Approach 1:
The patent implements dynamic S-CSCF selection where the control entity evaluates both the preferred S-CSCF status and its current availability. The system dynamically adjusts the serving entity assignment based on real-time conditions: selecting the most preferred S-CSCF when available, and alternatively selecting another S-CSCF when the preferred one is unavailable, thus maintaining service continuity while optimizing resource utilization
Solution Approach 2:
The control entity acts as an intermediary between the subscription entity and the serving entities. It receives the stored indication about preferred serving entity status, evaluates the availability of the preferred S-CSCF, and makes the final selection decision. This intermediary role allows the system to balance between optimal service quality and handling unavailability scenarios
3Measurement precision
If the I-CSCF always requests and processes capabilities to check for S-CSCF re-selection, then the most preferred S-CSCF can be identified, but the system complexity and processing overhead increase significantly
Solution Approach 1:
The patent extracts the S-CSCF preference indication information from the capability processing flow. Instead of always requesting and processing full capability sets to determine S-CSCF selection, the system extracts and stores a simplified indication about whether the current serving entity is the most preferred one. This extracted information is sufficient for re-selection decisions, reducing system complexity while maintaining selection accuracy
Data Source
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AI summary
The invention relates to a control entity (I-CSCF 5), serving entity (S-CSCF 1; S-CSCF 2) and a subscription entity (HSS 6), in which a control entity determines that the most preferred serving entity (S-CSCF 1) was not selected for a user and transmits an indication about selection of less preferred serving entity to the less preferred serving entity (S-CSCF 2) which in turn transmits corresponding in indication to a subscription entity. The subscription entity stores the indication and returns the server capabilities to the control entity when information about the same user is requested next time.