IMS Session Routing via Capability-Aware POI Selection
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Solution Overview
Problem
The existing routing of communication sessions from IMS networks to PSTN networks is inefficient, leading to high termination fees due to the reliance on expensive PSTN resources, as the routing path often involves distant points of interconnect, increasing costs for IMS network operators.
Innovation Solution
A method and system that utilize control nodes within the IMS network to determine breakout conditions and select the most capable and geographically closest points of interconnect for routing session invitations to PSTN networks, minimizing the use of PSTN resources by leveraging the IMS network's transport backbone for efficient routing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the BGCF routes the forwarded session invitation to the closest POI to the PSTN without considering capability information, then the routing decision is simple and fast, but the routing efficiency is poor and termination fees are high
Solution Approach 1:
The patent applies preliminary action by having the S-CSCF determine breakout conditions and attach capability information to the session invitation before forwarding to the BGCF. This pre-processing enables the BGCF to make informed routing decisions without complex real-time analysis, resolving the contradiction between routing efficiency and decision complexity.
Solution Approach 2:
The patent uses the session invitation message as an intermediary carrier to transmit capability information from the S-CSCF to the BGCF. This intermediary mechanism enables efficient information exchange without requiring direct complex interaction between nodes, improving routing efficiency while maintaining manageable system complexity.
2Loss of energy
If the IMS network routes sessions through distant POIs to reach PSTN, then the routing path is established, but the usage of expensive PSTN resources increases and termination fees are high
Solution Approach 1:
The patent applies local quality by selecting POIs based on their geographical proximity to the terminating UE and their capability to handle specific session types. This localized selection optimizes the routing path length and minimizes PSTN resource usage, directly addressing the contradiction between resource efficiency and path length.
Solution Approach 2:
The patent changes the routing parameter from simple distance-based selection to capability-aware selection, where the BGCF considers both the geographical location and the functional capabilities of POIs. This parameter change enables optimal routing that reduces PSTN resource usage while accounting for network capabilities.
3Reliability
If the BGCF selects POI without capability information, then the routing decision is made quickly, but the session may be routed to an inappropriate POI that cannot handle the session type
Solution Approach 1:
The patent uses preliminary action by having the S-CSCF attach capability information to the session invitation before it reaches the BGCF. This pre-attachment of capability data enables the BGCF to make reliable routing decisions quickly without performing complex real-time capability analysis, resolving the contradiction between reliability and decision time.
4Productivity
If the IMS network uses a centralized infrastructure with few regions having control nodes, then the network structure is simplified, but the routing of forwarded sessions to distant regions is inefficient
Solution Approach 1:
The patent changes the routing parameter to include capability information about control nodes and POIs, enabling the BGCF to select the most appropriate routing path based on both geographical distance and node capabilities. This parameter enhancement allows efficient forwarded session routing even in networks with centralized infrastructure, resolving the contradiction between network structure simplicity and routing efficiency.
Data Source
AI summary
System, methods, nodes, and instruction set for routing a session invitation from a first network (101) to a second network (112) are described. The first network (101) and the second network (112) are interconnected via at least two points of interconnect (114, 120). A first control node (124) receives a session invitation to a first user equipment (106), both are part of the first network (101). The first control node (124) determines whether a breakout condition for routing of the session invitation to the second network (112) is fulfilled. If so, a second control node (128) of the first network (101) selects a point of interconnect (114, 120) to the second network (112), considering a capability information characterizing the first control node (124). Therefore the session invitation may be routed in an efficient way from the first network (101) to the second network (112).