IMS Call Forwarding via SDP Parameter Matching
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Solution Overview
Problem
Current call forwarding services in IMS/SIP networks do not support forwarding based on media attributes such as call type, bandwidth, or codec type, limiting the ability to optimize call routing according to network conditions or user device capabilities.
Innovation Solution
A method and system that compare Session Description Protocol (SDP) parameters with user-defined call forwarding parameters to forward calls to a second terminal, using REFER messages with specific SDP information and unique identifiers, allowing for media-based call forwarding and partial forwarding to multiple destinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If call forwarding is based only on line status and subscriber identity, then the service is simple to implement, but it cannot optimize routing based on media attributes or device capabilities
Solution Approach 1:
The system performs preliminary evaluation of SDP parameters during the call setup phase before the call is fully established. The network element compares SDP attributes (media type, bandwidth, codec) with pre-configured call forwarding parameters to determine routing decisions in advance, enabling media-based call forwarding without adding significant complexity to the overall system architecture
Solution Approach 2:
The call forwarding functionality is segmented into independent evaluation components that assess different SDP parameters separately. The system divides the call forwarding decision into distinct stages: SDP parameter extraction, parameter comparison against forwarding rules, and routing determination. This segmentation allows the system to implement complex media-based routing without overwhelming system complexity
2Productivity
If the system evaluates SDP parameters for call forwarding, then media-based routing optimization is achieved, but network processing complexity increases
Solution Approach 1:
The system extracts only the necessary SDP parameters (media type, bandwidth, codec) from the complete SDP message for evaluation purposes. By taking out only the relevant parameters needed for call forwarding decisions rather than processing the entire SDP structure, the system achieves media-based routing optimization while minimizing the additional network processing complexity
Solution Approach 2:
The system performs partial evaluation of SDP parameters by focusing only on the specific attributes required for call forwarding (media type, bandwidth, codec) rather than analyzing the complete SDP message. This partial action approach enables efficient media-based routing decisions without requiring full SDP processing, thus improving call routing efficiency while controlling network processing complexity
3Adaptability or versatility
If call forwarding forwards the entire call to one destination, then the forwarding logic is simple, but it cannot provide partial forwarding to multiple destinations based on different media types
Solution Approach 1:
The call forwarding logic is segmented to handle different media types independently. The system divides the forwarding decision into separate evaluations for each media type (audio, video, data) based on SDP parameters. This allows partial forwarding where different media streams can be routed to different destinations, providing forwarding flexibility while managing logic complexity through structured segmentation of the forwarding rules
4Adaptability or versatility
If the system stores detailed call forwarding parameters in the database, then media-based forwarding capability is enhanced, but database access and retrieval time increases
Solution Approach 1:
The system extracts and stores only the essential call forwarding parameters (media type, bandwidth, codec, destination) in the database rather than storing complete SDP messages or detailed routing policies. By taking out only the critical parameters needed for media-based forwarding decisions, the system enhances media-based forwarding capability while keeping database access and retrieval time minimal
Data Source
AI summary
A method of forwarding a call based on media attributes of the call in a telecommunications network is disclosed. The call forwarding services includes call forwarding based on SDP attributes, media-based partial call forwarding and partial call forwarding to multiple destinations. The method comprises comparing parameters of SDP with call forwarding parameter of the user, obtaining a match between one of the SDP parameters and the call forwarding parameters, sending a REFER message in case of partial call forwarding, multiple REFER messages in case of partial call forwarding to multiple destinations to network of calling user, and forwarding the call to other terminals as specified in the call forwarding parameters. The call forwarding based on media attributes enables a served user to forward communications based on media attributes conveyed over SDP for an IMS/SIP user.