SDN-Controlled IMS Signaling Paths to Reduce Processing Overhead
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Solution Overview
Problem
The complex signaling path in Internet Protocol Multimedia Subsystem (IMS) systems leads to increased processing overhead and unnecessary computational load due to the multiple proxies, session control servers, and application servers involved in SIP message handling.
Innovation Solution
The implementation of Software Defined Networking (SDN) in IMS systems allows for a simplified signaling path by using an SDN controller to dynamically manage packet forwarding based on various attributes, reducing the need for intermediate hops and optimizing the flow of signaling and media packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple proxies and session control servers are used in IMS signaling path, then message routing and service invocation are ensured, but processing overhead and computational load increase
Solution Approach 1:
The patent extracts the complex IMS signaling path (including P-CSCF, S-CSCF, I-CSCF, and multiple application servers) and replaces it with a simplified SDN-based architecture. The SDN controller centralizes the intelligence that was distributed across multiple servers, removing unnecessary intermediaries while maintaining reliable message routing through SDN-defined forwarding rules.
Solution Approach 2:
The SDN controller serves multiple functions that were previously handled by separate IMS components: it performs message routing, service invocation, and packet forwarding that were distributed across P-CSCF, S-CSCF, I-CSCF, and application servers. This multi-functional approach reduces the number of specialized servers needed while maintaining system reliability.
2Reliability
If all messages are anchored through a common CSCF for filter criteria testing, then service policy enforcement is maintained, but processing overhead increases
Solution Approach 1:
The patent removes the mandatory anchoring of all messages through a common CSCF for filter criteria testing. Instead, the SDN controller selectively applies service policies only when necessary, based on the specific message type and service requirements, eliminating the universal anchoring overhead while maintaining policy enforcement for messages that require it.
Solution Approach 2:
Rather than applying filter criteria testing to all messages through a common CSCF (excessive action), the SDN controller applies service policies selectively only to messages that require them (partial action). This reduces processing overhead for messages that don't need policy enforcement while maintaining reliability for those that do.
3Productivity
If SDN is implemented to simplify signaling path, then processing overhead is reduced, but network control complexity increases
Solution Approach 1:
The SDN controller acts as an intermediary between the simplified forwarding plane and the network control plane. It handles the complexity of service policy enforcement, message routing decisions, and coordination with IMS applications, while presenting a simple forwarding interface to the rest of the network. This mediator approach consolidates control complexity in one element rather than distributing it across multiple servers.
Data Source
AI summary
Software Defined Networking (SDN) is used in IMS in order to provide a mechanism to forward (Internet Protocol) IP packets and provide a simplified solution to the complex signaling path of IMS according to directives from an SDN Controller. SDN is used in at least three particular scenarios. In the first scenario, communications are simplified using SDN directed signaling disaggregation. In the second scenario, SDN is used to direct media function chaining. In the third scenario, the system can be used as an SDN based media relay.