Call Media Redirection with Signaling Path Isolation
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Solution Overview
Problem
Incorporating unreliable servers into a telephony call path can lead to dropped calls due to server failures or performance drops, which negatively impact the call quality and continuity.
Innovation Solution
A network element redirects the media flow to an unreliable server while maintaining the signaling flow on the original path, allowing the server to process the media without disrupting the call if the server fails or experiences performance issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a server is added to the call path to provide call services, then call functionality is improved, but call reliability deteriorates due to server failures or performance drops
Solution Approach 1:
The patent segments the call flow into two independent paths: a signaling path and a media path. The signaling path maintains the original call flow between endpoints through the session border controller, while the media path can be redirected through an unreliable server for processing. This segmentation allows the call control plane to remain reliable while the media plane can utilize additional server resources, resolving the contradiction between adding server functionality and maintaining call reliability.
2Adaptability or versatility
If the server is included in the media flow path to process media, then call service capabilities are enhanced, but call stability deteriorates when the server fails
Solution Approach 1:
The session border controller acts as an intermediary between the unreliable server and the call endpoints. It maintains the original signaling path independently of the server, while only redirecting media flow through the server when needed. If the server fails, the session border controller can immediately switch back to the original media path without affecting call stability, as the intermediary isolates the endpoints from server failures.
3Adaptability or versatility
If the server is added to handle call services, then service functionality is improved, but the complexity of call path management increases
Solution Approach 1:
The session border controller is designed with multi-functionality, handling both signaling and media flow management in a unified manner. It can dynamically switch between different media paths (original path vs. server path) while maintaining the same signaling path, reducing the need for separate complex management systems for different call paths. This universal approach simplifies overall call path management despite enhanced service functionality.
Data Source
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AI summary
A network element receives a call between a first and second party on an original call path. The call comprises a signaling flow and a media flow. The network element determines that a server is to be added to the call, and then adds the server to the call by redirecting the media flow from the network element via the server. Determining that the server is to be removed from the call is achieved by any of: receiving a request from an orchestrator, receiving information about a failure of the server, receiving information about a performance drop in a communications link between the server and the network element. In response to determining that the server is to be removed from the call, the network element then returns the media flow to the original path of the call. The signaling flow is maintained on the original path.