Direct-Routed Telephony Media Flow via Intermediate SBCs

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Solution Overview

Problem

Organizations face challenges in implementing media bypass for network-based communication services due to the need to open their firewalls for external traffic, which increases latency and network resource usage, while also dealing with complex private network setups that restrict direct communication paths to preferred telephone networks.

Innovation Solution

A network-based communication service controls signaling and media flow within non-public networks using SIP protocol extensions to specify routes, determining primary and intermediate SBCs based on device location and organizational settings, allowing direct or indirect media paths through intermediate SBCs when the primary SBC is not reachable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If media bypass is implemented for network-based communication services, then network resource usage is reduced, but firewall security is compromised and latency increases

Engineering Contradiction:
Improvenetwork resource usageVSAvoidfirewall security
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent introduces an intermediate Session Border Controller (SBC) as a mediator between the network-based communication service and the private network. This intermediate SBC acts as a trusted intermediary that can establish direct media paths to end devices without requiring the organization's firewall to be opened to external traffic. The intermediate SBC maintains security by staying within the trusted network infrastructure while enabling optimized media routing, thus resolving the contradiction between reducing network resource usage and maintaining firewall security.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If direct media paths are established to preferred telephone networks, then communication efficiency is improved, but complex private network setups restrict direct communication paths

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidprivate network setup complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the communication path into multiple independent components: the network-based communication service, the intermediate SBC, the primary SBC, and the end devices. This segmentation allows each component to operate independently within its appropriate network zone. The intermediate SBC handles signaling and coordination, while media paths are established directly to end devices when possible. This segmentation enables communication efficiency improvements without requiring complex end-to-end direct paths through the entire private network infrastructure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The intermediate SBC serves as a mediator that simplifies the complex private network setup by handling the coordination and routing logic. It receives signaling from the network-based communication service, determines optimal media paths, and establishes connections accordingly. This intermediary approach abstracts the complexity of private network configurations from the communication service, enabling efficient direct media paths without requiring the communication service to manage complex network topology details.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If intermediate SBCs are used for indirect media paths, then firewall security is maintained, but latency increases compared to direct paths

Engineering Contradiction:
Improvefirewall securityVSAvoidcommunication latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements dynamic path selection where the media routing is adaptively determined based on device location, network conditions, and reachability. The system can dynamically switch between direct media paths (when security allows and latency is minimized) and indirect paths through intermediate SBCs (when direct paths are not feasible). This dynamic approach ensures that direct paths are used whenever possible to minimize latency, while fallback to indirect paths maintains security when needed, resolving the contradiction between security and latency.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4128688B1Media flow control for direct routing in network-based telephony
Publication Date: 2025.08.20 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP4128688B1 patent drawingFigure 1
  • EP4128688B1 patent drawingFigure 2
  • EP4128688B1 patent drawingFigure 3

AI summary

Disclosed in some examples are methods, systems, and machine-readable mediums that allow a network-based communication service to control a signaling path and media flow within non-public networks for direct-routed network-based communication sessions (e.g., telephony). The signaling and media flow may be controlled by using SIP protocol extensions to specify both the signaling route and the media route.