Media Stream Maintenance via Signaling and Blocking in SIP Networks

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Solution Overview

Problem

In SIP networks, media streams are closed by NAT-servers when idle, preventing re-establishment without a new connection, which hampers call-on-hold functions and media stream maintenance during temporary suspensions.

Innovation Solution

A method and network equipment with receiving, signalling, and blocking units to detect triggers for suspending media streams, send maintenance commands, and block connections, preventing NAT-server closure by simulating active connections through keep-alive messages and blocking media streams within the network equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the NAT-server closes the media stream connection when idle, then network resources are conserved, but the connection cannot be re-established without creating a new connection

Engineering Contradiction:
Improvenetwork resource conservationVSAvoidconnection re-establishment capability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The network equipment sends a signaling command to maintain the media stream connection before the NAT-server closes it due to idle status. This preliminary action keeps the connection alive in the NAT-server's view, allowing rapid re-establishment when needed without creating a completely new connection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The network equipment acts as an intermediary between the SIP-clients and the NAT-server. It blocks the media stream from being actually transmitted while maintaining the connection state, preventing the NAT-server from closing the connection while still achieving resource conservation through blocking.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the media stream connection is maintained during suspension, then call-on-hold functions are enabled, but network resources are consumed continuously

Engineering Contradiction:
Improvecall-on-hold function capabilityVSAvoidcontinuous resource consumption
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent extracts the connection maintenance function from actual media stream transmission. The signaling command maintains the connection state separately from the media data flow, allowing the connection to be kept alive without continuously transmitting media streams, thus reducing resource consumption while enabling call-on-hold functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The network equipment serves as a mediator that decouples connection state maintenance from media stream transmission. It receives the signaling command to maintain the connection while simultaneously blocking the actual media stream, allowing call-on-hold functionality without continuous resource consumption from active media transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the NAT-server pinholes are kept open during suspension, then connection re-establishment is seamless, but network security and resource management are compromised

Engineering Contradiction:
Improveconnection re-establishment smoothnessVSAvoidnetwork security and resource management
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The network equipment acts as a security intermediary that controls media stream flow while maintaining connection state. It blocks the media stream from reaching the core network while keeping the NAT-server pinholes open, thus enabling seamless re-establishment without compromising network security or resource management.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies local quality control by blocking the media stream at the network equipment level while maintaining the connection state at the NAT-server level. This localized blocking ensures that only the specific media stream is controlled without affecting the overall connection state or network security policies.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2020795B1Method and network equipment for maintaining a media stream through another network equipment while suspending an associated media stream connection in a communication network
Publication Date: 2017.11.22 NOKIA SOLUTIONS & NETWORKS OY
  • EP2020795B1 patent drawingFigure 1~2
  • EP2020795B1 patent drawingFigure 3~4
  • EP2020795B1 patent drawingFigure 5~6

AI summary

A method for maintaining a media stream through a first network equipment while suspending the associated media stream connection 313, 312, 314, 305 in a communication network, comprising receiving within a second network equipment 113 a trigger for suspending a media stream 313, 312, 314, 305, sending a signalling command for maintaining the media stream and blocking the maintained media stream 313, 312, 314, 305 is provided.