Session Border Controller Codec Negotiation Optimization

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Solution Overview

Problem

Current communication networks face inefficiencies in codec negotiation due to unnecessary gateways in the user plane path, leading to potential call failures when intermediate nodes lack knowledge about transcoding requirements, resulting in incorrect codec offerings and increased signaling load.

Innovation Solution

Implementing a mechanism where Session Border Controllers (SBCs) closer to the terminating UE can modify and manage codec lists within Session Description Protocol (SDP) messages to ensure only supported codecs are offered, allowing downstream SBCs to remove unnecessary gateways and optimize media routing by using additional codec lists and identifiers to enforce network policies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If intermediate nodes perform transcoding without knowledge of terminating network properties, then codec negotiation can proceed, but call failures occur due to incorrect codec offerings

Engineering Contradiction:
Improvecodec negotiation capabilityVSAvoidcall success rate
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by having the terminating SBC pre-configured with knowledge of terminating network properties and terminal capabilities before the call setup completes. The SBC uses this pre-established knowledge to make informed codec selection decisions during the negotiation process, ensuring reliable call setup without requiring real-time analysis of terminating network properties.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the terminating SBC provides information about supported codecs and network properties back to intermediate SBCs during the negotiation process. This feedback loop allows intermediate nodes to adjust their codec offerings based on actual terminating network capabilities, preventing call failures while maintaining negotiation flexibility.

Inventive Principle:
Principle #23Feedback

2Productivity

If unnecessary gateways are removed from user plane path to optimize media routing, then routing efficiency improves, but call failures occur when nodes not supporting OMR are removed

Engineering Contradiction:
Improvemedia routing efficiencyVSAvoidcall setup reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by enabling individual SBCs to make localized decisions about gateway removal based on their specific knowledge of network properties and terminal capabilities. Each SBC evaluates whether gateway removal is appropriate for its specific context rather than applying a uniform policy, allowing optimization where safe while maintaining reliability where necessary.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses the terminating SBC as an intermediary that coordinates gateway removal decisions across the user plane path. This intermediary node ensures that only gateways can be removed when all intermediate nodes support the optimization, preventing call failures while enabling efficient routing where conditions are met.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If upstream nodes perform transcoding without knowledge of terminating network properties, then codec selection can be made, but policies in intermediate networks cannot be properly applied

Engineering Contradiction:
Improvecodec selection processVSAvoidnetwork policy applicability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent inverts the traditional codec selection approach by having downstream SBCs (closer to terminating UE) make codec decisions based on terminating network properties rather than having upstream nodes make decisions without this knowledge. This inversion allows network policies to be properly applied while simplifying the selection process through better information availability.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP2471238B1Control of codec negotiation for communication connection
Publication Date: 2021.04.14 NOKIA SOLUTIONS & NETWORKS OY
  • EP2471238B1 patent drawingFigure 1a~1b
  • EP2471238B1 patent drawingFigure 2

AI summary

The invention relates to a session control entity, method and a computer program product for receiving a request for a session, deciding on removal of a user plane gateway from a user plane of the session, extracting, when the user plane gateway is to be removed, a first codec list in the second encoding and removing the first codec list from the request for the session. Further, removing a second codec list in the first encoding from the request for the session, deriving a third codec list, when the user plane gateway is to be removed, from the first codec list, or, when the user plane gateway is not to be removed, from the second codec list, including in the request for the session, a third codec list in the first encoding, and transmitting the request for the session.