Congestion Control Apparatus for RTP over UDP Traffic

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Solution Overview

Problem

Current data networks, especially those supporting real-time traffic like voice and video, face challenges in managing congestion effectively, particularly when using connectionless protocols like UDP, which are not compliant with conventional Explicit Congestion Notification (ECN) schemes, leading to potential network delays and poor Quality of Service (QoS).

Innovation Solution

A congestion control apparatus that modifies control instructions within the network to detect congestion indicators in packet headers, allowing for adaptive rate adjustments in real-time data streams, particularly for RTP over UDP traffic, using a modular architecture to support multiple protocols and adaptation methods, thereby optimizing streaming media transfers and alleviating network congestion without relying on ECN-compliant operating systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ECN schemes are used for congestion notification, then congestion avoidance is improved, but compatibility with connectionless protocols like UDP deteriorates

Engineering Contradiction:
Improvecongestion avoidanceVSAvoidprotocol compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a proxy server as an intermediary between the UDP-based real-time data transmission system and the ECN congestion notification mechanism. The proxy server intercepts ECN-marked packets, translates the congestion information into appropriate control signals for UDP traffic, and forwards adjusted packets to the destination. This intermediary approach allows ECN functionality to be applied to protocols that natively lack ECN support, resolving the contradiction between congestion avoidance reliability and protocol compatibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If real-time traffic is prioritized to ensure QoS, then quality of service is improved, but network congestion management becomes more complex

Engineering Contradiction:
ImproveQuality of ServiceVSAvoidcongestion management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements differentiated congestion management by applying specific handling rules based on traffic type and priority level. The system identifies real-time traffic (voice, video) and applies specialized congestion notification and rate adjustment mechanisms tailored to these traffic characteristics, while allowing different handling for best-effort traffic. This local quality approach ensures QoS for critical traffic without requiring complex global congestion management mechanisms for all traffic types.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically adjusts transmission rates based on real-time congestion conditions detected through ECN marking. When congestion is detected, the proxy server dynamically modifies the rate at which real-time data is transmitted, allowing the system to adapt to changing network conditions. This dynamic rate adjustment maintains QoS during normal conditions while preventing degradation during congestion, reducing the need for static complex management mechanisms.

Inventive Principle:
Principle #15Dynamics

3Loss of substance

If packet marking is used instead of dropping for congestion notification, then data loss is reduced, but transmission rate adaptation becomes more difficult

Engineering Contradiction:
Improvepacket lossVSAvoidrate adaptation
Core Design Contradiction:
Loss of substanceVSEase of operation

Solution Approach 1:

The patent implements a feedback mechanism where the proxy server continuously monitors ECN-marked packets returning from the network and uses this information to adjust transmission rates. The system establishes a feedback loop where congestion information flows back from the network to the sender through the proxy server, enabling automatic rate adaptation without manual intervention. This feedback mechanism resolves the difficulty of rate adaptation by providing continuous congestion information that automatically drives rate adjustments.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2286555B1Improvements in and relating to the management of data congestion in a data network
Publication Date: 2016.06.15 BRITISH TELECOM PLC
  • EP2286555B1 patent drawingFigure 1~2
  • EP2286555B1 patent drawingFigure 3
  • EP2286555B1 patent drawingFigure 4

AI summary

A congestion management apparatus for receiving a traffic data stream and an associated control signal, wherein the apparatus detects a congestion indicator in the traffic data stream and generates congestion control data. The apparatus incorporates the congestion control data into the control signal and sends the control signal to a streaming server to control the rate at which the streaming server sends the traffic data. The apparatus selects an adaptation method depending on a protocol associated with the control signal and generates the congestion control data in accordance with the adaptation method. The apparatus is modular and may be adapted to support a plurality of protocols and adaptation methods. The traffic data may comprise real time data, especially video data and/or audio data, transmitted using one or more connectionless transport protocol, such as Real-time Transport Protocol (RTP) over User Datagram Protocol (UDP).