QoS Packet Forward Error Correction for Multicast Reliability

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Solution Overview

Problem

Packet-based networks, such as the Internet, often fail to provide reliable quality of service guarantees for in-order packet delivery, packet error rate, and packet delivery latency, especially in multicast and delay-sensitive networks, due to their unpredictable nature.

Innovation Solution

Implementing forward error correction (FEC) to mark packets with quality of service levels, adding FEC data to packets, and using it to recover lost or corrupted packets at the receive endpoint, while delaying error reporting until a QoS-based threshold is exceeded, thereby enabling reliable QoS levels over packet-based networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If TCP retransmission mechanisms are used to provide reliable data transport, then packet delivery reliability is improved, but latency increases and multicast network support fails

Engineering Contradiction:

Improvepacket delivery reliabilityVSAvoidlatency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Forward error correction data is added to packets in advance before transmission, enabling the receiver to correct errors without waiting for retransmission. This preliminary preparation of correction data eliminates the need for post-transmission retransmission requests, thereby reducing latency while maintaining reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Forward error correction codes act as an intermediary mechanism between the transmitter and receiver, providing a middle ground that doesn't require direct interaction (retransmission requests) between endpoints. The FEC data mediates the error correction process unilaterally at the receiver side

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If TCP retransmission mechanisms are used to provide reliable data transport, then packet delivery reliability is improved, but multicast network support fails

Engineering Contradiction:

Improvepacket delivery reliabilityVSAvoidmulticast network support

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The error correction functionality is segmented from the traditional TCP retransmission mechanism. Instead of requiring end-to-end interaction, error correction is divided into independent FEC encoding at the transmitter and FEC decoding at the receiver, enabling unilateral operation that supports multicast scenarios where multiple receivers cannot individually request retransmissions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If forward error correction data is added to packets, then packet loss recovery capability is improved, but device complexity increases

Engineering Contradiction:

Improvepacket loss recovery capabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system changes the parameter of error correction strength by selecting different FEC codes and data rates based on network conditions and QoS requirements. This allows optimization of the balance between recovery capability and complexity, using stronger FEC only when necessary rather than always

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10389791B2System and method of implementing quality of service over a packet-based network

Publication Date: 2019.08.20 AT&T INTELLECTUAL PROPERTY I L P

AI summary

A method includes transmitting a first stream of packets from a first network endpoint to a second network endpoint. The first stream of packets includes a quality of service indicator having a value that indicates a packet loss rate tolerance. The method also includes receiving a retransmission request at the first network endpoint from the second network endpoint for retransmission of at least a portion of the first stream of packets.