Multicast Acknowledgment Staggering to Reduce Traffic Collisions

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Solution Overview

Problem

Conventional multicast communication systems face significant traffic collisions when acknowledging message receipt, leading to inefficiencies and potential failures in ensuring all devices in a multicast group have successfully received messages.

Innovation Solution

Implementing a system where devices in a multicast group wait for a defined transmit delay period before re-transmitting acknowledgment messages, and using specific identification within the multicast message to target only devices that have not acknowledged, reducing unnecessary re-transmissions and collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If every device in the multicast group sends an acknowledgment message to confirm receipt, then the MSD can ensure reliable delivery, but significant numbers of multicast traffic collisions occur

Engineering Contradiction:

Improvemessage delivery confirmationVSAvoidtraffic collisions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The acknowledgment process is segmented by dividing the multicast group into smaller subsets. Each subset sends acknowledgments at different times or through different paths, preventing all devices from transmitting simultaneously and causing collisions. This segmentation maintains reliable delivery confirmation while reducing traffic collision density.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Acknowledgment messages are transmitted periodically rather than all at once. The system implements time-based scheduling where different devices send acknowledgments at staggered intervals, ensuring reliable delivery confirmation while avoiding the simultaneous transmission that causes traffic collisions.

Inventive Principle:

Principle #19Periodic action

2Reliability

If the MSD multicasts a request for re-transmission to the entire group, then devices that missed the message can re-transmit, but unnecessary re-transmissions from devices that already received the message increase traffic collisions

Engineering Contradiction:

Improvemessage receipt assuranceVSAvoidnetwork efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The re-transmission request mechanism implements local quality by providing different instructions to different devices based on their individual receipt status. Devices that missed the original message receive re-transmission requests, while devices that successfully received the message are identified and excluded from re-transmitting, thereby maintaining reliability while improving network efficiency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system uses feedback from initial acknowledgment messages to determine which devices need re-transmission requests. By analyzing which devices did not send acknowledgments, the MSD can selectively request re-transmission only from those specific devices, avoiding unnecessary re-transmissions and reducing traffic collisions.

Inventive Principle:

Principle #23Feedback

3Loss of time

If acknowledgment messages are sent immediately upon receiving the multicast message, then the response time is minimized, but traffic collisions increase due to simultaneous transmissions

Engineering Contradiction:

Improveacknowledgment response timeVSAvoidtraffic collisions

Core Design Contradiction:

Loss of timeVSObject-generated harmful factors

Solution Approach 1:

The system implements periodic acknowledgment transmission with carefully controlled intervals. Instead of immediate simultaneous transmissions, devices send acknowledgments at staggered periodic intervals that are optimized to maintain acceptable response times while avoiding the traffic collisions caused by simultaneous transmissions.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system performs preliminary scheduling of acknowledgment transmissions before actual transmission occurs. Devices are pre-assigned transmission slots or sequences, allowing them to prepare their acknowledgment messages in advance and transmit at predetermined times, reducing overall response time while preventing simultaneous transmissions and collisions.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9479961B2Facilitating multicast traffic collision reduction

Publication Date: 2016.10.25 AT&T INTELLECTUAL PROPERTY I L P

AI summary

The reduction of multicast traffic collisions is facilitated. A device that is associated with a multicast group receives a multicast message requesting re-transmission of an acknowledgment message from the device. The multicast message includes information identifying the device within the multicast group of devices. In response to the device being determined to be identified by the information, the acknowledgement message can be re-transmitted after a defined transmit delay period after receipt of the multicast message. The defined transmit delay period can be based on the number of devices in the multicast group, based on the number of previous re-transmissions by the device and/or based on the number of devices for which re-transmission is requested.