DTN Node Device ACK List Exchange for Message Copy Prevention
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Solution Overview
Problem
Existing routing protocols in Disruption/Delay/Disconnect Tolerant Networks (DTNs) generate multiple copies of messages, leading to copies remaining in the network even after the final destination is reached, which reduces message delivery success rates as these copies continue to be spread within the DTN.
Innovation Solution
A node device in the DTN manages a summary vector and an Acknowledgement (ACK) list to identify and prevent the spread of message copies that have already arrived at the final destination by exchanging ACK lists with adjacent nodes, updating the summary vector to remove entries for delivered messages, and deleting these messages from the buffer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If routing protocols generate multiple copies of messages and spread them within the DTN, then message delivery success rate is improved, but unnecessary message propagation occurs after reaching the final destination
Solution Approach 1:
The patent implements a feedback mechanism where the final destination node sends an acknowledgment (ACK) message back to intermediate nodes when a message successfully arrives. This ACK message contains the message identifier, allowing intermediate nodes to recognize that the message has reached its destination and stop propagating additional copies, thus eliminating unnecessary message propagation while maintaining high delivery success rates
Solution Approach 2:
The patent applies preliminary action by having intermediate nodes proactively check whether they possess an ACK message for each message in their buffer before forwarding it to adjacent nodes. This preliminary verification prevents the spread of messages that have already reached their destination, avoiding redundant propagation while ensuring reliable delivery
2Reliability
If multiple copies of messages are stored in message buffers, then message delivery reliability is improved, but buffer storage efficiency deteriorates
Solution Approach 1:
The feedback mechanism through ACK messages enables intermediate nodes to identify and remove message copies that have already reached their destination. This reduces the number of redundant message copies stored in buffers, improving storage efficiency while maintaining the reliability benefits of having multiple copies for propagation
Solution Approach 2:
The patent implements discarding and recovering by systematically removing message copies from buffers once acknowledgment of successful delivery is received. This frees up buffer space for storing and propagating other messages that have not yet reached their destinations, optimizing buffer utilization while preserving message delivery reliability
Data Source
AI summary
A node device (1A) receives a second ACK list in communication with an adjacent node (1B) and updates a first ACK list and a first summary vector on the basis of the second ACK list. The first summary vector, which indicates messages stored in a message buffer of the node device (1A), is transmitted to the adjacent node (1B) prior to transmission of the messages in the communication with the adjacent node (1B). The first ACK list indicates ACK messages recognized by the node device (1A). The second ACK list indicates ACK messages recognized by the adjacent node (1B). Each ACK message represents a message of arrival at an ultimate destination node via a DTN (100). In this way, for example, a copy having the same content as a message having arrived at an ultimate destination node can be prevented from being scattered in the Disruption Tolerant Network (DTN).