Packet Extracting Device for Accurate RTT Measurement
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Solution Overview
Problem
Existing methods for measuring round trip time (RTT) in data communication networks face accuracy issues due to the inclusion of delayed ACK packets transmitted by timeout, which are not related to network delays, making it difficult to accurately assess communication quality and network utilization efficiency.
Innovation Solution
A packet extracting device that associates sequence numbers, packet sizes, and reception times of data packets with ACK numbers, window sizes, and reception times of ACK packets, allowing it to determine whether an ACK packet is delayed and exclude it from RTT calculations by comparing window sizes between consecutive ACK packets, thereby ensuring accurate RTT measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If delayed ACK packets are used to improve network utilization efficiency, then communication efficiency is improved, but RTT measurement accuracy deteriorates due to timeout-related delays
Solution Approach 1:
The patent extracts and identifies delayed ACK packets from the stream of ACK packets by comparing window sizes between consecutive ACK packets. By separating delayed ACK packets (which contain timeout-related delays) from normal ACK packets, the system can exclude them from RTT calculations, thus maintaining measurement accuracy while preserving the benefits of delayed ACK usage for network utilization.
Solution Approach 2:
The patent introduces window size comparison as an intermediary mechanism to identify delayed ACK packets. By using the window size parameter as a mediator, the system can distinguish between normal and delayed ACK packets without directly measuring or interfering with the ACK timing, thereby maintaining both network efficiency and measurement accuracy.
2Adaptability or versatility
If timeout-based delayed ACK packets are transmitted, then network communication flexibility is improved, but the ability to accurately detect network delays deteriorates
Solution Approach 1:
The patent extracts delayed ACK packets identified through window size comparison and excludes them from RTT measurement calculations. This separation allows the system to maintain flexible timeout-based ACK transmission while preventing these packets from corrupting network delay measurements.
Solution Approach 2:
The patent implements a feedback mechanism where the measured RTT values are used to adjust the timeout threshold. By continuously monitoring RTT and adjusting the timeout based on actual network conditions, the system adapts to varying network latencies while maintaining the ability to distinguish between normal and delayed ACK packets.
Data Source
AI summary
An operation unit detects that a received first ACK packet is an ACK packet transmitted in response to a single data packet. The operation unit determines whether to calculate a round trip time by using reception time of the first ACK packet on the basis of a window size included in the first ACK packet and a window size included in a second ACK packet acquired immediately before the first ACK packet. If the operation unit determines to calculate the round trip time, the operation unit outputs the round trip time calculated by using the reception time of the first ACK packet.