Communication Path Latency Estimation Through QUIC Burst Signatures
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Solution Overview
Problem
Existing methods for estimating latency in communication networks fail to accurately measure Round Trip Time (RTT) for QUIC packets due to the encrypted nature of the protocol, which prevents passive observation of acknowledgement patterns.
Innovation Solution
A method involving a data flow shaping node that transmits a sample burst with reordered packets, causing a distinct pattern of acknowledgement packets, allowing a probe node to identify and determine latency based on timing information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If QUIC packets are used for data transmission, then security and performance are improved, but latency measurement becomes impossible due to encrypted acknowledgements
Solution Approach 1:
The patent introduces an intermediary mechanism (spin bit) within the encrypted QUIC protocol that allows passive observers to infer acknowledgement patterns without decrypting the traffic. This mediator enables latency measurement while preserving the security benefits of encrypted QUIC communication.
Solution Approach 2:
The patent uses the spin bit as a detectable marker that changes state (similar to color changes) to indicate packet acknowledgements. This allows observation tools to detect acknowledgement patterns through these state changes in the packet structure without needing to break encryption.
2Measurement precision
If packet reordering is applied to create identifiable patterns, then latency estimation accuracy is improved, but network protocol complexity increases
Solution Approach 1:
Instead of reordering all packets, the patent applies partial reordering only to specific packets within a burst, using the spin bit to mark these specially. This selective approach achieves the needed pattern identification while minimizing protocol complexity and maintaining compatibility with standard QUIC operation.
Solution Approach 2:
The spin bit is pre-configured in the packet structure before transmission, allowing receiving nodes to identify acknowledgements without complex real-time analysis. This preliminary preparation simplifies the measurement process at runtime.
Data Source
AI summary
Method and device(s) for supporting estimation of latency over a communication path in a communication network between a data flow shaping node, providing a data flow in bursts towards a data flow target node, and a probe node. The devices(s) initiate to transmit, by the data flow shaping node, a sample burst being a burst of said bursts that differs in a predefined manner from preceding and subsequent bursts so that the data flow target node in response to the sample burst transmits a certain pattern of acknowledgement packets that differs compared to patterns of acknowledgement packets transmitted by the data flow target node in response to said preceding and subsequent bursts. The device(s) initiates to identify, by the probe node, receipt of potential acknowledgement packets according to said certain pattern.