QUIC Path Latency Estimation Using Marker Burst Acknowledgements

Solution Overview

Problem

Existing methods for estimating latency in communication networks, particularly with QUIC packets, are hindered by the encryption of QUIC, which prevents passive observers from measuring Round-Trip-Time (RTT) using conventional techniques, making it difficult to assess network conditions and congestion.

Innovation Solution

A method involving a data flow shaping node that transmits a sample burst with reordered or missing packets, allowing a probe node to identify a distinct pattern of acknowledgement packets, enabling latency estimation based on timing information, even without the QUIC spin bit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If QUIC packets are encrypted to provide security, then security is improved, but the ability to measure RTT using conventional techniques deteriorates

Engineering Contradiction:

ImprovesecurityVSAvoidRTT measurement capability

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the data flow into regular bursts and special marker bursts. The marker bursts contain deliberately reordered packets that create a distinctive acknowledgment pattern, allowing the probe node to identify and measure RTT for these specific segments without decrypting the encrypted QUIC traffic.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses packet reordering within marker bursts to create a distinctive 'pattern' or 'color' in the acknowledgment sequence. This pattern acts as a visible identifier that allows the probe node to distinguish marker burst acknowledgments from regular traffic acknowledgments, enabling measurement without breaking encryption.

Inventive Principle:

Principle #32Color changes

2Loss of information

If QUIC packets are encrypted to prevent passive observation, then privacy is improved, but the ability to identify acknowledgment packets deteriorates

Engineering Contradiction:

Improveinformation visibility to passive observersVSAvoidacknowledgment packet identification

Core Design Contradiction:

Loss of informationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the data flow into regular bursts and special marker bursts. The marker bursts contain deliberately reordered packets that create a distinctive acknowledgment pattern, allowing the probe node to identify and measure RTT for these specific segments without decrypting the encrypted QUIC traffic.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses packet reordering within marker bursts to create a distinctive 'pattern' or 'color' in the acknowledgment sequence. This pattern acts as a visible identifier that allows the probe node to distinguish marker burst acknowledgments from regular traffic acknowledgments, enabling measurement without breaking encryption.

Inventive Principle:

Principle #32Color changes

3Productivity

If data is transmitted in bursts to improve efficiency, then productivity is improved, but the ability to measure latency accurately deteriorates

Engineering Contradiction:

Improvedata transmission efficiencyVSAvoidlatency estimation accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the data flow into regular bursts and special marker bursts. The marker bursts contain deliberately reordered packets that create a distinctive acknowledgment pattern, allowing the probe node to identify and measure RTT for these specific segments without decrypting the encrypted QUIC traffic.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces periodic marker bursts at known intervals within the data stream. These periodic insertions of specially structured bursts create predictable acknowledgment patterns that enable accurate timing measurements while maintaining the overall burst-based efficient transmission mode.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentEP4201037B1Methods and arrangements for supporting estimation of latency over a communication path in a communication network

Publication Date: 2026.03.11 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

Figure 1
Figure 2
Figure 3

AI summary

Method and device(s) (111; 140; 141; 211; 600) for supporting estimation of latency over a communication path (160a-b; 260) in a communication network (100; 200) between a data flow shaping node (111; 211), providing a data flow (150; 250) in bursts towards a data flow target node (120; 220), and a probe node (110; 210; 111; 211. The devices(s) initiate (801) to transmit, by the data flow shaping node (111; 211), a sample burst (503) being a burst of said bursts that differs in a predefined manner from preceding and subsequent bursts (502a, 502c) so that the data flow target node (120; 220) in response to the sample burst (503) transmits a certain pattern of acknowledgement packets that differs compared to patterns of acknowledgement packets transmitted by the data flow target node (120; 220) in response to said preceding and subsequent bursts. The device(s) initiates (802) to identify, by the probe node (110; 210; 111; 211), receipt of potential acknowledgement packets according to said certain pattern.