Hi Tong Li, Thanks for sharing. I think this is an interesting idea.
If I understand your draft correctly, this introduces a TIMESTAMP frame that the sender sends to allow the receiver to calculate a one way delay. When the receiver observes a new minimum, it will use the instigating packet's arrival time for the ack delay field in the next ack. This requires redefining the ack delay field depending on the negotiated transport, which seems tricky at best. Why not simply send an ack immediately when the receiver observes a new one way delay minimum? You can limit this to at most once an RTT which should be a negligible cost. Do you know of any research and data that shows how accurately something like your draft can lead to discovering the minRTT? And, relatedly, do you know of research and data showing how incorrect a minRTT estimate is with a reduced ack frequency of around ~4 acks per RTT? You may also find Christian Huitema's draft "Quic Timestamps For Measuring One-Way Delays" [0] helpful. -Marco [0]: https://datatracker.ietf.org/doc/draft-huitema-quic-ts/ On Thu Nov 13, 2025 at 6:31 PM PST, tong.li wrote: > Hi everyone, > As we know, networks like WLAN, cellular, and satellite often perform better > with fewer ACKs to reduce overhead. Inspired by drafts such as > "draft-ietf-quic-ack-frequency" (Iyengar et al.), I've been working on a > draft that improves min RTT estimation for QUIC when ACK frequency is low. > I'm keen to hear your perspectives if this is an area of interest. > -Tong Li > > Renmin University of China > > [email protected] > Room 421, Information Building > 100872 > > http://iir.ruc.edu.cn/~litong/index.html > > > ---- Forwarded Message ---- > From <[email protected]> Date 11/8/2025 22:11 To Bo > Wu<[email protected]>, > Ke Xu<[email protected]>, > Tong Li<[email protected]>, > Youjian Zhao<[email protected]> Subject New Version Notification > for draft-li-quic-minimum-rtt-estimation-00.txt > A new version of Internet-Draft draft-li-quic-minimum-rtt-estimation-00.txt > has been successfully submitted by Tong Li and posted to the > IETF repository. > > Name: draft-li-quic-minimum-rtt-estimation > Revision: 00 > Title: Minimum RTT Estimation Under Low ACK Frequency > Date: 2025-11-08 > Group: Individual Submission > Pages: 10 > URL: > https://www.ietf.org/archive/id/draft-li-quic-minimum-rtt-estimation-00.txt > Status: > https://datatracker.ietf.org/doc/draft-li-quic-minimum-rtt-estimation/ > HTMLized: > https://datatracker.ietf.org/doc/html/draft-li-quic-minimum-rtt-estimation > > > Abstract: > > In traditional acknowledgment mechanisms, the sender frequently > "pulls" ACK packets, resulting in significant protocol control > overhead. This leads to wasted CPU and I/O resources, contention for > packet spectrum on half-duplex links (e.g., WLAN), and reverse-path > congestion in asymmetric links (e.g., satellite network). Reducing > the number of ACKs is essential in scenarios where ACK overhead is > non-negligible. However, a lower ACK frequency can introduce biases > in delay estimation, such as overestimating the minimum round-trip > time (minRTT). This document proposes how to calibrate the > estimation of the minRTT under low ACK frequency conditions. > > > > The IETF Secretariat
