Reporting Packet Receive Timestamps for MOQ

[PFpengfeng]

Currently, BBR is employed as the default congestion control algorithm (CCA) in moq-rs. Other algorithms, such as WebRTC's GCC, may be able to achieve better performance. However, QUIC lacks a mechanism to provide feedback on packet receive timestamps, which is indispensable for GCC. Although [I-D.draft-smith-quic-receive-ts] proposed a solution, it was not adopted. Therefore, could moq implement a mechanism, perhaps through a new control message, to achieve the same objective?

[kixelated]

Hey @PFpengfeng

You might be interested in this Quinn fork that implements receiver timestamps and GCC. I haven't tried it yet. Independently for work, I ported the C++ GCC code to Rust: https://docs.rs/goog_cc/0.1.0/goog_cc/

[PFpengfeng]

Thanks @kixelated
I will test the Quinn fork. But I'm still confused about the implementation of receiver timestamps. QUIC RFC does not define an ack frame with receiver timestamps. If we do want GCC, a mechanism to report packet receive timestamps is the first step. There are two two solutions:

• Using ACK frame like[I-D.draft-smith-quic-receive-ts] which means a new extension to standard QUIC.
• Reporting receiver timestamps by upper layer messages, for example defining a new moq control message. A advantage of this scheme is that we don't need any new extension.

Which solution do you think is better?