Flow-control-wise, if you do nothing (rely on the notification of the expired data to trigger the other endpoint to open up more stream and connection flow control so you can send more actual data), you end up underutilizing your bandwidth after the expiration event. You are waiting for 1 RTT (at least) before you can send additional (unexpired) data – not the best thing, especially for low-latency media streaming and especially while recovering from a hiccup that caused the expiration.
* Igor From: Yongyi Yu <[email protected]> Sent: Friday, September 30, 2022 3:24 AM To: Lubashev, Igor <[email protected]> Cc: Tommy Pauly <[email protected]>; Ryan Hamilton <[email protected]>; [email protected]; 陈鉴平 <[email protected]>; 景君羡 <[email protected]>; 刘天一 <[email protected]> Subject: Re: RE: RE: [External] New Version Notification for draft-chen-quic-quicu-01.txt Hi Igor, Currently the data expired is treated just as normally received so the receiver will enlarge the flow control window accordingly as usual. And we really miss out the case where some data blocks are so large that they exceed the flow control window size. Will a negotiation to decide the minimum flow control window size during handshake help deal with this, since all data blocks then would have size not exceeding the minimum flow control window size? About the APIs, we hope to provide an additional API to receive data blocks. But the receiver could also read a byte stream by buffering data blocks received and reading content from them. This could be implemented by the transport layer and the application layer could be not aware of it. Thanks, Yongyi. From: "Lubashev, Igor"<[email protected]<mailto:[email protected]>> Date: Wed, Sep 28, 2022, 00:11 Subject: RE: RE: [External] New Version Notification for draft-chen-quic-quicu-01.txt To: "Yongyi Yu"<[email protected]<mailto:[email protected]>> Cc: "Tommy Pauly"<[email protected]<mailto:[email protected]>>, "Ryan Hamilton"<[email protected]<mailto:[email protected]>>, "[email protected]<mailto:[email protected]>"<[email protected]<mailto:[email protected]>>, "陈鉴平"<[email protected]<mailto:[email protected]>>, "景君羡"<[email protected]<mailto:[email protected]>>, "刘天一"<[email protected]<mailto:[email protected]>> Yongyi, Without going into the question of whether partially reliable streams are necessary (as Matt said, Meta implemented them but is not using that implementation in production), here are a few comments I have. 1. Have you thought about the interaction of you draft with stream and connection flow control? 95% of the time I spent on my design was spent on thinking of ways to augment flow control to avoid extra round trips just to open a flow control window, while still ensuring that the resulting protocol is resilient against an adversarial endpoint forcing the peer to commit an unreasonable amount of resources (memory) to the connection. * 1. Our proposal splits a QUIC stream into many data blocks by Boundary Frame. The receiver would provide data to the application layer only when a data block is completely received. Therefore, the application layer needn't be aware of the gap at the expiration point or discard data already read. * 2. Because the stream is split into blocks, the sender could send or expire data by data blocks. Then the transport layer could track the message boundaries instead of the application layer. 1. Section 4.4 Data Receiving of your draft is saying the same. It seems wrong to have the transport protocol specify the behavior of the QUIC library APIs so precisely. It is ok to try to enable a particular library API, but the transport protocol’s specification ought to limit itself to the semantics of bytes on the wire. Very best, * Igor From: Yongyi Yu <[email protected]<mailto:[email protected]>> Sent: Tuesday, September 27, 2022 11:04 AM Hi Igor, Thanks for your replying. Our proposal indeed shares similar ideas with yours, but there are also some difference. We'd like to update our draft to clarify the difference in detail, and to briefly summary here, there are three major points. 1. Our proposal splits a QUIC stream into many data blocks by Boundary Frame. The receiver would provide data to the application layer only when a data block is completely received. Therefore, the application layer needn't be aware of the gap at the expiration point or discard data already read. 2. Because the stream is split into blocks, the sender could send or expire data by data blocks. Then the transport layer could track the message boundaries instead of the application layer. 3. With the introduction of Correlation Frame, we can combine multiple QUIC streams into single data stream while avoiding head of line blocking. This feature could be quite useful in many scenarios, e.g., transmitting both video and audio data through single HTTP response. Please do let me know if you have any further advice, and please do not hesitate to point out if I make any mistakes. Thanks, Yongyi. From: "Lubashev, Igor"<[email protected]<mailto:[email protected]>> Date: Mon, Sep 26, 2022, 00:29 Subject: RE: [External] New Version Notification for draft-chen-quic-quicu-01.txt To: "Yongyi Yu"<[email protected]<mailto:[email protected]>>, "Tommy Pauly"<[email protected]<mailto:[email protected]>> Cc: "Ryan Hamilton"<[email protected]<mailto:[email protected]>>, "[email protected]<mailto:[email protected]>"<[email protected]<mailto:[email protected]>>, "陈鉴平"<[email protected]<mailto:[email protected]>>, "景君羡"<[email protected]<mailto:[email protected]>>, "刘天一"<[email protected]<mailto:[email protected]>> Are you trying to implement something like https://datatracker.ietf.org/doc/html/draft-lubashev-quic-partial-reliability-02<https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/html/draft-lubashev-quic-partial-reliability-02__;!!GjvTz_vk!UnVViQtu5EFoYEbX4UDTPy7y6wuQYa-hikv2VKgCPBioC4NnnTuVE0pxQKeeP9hs7maUF711jPBLmDK9UK2equuu$> or https://datatracker.ietf.org/doc/html/draft-lubashev-quic-partial-reliability-03<https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/html/draft-lubashev-quic-partial-reliability-03__;!!GjvTz_vk!UnVViQtu5EFoYEbX4UDTPy7y6wuQYa-hikv2VKgCPBioC4NnnTuVE0pxQKeeP9hs7maUF711jPBLmDK9UP9Exa9q$>? (The -02 and -3 versions have somewhat different properties, and some people prefer -02 version.) * Igor From: Yongyi Yu <[email protected]<mailto:[email protected]>> Sent: Friday, September 23, 2022 1:11 AM To: Tommy Pauly <[email protected]<mailto:[email protected]>> Cc: Ryan Hamilton <[email protected]<mailto:[email protected]>>; [email protected]<mailto:[email protected]>; 陈鉴平 <[email protected]<mailto:[email protected]>>; 景君羡 <[email protected]<mailto:[email protected]>>; 刘天一 <[email protected]<mailto:[email protected]>> Subject: Re: [External] New Version Notification for draft-chen-quic-quicu-01.txt Thanks for your replying. I agree "partial reliability" fits our draft better, since we do retransmit lost data and provide in-order transmission. And, our proposal could be compatible with H3, should we clarify the behavior in the draft? Please do let me know if you have any further advice. Thanks, Yongyi. From: "Tommy Pauly"<[email protected]<mailto:[email protected]>> Date: Thu, Sep 22, 2022, 11:32 Subject: Re: [External] New Version Notification for draft-chen-quic-quicu-01.txt To: "Ryan Hamilton"<[email protected]<mailto:[email protected]>> Cc: "于涌溢"<[email protected]<mailto:[email protected]>>, "[email protected]<mailto:[email protected]>"<[email protected]<mailto:[email protected]>>, "陈鉴平"<[email protected]<mailto:[email protected]>>, "景君羡"<[email protected]<mailto:[email protected]>>, "刘天一"<[email protected]<mailto:[email protected]>> I noticed that this draft does reference RFC 9221, and DATAGRAM frames. If I’m understanding correctly, it seems like this is trying to define an approach for what’s more commonly referred to as “partial reliability”, which was something DATAGRAM explicitly didn’t try to include. If this is the case, I think it would be useful to reframe the document in terms of that, since the heavy use of “unreliable” is quite confusing. It also isn’t clear to me how this proposal would work with specific application protocols on top of QUIC — is this something that’s meant to be compatible with H3, or is it for entirely separate use cases? Best, Tommy On Sep 21, 2022, at 3:17 PM, Ryan Hamilton <[email protected]<mailto:[email protected]>> wrote: QUIC has support for unreliable data via the DATAGRAM frame, RFC 9221<https://urldefense.com/v3/__https:/www.rfc-editor.org/info/rfc9221__;!!GjvTz_vk!VHC6upHgCOojEiYhln21JerQBPYz1cbPLifo7gevl5sFTM-5qEoTkN-TxpvuKG1MQfnSBiZsXrrQ2OC2qjWu1aws$>. It seems that this new proposal attempts to add unreliable data support not to QUIC, but to QUIC *streams*. QUIC streams, of course, offer a reliable, in-order, sequence of bytes. Did you consider starting with DATAGRAMs, and building from there instead? Cheers, Ryan On Wed, Sep 21, 2022 at 1:14 AM 于涌溢 <[email protected]<mailto:[email protected]>> wrote: Deal all, We would like to introduce an extension of the QUIC protocol for unreliable data transmission called QUIC Unreliable (QUICU) . The following draft is submitted for your consideration and comments. We would also like to present this at IETF 115 to discuss further. To summarize on this draft: it describes an extension of the QUIC protocol for unreliable data transmission called QUIC Unreliable (QUICU), which mainly through the definition and use of three new types of frames, namely the Expire Offset Frame, Boundary Frame, and Correlation Frame. The main purpose of this extension is to reduce data delivery delay. Through controlling the timing and scope of packet losses, QUICU reduces useless transmission to improve transmission efficiency, reduces head-of-line blocking to improve transmission timeliness, which are beneficial to delay-sensitive applications, especially audio and video applications. This document describes the motivation, the operations, and the wire formats of the three new types of frames. Link to html: https://datatracker.ietf.org/doc/html/draft-chen-quic-quicu-01<https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/html/draft-chen-quic-quicu-01__;!!GjvTz_vk!UnVViQtu5EFoYEbX4UDTPy7y6wuQYa-hikv2VKgCPBioC4NnnTuVE0pxQKeeP9hs7maUF711jPBLmDK9UH7juF7a$> Please feel free to reach us for any comments or questions on this. Thanks, Yongyi. ---------- Forwarded message --------- From: [email protected]<mailto:[email protected]> Date: Mon, Sep 19, 2022, 20:54 Subject: [External] New Version Notification for draft-chen-quic-quicu-01.txt To: "Jianping Chen"<[email protected]<mailto:[email protected]>>, "Junxian Jing"<[email protected]<mailto:[email protected]>>, "Tianyi Liu"<[email protected]<mailto:[email protected]>>, "Yongyi Yu"<[email protected]<mailto:[email protected]>> A new version of I-D, draft-chen-quic-quicu-01.txt has been successfully submitted by Yongyi Yu and posted to the IETF repository. Name: draft-chen-quic-quicu Revision: 01 Title: An Unreliable Extension to QUIC Document date: 2022-09-19 Group: Individual Submission Pages: 10 URL: https://www.ietf.org/archive/id/draft-chen-quic-quicu-01.txt<https://urldefense.com/v3/__https:/www.ietf.org/archive/id/draft-chen-quic-quicu-01.txt__;!!GjvTz_vk!UnVViQtu5EFoYEbX4UDTPy7y6wuQYa-hikv2VKgCPBioC4NnnTuVE0pxQKeeP9hs7maUF711jPBLmDK9UHAAR-M6$> Status: https://datatracker.ietf.org/doc/draft-chen-quic-quicu/<https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/draft-chen-quic-quicu/__;!!GjvTz_vk!UnVViQtu5EFoYEbX4UDTPy7y6wuQYa-hikv2VKgCPBioC4NnnTuVE0pxQKeeP9hs7maUF711jPBLmDK9UOSj5Mnd$> Htmlized: https://datatracker.ietf.org/doc/html/draft-chen-quic-quicu<https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/html/draft-chen-quic-quicu__;!!GjvTz_vk!UnVViQtu5EFoYEbX4UDTPy7y6wuQYa-hikv2VKgCPBioC4NnnTuVE0pxQKeeP9hs7maUF711jPBLmDK9UCSdkj_s$> Diff: https://www.ietf.org/rfcdiff?url2=draft-chen-quic-quicu-01<https://urldefense.com/v3/__https:/www.ietf.org/rfcdiff?url2=draft-chen-quic-quicu-01__;!!GjvTz_vk!UnVViQtu5EFoYEbX4UDTPy7y6wuQYa-hikv2VKgCPBioC4NnnTuVE0pxQKeeP9hs7maUF711jPBLmDK9UBzjmjRr$> Abstract: QUIC Unreliable (QUICU) is an extension of the QUIC protocol for unreliable data transmission, mainly through the definition and use of three new types of frames, namely the Expire Offset Frame, Boundary Frame, and Correlation Frame. The main purpose of this extension is to reduce data delivery delay. Through controlling the timing and scope of packet losses, QUICU reduces useless transmission to improve transmission efficiency, reduces head-of-line blocking to improve transmission timeliness, which are beneficial to delay- sensitive applications, especially audio and video applications. This document describes the motivation, the operations, and the wire formats of the three new types of frames. The IETF Secretariat
