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Low Latency, Low Loss, and Scalable Throughput (L4S) Internet Service: RFC 9330

datatracker.ietf.org

81–90 of 91 posts

Re: Low Latency, Low Loss, and Scalable Throughput (L4S) Internet Service: RFC 9330

#81

In case anyone else was curious, I found a brief demo of this in use with a video feed from an RC car: https://www.youtube.com/watch?v=RZmS10djDEg

Found another looking up L4S https://www.youtube.com/watch?v=l6WSMU71Ub8

Re: Low Latency, Low Loss, and Scalable Throughput (L4S) Internet Service: RFC 9330

#82

If you are interesting in learning more on L4S, there is a webinar series starting today on understandinglatency.com. Some of the authors of L4S, the head of Comcasts L4S field trail and some critical voices are speaking

Fixed link https://www.understandinglatency.com/ to be clickable.

Re: Low Latency, Low Loss, and Scalable Throughput (L4S) Internet Service: RFC 9330

#86
post #37

Earlier quoted context omitted.

TCP congestion control can use this new signal, if present. An update to the TCP protocol which allows it to do is going through IETF at present: https://datatracker.ietf.org/doc/draft-ietf-tcpm-accurate-ec...

Can anyone guess a timeline when this will be available in OSes, middleboxes and whatnot? So when can we reap the benefits?

The slowest part is likely to be the network component, and there you can look at the experimental deployment by Comcast, that others have linked to in comments. So far I have not heard of moves by other network providers. Apple already has experimental L4S support for QUIC and TCP: https://developer.apple.com/documentation/network/testing_an...

Re: Low Latency, Low Loss, and Scalable Throughput (L4S) Internet Service: RFC 9330

#87
post #43

What does this mean in practicality as a user? Will e.g. video calls be closer to real-time? There's usually about 0.5-1 second delay which leads to a lot of hiccups and interruptions when speaking with each other. What other application uses will be significantly improved?

This only resolves one source of delay in one ISP's network. Internet video chat is a mess because it's "best effort" at every level.

The need for Wi-Fi adds latency, especially when a laptop is on battery

To deal with NAT many video chat services relay through cloud servers adding latency.

https://hpbn.co/wifi/#measuring-and-optimizing-wifi-performa...

Re: Low Latency, Low Loss, and Scalable Throughput (L4S) Internet Service: RFC 9330

#88

Im confused, everyone here is talking about improvements to video conferencing and streaming, but those applications use UDP instead of TCP so I don’t understand how this will change anything.

You ever get that robotic latency thing? That’s because of udp and the stream allowing dropped packets at all. It’s a horrible experience.

You can use udp and still do much better through things like adapting reed solomon or simple XOR error correction to packet loss statistics.

Re: Low Latency, Low Loss, and Scalable Throughput (L4S) Internet Service: RFC 9330

#90
post #51
post #42

How does this interact with eg BBR?

BBRv1 doesn't take ECN into account. BBRv2/v3 do, and it's mentioned in the RFC: Scalable variants are under consideration for more recent transport protocols (e.g., QUIC), and the L4S ECN part of BBRv2 [BBRv2] [BBR-CC] is a Scalable congestion control intended for the TCP and QUIC transports, amongst others.

Thanks. I saw that mention in the article, but couldn't really make much of it.
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