nanog mailing list archives

Re: New minimum speed for US broadband connections


From: "Livingood, Jason via NANOG" <nanog () nanog org>
Date: Tue, 1 Jun 2021 13:28:54 +0000

I have seen a lot of questions about what is needed for video/eLearning/telehealth. IMO the beauty of those apps is 
that they use adaptive bitrate protocols and can work in a wide range of last mile environments – even quite acceptably 
via mobile network while you are in transit. In my experience most of the challenges people experience are due to home 
LAN (especially WiFi) issues, with working latency an underlying issue (aka latency under load).

Some recent papers from NetForecast on video conferencing 
(https://www.netforecast.com/wp-content/uploads/NFR5137-Videoconferencing_Internet_Requirements.pdf) and eLearning 
(https://www.netforecast.com/wp-content/uploads/NFR5141-eLearning-Bandwidth-Requirements.Final_.pdf) were based on 
observed actual usage rather than theoreticals. What caught my eye was their unique focus in the 1st paper in Figure 8 
– laying out the rationale for a network “latency budget”. In essence, after 580 ms of delay someone will notice audio 
delay and feel the session is bad. A conference platform’s clients & servers may use up 300 ms of their own in 
processing, leaving about 280 ms for the network. If you working latency starts to exceed that on the LAN (not 
uncommon) then user QoE degrades.

JL

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