[LINK] Propose Video Bandwidth Limit During COVID19 Emergency

[Paul Brooks]

On 22/03/2020 9:04 am, Tom Worthington wrote:
> On 20/3/20 5:04 pm, Paul Brooks wrote:
>
>> Actually, videoconferencing ... I'm not convinced its a problem ...
>
> If most people in Australia are at home, what proportion of them can be on a video
> conference at the same time?

Local effects, gated by the capacity of each home's link and how many people in the
home are on VCs simultaneously. The main effect is congestion of the local house's
access line. Right now I have 3 of the 4 occupants on conference calls either audio or
video quite successfully on a 50/20 link, leaving plenty of bandwidth to spare, but
slower access lines may not be able to support so many simultaneously.

If its one person per house, then a very large proportion of Australia could on VCs at
the same time, outside peak hours - perhaps up to 30 - 40% which would be highly
unlikely in practice.

Secondary effects may be congestion of the POI, and the general
interstate/international backbone, however most VCs are done during daytime or
non-peak hours, when the POI links and backbone/backhaul links are at 50% utilisation
or thereabouts. Very few videoconferences amongst the Australian population would
occur during the Internet busy-hours of 8pm-10pm. Those hours are peak hours on local
access lines primarily due to one-way intertainment streaming, which does auto-adjust
up, and the main services have made steps to reduce their bandwidth usage by 25% or so
per user.

More to the point, for backhaul, longhaul and POI links, if traffic was to rise to the
point that congestion was close (e.g. due to a rise in VC use from homes), capacity
upgrades can occur within hours, days or at worst around 6-8 weeks if new DWDM
transmission linecards are required - there is so much unused fibre lying around that
can be quickly lit up that congestion in the backbone should never be apparent to the
general population.

You can check out the utilisation and diurnal curve of one mid-sized ISP at
https://www.aussiebroadband.com.au/cvc-graphs/. Note that almost all of them, actual
utilisation between 8am and 6pm is roughly 50% used, 50% idle. That 50% idle capacity
can support a very large proportion of the population on VCs during those hours,
without even needing augmentation of the backbones/backhauls.

The best way to limit congestion of Internet infrastructure is for the entertainment
streaming services to limit their usage, as they are doing described at:

https://www.itnews.com.au/news/netflix-to-slash-traffic-across-europe-to-relieve-virus-strain-on-internet-providers-539668

https://www.itnews.com.au/news/youtube-amazon-prime-forgo-streaming-quality-to-relieve-european-networks-539673

Paul.