[Bloat] [Rpm] [Starlink] [LibreQoS] On FiWi

rjmcmahon rjmcmahon at rjmcmahon.com
Wed Mar 15 15:39:33 EDT 2023

> I have sometimes thought that LiFi (https://lifi.co/) would suddenly
> come out of the woodwork,
> and we would be networking over that through the household.

I think the wishful thinking is "coming from woodwork" vs coming from 
the current and near future state of engineering. Engineering comes from 
humans solving problems who typically get paid to do so.

FiWi would leverage SFP tech. The Fi side of FiWi comes from mass NRE 
investments into the data center networks. The Wi side from mass 
investment into billions of mobile phones. Leveraging WiFi & SFP parts 
is critical to success as semiconductors are a by-the-pound business. I 
think a 1X25G VCSEL SFP, which is tolerant to dust over MMF, has a 
retail price of $40 today.  The sweet spot for DC SFP today is driven by 
1x100Gb/s serdes and I suspect angel investors are trying to improve the 
power significantly of the attached lasers. It's been said that one 
order of improvement in lowering laser power gives multiple orders of 
laser MTBF improvements. So lasers, SERDES & CMOS radios are not static 
and will constantly improve year to year per thousands of engineers 
working on them today, tomorrow & on.

The important parts of FiWi have to be pluggable - just like a light 
bulb is. The socket and wiring last (a la the fiber and antennas) - we 
just swap a bulb if it burns out, if we want a different color, if we 
want a higher foot candle rating, etc. This allows engineering cadences 
to match market cadences and pays staffs. Most engineers don't like to 
wait decades between releases so-to-speak and don't like feast & famine 
lifestyles. Moore's law was and is about human cadences too.

I don't see any engineering NRE that LiFi could leverage. Sounds cool 


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