private 5G networks?

Wed Dec 1 17:04:46 UTC 2021

On Wed, Dec 01, 2021 at 12:23:46PM +0100, Baldur Norddahl wrote:

[ snip ]

> 
> And yes these are low bandwidth but on the other hand often stretch wifi to
> the very limits on the distance between bases. I am not claiming this is
> the same use case as a warehouse. I am pointing out that the argument that
> a system critical implementation _must_ be based on licensed frequencies
> does not hold as nothing could be more critical than a system that prevents
> trains from colliding.

The public transit market of rail industry has been in discussions for a while re:
mitigation measures (such as licensed band) against possible interference on CBTC
signalling data links.  It is however a standardization issue (much like we here
in internet infrastructure continue to discuss improvements to BGP and its lingering
security issues, nothing is perfect in every industry I suppose..).

> 
> I do claim that the reason these metro train systems can boast of a very
> high uptime is not that it would be especially hard to jam their wifi based
> systems.

Moreover, the degree of disruption to loss of data on CBTC is further dependent upon
individual deployment cases.  One example is system falling back to ABS (non-moving
block) operation during loss of confirmations on movement authorities, with trains
continuing to run, albeit at reduced capacity.

Anyhow it has not been a serious enough issue from operational and security standpoints
to date to warrant immediate concern.  It's a standardization matter.

James