Does the government not maintain its own dedicated communication infrastructure between important installations? Or has it all been replaced with public connections?
"It depends." Two data points that I know of first hand:
1) There is a dedicated microwave link between Vandenberg Space Force Base and Edwards Air Force Base. Mil. owned and operated solely for their own use.
2) The US Federal government decided to build a standardized communications network for government/first responders/etc. This is FirstNet. They farmed the build-out to AT&T and gave them 20 MHz of bandwidth (Band 14) but it runs over their standard wireless infrastructure and network but FirstNet traffic gets prioritized.
It’s been a 25 years since I’ve even been remotely exposed to them, but I believe the military currently has a non-classified NIPRnet, a classified secret SIPRnet, and a network called JWICS for top secret.
I think all three are physically seperated from the commercial internet and each other but don’t quote me on it.
