Hacker News Reader

Comment by no-one-yet | Hacker News Reader

While the internet is fairly reliable, I see a value in having alternative that doesn't depend on the internet.

Reminds me of a tweet that I saw last year in which someone said:

"In breaking news moments like this, there should be a type of podcast you can listen to in real time, easily accessible for free."

To which someone replied: "Radio. You're thinking of radio."

https://twitter.com/jodyavirgan/status/1234998790139940865

Or at least an alternative that doesn't require an internet connection at the edge. I really don't care if the messages are actually routed via the internet once they get to the "carrier" but there should be a way to get messages in/out using just cellular or sattelite for when you can't get a reliable internet connection.

I suspect that even SMS are routed over the internet. I’m not sure how else they could easily be exchanged between operators.

It looks like they go over the cell network rather than the Internet, but they have lots of the same concepts. SMSCs act like routers, for example.

https://en.wikipedia.org/wiki/SMS#Interconnectivity_with_oth...

But in some circumstances is that PLMN/PTSN interconnectivity just an “application layer” on top of existing IPv4/v6 infrastructure...similar to how VoIP/SIP works?

But the end users can send & receive messages when there's no 3G/4G data signal, just good old GSM. Admittedly it's pretty rare to have a GSM single and no data, but it can happen

I was talking more about what happens after the SMS reaches the tower. How is that message delivered to the cell tower that the receiver is affiliated with, especially if that tower is owned by a different operator?

They traverse the SS7 signaling network. This is the network that routes voice calls on the POTS lines.

Oh interesting...but it also sounds like SIGTRAN provides signaling using SCTP associations over the Internet Protocol?

Same idea just much older protocols. No security, plain text, easy to spoof just like caller ID which also uses SS7.

Reply on news.ycombinator.com