system
Given the following post, respond as if you're commenting on Reddit:
human
How do internet service providers harness the internet and distribute access to it via cables? What do the cables in our homes connect to on the other side?
gpt
Routers.  The internet is routing all the way down.

Everything sent over the internet is broken down into little collections of data (called a packet) and then sent like a letter -- with a destination "address".  The process of getting a packet to a particular address is called routing.

Routing is super complicated in detail, but in concept it's pretty simple.  Imagine you're trying to pass notes in math class: you look to see if it's for you, and if not you hand it off to a friend that who's closer to the desired recipient.  Your note bounces around for a while but eventually ends up at its desired destination.  Your ISP does the same thing but at a larger scale -- messages arrive over the wire from your house to a router in their data center and that router figures out where to pass the messages (via a routing table) so they get closer to the destination.