I know that we use radio waves to connect to the modem, but then do the wires run ALL THE WAY across the country, through the ocean, and to the country halfway around the world? And if so, how does that happen in 1-2 seconds?
In: Engineering
The speed of electricity through cables is close to the speed of light. This is why latency (the delay between your signal and the recipient, and back to you) is within the tens of milliseconds, even when communicating across the globe.
When you’re sending and receiving huge amounts of data (like watching a 4K video on YouTube), this miniscule latency adds up, which is why a bunch of smart folks from MIT came up with Content Delivery Networks (CDNs). Half the internet’s traffic is delivered through CDNs, whether you’re surfing facebook, watching YouTube videos, buying Gamestock stock, or spamming the chat in your favorite Twitch stream. CDNs help people avoid *needing* to send and receive data across the globe. Instead, they are huge servers that are constantly synced up with copies of the internet, and located around the world. For instance, if you’re someone from Boston, MA trying to load your Parisian friend’s vacation pictures from Instagram, chances are they’ve been copied (cached) to a CDN server located either directly in Boston, or in NYC. This is done constantly, and your friend’s pictures can be cached within a few hours or a few days of her posting them.
CDNs are also located near internet backbones, which are hubs that data travel through before moving off content, or between major cities. This allows them to download, copy, and upload data super fast.
Latest Answers