Summary
Highlights
The video begins by explaining that the content you're watching travels thousands of miles from a Google Data Center. It quickly dismisses satellites as an efficient means of data transmission due to the immense distance (44,000 miles) and the resulting significant latency, which is unacceptable for most internet applications.
Instead of satellites, the internet relies on a complex network of optical fiber cables to connect data centers to your device. Whether through cellular data or Wi-Fi, your device ultimately connects to this optical fiber network.
The video you're watching is stored in a solid-state device within a server in a data center. A server is a powerful computer providing content upon request. To transfer this data, every device connected to the internet has a unique IP address, similar to a home address, which ensures information reaches its correct destination.
Since remembering numerous IP addresses is difficult, domain names (like youtube.com) are used as easier-to-remember aliases. The internet uses a 'huge phone book' called DNS (Domain Name System) to translate these domain names into their corresponding IP addresses. ISPs often manage DNS servers.
When you enter a domain name, your browser requests the IP address from the DNS server. Once obtained, the request is forwarded to the data center's server. Data is then transferred as light pulses via optical fiber cables, which are laid and maintained by global companies, often across challenging terrains and under the sea. These cables are the backbone of the internet.
Optical fiber cables extend to your doorstep and connect to a router, which converts light signals into electrical signals for devices connected via Ethernet. For cellular data, the signal travels from the optical cable to a cell tower and then to your phone as electromagnetic waves.
ICANN (located in the USA) is an organization that manages internet aspects like IP address assignment and domain name registration. The internet's efficiency in transmitting data is due to how data (zeros and ones) is chopped into small chunks called 'packets'. Each packet contains video bits, a sequence number, and the IP addresses of the server and your phone, allowing them to be routed independently and reassembled upon arrival. Lost packets are re-sent upon acknowledgment.
Protocols are essential for managing the complex flow of data packets, setting rules for conversion, address attachment, and routing. Different applications use different protocols to ensure smooth and accurate data transmission.