Networks & The Internet
How packets cross oceans through submarine fiber-optic cables, navigate 115,000 autonomous networks via BGP, and resolve domain names to encrypted sockets in milliseconds.
Pieces in this series
How the Internet Actually Works
Submarine fiber cables, autonomous systems, BGP path routing, and the physics of packet switching
The internet is not a mystical cloud or a satellite mesh. It is a physical lattice of 500+ undersea fiber-optic cables and 115,000 independent commercial networks called Autonomous Systems, dynamically routing 1,500-byte packets via Border Gateway Protocol (BGP).
What Happens When You Type a Website Address
URL parsing, recursive Anycast DNS, ARP, the TCP 3-way handshake, TLS 1.3 key exchange, and browser DOM rendering
When you press Enter on a URL, your device triggers an orchestrated millisecond cascade across all seven layers of the OSI model: parsing the URI scheme, traversing recursive Anycast DNS, resolving local hardware MAC addresses with ARP, negotiating a TCP handshake and 1-RTT TLS 1.3 cryptographic session, multiplexing HTTP/2 binary streams, and executing the critical browser rendering pipeline.
How Packets Actually Travel Across the Internet
From MTU slicing and IP headers to BGP router forwarding, submarine fiber lasers, and TCP reassembly
The internet does not transmit continuous files or dedicated open telephone wires. Every video stream, webpage, database query, and chat message is chopped into microscopic digital chunks called packets—typically 1,500 bytes each (the Maximum Transmission Unit). A packet's transcontinental journey is an astonishing feat of decentralized relay physics: encapsulated into Ethernet frames with hardware MAC addresses, stamped with 32-bit or 128-bit IP destinations, evaluated by tier-1 core routers in nanoseconds using Longest Prefix Match algorithms, modulated into infrared laser pulses flashing through glass fibers across ocean floors, and reassembled by TCP sliding-window state machines.