Skip to content
All paths

Learning path · 5 parts

Networks in Depth

The layers the first tour skipped and the extensions built on top — how bits reach the wire and the airwaves, how independent networks agree on routes, how the web reinvented its transport, and how private networks span the public internet.

About 1 hour of reading · 10 widgets

Start with Ethernet: How Machines Share a Wire
  1. Networks & the Internet10 min

    Part 1: Ethernet: How Machines Share a Wire

    The layer beneath IP: how a packet physically crosses a local network, why every device has a 48-bit MAC address, how a switch learns where each machine lives, and how ARP turns an IP into the MAC needed to actually deliver a frame.

  2. Networks & the Internet10 min

    Part 2: Wi-Fi: Networking Through the Air

    How Wi-Fi carries a link-layer over a shared radio medium, why it must avoid collisions instead of detecting them, and why the rated speed on the box is a ceiling everyone shares, not a promise to each device.

  3. Networks & the Internet10 min

    Part 3: BGP: How the Internet's Networks Agree on Routes

    The internet is a mesh of ~75,000 independently run networks. BGP is how they advertise reachable prefixes to each other and negotiate routes — driven by business policy, not shortest path, and held together by trust.

  4. Networks & the Internet10 min

    Part 4: HTTP/2 and HTTP/3: Reinventing the Web's Transport

    The verbs and headers of HTTP are the same as 1997, but the transport under them was re-engineered twice. HTTP/2 multiplexes many streams over one TCP connection; HTTP/3 throws out TCP entirely for QUIC over UDP to escape head-of-line blocking.

  5. Networks & the Internet10 min

    Part 5: VPNs and Tunneling

    A VPN builds an encrypted tunnel across the public internet by wrapping one network's packets inside another's — encapsulation — so a remote device can reach a private network as if plugged into the office wall.