Tech World Software SchoolTWSS

from first concept to confident practice

Networking

Follow data from a local link to the services that power the web.

Start learning 15 lessons · first lesson about 20 min · free · no account needed
About this track

Learn how networks really move data, by playing the part of each device: be a switch filling its table, a router choosing a route, a resolver walking the DNS tree. You'll go from Ethernet and subnets through routing, TCP, DNS and TLS, then use it all to diagnose broken networks. Along the way you'll practice what network engineers really do: reading tool output, decoding packets, planning subnets and finding the fault in a config.

Before you start
  • No networking or programming experience needed.
  • A modern browser with JavaScript enabled.

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  1. Unit 1 · 0/5 lessons

    Network foundations

    Meet protocol layers, real hardware, frames, IPv4 networks and ARP. Badge: Packet mapper

    1. 0x001Understand network layersSee how protocols divide a message into manageable jobs. 20 min 20 min
    2. 0x102Meet the hardware of the InternetSee the real devices and cables behind the ideas, from your router to the sea floor. 25 min 25 min
    3. 0x203Deliver frames on a local networkDistinguish link-layer addresses from network addresses. 20 min 20 min
    4. 0x304Read IPv4 addresses and prefixesUse a network prefix to identify addresses in the same subnet. 30 min 30 min
    5. 0x405Connect IP addresses to the local linkSee how ARP finds the MAC address of the next hop. 15 min 15 min
  2. Unit 2 · 0/5 lessons

    Routing and transport

    Forward packets, share addresses, and see how TCP and UDP carry data. Badge: Route finder

    1. 0x506Choose a route for a packetFollow next hops and understand longest-prefix matching. 25 min 25 min
    2. 0x607Join a network and share an addressSee how devices get addresses and how NAT and IPv6 handle the shortage. 25 min 25 min
    3. 0x708Compare TCP and UDPLearn what transport protocols add above IP. 25 min 25 min
    4. 0x809Keep data flowing with TCPPlay with sliding windows, retransmission and congestion control. 25 min 25 min
    5. 0x9010Measure latency and throughputFind out why more bandwidth doesn't always make the web faster. 20 min 20 min
  3. Unit 3 · 0/3 lessons

    Network services

    Resolve names, secure a request and control traffic. Badge: Web navigator

    1. 0xA011Resolve names with DNSFollow the lookup from a name to a network address. 25 min 25 min
    2. 0xB012Follow a web request safelyConnect DNS, transport, HTTP, and TLS in a browser request. 30 min 30 min
    3. 0xC013Control traffic with firewallsWrite rules that let the right traffic through and stop the rest. 20 min 20 min
  4. Unit 4 · 0/2 lessons

    Diagnose and connect

    Find faults layer by layer, then follow one click across the Internet. Badge: Network detective

    1. 0xD014Diagnose a broken networkWork up the layers with real tools to find a root cause. 30 min 30 min
    2. 0xE015Follow one click across the InternetPut every layer together in the journey of a single request. 25 min 25 min