How data moves Subnetting, transport with TCP and UDP, switching inside a network, routing between networks, dynamic routing with OSPF, then the journey of opening a site from start to end.
Lessons 0 Overview Subnetting, transport with TCP and UDP, switching inside a network, routing between networks, dynamic routing with OSPF, then the journey of opening a site from start to end. 1 Subnets: masks and splitting a network The most important arithmetic skill in networking: from the prefix you get the network address, the broadcast and the host count, and you split any network into equal or unequal parts. With a calculator that shows the bits as they change. 2 Transport: TCP, UDP and ports The IP address gets you to the machine; the port gets you to the program. You learn when to pick registered mail (TCP) and when a fast broadcast (UDP), and you watch the three-way handshake message by message. 3 Switching and VLANs How a switch learns where each device is, how one set of cables becomes isolated networks with VLANs, and why STP blocks ports on purpose. 4 Routing and address translation (NAT) How a router picks the road with its routing table and longest match, how static routes, OSPF and BGP differ, and how your whole home goes out on one public address through NAT. 5 Dynamic routing: OSPF step by step How routers build the network map on their own: Hello messages and neighbours, the link-state database, the Dijkstra algorithm that finds the cheapest path by cost, areas and the designated router, then the commands that prove it all works. It includes a script that finds the path the way a router does. 6 What happens when you open a website? The question that ties everything together: from the moment your phone joins the network until the page shows up. Six stops in order: DHCP, ARP, DNS, TCP, TLS, HTTP, and you see every message for yourself. 7 Wrap-up and resources The takeaways and glossary of this track.