How Networks Work: From Cable to Cloud

What's inside

1. Level 1: What a Network IsFree
   Learn what a computer network is: devices, links, packets and the idea of addresses, and see your own computer's network connection for the first time.
2. Level 2: The OSI and TCP/IP ModelsFree
   Understand how the OSI and TCP/IP layer models break networking into separate jobs, and why engineers use them to talk about problems and fix them.
3. Level 3: Ethernet, MAC Addresses and Switches
   Learn how Ethernet frames carry data across a local network, what a MAC address is, and how a switch learns where to send each frame.
4. Level 4: ARP: Finding MACs from IP Addresses
   Learn how ARP turns an IP address on the local network into a MAC address, and inspect your computer's ARP cache.
5. Level 5: Wi-Fi Basics
   Understand how Wi-Fi carries the same Ethernet-style frames over radio: access points, SSIDs, frequency bands, channels, signal strength and security modes.
6. Level 6: IPv4 Addresses and Private Ranges
   Learn how a 32-bit IPv4 address is written, which address ranges are private, loopback or special, and why your laptop's address is probably not the one the internet sees.
7. Level 7: Subnet Masks, CIDR and Worked Subnetting
   Learn how subnet masks and CIDR prefixes split an address into network and host parts, and work out subnets by hand.
8. Level 8: IPv6 in Outline
   Get a working outline of IPv6: why it exists, how its addresses are written and shortened, and which address types you will see on your own machine.
9. Level 9: Routing and Default Gateways
   Learn how a host decides whether a destination is local or remote, how the default gateway and routing tables forward packets hop by hop, and how to trace that path.
10. Level 10: TCP, UDP, Ports and the Handshake
    Learn how ports deliver data to the right application, how TCP and UDP differ, and what the TCP three-way handshake looks like on the wire.
11. Level 11: DNS Resolution and Record Types
    Learn how DNS turns names into addresses through resolvers, root, TLD and authoritative servers, and query the common record types yourself.
12. Level 12: DHCP and Address Leases
    Learn how DHCP hands out IP addresses, gateways and DNS servers automatically through the discover, offer, request, acknowledge exchange.
13. Level 13: NAT at Your Home Router
    Learn how network address translation lets many private devices share one public address, and what that means for incoming connections.
14. Level 14: HTTP, HTTPS and TLS Certificates
    Learn how HTTP requests and responses work, how TLS encrypts and authenticates HTTPS, and how to inspect both with curl.
15. Level 15: VPNs and Encrypted Tunnels
    Learn how VPNs build encrypted tunnels over the internet for remote access and site-to-site links, and how they change your routes and DNS.
16. Level 16: Firewalls and Security Groups
    Learn how firewalls filter traffic by address, port and connection state, from your laptop's host firewall to cloud security groups.
17. Level 17: Cloud Virtual Networks
    See how cloud virtual networks such as AWS VPCs and Azure VNets map onto everything so far: CIDR blocks, subnets, route tables, gateways, NAT and security groups.
18. Level 18: Latency, Bandwidth and Packet Loss
    Learn what latency, jitter, bandwidth and packet loss mean, how they differ, and how to measure each one from your own computer.
19. Level 19: Bottom-Up Troubleshooting Method
    Apply a repeatable method that works up the layers, from link to IP to DNS to application, to find real network faults quickly.
20. Level 20: Final Challenge: Cable to Cloud Exam
    A comprehensive final challenge covering the whole course: following a request from your laptop to a cloud web server, and solving mixed faults on the way.

Access

The first 2 levels are free with a free account. Every level, the podcast edition and the AI tutor come with All Access at £4.99/month or any Creator plan — see pricing.

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