Cisco CCST Networking

Networks work because everyone agrees on layers and rules. This module covers the OSI and TCP/IP models, what each layer adds to your data, and how TCP, UDP and port numbers deliver a request to the right application.

• The OSI and TCP/IP models side by side
• Encapsulation: how data gains headers on the way out
• TCP and UDP: reliable against fast
• Ports and the applications behind them
• DNS, DHCP, HTTP and the protocols you meet daily
• Placing a symptom on the right layer

You build A layer-by-layer trace of one web page request, from click to response.

Every device needs an address and a way to tell who is local. You learn to read an IPv4 address, apply a subnet mask and slash notation, and work out which hosts share a network without reaching for a calculator.

• Binary and decimal in an IPv4 address
• Network and host portions of an address
• Subnet masks and slash notation
• Finding the network address and host range
• Default gateways and why hosts need one

You build A worked subnet plan for a small site, with a table of every range.

Not every address is reachable from the internet, and not every network still runs on IPv4. This module compares private and public ranges, explains how address translation bridges them, and introduces IPv6 prefixes and their notation.

• Private and public IPv4 ranges
• Network address translation in plain terms
• Link-local and loopback addresses
• Reading and shortening IPv6 addresses
• IPv6 prefixes and what the length tells you
• Static and dynamically assigned addresses

You build An address audit of a home or lab network that classifies every address found.

The physical layer is where many problems begin. You identify copper and fiber cables and their connectors, compare Wi-Fi bands and cellular links, and describe the endpoints, including IoT devices, that attach to a network.

• Twisted pair, fiber and coaxial cable
• Connectors and the ports they fit
• Wi-Fi bands, channels and range
• Cellular and other wireless links
• Endpoints from laptops to IoT sensors
• Checking client network settings on common systems

You build A cable and connector reference sheet built from real hardware.

Learn what the boxes in a network closet actually do. You read status lights and port labels, see how a switch builds its MAC table and how a router uses its default gateway, then cable equipment correctly from a diagram.

• What a switch does with frames and MAC addresses
• What a router does with packets and routes
• Access points, firewalls and where they sit
• Ports, SFP modules and uplinks
• Reading status lights and port indicators
• Cabling equipment from a network diagram

You build A lab cabled from a diagram, with every link verified.

Fixing a network is a repeatable process, not guesswork. You follow a troubleshooting method, test connectivity with ping, traceroute and nslookup, inspect device state with show commands, and watch real traffic in Wireshark.

• A troubleshooting method from symptom to fix
• Ping and traceroute: what each result tells you
• Resolving names with nslookup
• Capturing and filtering packets in Wireshark
• Show commands for interfaces and addresses
• Reaching a device by console and SSH

You build A fault log for three planted faults, each traced to its cause and fixed.

A network that works must also be defended. You see how a firewall decides what to allow, what confidentiality, integrity and availability mean on a network, how authentication, authorization and accounting fit together, and how to secure a home router’s Wi-Fi.

• The CIA triad applied to a network
• How a firewall filters traffic
• Authentication, authorization and accounting
• Multi-factor authentication
• WPA2 and WPA3 on a home router
• Common threats to small networks

You build A hardening checklist applied to a real home or lab router.

Take an unfamiliar small network and make sense of it. You survey it, record its addresses and links, test it layer by layer, fix what is wrong and hand it over with notes that another technician can follow.

• Surveying an unfamiliar network
• Recording addresses, devices and links
• Testing connectivity layer by layer
• Explaining a fault to a non-technical user
• Writing handover notes

You build A network document set for a small site, with a verified fix for one fault.