- 01Getting Started
- 02Understanding the Operating Modes of Network Devices
- 03Entering Privileged EXEC Mode with enable
- 04Entering Configuration Mode with configure terminal
- 05Renaming the Switch with hostname
- 06Moving Between Modes with exit and end
- 07Entering Port Configuration with interface
- 08Enabling a Port with no shutdown
- 09Assigning an IP Address with ip address
- 10Labeling a Port with description
- 11Viewing the Configuration with show running-config
- 12Listing Interfaces with show ip interface brief
- 13What Is a VLAN? Splitting a Network Logically
- 14Creating a VLAN with vlan
- 15Naming a VLAN with name
- 16Setting the Port Type with switchport mode
- 17Assigning a Port to a VLAN with switchport access vlan
- 18Listing VLANs with show vlan brief
- 19Adding a Static Route with ip route
- 20Viewing the Routing Table with show ip route
- 21Testing Reachability with ping
- 22Tracing the Path with traceroute
- 23Checking OS Information with show version
- 24Checking the Time with show clock
- 25Saving the Configuration with copy running-config startup-config
- 26Saving with write memory (the Short Form)
- 27Setting a Login Message with banner motd
- 28Configuring the Console Line with line console 0
- 29Setting a Password with password
- 30Requiring the Password at Login with login
- 31Configuring Remote Access with line vty 0 4
- 32Creating an Access List with access-list
- 33Checking Access Lists with show access-lists
- 34Viewing the MAC Address Table with show mac address-table
- 35Discovering Neighbors with show cdp neighbors
- 36Viewing the ARP Table with show arp
- 37Understanding Loop Prevention with spanning-tree mode
- 38Rebooting the Device with reload
- 39Hands-On: Configure a Small Office Network
What Is a VLAN? Splitting a Network Logically
When you want to divide the devices on one switch into per-department networks, the concept to understand is the VLAN. VLAN stands for Virtual LAN: a technique for logically splitting a network into groups while leaving the physical cabling untouched.
Normally, devices on the same switch can all talk to each other as one network. With VLANs, you assign each port a group number, and devices in different groups are kept apart.
For example, put the sales team's PCs in VLAN 10 and the accounting team's in VLAN 20, and even though they share a switch, traffic between the departments is blocked by default — better security and easier management.
A common misunderstanding is thinking VLAN separation makes inter-department communication impossible forever. In reality, traffic can cross VLANs via a router or layer-3 switch.
In real work, splitting VLANs by department and by purpose (servers, guest Wi-Fi, and so on) is the absolute foundation of corporate network design.
🧑💻 You can type this command into the Networking pseudo terminal to try it yourself (this page itself has no interactive terminal).