VLAN Configuration

Master virtual network segmentation through interactive CLI labs and network topology simulations

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Understanding VLAN Basics

VLANs allow network segmentation using virtual rather than physical connections. Key concepts include:

• Broadcast domain separation
• Trunk vs Access ports
• VLAN tagging (802.1Q)
• Inter-VLAN routing

VLAN Configuration Example

show vlan brief

VLAN Name                             Status    Ports
10   Management                       active    Gi0/1, Gi0/2
20   Engineering                      active    Gi0/3-10
30   Guest                            active    Gi0/11-15

VLAN Access Ports

Access port configuration:

interface FastEthernet0/1
 switchport mode access
 switchport access vlan 20

Trunk port configuration:

interface FastEthernet0/24
 switchport mode trunk
 switchport trunk allowed vlan 10,20,30

Cisco 2960 Switch - Lab VLAN Configuration 2025-08-20 14:30:11 UTC

Switch>enable Switch>configure terminal (config)>vlan 10 VLAN 10 added: Name: VLAN0010 (config-vlan)>exit (config)>interface FastEthernet0/1 (config-if)>switchport mode access (config-if)>switchport access vlan 10

VLAN Configuration Challenge

Create VLAN 30 with 3 access ports and 1 trunk port configuration

Configuration

switch(config)#vlan 30 switch(config-vlan)#exit switch(config)#interface GigabitEthernet0/2 switch(config-if)#switchport mode trunk switch(config-if)#end

Status Output

VLAN Trunk Ports : Gi0/2
Active VLANs : 10, 20, 30
Interface Gi0/1: access vlan 30

Your Task

Configure VLAN 30 with 3 access ports
Set trunk on a separate interface
Verify configuration with 'show vlan'

VLAN Best Practices

Security Zones

• Isolate sensitive services
• Control inter-VLAN traffic
• Prevent VLAN hopping attacks

Performance

• Reduce broadcast traffic
• Optimize routing performance
• Segment by department/function

Management

• Centralized VLAN database
• VTP for dynamic management
• NetFlow monitoring