Labs · · 4 min read

Lab na-02 - VLANs and Access Ports

Lab na-02 - VLANs and Access Ports - PingLabz Labs article title card

A VLAN is a logical broadcast domain that lives on top of a physical switch. The switch can have a hundred ports but be carved into ten broadcast domains - so a broadcast on VLAN 10 reaches only the ports in VLAN 10, not the other ninety. Access ports are the simplest connection to a VLAN: one port, one VLAN, untagged frames. This lab configures three VLANs on a Cisco IOSvL2 switch, assigns access ports to them, and verifies with the canonical show commands.

What you will learn

  • How to create VLANs and give them human-readable names
  • How to configure an access port and assign it to a VLAN
  • The difference between an access port and a trunk port (preview of na-03)
  • How to read show vlan brief and what each column means
  • The output of show interfaces switchport on an access port

What this lab does NOT cover

  • Trunking - that is the next lab, na-03
  • Voice VLANs - covered in na-05
  • VLAN database synchronization with VTP - touched on briefly in na-03

Topology

Download the STP+VLAN Reference Lab .yaml

Drop this into CML's Import dialog. Three IOSvL2 switches in a triangle with VLANs 10/20/99, dot1q trunks, rapid-PVST root election, and an LACP EtherChannel between SW1 and SW2.

Download STP+VLAN Reference Lab

Read next

Terminal card showing a repeating CDP native VLAN mismatch log naming Ethernet0/0 native VLAN 1 against SW2 Ethernet0/0 native VLAN 99
VLANs ·

Native VLAN Mismatch: Read the CDP Log, Fix the Trunk

%CDP-4-NATIVE_VLAN_MISMATCH hands you both interfaces and both native VLANs in one line. The real damage is underneath it: untagged frames get re-homed at the trunk boundary and two VLANs quietly become one. Captured live on IOS XE 17.18.2 in CML.