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BeginnerPublished 2026-06-30

Trunking Basics: Access Ports vs Trunk Ports

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Hands-on CCNA switching lab contrasting single-VLAN access ports with 802.1Q trunks. You begin with the inter-switch link configured as a plain access port, so only one VLAN reaches the router-on-a-stick gateway while the other cannot. You will diagnose the connectivity problem, convert the link into a properly hardened 802.1Q trunk, and validate that both VLANs regain access to their gateway.

Track
Est. time
55 minutes
Difficulty
Beginner
Topics

Learning objectives

  • Differentiate access and trunk ports and when to use each
  • Configure access ports for end hosts and verify VLAN membership
  • Convert a switch-to-switch link from access to an 802.1Q trunk
  • Harden trunks: set native VLAN 999, prune VLAN 1, set allowed VLAN lists, and disable negotiation
  • Use show interfaces switchport and show interfaces trunk to verify administrative vs operational mode

Troubleshooting focus

  • Identify symptoms when an inter-switch link is accidentally configured as an access port
  • Detect and correct native VLAN mismatches
  • Find and fix missing VLANs on the trunk allowed list
  • Validate end-host placement and isolate wrong access VLAN assignments

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Learn VLANs, Trunking & Inter-VLAN RoutingWhat Is a VLAN? VLANs Explained for Beginners

Grade your work

How this lab is graded
  • Build it your way. Where a lab lets you choose a value — a VLAN name, an interface description — grading checks that you configured it, not which name you picked. Names that another line has to reference, like an ACL applied with access-class, are stated in the guide and do have to match.
  • Addresses, modes and protocol keywords are exact. An IP address, a subnet mask, switchport mode trunk, an encapsulation — these carry the meaning of the lab, so they are graded as written in the guide.
  • Grading reads your saved configuration. Export the lab from CML after you have configured it, and make sure anything you set is in the running-config — a change that only exists in a terminal session never reaches the grader.
  • You can submit as many times as you like. Your best score stands, and each attempt tells you which checks passed so you can work the gaps.
  • Scored something you believe is correct? Use Report an issue on this page — that is exactly how the grading fixes in the changelog got found.

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