IntermediatePublished 2026-08-05

CCNA EtherChannel: Why Won't It Bundle?

Today's daily lab

Troubleshoot and fix an LACP EtherChannel between campus switches so both physical members bundle and the trunk reliably carries VLAN 10. Two independent faults are seeded: an intra-bundle trunk mismatch on one switch and an administratively down member on the other. Learners diagnose with show commands, align trunk attributes, and verify end-to-end host reachability.

Track

CCNA

Est. time

55 minutes

Difficulty

Intermediate

Topics

CCNA, Switching, EtherChannel, LACP, Troubleshooting

Learning objectives

Identify EtherChannel formation failures caused by inconsistent member interface settings.
Align trunk attributes (mode, native VLAN, allowed VLANs, negotiation) across all member links.
Recover an EtherChannel member that is administratively down or missing from the bundle.
Verify EtherChannel health using show etherchannel summary and show interfaces trunk.
Validate end-to-end data-plane success from hosts after control-plane repairs.

Troubleshooting focus

Use show etherchannel summary to spot suspended or standalone members versus (P) bundled ports.
Compare trunk native VLAN and allowed VLAN lists across all member interfaces and the port-channel.
Confirm both sides run the same channel-group number and LACP mode, and that no member is shutdown.
Ensure switch-to-switch links are true 802.1Q trunks with nonegotiate and dot1q encapsulation set.
Validate VLAN presence on all switches; a VLAN must exist locally to be carried over the trunk.

Topology

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What's included in the package

Work / baseline CML import — lab-work.yaml
Topology diagram — topology.svg
Print-ready topology diagram (PDF) — topology.pdf
Step-by-step learner guide (Markdown — for Obsidian/VS Code) — lab-guide.md
Branded PDF lab guide — open in any viewer (Adobe/Preview) — lab-guide.pdf
Getting-started README — README.md
Verification checklist — verification-checklist.md

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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CCNA EtherChannel: Why Won't It Bundle?

Learning objectives

Troubleshooting focus

Topology

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