IntermediatePublished 2026-08-05
CCNA EtherChannel: Why Won't It Bundle?
Archive lab
CCNA exam domain: Network Access
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.
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.
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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.
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