BeginnerPublished 2026-08-02
CCNA Foundations: Layer 2 EtherChannel with LACP — Two Links, One Trunk
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Bundle two parallel switch uplinks into a single Port-Channel using LACP so that Spanning Tree no longer blocks one link. You will convert two existing 802.1Q trunks into one logical trunk, verify both member links are active in the Port-Channel, and confirm end-to-end host reachability.
Learning objectives
- Configure LACP-based EtherChannel on parallel inter-switch trunks
- Build and harden a Port-Channel as an 802.1Q trunk with native VLAN 999 and limited allowed VLANs
- Verify EtherChannel state and membership with show etherchannel and trunk commands
- Observe how STP treats a Port-Channel as a single logical link
- Validate end-to-end connectivity across the aggregated uplink
Troubleshooting focus
- If the Port-Channel stays down or members
show suspended: Compare LACP mode on both ends (the lab expects LACP, not forced on).; Check that native VLAN and allowed VLAN lists on the Port-Channel match identically on both switches.; Ensure the physical member ports have identical switchport settings and are not err-disabled.; Useshow etherchannel summaryto verify flags (SU on the Port-Channel; P on members) andshow interfaces trunkto confirm the Port-Channel is actually carrying VLAN 20. - If pings fail intermittently: Re-check that the Port-Channel is up and both links are bundled; if only one link is forwarding outside the bundle, STP may still be blocking the other.; Confirm both switches define VLAN 20 locally (vtp transparent in this lab) and the access ports are in VLAN 20.
Topology
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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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