Lab 11: EtherChannel with LACP
Bundle two links between switches into a single LACP EtherChannel — double the bandwidth, instant failover, and no STP blocking. Difficulty: Intermediate · Time: ~30 min.
Lab objectives
- Bundle two ports with channel-group (LACP active)
- Configure the port-channel as a trunk
- Verify with show etherchannel summary
- Prove failover by shutting one member
Topology & addressing
2× 2960 switches connected by TWO cables: Gi0/1↔Gi0/1 and Gi0/2↔Gi0/2. PCs on each switch in VLAN 10 for testing.
Step-by-step configuration
interface range gi0/1 - 2channel-group 1 mode active | Both members join channel 1 via LACP (do this on BOTH switches) |
interface port-channel 1switchport mode trunk | Configure the logical bundle — settings apply to members |
show etherchannel summary | Look for Po1(SU) and members (P) |
Verification
show etherchannel summary — flags SU (Layer2, in use) with both ports (P) bundled. show spanning-tree shows Po1 as ONE forwarding link — no blocked member. Shut Gi0/1 and pings continue over Gi0/2: failover proven.
Next lab: labs hub · test yourself: CCNA practice test.
Frequently asked questions
What does mode active mean in LACP?
The port actively negotiates bundling. active+active or active+passive forms a channel; passive+passive does not.
Why configure the port-channel interface instead of members?
The logical Po interface pushes settings to all members, keeping them consistent — mismatched members break bundles.
What do the SU and P flags mean?
S=Layer2, U=in use for the bundle; P=port bundled in the port-channel. That combination is a healthy channel.
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