show etherchannel protocol
Displays the protocol (LACP or PAgP) used by each EtherChannel bundle, useful for verifying that all member ports are using the same negotiation protocol.
show etherchannel protocolWhen to Use This Command
- Verify that all ports in a bundle are using LACP (active/passive) or PAgP (desirable/auto) after configuration.
- Troubleshoot why an EtherChannel is not forming due to protocol mismatch between switches.
- Confirm that a port channel is using the intended protocol before making changes to the bundle.
- Audit existing EtherChannel configurations across multiple switches for consistency.
Command Examples
Basic show etherchannel protocol
show etherchannel protocolEtherChannel Protocol: LACP Channel-group 1: Ports: Gi0/0, Gi0/1 Protocol: LACP Channel-group 2: Ports: Gi0/2, Gi0/3 Protocol: PAgP
Line 1: The global EtherChannel protocol is LACP (set by 'lacp system-priority' or default). Channel-group 1: Shows that ports Gi0/0 and Gi0/1 are using LACP. Channel-group 2: Shows that ports Gi0/2 and Gi0/3 are using PAgP.
Show etherchannel protocol with no bundles
show etherchannel protocolEtherChannel Protocol: LACP No EtherChannel bundles configured.
Indicates that the global protocol is LACP but no port channels have been created yet.
Understanding the Output
The first line shows the global EtherChannel protocol (LACP or PAgP) configured on the switch. This is set by the 'lacp system-priority' command for LACP or 'pagp system-priority' for PAgP. Then, for each channel-group, it lists the member ports and the protocol they are using. All ports in a channel-group must use the same protocol; otherwise, the bundle will not form. If you see a mix of protocols in the same group, there is a configuration error. The output also helps verify that the correct protocol is being used (e.g., LACP for cross-vendor links).
CCNA Exam Tips
CCNA exam may ask which protocol is used when both LACP and PAgP are configured on the same switch; the global protocol takes precedence.
Remember that LACP is IEEE standard and works with any vendor; PAgP is Cisco proprietary.
The 'show etherchannel protocol' command does not show the port channel number; use 'show etherchannel summary' for that.
If no bundles exist, the output still shows the global protocol.
Common Mistakes
Assuming all EtherChannels use the same protocol; they can be mixed per channel-group.
Confusing the global protocol with per-channel protocol; the global setting only affects new bundles.
Forgetting that LACP and PAgP cannot be mixed within the same channel-group.
Related Commands
show etherchannel port
Displays detailed port-level information for all ports that are part of an EtherChannel bundle, including port state, aggregation protocol, and partner details.
show etherchannel summary
Displays the status and configuration of all EtherChannel interfaces on the switch, used to verify channel bundling, port membership, and protocol state.
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