Cisco "show etherchannel summary" Command Explained
show etherchannel summary — shows the status of all EtherChannel bundles on a switch — which ports are members, whether they're actually bundled, and the protocol used. Runs in privileged EXEC mode.
Syntax and common variants
| Variant | Purpose |
|---|---|
show etherchannel summary | All port-channels and their member status |
show etherchannel 1 detail | Full detail on one channel group |
Reading the output
| Output / element | Meaning |
|---|---|
Flags: SU | Layer2, in use — a healthy bundled channel |
Flags: P | Port bundled in the port-channel |
Flags: I | Individual — NOT bundled (a problem) |
Protocol | LACP, PAgP, or blank (static "on" mode) |
When to use it
The definitive check after configuring EtherChannel: are the ports actually bundled (P flag) or sitting individually (I flag, meaning something's misconfigured)? A channel showing "I" instead of "P" means the two sides disagree on mode or one side isn't configured — a very common lab and real-world mistake. Browse more in the command reference or practise in the free labs.
Frequently asked questions
What does the I flag mean in EtherChannel output?
Individual — the port did NOT join the bundle, usually because the two ends have mismatched channel modes or one side isn't configured for EtherChannel.
What is the difference between SU and P flags?
SU describes the port-channel interface itself (Layer2, in use); P describes each physical member port that's successfully bundled into it.
Why would ports fail to bundle?
Mismatched channel-group modes (e.g. active on one side, nothing on the other), or mismatched trunk/access settings, speed or duplex between the member ports.
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