EtherChannelPrivileged EXEC

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.

Syntax·Privileged EXEC

show etherchannel summary

When to Use This Command

Verify that a newly configured EtherChannel is up and all member ports are bundled correctly.
Troubleshoot why an EtherChannel is not forming, e.g., mismatched port parameters or protocol.
Check the load-balancing method or the number of active ports in a production environment.
Monitor the EtherChannel status after a link failure to confirm failover behavior.

Command Examples

Basic EtherChannel Summary

show etherchannel summary

Flags:  D - down        P - bundled in port-channel
        I - stand-alone s - suspended
        H - Hot-standby (LACP only)
        R - Layer3      S - Layer2
        U - in use      N - not in use, no aggregation
        f - failed to allocate aggregator

        M - not in use, minimum links not met
        u - unsuitable for bundling
        w - waiting to be aggregated
        d - default port


Number of channel-groups in use: 2
Number of aggregators:           2

Group  Port-channel  Protocol    Ports
------+-------------+-----------+---------------------------------------------
1      Po1(SU)        LACP      Gi0/0(P)    Gi0/1(P)    Gi0/2(P)    Gi0/3(P)
2      Po2(SU)        PAgP      Gi0/4(P)    Gi0/5(P)    Gi0/6(P)    Gi0/7(P)

Line 1: Flags legend defines status codes. Line 2: Shows 2 channel-groups in use. Line 3: Group 1 uses LACP, Po1 is Layer2 (S) and in use (U), all 4 ports bundled (P). Group 2 uses PAgP, Po2 also Layer2 and in use, all 4 ports bundled.

EtherChannel with Suspended Ports

show etherchannel summary

Flags:  D - down        P - bundled in port-channel
        I - stand-alone s - suspended
        H - Hot-standby (LACP only)
        R - Layer3      S - Layer2
        U - in use      N - not in use, no aggregation
        f - failed to allocate aggregator

        M - not in use, minimum links not met
        u - unsuitable for bundling
        w - waiting to be aggregated
        d - default port


Number of channel-groups in use: 1
Number of aggregators:           1

Group  Port-channel  Protocol    Ports
------+-------------+-----------+---------------------------------------------
1      Po1(SU)        LACP      Gi0/0(P)    Gi0/1(s)    Gi0/2(P)    Gi0/3(P)

Port Gi0/1 shows (s) indicating suspended. This usually happens due to mismatched port parameters (speed, duplex, VLAN) or LACP configuration. The other three ports are bundled (P). The channel is still up but with reduced bandwidth.

Understanding the Output

The output begins with a legend explaining flags: D (down), P (bundled), I (stand-alone), s (suspended), H (Hot-standby for LACP), R (Layer3), S (Layer2), U (in use), N (not in use), f (failed to allocate aggregator), M (minimum links not met), u (unsuitable), w (waiting), d (default). The summary shows the number of channel-groups and aggregators. The table lists each group number, port-channel interface with flags in parentheses (e.g., Po1(SU) means Layer2, in use), protocol (LACP or PAgP), and member ports with their status flags. Key things to check: all member ports should show (P) for bundled; any (s) indicates a problem; (D) means down; (I) means not part of any channel. The protocol column should match on both sides of the link. A healthy EtherChannel shows all ports bundled and the port-channel interface up (U).

CCNA Exam Tips

CCNA exam often tests the meaning of flags: (SU) means Layer2 and in use, (RU) means Layer3 and in use.

Remember that LACP uses the same system priority to determine which side controls the channel; mismatched priorities can cause issues.

A suspended port (s) is often due to mismatched speed, duplex, or VLAN configuration; the exam may ask you to identify the cause.

PAgP is Cisco proprietary; LACP is IEEE 802.3ad standard; know the difference for the exam.

Common Mistakes

Mistake: Assuming all ports in the channel are automatically bundled; forgetting to check for mismatched port parameters like speed or duplex.

Mistake: Confusing the flags (s) suspended with (D) down; suspended means the port is administratively up but not bundled due to configuration mismatch.

Mistake: Not verifying that the protocol (LACP/PAgP) matches on both ends; mismatched protocols prevent channel formation.

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.

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