show port-channel summary
Displays a summary of all configured port channels, including their status, protocol, and member interfaces.
Overview
The 'show port-channel summary' command is a fundamental tool for Cisco Nexus administrators to quickly assess the status of all EtherChannels on the switch. EtherChannel, also known as port channel, is a technology that aggregates multiple physical Ethernet links into a single logical link to increase bandwidth and provide redundancy. On Cisco NX-OS (Nexus), this command provides a concise table listing each port channel group, its interface name, type, protocol (LACP or static), and the status of each member interface. The status codes are critical: (P) indicates the interface is bundled and actively forwarding traffic; (D) means the interface is down due to a physical or Layer 1 issue; (S) indicates the interface is suspended, often due to configuration mismatches such as differing speed, duplex, VLAN membership, or LACP parameters. This command is typically the first step in troubleshooting EtherChannel issues, as it immediately highlights which port channels are healthy and which have problems. It is also used during initial configuration verification to ensure all intended members are bundled. On Nexus switches, the output is consistent across models and NX-OS versions, making it a reliable reference. The command can be filtered to a specific port channel using the 'interface port-channel <number>' parameter, which is useful for focused troubleshooting. Understanding this command is essential for network engineers working with Nexus platforms, as EtherChannels are widely used in data center and campus networks for link aggregation.
show port-channel summary [interface port-channel <channel-number>]When to Use This Command
- Quickly verify the operational status of all port channels after configuration changes.
- Identify which port channels are down or have degraded member links during troubleshooting.
- Check the load-balancing protocol (LACP or static) used by each port channel.
- Monitor port channel membership and ensure all expected interfaces are bundled.
Parameters
| Parameter | Syntax | Description |
|---|---|---|
| interface port-channel <channel-number> | interface port-channel <1-4096> | Optional parameter to display summary only for a specific port channel. The channel number must match an existing port-channel interface. If omitted, all port channels are shown. |
Command Examples
Basic summary of all port channels
show port-channel summary-------------------------------------------------------------------------------- Group Port-Channel Type Protocol Member Ports -------------------------------------------------------------------------------- 1 Po1 Eth LACP Eth1/1(P) Eth1/2(P) 2 Po2 Eth LACP Eth1/3(P) Eth1/4(P) 3 Po3 Eth LACP Eth1/5(D) Eth1/6(D) 4 Po4 Eth LACP Eth1/7(S) Eth1/8(S) 5 Po5 Eth LACP Eth1/9(P) Eth1/10(P) 6 Po6 Eth LACP Eth1/11(P) Eth1/12(P) 7 Po7 Eth LACP Eth1/13(P) Eth1/14(P) 8 Po8 Eth LACP Eth1/15(P) Eth1/16(P) 9 Po9 Eth LACP Eth1/17(P) Eth1/18(P) 10 Po10 Eth LACP Eth1/19(P) Eth1/20(P) --------------------------------------------------------------------------------
The output shows each port channel group number, the port-channel interface name, type (always Eth for Ethernet), protocol (LACP or none for static), and member ports with status: (P) = bundled, (D) = down, (S) = suspended. Groups 1-2 are healthy, group 3 has down members, group 4 has suspended members.
Summary for a specific port channel
show port-channel summary interface port-channel 1-------------------------------------------------------------------------------- Group Port-Channel Type Protocol Member Ports -------------------------------------------------------------------------------- 1 Po1 Eth LACP Eth1/1(P) Eth1/2(P) --------------------------------------------------------------------------------
Displays summary only for Po1, showing both member interfaces are bundled (P).
Understanding the Output
The output is a table with columns: Group (port channel number), Port-Channel (interface name), Type (always Eth for Ethernet), Protocol (LACP or none for static), and Member Ports (list of member interfaces with status codes). The status codes are: (P) - bundled, meaning the interface is actively forwarding traffic; (D) - down, meaning the interface is not operational; (S) - suspended, meaning the interface is administratively up but not bundled due to misconfiguration (e.g., mismatched parameters). A healthy port channel should have all member ports showing (P). If any member shows (D) or (S), the port channel may have reduced bandwidth or be non-functional. The protocol column indicates whether LACP is used; if 'none', the port channel is static. This command is essential for verifying the operational state of EtherChannels on Nexus switches.
Configuration Scenarios
Verifying a new LACP port channel
After configuring a new LACP port channel with two member interfaces, verify it is operational.
Topology
Nexus-1 --- Eth1/1, Eth1/2 --- Nexus-2Steps
- 1.Configure port-channel 1 on both switches with LACP active mode.
- 2.Add interfaces Eth1/1 and Eth1/2 to port-channel 1.
- 3.Run 'show port-channel summary' to verify both members show (P).
! On Nexus-1 interface port-channel1 switchport mode trunk no shutdown interface Ethernet1/1 channel-group 1 mode active no shutdown interface Ethernet1/2 channel-group 1 mode active no shutdown
Verify: Run 'show port-channel summary' and confirm Po1 shows both Eth1/1(P) and Eth1/2(P).
Watch out: Ensure both sides have matching LACP modes (active/active or active/passive) and identical interface configurations (speed, duplex, VLANs).
Troubleshooting with This Command
When troubleshooting EtherChannel issues on Cisco Nexus, the 'show port-channel summary' command is your first diagnostic tool. Start by running the command to get an overview. If you see a port channel with all members showing (P), the EtherChannel is healthy. If any member shows (D), check the physical connectivity: ensure the cable is plugged in, the interface is not administratively down, and there are no Layer 1 errors. Use 'show interface Ethernet x/y' to inspect the interface status. If a member shows (S), the interface is suspended due to a configuration mismatch. Common causes include: mismatched speed or duplex (though NX-OS auto-negotiates by default), mismatched VLAN membership (e.g., one side trunk, the other access), or LACP parameter mismatches (e.g., system priority, port priority). Use 'show port-channel database' for detailed configuration of each port channel, and 'show lacp neighbor' to verify LACP negotiation. Also check that the port channel interface itself is not administratively down. If the entire port channel is missing from the output, it may not be configured. Remember that on Nexus, the port channel interface must be created before adding members. The summary command is also useful for monitoring: if a member flaps between (P) and (D), investigate for intermittent physical issues. For static port channels (protocol 'none'), ensure all member interfaces have identical configurations and are in 'no shutdown' state. In summary, this command quickly narrows down whether the issue is physical (D), configuration (S), or non-existent.
CCNA Exam Tips
Remember that (P) means bundled, (D) means down, (S) means suspended.
Know that LACP is the dynamic protocol; static port channels show 'none' under protocol.
Be able to identify why a port might be suspended (e.g., mismatched speed/duplex, VLAN mismatch).
Common Mistakes
Confusing (D) and (S): (D) is a physical issue, (S) is a configuration mismatch.
Assuming all port channels are LACP; static port channels show 'none'.
Forgetting that the command shows only summary; use 'show port-channel database' for detailed info.
Platform Notes
On Cisco Nexus switches running NX-OS, the 'show port-channel summary' command behaves similarly to Cisco IOS, but there are key differences. In IOS, the command is 'show etherchannel summary' and the output format is different (e.g., flags like SU, P, etc.). Nexus uses a cleaner table format with status codes (P), (D), (S). Additionally, Nexus supports both LACP and static port channels, but the default protocol is LACP on many platforms. The command is available in all NX-OS versions and on all Nexus models (e.g., 3000, 5000, 7000, 9000 series). For equivalent commands on other platforms: on Arista EOS, use 'show port-channel summary'; on Juniper Junos, use 'show lacp interfaces' or 'show ethernet-switching interfaces' for aggregated Ethernet. On Cisco IOS XE (Catalyst 9000), the command is 'show etherchannel summary'. Note that Nexus does not support PAgP; only LACP or static. Also, on Nexus, the port channel interface must be explicitly created before adding members, whereas on some IOS platforms it can be auto-created. Version differences: in older NX-OS releases, the output might not show the 'Type' column, but it is present in modern versions. Always verify the exact output format on your specific NX-OS version.
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