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.
Definition: show etherchannel port is a Cisco IOS privileged exec command. Displays detailed port-level information for all ports that are part of an EtherChannel bundle, including port state, aggregation protocol, and partner details.
Overview
The `show etherchannel port` command is a critical diagnostic tool for any network engineer working with Cisco switches that implement link aggregation via EtherChannel. EtherChannel, also known as port channel, allows multiple physical Ethernet links to be bundled into a single logical link, providing increased bandwidth and redundancy. This command displays detailed port-level information for all interfaces that are members of an EtherChannel group, including the port's state (active, standby, or failed), the aggregation protocol in use (PAgP or LACP), and key partner details such as partner system ID, partner port ID, and partner operational key. Understanding this output is essential for verifying correct EtherChannel operation, troubleshooting bundle inconsistencies, and ensuring that both ends of the link are configured compatibly.
The underlying concept is that EtherChannel relies on consistent configuration across all member ports: same speed, duplex, VLAN membership, and trunking mode. The aggregation protocol (PAgP or LACP) negotiates the bundle and maintains state. When a port fails or becomes misconfigured, the EtherChannel may suspend that port or even bring down the entire bundle. The `show etherchannel port` command reveals which ports are successfully aggregated and which are not, along with the reason (e.g., mismatched parameters, partner not responding).
Network engineers reach for this command when verifying a new EtherChannel configuration, after a link failure, or when performance issues suggest a bundle is not operating at full capacity. It is more granular than `show etherchannel summary`, which only shows bundle-level status, and complements `show etherchannel detail`, which provides protocol-specific information. In a troubleshooting workflow, you would typically start with `show etherchannel summary` to see the overall health, then drill into `show etherchannel port` to inspect individual member ports. The command is also useful when comparing configurations across switches to ensure both sides agree on parameters like port priority and system priority.
Important IOS behavior: The output can be lengthy if many ports are bundled, so using the `| include` or `| section` filter is common. The command requires privileged EXEC mode (enable). It does not modify the running configuration. In some IOS versions, the output includes a 'Flags' field that indicates port state (e.g., 'A' for active, 'S' for standby). Understanding these flags is key to rapid diagnosis. The command also shows the 'Port Security' status if configured, which can cause ports to be suspended if violated. Overall, `show etherchannel port` is an indispensable command for any CCNA or CCNP candidate mastering link aggregation.
show etherchannel portWhen to Use This Command
- Verifying which ports are successfully bundled in an EtherChannel after configuration.
- Troubleshooting a non-functional EtherChannel by checking port state and protocol mismatches.
- Confirming that all member ports have consistent speed, duplex, and VLAN settings.
- Checking the LACP or PAgP neighbor state to ensure proper negotiation with the peer switch.
Parameters
| Parameter | Syntax | Description |
|---|---|---|
| channel-group-number | <1-48> | Specifies the EtherChannel group number to display port information for. If omitted, all EtherChannel groups are shown. Valid values are 1 to 48 on most Catalyst switches. Common mistake: using a number that does not exist on the switch, which results in no output. |
| port-channel | port-channel channel-group-number | Displays port information for a specific port-channel interface. The channel-group-number must match an existing port-channel. This parameter is useful when you want to focus on a single bundle. Example: `show etherchannel port port-channel 1`. |
Command Examples
Basic show etherchannel port output
show etherchannel portChannel-group listing:
----------------------
Group: 1
----------
Ports in the group:
-------------------
Port: Gi0/1
--------
Port state = Up/Active
Negotiation = LACP
Flags: S - Device sends requests (Slow)
A - Device is in Active mode
Local information:
-------------------
Port State Flags Priority Key
Gi0/1 Up/Active SA 0x80 0x1
Partner's information:
----------------------
Port State Flags Priority Key
Gi0/1 Up/Active SA 0x80 0x1
Age of the port in the current state: 0d:00h:15m:32s
Port: Gi0/2
--------
Port state = Up/Active
Negotiation = LACP
Flags: S - Device sends requests (Slow)
A - Device is in Active mode
Local information:
-------------------
Port State Flags Priority Key
Gi0/2 Up/Active SA 0x80 0x1
Partner's information:
----------------------
Port State Flags Priority Key
Gi0/2 Up/Active SA 0x80 0x1
Age of the port in the current state: 0d:00h:15m:30sThe output shows EtherChannel group 1 with two member ports (Gi0/1 and Gi0/2). Each port section displays: Port state (Up/Active means the port is up and actively participating in the bundle), Negotiation (LACP indicates the protocol used), Flags (S for slow rate, A for active mode), Priority (port priority, default 0x80), Key (aggregation key, must match across bundle), Partner's information (should mirror local for a working bundle), and Age (time since last state change).
Troubleshooting a port not joining the bundle
show etherchannel portChannel-group listing:
----------------------
Group: 1
----------
Ports in the group:
-------------------
Port: Gi0/1
--------
Port state = Up/Active
Negotiation = LACP
Flags: S - Device sends requests (Slow)
A - Device is in Active mode
Local information:
-------------------
Port State Flags Priority Key
Gi0/1 Up/Active SA 0x80 0x1
Partner's information:
----------------------
Port State Flags Priority Key
Gi0/1 Up/Active SA 0x80 0x1
Age of the port in the current state: 0d:00h:10m:00s
Port: Gi0/2
--------
Port state = Down/Inactive
Negotiation = LACP
Flags: S - Device sends requests (Slow)
A - Device is in Active mode
Local information:
-------------------
Port State Flags Priority Key
Gi0/2 Down/Inactive SA 0x80 0x1
Partner's information:
----------------------
Port State Flags Priority Key
Gi0/2 Down/Inactive SA 0x80 0x1
Age of the port in the current state: 0d:00h:05m:00sHere, Gi0/2 shows Down/Inactive, indicating it is not participating in the EtherChannel. Possible causes: the port is administratively down, speed/duplex mismatch, or VLAN inconsistency. Check interface status with 'show interfaces Gi0/2' and verify that all member ports have identical configuration.
Understanding the Output
The 'show etherchannel port' command provides per-port details for each EtherChannel group. Key fields: 'Port state' shows Up/Active (working) or Down/Inactive (problem). 'Negotiation' indicates the protocol (LACP, PAgP, or On).
'Flags' show LACP/PAgP settings: S (slow rate), F (fast rate), A (active), P (passive). 'Priority' is the port priority used for tie-breaking. 'Key' is the aggregation key; all ports in a bundle must have the same key.
'Partner's information' should match local for a successful bundle. 'Age' shows how long the port has been in its current state. In a healthy EtherChannel, all member ports should show Up/Active with matching local and partner info.
Mismatches in speed, duplex, VLAN, or trunk mode cause ports to stay Down/Inactive.
Configuration Scenarios
Verify EtherChannel Port Status After Configuration
After configuring an EtherChannel between two switches, you need to confirm that all member ports are active and bundled correctly. This scenario uses LACP (802.3ad) on a trunk link.
Topology
SW1(Gi0/1-2)---(Gi0/1-2)SW2Steps
- 1.Step 1: Enter privileged EXEC mode on SW1: SW1> enable
- 2.Step 2: Issue the command: SW1# show etherchannel port
- 3.Step 3: Examine the output for each port. Look for 'Flags: A' (active) and 'Port state: Up'.
- 4.Step 4: Verify that the partner information matches the expected switch (SW2).
- 5.Step 5: If any port shows 'Flags: S' (standby) or 'Port state: Down', investigate further.
! On SW1: interface GigabitEthernet0/1 channel-group 1 mode active ! interface GigabitEthernet0/2 channel-group 1 mode active ! interface Port-channel1 switchport mode trunk ! ! On SW2: interface GigabitEthernet0/1 channel-group 1 mode passive ! interface GigabitEthernet0/2 channel-group 1 mode passive ! interface Port-channel1 switchport mode trunk
Verify: SW1# show etherchannel port Channel-group listing: ---------------------- Group: 1 ---------- Ports in the group: Port: Gi0/1 -------- Port state = Up Flags: A - active Aggregation state: Bundled Partner information: Partner system ID: 0x8000,00-11-22-33-44-55 Partner port ID: 0x8000,0x102 Partner operational key: 1 Port: Gi0/2 -------- Port state = Up Flags: A - active Aggregation state: Bundled Partner information: Partner system ID: 0x8000,00-11-22-33-44-55 Partner port ID: 0x8000,0x103 Partner operational key: 1
Watch out: Ensure both sides use the same EtherChannel mode (active/passive for LACP, desirable/auto for PAgP). Mismatched modes can prevent bundling. Also, verify that all member ports have identical speed, duplex, and VLAN configuration.
Troubleshoot a Mismatched EtherChannel Bundle
A user reports intermittent connectivity on a trunk link that uses EtherChannel. You suspect a port is not bundled due to configuration mismatch. This scenario demonstrates using the command to identify the problematic port.
Topology
SW1(Gi0/1-2)---(Gi0/1-2)SW2Steps
- 1.Step 1: Enter privileged EXEC mode: SW1> enable
- 2.Step 2: Run: SW1# show etherchannel port
- 3.Step 3: Look for ports with 'Flags: S' (standby) or 'Port state: Down'.
- 4.Step 4: Check the 'Aggregation state' field; if it says 'Not in bundle', the port is not aggregated.
- 5.Step 5: Compare the partner information for the working port vs the failed port. Mismatched partner system IDs or port IDs may indicate a cabling issue or wrong neighbor.
- 6.Step 6: Verify physical layer: speed, duplex, and cable integrity.
! On SW1 (correct config): interface GigabitEthernet0/1 channel-group 1 mode active ! interface GigabitEthernet0/2 channel-group 1 mode active ! ! On SW2 (misconfigured - Gi0/2 is in a different channel-group): interface GigabitEthernet0/1 channel-group 1 mode passive ! interface GigabitEthernet0/2 channel-group 2 mode passive
Verify: SW1# show etherchannel port Group: 1 ---------- Port: Gi0/1 -------- Port state = Up Flags: A - active Aggregation state: Bundled Partner information: Partner system ID: 0x8000,00-11-22-33-44-55 Partner port ID: 0x8000,0x102 Partner operational key: 1 Port: Gi0/2 -------- Port state = Up Flags: S - standby Aggregation state: Not in bundle Partner information: Partner system ID: 0x8000,00-11-22-33-44-66 (different switch?) Partner port ID: 0x8000,0x202 Partner operational key: 2
Watch out: A common mistake is assuming that all ports in the same physical bundle must be in the same channel-group number on both sides. In this scenario, Gi0/2 on SW2 is in group 2, causing a mismatch. Also, check that the partner system ID is consistent; if it changes, you may be connected to a different switch.
Troubleshooting with This Command
When troubleshooting EtherChannel issues, `show etherchannel port` is your go-to command for granular port-level insight. Healthy output shows all member ports with 'Port state = Up', 'Flags: A' (active), and 'Aggregation state: Bundled'. The partner information should be consistent across all ports in the group, with the same partner system ID and operational key. If a port shows 'Flags: S' (standby) or 'Flags: D' (down), it indicates a problem. Standby ports occur in PAgP when there are more than eight ports; LACP does not use standby. A 'Port state = Down' suggests a physical layer issue or administrative shutdown.
Key fields to focus on: - **Flags**: 'A' = active, 'S' = standby, 'D' = down, 'B' = bundling. 'A' is what you want. - **Port state**: Up or Down. - **Aggregation state**: 'Bundled' or 'Not in bundle'. 'Not in bundle' means the port is not part of the logical channel. - **Partner information**: Compare across ports. If one port shows a different partner system ID, you may be connected to a different switch or there is a cabling error. The partner port ID should be unique per port on the remote side. - **Partner operational key**: Should be the same for all ports in the bundle on the remote switch. A mismatch indicates the remote ports are in different channel groups.
Common symptoms and their meanings: - **Port is 'Not in bundle' with 'Flags: S'**: Usually due to LACP or PAgP negotiation failure. Check that both sides use compatible modes (active/active or active/passive for LACP; desirable/desirable or desirable/auto for PAgP). Also verify that the port is not error-disabled. - **Port is 'Not in bundle' with 'Flags: A'**: Rare; may indicate a software bug or that the port is waiting for partner. - **All ports show 'Not in bundle'**: The entire EtherChannel is down. Check the port-channel interface state with `show interfaces port-channel 1`. - **Partner system ID changes**: You might be connected to multiple switches (e.g., via a hub) or there is a loop. Ensure only two switches are involved.
Diagnostic flow: 1. Start with `show etherchannel summary` to see the overall status of all bundles. 2. For a problematic bundle, use `show etherchannel port <group>` to inspect member ports. 3. Identify any port that is not bundled. Note its flags and state. 4. Check physical layer: `show interfaces <interface>` for speed/duplex mismatches, errors, or down state. 5. Verify configuration on both ends: `show running-config interface <interface>` to ensure channel-group and mode match. 6. If using LACP, use `show lacp neighbor` to see LACP negotiation details. For PAgP, use `show pagp neighbor`. 7. If all else fails, shut/no shut the port-channel or individual member ports to reset negotiation.
Correlate with other commands: `show etherchannel detail` provides protocol-specific counters and state machines. `show logging` may reveal EtherChannel state changes. `debug etherchannel` can be used in lab environments but is heavy for production. The key is to systematically isolate whether the issue is physical, configuration, or protocol-related.
CCNA Exam Tips
CCNA exam tip: Remember that all ports in an EtherChannel must have identical speed, duplex, VLAN (access or allowed VLANs), and trunking mode.
CCNA exam tip: LACP uses active/passive modes; PAgP uses desirable/auto. At least one side must be active or desirable to form a bundle.
CCNA exam tip: The 'show etherchannel port' command is useful for verifying that each port's state is Up/Active and that the partner information matches.
CCNA exam tip: A common exam scenario is troubleshooting a non-functional EtherChannel; check for mismatched port settings or protocol modes.
Common Mistakes
Mistake 1: Assuming all ports in a channel group are automatically bundled; they must have matching configurations (speed, duplex, VLAN).
Mistake 2: Forgetting to set the channel-group mode correctly; e.g., using 'active' on one side and 'passive' on the other for LACP works, but 'passive' on both sides fails.
Mistake 3: Misinterpreting 'Down/Inactive' as a physical issue; it often indicates a configuration mismatch rather than a cable problem.
show etherchannel port vs show etherchannel summary
Both show etherchannel port and show etherchannel summary are used to verify and troubleshoot EtherChannel configurations, but they provide different levels of detail. The port command focuses on individual port membership and negotiation details, while the summary command gives a high-level overview of all EtherChannel bundles.
| Aspect | show etherchannel port | show etherchannel summary |
|---|---|---|
| Scope | Individual member ports of all bundles | EtherChannel interfaces (port-channels) overall |
| Output Detail | Detailed per-port state, counters, partner info | Brief summary including bundle status, protocol, member ports |
| Protocol Information | LACP/PAgP state per port | Aggregation protocol per channel |
| Typical Use | Diagnose port-level issues like mismatched VLANs or partner | Quickly verify which port-channel bundles are up/down |
| Partner Information | Detailed partner system ID, port, state | Not provided |
Use show etherchannel port when you need to investigate a specific port's etherchannel membership or LACP/PAgP negotiation details.
Use show etherchannel summary when you need a quick overview of all EtherChannel bundles and their operational status.
Platform Notes
In IOS-XE (e.g., Catalyst 3650/3850/9300), the `show etherchannel port` command syntax and output are largely identical to classic IOS. However, IOS-XE may include additional fields such as 'Port Security' status and 'Flow Control' settings. The command is available in privileged EXEC mode.
On NX-OS (e.g., Nexus 9000), the equivalent command is `show port-channel database` or `show port-channel summary`. For detailed port-level info, use `show port-channel database interface port-channel <number>`. NX-OS also supports `show lacp interface ethernet <slot/port>` for LACP-specific details.
The ASA platform does not support EtherChannel in the same way; it uses failover or redundant interfaces. For IOS-XR, the command is `show ethernet bundle` or `show lacp bundle <bundle-id>`. In IOS 12.x and 15.x, the output format is consistent, but 16.x (IOS-XE) may show slightly different flag descriptions (e.g., 'A' for active, 'B' for bundling).
Always check the specific platform documentation for exact syntax. The command is not available in IOS-XR; instead, use `show ethernet bundle <bundle-name>` for similar information.
Related Commands
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.
show interfaces
Displays detailed Layer 1 and Layer 2 statistics for all interfaces or a specific interface: line protocol state, hardware type, MAC address, MTU, bandwidth, duplex, speed, input/output rates, error counters, and queue statistics.
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