show module
Displays the status, hardware model, serial number, and software version of all modules installed in the chassis.
Overview
The 'show module' command is a fundamental diagnostic tool on Cisco Nexus switches running NX-OS. It provides a comprehensive view of all hardware modules installed in the chassis, including line cards, supervisor modules, fabric modules, and system controllers. This command is essential for verifying that all components are online and operational, especially after a system reboot, software upgrade, or hardware replacement. The concept behind it is straightforward: a modular chassis consists of multiple slots, each housing a specific type of module. The command queries the system's module manager to retrieve status, model, serial number, software version, and MAC address ranges. On Nexus platforms, the output is divided into three clear sections for easy reading. Network engineers use this command during initial deployment to confirm all modules are recognized, during troubleshooting to isolate a faulty module, and for inventory management to track hardware assets. In troubleshooting workflows, 'show module' is often the first step when a line card fails to come online or when a supervisor redundancy issue arises. It helps quickly identify whether the problem is hardware-related (e.g., module status 'failed') or software-related (e.g., version mismatch). The command is also used in conjunction with 'show environment' to check power and temperature, and 'show system redundancy' to verify supervisor failover readiness. Platform-specific behavior on Nexus includes the asterisk (*) next to the active supervisor and the inclusion of fabric modules and system controllers in the output, which are not present on all modular platforms. Understanding this command is critical for CCNP Data Center and other Nexus-focused certifications.
show module [all | slot slot-number]When to Use This Command
- Verify that all line cards and supervisor modules are online and operational after a reboot or upgrade.
- Identify the hardware model and serial numbers of modules for inventory management or RMA requests.
- Check the software version running on each module to ensure consistency across the chassis.
- Troubleshoot a module that is not coming online by checking its status and power state.
Parameters
| Parameter | Syntax | Description |
|---|---|---|
| all | all | Displays detailed information for all modules, including those that are powered down or failed. Without this parameter, only operational modules are shown. |
| slot slot-number | slot slot-number | Displays information only for the module installed in the specified slot number. Useful for focusing on a particular module. |
Command Examples
Basic module status display
show moduleMod Ports Module-Type Model Status --- ----- ----------------------------------- ----------------- ----------- 1 48 10/25/40/50 G Ethernet Module N9K-X9564PX ok 2 48 10/25/40/50 G Ethernet Module N9K-X9564PX ok 3 0 Supervisor Module N9K-SUP-A active * 4 0 Supervisor Module N9K-SUP-A standby 5 0 System Controller N9K-SC-A ok 6 0 System Controller N9K-SC-A ok 7 0 Fabric Module N9K-C9508-FM ok 8 0 Fabric Module N9K-C9508-FM ok Mod Sw Hw Slot --- -------------- ------ ---- 1 9.3(5) 1.0 1 2 9.3(5) 1.0 2 3 9.3(5) 1.0 3 4 9.3(5) 1.0 4 5 9.3(5) 1.0 5 6 9.3(5) 1.0 6 7 9.3(5) 1.0 7 8 9.3(5) 1.0 8 Mod MAC-Address(es) Serial-Num --- -------------------------------------- ----------- 1 84b8.0234.5678 to 84b8.0234.56a7 FOC12345678 2 84b8.0234.56a8 to 84b8.0234.57d7 FOC12345679 3 84b8.0234.57d8 to 84b8.0234.57e7 FOC12345680 4 84b8.0234.57e8 to 84b8.0234.57f7 FOC12345681 5 not available FOC12345682 6 not available FOC12345683 7 not available FOC12345684 8 not available FOC12345685
The first section shows module number, port count, type, model, and status. 'ok' means operational; 'active *' indicates the active supervisor. The second section shows software version per module. The third section shows MAC address ranges and serial numbers.
Display module details for a specific slot
show module slot 3Mod Ports Module-Type Model Status --- ----- ----------------------------------- ----------------- ----------- 3 0 Supervisor Module N9K-SUP-A active * Mod Sw Hw Slot --- -------------- ------ ---- 3 9.3(5) 1.0 3 Mod MAC-Address(es) Serial-Num --- -------------------------------------- ----------- 3 84b8.0234.57d8 to 84b8.0234.57e7 FOC12345680
Filters output to show only the supervisor module in slot 3. Useful for quickly checking a specific module's status without scrolling through all modules.
Understanding the Output
The 'show module' output is divided into three sections. The first section lists each module by slot number, port count, module type, model number, and status. The status field is critical: 'ok' means the module is fully operational; 'active *' indicates the active supervisor; 'standby' is the redundant supervisor; 'powered-down' means the module is installed but not powered; 'failed' indicates a hardware fault. The second section shows the software version (Sw) and hardware revision (Hw) for each module. All modules should ideally run the same software version for consistency. The third section displays MAC address ranges (for line cards) and serial numbers. Serial numbers are essential for inventory and support cases. If a module shows 'not available' for MAC addresses, it is typical for fabric modules or system controllers that do not have front-panel ports. A healthy chassis shows all modules with status 'ok' or 'active'/'standby' for supervisors. Any 'failed' or 'powered-down' status indicates a problem that needs investigation.
Configuration Scenarios
Verifying module status after a reboot
After a scheduled maintenance reboot of a Nexus 9508 chassis, you need to confirm all modules are online.
Topology
Nexus 9508 chassis with 2 supervisors, 2 line cards, 2 fabric modules, and 2 system controllers.Steps
- 1.Access the switch via SSH or console.
- 2.Enter EXEC mode.
- 3.Run 'show module' and check that all modules show status 'ok' or 'active'/'standby'.
! No configuration required; this is a show command.
Verify: All modules should have status 'ok' except supervisors which show 'active *' and 'standby'. No 'failed' or 'powered-down' statuses.
Watch out: If a module shows 'powered-down', it may be due to power budget issues; check 'show environment power'.
Identifying a faulty line card
A line card in slot 2 is not passing traffic; you suspect hardware failure.
Topology
Nexus 9508 with line cards in slots 1-2.Steps
- 1.Run 'show module slot 2' to check the specific module.
- 2.Look for status 'failed' or 'powered-down'.
- 3.If failed, note the serial number for RMA.
! No configuration required.
Verify: The output shows status 'failed' for slot 2. Serial number is FOC12345679.
Watch out: A module may show 'ok' but still have hardware issues; check 'show logging last 10' for error messages.
Troubleshooting with This Command
When troubleshooting module issues on Cisco Nexus switches, 'show module' is your starting point. Begin by running the command without parameters to get an overview. Look for any module with a status other than 'ok', 'active', or 'standby'. Common problem statuses include 'failed' (hardware fault), 'powered-down' (insufficient power or manually powered off), 'updating' (firmware upgrade in progress), or 'unknown' (communication lost). If a module shows 'failed', note the slot number and serial number, then check 'show logging last 20' for hardware error messages. For 'powered-down', verify power supply status with 'show environment power' and ensure the module is not administratively powered off using 'poweroff module' command. If a supervisor shows 'standby' but not 'hot standby', redundancy may be compromised; check 'show system redundancy status'. For line cards, if the status is 'ok' but interfaces are down, use 'show interface status' to check interface-level issues. Also compare software versions across modules; mismatches can cause instability. If a module is missing from the output entirely, it may not be seated properly or the slot may be disabled. In that case, physically reseat the module and check again. For persistent issues, collect 'show tech-support' for TAC. Remember that fabric modules and system controllers are critical for chassis operation; if they show 'failed', the entire chassis may be affected. Always ensure all modules run the same NX-OS version for consistency.
CCNA Exam Tips
Remember that 'show module' is the primary command to verify module status; 'show inventory' provides more detailed hardware IDs.
On Nexus switches, the active supervisor is marked with an asterisk (*) and 'active' status; the standby supervisor shows 'standby'.
Know that fabric modules and system controllers do not have MAC addresses; their MAC field shows 'not available'.
Common Mistakes
Confusing 'show module' with 'show interface status' – the former shows hardware modules, the latter shows interface line protocol status.
Assuming all modules must have MAC addresses; fabric modules and system controllers do not.
Overlooking the software version column; mismatched versions across modules can cause issues.
Platform Notes
On Cisco Nexus switches, 'show module' differs from Cisco IOS in several ways. IOS uses 'show module' on Catalyst 6500/6800 series, but the output format is different: IOS typically shows a single table with module, ports, type, model, and status, while NX-OS splits the output into three sections. NX-OS also includes fabric modules and system controllers, which are not present on all IOS modular platforms. The asterisk (*) next to the active supervisor is unique to NX-OS. On IOS, the active supervisor is indicated by 'active' in the status column. Additionally, NX-OS supports the 'all' parameter to show powered-down modules, which is not available in IOS. Equivalent commands on other platforms: on Juniper Junos, 'show chassis hardware' provides similar information; on Arista EOS, 'show inventory' and 'show module' are used. For Nexus 9000 series, the command is consistent across all models. In NX-OS versions prior to 7.0, the output might have slight formatting differences, but the key fields remain the same. Always use the latest NX-OS documentation for your specific version.
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