KB 702007 - Cisco Nexus 9300 Series Switches: Features & Generic Troubleshooting Commands
This
article provides a comprehensive document for enabling features and Generic troubleshoot commands on
Cisco Nexus 9300 Series switches operating NX-OS . The scope of
this includes physical Ethernet ports, Layer 2&3 , management interfaces.
1.Product Overview
The Cisco Nexus 9300 Series represents a
family of high-performance, fixed-configuration Ethernet switches engineered to
meet the rigorous demands of contemporary data center architectures.
Purpose-built for scalable and resilient operations, these platforms deliver
high-density, wire-speed, nonblocking throughput to ensure deterministic
performance for latency-sensitive applications.
2.Initial Troubleshooting Checklist
Follow these steps for a systematic approach to interface
issues:
- Verify Physical Media: Inspect cables and connectors for any visible damage.
- Check SFPs/Transceivers: Ensure you are using only Cisco-authorized SFPs. Verify that they are securely seated and not defective.
- Enable the Port: Confirm the interface is not administratively down by using the no shutdown command in interface configuration mode.
- Check Interface State: Use the show interface <interface> command to see the current status (e.g., up, down, err disabled).
- Review Port Group Configuration: If the port is in a dedicated port group, ensure no cables are connected to the other three ports in that group.
- Baseline Counters: To get accurate data for error analysis, clear the interface counters to reset the baseline:
3. Common CLI Commands for Troubleshooting
- show interface <interface>:Displays detailed status, speed, duplex, VLAN, and error statistics.
- show interface status: Provides a summary of interface administrative status and operational status.
- show interface counters: Displays packet and error counters for all interfaces.
Need to clear all counter use clear
counters interface all
- show interface capabilities: Shows the hardware capabilities and supported configurations for an interface.
- show vlan brief: Displays the status of all VLANs and their associated ports.
- show logging logfile: Displays system logs which are critical for identifying the cause of interface resets or errors.
- show udld / show tech-support udld: Used for troubleshooting Unidirectional Link Detection (UDLD) issues.
- show running-config interface <interface>:Shows the current running configuration applied to a specific interface.
Reference image
4.Common Feature Commands by Category
Layer 2 Features
|
Command |
Purpose |
|
feature lacp |
Enables Link Aggregation Control Protocol for dynamic port channels |
|
feature vpc |
Enables Virtual Port Channel functionality |
|
feature interface-vlan |
Enables creation of SVIs for Layer 3 VLAN interfaces |
|
feature lldp |
Enables Link Layer Discovery Protocol |
|
feature cdp |
Enables Cisco Discovery Protocol |
|
feature span |
Enables Switched Port Analyzer (port mirroring) |
|
feature udld |
Enables UniDirectional Link Detection |
|
feature stp |
Enables Spanning Tree Protocol (though basic STP is often on by default) |
Layer 3 Features
|
Command |
Purpose |
feature ospf |
Enables OSPF routing protocol |
|
feature eigrp |
Enables EIGRP routing protocol |
|
feature isis |
Enables IS-IS routing protocol |
|
feature bgp |
Enables BGP routing protocol |
|
feature rip |
Enables RIP routing protocol |
|
feature static |
Enables static routing extensions (usually on by default) |
5.Reference
- Cisco Documentation: Cisco Nexus 93120TX Switch - Cisco [Link to Cisco Nexus Cisco Nexus 93120TX Switch]
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