Troubleshooting TechNotes
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- Configuring MST (802.1s)/RSTP (802.1w) on Catalyst Series Switches Running CatOS 16/Nov/2007
- Spanning Tree PortFast BPDU Guard Enhancement 12/May/2025
- Spanning Tree Protocol Problems and Related Design Considerations 10/Jul/2025updated
- Spanning Tree Protocol Root Guard Enhancement 13/Dec/2024
- Troubleshooting Spanning Tree PVID- and Type-Inconsistencies 14/Mar/2024
- Troubleshooting STP on Catalyst Switches Running Cisco IOS System Software 28/Aug/2024
- Understanding and Configuring Backbone Fast on Catalyst Switches 19/Apr/2016
- Understanding and Configuring the Cisco UplinkFast Feature 18/Aug/2008
- Understanding and Tuning Spanning Tree Protocol Timers 02/Feb/2023
- VLAN Load Balancing Between Trunks Using the Spanning-Tree Protocol Port Priority 30/Aug/2005
- Common Causes of Slow IntraVLAN and InterVLAN Connectivity in Campus Switch Networks 16/Nov/2007
- Configuring and Troubleshooting IP MLS on Catalyst 6500/6000 Switches with an MSFC 30/Aug/2005
- Supported Platforms for Unique MAC Address Configuration on VLAN or L3 Interfaces for Catalyst Switches 02/Mar/2007
- Understanding Issues Related to Inter-VLAN Bridging 09/Sep/2005
- Understanding VLAN Trunk Protocol (VTP) 02/Apr/2025
- Configuring ISL Trunking on Catalyst 5500/5000 and 6500/6000 Family Switches 07/Dec/2007
- Inter-Switch Link and IEEE 802.1Q Frame Format 25/Aug/2006
- Trunking Between Catalyst 4500/4000, 5500/5000, and 6500/6000 Series Switches Using 802.1Q Encapsulation with Cisco CatOS System Software 26/May/2006
- Understanding EtherChannel Inconsistency Detection 11/Apr/2024
- Understanding EtherChannel Load Balancing and Redundancy on Catalyst Switches 30/Nov/2023
- Comparing Layer 2 Operations in CatOS and Cisco IOS System Software on the Catalyst 6500/6000 10/Jan/2006
- Configuring and Troubleshooting Ethernet 10/100/1000Mb Half/Full Duplex Auto-Negotiation 04/Dec/2024
- Configuring System Information on Catalyst Switches
- How to Get Catalyst Switch Backplane Utilization Using SNMP 21/May/2006
- Troubleshooting LAN Switching Environments 02/Dec/2022
- Troubleshooting Transparent Bridging Environments 04/Oct/2005
- Understanding and Configuring the Unidirectional Link Detection Protocol Feature 09/Jul/2007
- Unicast Flooding in Switched Campus Networks 08/Feb/2016
- Catalyst 6500 Switches QoS Troubleshooting 03/Oct/2006
- QoS Classification and Marking on Catalyst 6500/6000 Series Switches That Run Cisco IOS Software 08/Dec/2005
- QoS Output Scheduling on Catalyst 6500/6000 Series Switches Running Cisco IOS System Software
- QoS Policing on Catalyst 6500/6000 Series Switches 02/Jan/2006
- Catalyst 6500/6000 Switch High CPU Utilization 27/Aug/2012
- Catalyst 6000/6500 System Crashes Troubleshooting 13/Jun/2016
- Catalyst 6500/6000 Series Switches with Supervisor Engine 720 and Cisco IOS System Software Troubleshoot of Unicast IP Routing Problems That Involve CEF 11/Dec/2008
- Common CatOS Error Messages on Catalyst 6500/6000 Series Switches 28/Nov/2008
- Troubleshoot Unicast IP Routing Involving CEF on Catalyst 6500/6000 Series Switches with a Supervisor Engine 2 and Running CatOS System Software 05/Jun/2008
Configuration and Troubleshooting - Spanning Tree Protocol
Configuration and Troubleshooting - SPAN and ARP
Configuration and Troubleshooting - VLAN, VTP, Layer 3 and MLS
Configuration and Troubleshooting - EtherChannel and Trunking (802.1Q/ISL)
Configuration and Troubleshooting - General
Configuration and Troubleshooting - IP Services
Configuration and Troubleshooting - Multicast
Configuration and Troubleshooting - Quality Of Service(QoS)
Configuration and Troubleshooting - VSS
Connectors and Cabling, Connecting Terminal/Modem to Console
DLSw and MSFC
Hardware
Security and VPN
Software Conversion, Upgrade and Recovery
Troubleshooting Hardware
Troubleshooting Modules
Troubleshooting Switch Port Problems
Troubleshooting System Crashes and High CPU utilization
Troubleshooting – Unicast IP routing and common error messages
Voice and Unified Communications
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- CAT 6500 and 7600 Series Routers and Switches TCAM Allocation Adjustment Procedures 18/Aug/2014
- Catalyst 6500 Series Switch ISSU Upgrade Procedure with 6800IA (FEX) Connected 06/May/2014
- Cisco Small Form-Factor Pluggable (SFP) Transceiver Modules Maintenance and Troubleshooting (PDF - 345 KB) 23/Sep/2014
- Troubleshooting Cisco Catalyst Switches to NIC Compatibility Issues (PDF - 183 KB) 19/Sep/2014
- Best Practices for Catalyst 4500/4000, 5500/5000, and 6500/6000 Series Switches Running CatOS Configuration and Management 29/Nov/2007
- Catalyst 6500 Series Switches Netflow TCAM Utilization Management 20/Aug/2013
- Catalyst 6500 Series Switches SPAN Captures for CPU-Bound Traffic 20/Sep/2013
- Catalyst 6500 Series Switches with Supervisor Engine 720 ELAM Procedure 11/Nov/2013
- Catalyst 6500 Series Switches with Supervisor Engine 2T ELAM Procedure 21/Oct/2013
- Catalyst 6500 Series Switches: Identify a Module Affected by an LTL Parity Check 16/Aug/2013
- Catalyst 6500, 4500, and 3750 Series Switches EtherChannel Load-Balancing 25/Jul/2013
- Common Error Messages on Catalyst 6500/6000 Series Switches Running Cisco IOS Software 14/Jul/2016
- Configuring a Management IP Address on Catalyst 4500/4000, 5500/5000, 6500/6000, and Catalyst Fixed Configuration Switches 15/Mar/2006
- ELAM Overview 27/Sep/2016
- Upgrade Software Images on Catalyst Switch Layer 3 Modules 04/Dec/2006
- Line Cards Power Down due to Communication Failures Troubleshooting Guide 20/Jun/2013
- Use Parity Errors Troubleshooting Guide 15/Nov/2023
- Troubleshoot Catalyst Switches to NIC Compatibility Issues 27/Oct/2009
- Understanding and Troubleshooting the Autostate Feature in Catalyst Switches 06/May/2005
- Use of EEM Scripts to Monitor High CPU Utilization on Cisco Catalyst Series Switches 22/Nov/2017
- WiSM-2 2DP Deployment Guide 16/Jan/2015
- EARL 8 Classification Manager: A Behavioral Examination of LOUs, L4Ops, and Capmap Tables 30/Nov/2016
- Multicast Catalyst Switches Support Matrix (PDF - 133 KB)
- Troubleshooting STP on Catalyst Switches Running Cisco IOS System Software (ZIP - 76 KB)
- Troubleshooting Spanning Tree PVID- and Type-Inconsistencies (ZIP - 69 KB)
Support Documentation
Troubleshooting