Chapter 8. Troubleshooting the Data Link Layer

Terms you'll need to understand:

• Convergence Time

• Internetwork Operating System (IOS)

• Inter-Switch Link (ISL)

• POST (Power-on Self Test)

• Spanning Tree Protocol (STP)

Techniques you'll need to master:

• Troubleshoot switched connections

• Identify switch troubleshooting commands

• Troubleshoot switch hardware and software

• Troubleshoot VTP, ISL, and Spanning Tree Protocol configurations

• Identify switch troubleshooting and configuration software

• Recover a lost password

• Learn the diagnostic tools to apply to Catalyst 5000 problems

• Learn which diagnostic tools to apply to VLAN configuration problems

• Troubleshoot inter-VLAN routing configurations

• Troubleshoot trunk links and switches and routers

The Cisco Support Exam Layer 2 switch-troubleshooting objective focuses on your knowledge of the Set/Clear command set IOS, such as that used on the Cisco 5000 series switch and the Cisco Command Line Interface (CLI) IOS used in the Cisco 4500 series switch. The exam tests your knowledge on the LEDs found on the switch and its modules, the Set/Clear command set, and the show commands associated with the switch.

Cisco is introducing so many generations of switches and protocols that it seems natural that implementing different switches will cause problems. Switches have provided so many advantages over hubs and bridges that Cisco has implemented components , as well as software, to support data traffic not only at Layer 2, but also at Layers 3, 4, and even 5.