Cisco TSHOOT 2.0: Troubleshooting Layer 2 Switching and Inter-VLAN Routing

This course is included in our On-demand training solution.


Switched Ethernet has been the dominant LAN technology for more than a decade and VLAN-based switched infrastructures are at the core of every campus network. A good understanding of the processes involved in Layer 2 switching and being able to diagnose and resolve Layer 2 switching problems in those environments is a fundamental skill that any network engineer should have.
A primary tool in building highly available networks is the use of redundant devices and links. With these redundant links, bridging loops can be introduced, resulting in broadcast storms that can potentially cripple the network. The Spanning Tree Protocol (STP) acts as a safety net by breaking those loops and preventing broadcast storms. Spanning tree failures can be catastrophic when they happen, so recognizing the symptoms and having an action plan for these types of failures is a skill that is essential in reducing network downtime.
The traditional distinction between routers and switches has become blurred over the past decade and multilayer switches have taken over the role of the router in the campus LAN environment. It is important for network engineers to understand the differences between hardware-accelerated Layer 3 switching and software-based routing architectures, and how these differences translate to the troubleshooting process.
In this course, the Layer 2 switching process and associated switch data structures are reviewed, as is the diagnosing of VLAN and trunking problems using the Cisco IOS command line interface. It will also explain how to diagnose spanning-tree problems using the Cisco IOS command line interface. Multilayer switching concepts and how to diagnose specific problems related to multilayer switching, switched virtual interfaces (SVIs), and inter-VLAN routing are also detailed.

Target Audience

Professionals who work in complex network environments desiring the skills they need to maintain their networks and to diagnose and resolve network problems quickly and effectively. The TSHOOT learning path will provide information about troubleshooting and maintaining particular technologies, as well as procedural and organizational aspects of the troubleshooting and maintenance process. A large part of the training will consist of practicing these skills and reinforcing the concepts by putting them to use in a controlled environment. At the end of the learning path, you should have increased your skill level and developed a set of best practices that are based on your own experience that you can take back to your organization.



Expected Duration

120 min.

Course Objectives

Course Introduction

Troubleshooting Layer 2 Forwarding

  • identify the commands that can be used when troubleshooting Layer 2 forwarding
  • Troubleshooting SDM Templates

  • recognize how an SDM template can affect switch features
  • Troubleshooting 802.1q Trunks

  • describe issues that may affect 802.1q trunks
  • Troubleshooting Trunking: Partial VLANs over a Trunk

  • troubleshoot a trunking issue
  • Troubleshooting VLANs

  • identify issues that are specific to VLAN operations
  • Troubleshooting Inactive, Suspended, and Shutdown VLANs

  • troubleshoot a VLAN issue
  • Troubleshooting VTP

  • identify issues that are specific to VTP operations
  • Troubleshooting Layer 2 EtherChannel

  • identify issues that are specific to EtherChannel operations
  • Troubleshooting STP

  • describe issues that affect STP operation
  • Troubleshooting RSTP and MSTP

  • troubleshoot an RSTP issue
  • Troubleshooting the STP Toolkit

  • describe the functionality of features of the STP Toolkit
  • Router-on-a-Trunk Operation Issues

  • describe router-on-a-trunk operational issues
  • Router-on-a-Trunk Configuration

  • configure router-on-a-trunk
  • Router-on-a-Trunk Operation: Trunk Encapsulation

  • troubleshoot a trunk encapsulation issue
  • Router-on-a-Trunk Operation: VLAN Issues

  • troubleshoot a router-on-a-trunk VLAN issue
  • Router-on-a-Trunk Operation: Subinterface Parameters

  • troubleshoot a router-on-a-trunk subinterface issue
  • Switch Virtual Interface (SVI) Operation Issues

  • describe SVI operational issues
  • SVI Configuration

  • configure an SVI
  • SVI Operation

  • troubleshoot SVI operation
  • SVI Operation: No Ports in the STP Forwarding State

  • troubleshoot an SVI port state issue
  • Routed Ports

  • recognize routed port operational issues
  • Routed Port Operation: Switchport Operation

  • troubleshoot a routed port issue
  • Layer 3 EtherChannel

  • recognize Layer 3 EtherChannel operational issues
  • Layer 3 EtherChannel Protocols

  • troubleshoot an EtherChannel protocol issue
  • Troubleshooting InterVLAN Routing

  • troubleshoot an inter-VLAN routing issue
  • Exercise: Troubleshoot Layer 2 Issues