Content

| Overview

Troubleshooting Layer 2 problems can be a challenging process. Although data link protocols are usually quite simple, the configuration and operation of these protocols is critical to creating a functional, well-tuned network.

This module explores the following Layer 2 protocols and technologies and outlines troubleshooting strategies and common problems for each of them:

- Switches and switched technologies
- PPP
- ISDN
- Frame Relay

The interaction of Layer 3 protocols with various Layer 2 protocols is often the source of network problems. Specific examples and trouble shooting techniques for routed and routing protocols in various Layer 2 environments are also examined.