Content

| Overview

Network layer problems include any problem which involves a Layer 3 protocol, both routed protocols and routing protocols. This module will focus primarily on IP routing protocols. Issues concerning routed protocols, such as IP, and other Layer 3 IP protocols, are discussed in the other modules.

Network layer problems may also include issues at the other layers. Configuring routing over a nonbroadcast multiaccess (NBMA) or dialup network can involve specific configuration and troubleshooting issues. Because these configurations involve a specific Layer 2 technology such as Frame Relay, ISDN, and so on, routing problems involving these technologies will be discussed in the module Troubleshooting Layer 2.

This module will focus on the most common troubleshooting issues regarding both static routing and dynamic routing protocols. Troubleshooting dynamic routing protocols is separated by common issues pertaining to most routing protocols, such as Layer 1 issues, incorrect network statements, and by routing protocols including RIP, IGRP, EIGRP, OSPF, IS-IS, and BGP. Troubleshooting redistribution issues with routing protocols are also discussed in this module.