Module 9: Basic Router Troubleshooting

Module 9: Basic Router Troubleshooting

Overview A router uses a dynamic routing protocol to learn about routes to destination networks. Most routers use a combination of dynamic routing and manually configured static routes. Regardless of the method used, when a router determines that a route is the best path to a destination, it installs that route in its routing table. This module will describe methods that are used to examine and interpret the contents of the routing table.
Network testing and troubleshooting are perhaps the most time consuming components of every network administrator’s job. Efficient testing and troubleshooting must be done in a logical, orderly, and well-documented fashion. Otherwise, the same problems will reoccur, and the network administrator will never truly understand the network. This module describes a structured approach to network troubleshooting and provides some tools to use in the troubleshooting process.
Routing problems are among the most common and difficult for network administrators to diagnose. There are many tools that make it easier to identify and solve routing problems. This module will introduce several of the most important of these tools and provide practice in their use.
This module covers some of the objectives for the CCNA 640-801, INTRO 640-821, and ICND 640-811 exams. - 
Students who complete this module should be able to perform the following tasks:

• Use the show ip route command to gather detailed information about the routes installed on the router
• Configure a default route or default network
• Understand how a router uses both Layer 2 and Layer 3 addressing to move data through the network
• Use the ping command to perform basic network connectivity tests
• Use the telnet command to verify the application layer software between source and destination stations
• Troubleshoot by sequential testing of OSI layers
• Use the show interfaces command to confirm Layer 1 and Layer 2 problems
• Use the show ip route and show ip protocol commands to identify routing issues
• Use the show cdp command to verify Layer 2 connectivity
• Use the trace route command to identify the path packets take between networks
• Use the show controllers serial command to ensure the proper cable is attached

Use basic debug commands to monitor router activity