This article describes how to resolve the problems and troubles on router network layering. Network diagnosis is an important technical work to maintain networks.
Network diagnostics can use many tools: router trouble shooting commands, network management tools and LAN/WAN analyzers. Checking the routing table is a good way to find network failures. The commands of ICMP ping, trace, show and debug and Cisco is useful networking tools for obtaining useful troubleshooting information. How to monitor the details and failures under normal networking conditions? Using the command of show interface could easily get the information on each interface that you want to check. Show buffer command could display buffer size and usage regularly. Show proc command and show proc mem command could track the usage of processor and memory. These commands could collect data on a regular basis, and could be used as diagnostic reference.
Steps of network troubleshooting
The first step, you should determine the specific failure phenomena, and analyze the cause. For example, the host has no response on clients request, there are some possible causes such as hosting configuration issue, interface card failure, or router configuration command is missing, and so on.
The second step, you should gather information that could help isolating faults, and collect useful information from network management systems, protocol analysis trace, router output reports or other software introduction.
The third step, you should consider possible failure reasons according to the gathered information, and exclude some certain cause of the failure. For example, you could exclude the hardware failure according to the info and put your focus on the software causes.
The fourth step, you should set up a diagnostic program according to the last possible reasons.
The fifth step, you should perform the diagnostics program, and do every test and observation seriously, and confirm its results when you change a parameter. At last, you should check whether you resolve the failure, if you don’t, go on, until it’s done.
The basic method of troubleshooting network layering: along the path from the source to the target, check the routing table, as well as check the IP address of the interface. If the routing doesn’t appear in the routing table, you should check whether you have entered the appropriate static route, default route, or dynamic route. Then you should manually configure some lost routing or exclude some faults during the process of dynamic routing choice, including the RIP and IGRP routing protocol failure.