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The goal of this publication is to help you isolate and resolve the most common connectivity and performance problems for your Cisco ATM switch as it fits into your network environment.
This chapter contains the following sections:
Failures in internetworks are characterized by certain symptoms. These symptoms might be general (such as clients that are unable to access specific servers) or more specific (routes that are not in the routing table). Each symptom can be traced to one or more problems or causes by using specific troubleshooting tools and techniques. When you know what the problem is, you can take steps to fix it.
This publication describes how to define symptoms, identify problems, and implement solutions in Cisco ATM switch environments.
Figure 1-1 illustrates the process for the general model of problem solving. This process is not a rigid outline for troubleshooting an internetwork. It is a foundation on which you can build a problem-solving process for your environment.
The following steps detail the problem-solving process outlined in Figure 1-1:
Step 1 When you analyze a network problem, create a clear statement of the problem. You should define symptoms and potential causes.
Step 2 Gather the facts you need to help isolate possible causes.
Step 3 Consider possible problems based on the facts you gathered, which can help eliminate potential problems from your list.
Step 4 Create an action plan based on the remaining potential problems. Begin with the most likely problem and devise a plan in which only one variable is manipulated.
Step 5 Implement the action plan, performing each step carefully while testing to see if the symptom disappears.
Step 6 Analyze the results to determine whether the problem has been resolved. If it has, then the process is complete.
Step 7 If the problem has not been resolved, create an action plan based on the next most likely problem in your list. Return to Step 4 and repeat the process until the problem is solved.
Make sure that you undo anything you changed while implementing your action plan. Remember that you want to change only one variable at a time.
1. Do you have an accurate physical and logical map of your internetwork that outlines the physical location of all of the devices on the network and how they are connected, as well as a logical map of network addresses, network numbers, subnetworks, and so forth?
2. Do you have a list of all network protocols implemented in your network for each of the protocols implemented, do you have a list of the network numbers, subnetworks, zones, areas, and so on that are associated with them?
3. Do you know which protocols are being routed and have correct, up-to-date configuration information for each protocol?
4. Do you know which protocols are being bridged? Are there any filters configured in any of these bridges, and do you have a copy of these configurations?
5. Do you know all the points of contact to external networks, including any connections to the Internet? For each external network connection, do you know what routing protocol is being used?
If you can answer yes to these questions, you will be able to recover from a failure more quickly and more easily than if you are not prepared.
This section describes where to find troubleshooting, installation, and configuration information for non-ATM related switch problems, and includes:
Refer to the following publications for specific software configuration and command reference information:
Refer to the following publications for more detailed information about booting problems, specific hardware, including descriptions of specific LEDs, configuration information, and additional troubleshooting information:
Refer to the chapter "Troubleshooting Hardware and Booting Problems" in the Internetwork Troubleshooting Guide for general information describing booting problems.
The information referred to here is by no means comprehensive. Instead, it offers solutions to the problems most commonly encountered when using Ethernet media.
Refer to the LightStream 1010 ATM Switch ASP Configuration Guide and the LightStream 1010 ATM Switch Hardware Installation Guide for more detailed information about specific Ethernet LAN media problems, including descriptions of specific LEDs, configuration information, and additional troubleshooting information.
Refer to the chapter "Troubleshooting LAN Media Problems" of the Internetwork Troubleshooting Guide for general information describing Ethernet LAN media problems.
Refer to the LightStream 1010 ATM Switch ASP Configuration Guide for more detailed information about specific Ethernet, auxiliary and console port connection information, including descriptions of specific LEDs, configuration information, and additional troubleshooting information.
Refer to the chapter "Troubleshooting Dialin Connections" of the Internetwork Troubleshooting Guide for general information describing Ethernet, auxiliary, and console port connection problems.
Refer to the chapter "Troubleshooting TCP/IP" of the Internetwork Troubleshooting Guide for general information describing TCP/IP configuration problems.
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