Cisco 7400 Series Routers

Document ID: 18676

Interactive: This document offers customized analysis of your Cisco device.

Contents

Introduction
Prequisites
      Requirements
      Components Used
      Hardware-Software Compatibility and Memory Requirements
      Background
      Conventions
Identifying the Issue
      Capturing Information
      Misleading Symptoms
Step-by-Step Troubleshooting
Information to Collect if You Open a TAC Service Request
Related Information

Introduction

Valuable time and resources are often wasted replacing hardware that actually functions properly. This document helps troubleshoot potential hardware issues with the Cisco 7400 Series Router, and provides pointers for identifying a hardware failure.

Note: This document does not cover any software-related failures except for those that are often mistaken as hardware issues.

Prequisites

Requirements

We recommend that you review the following documents before proceeding with this document:

• Cisco 7400 Router Documentation Master Index

• Cisco 7400 Router Port Adapter Documentation Master Index

• Troubleshooting Router Crashes

• Cisco 7400 Series Router Field Notices

Components Used

The information in this document is not specific to any Cisco IOS® software release, but applies to all Cisco IOS software versions that run on the 7400 Series Router. This document covers troubleshooting on the 7400 Series Router for both the Back Bone (BB) and Customer Premise (CP) models.

Hardware-Software Compatibility and Memory Requirements

Whenever you install a new line card, module, or Cisco IOS software image, it is important to verify that the router has enough memory, and that the hardware and software are compatible with the features you wish to use.

Perform the following recommended steps to check for hardware-software compatibility and memory requirements:

1. Use the Software Advisor (registered customers only) tool to choose software for your network device.

   Tips:

   • The Software Support for Hardware (registered customers only) section helps you verify whether the modules and cards installed on the router are supported by the desired Cisco IOS software version.

2. Use the IOS Upgrade Planner (registered customers only) to check the minimum amount of memory (RAM and Flash) required by the Cisco IOS software, and/or download the Cisco IOS software image. To determine the amount of memory (RAM and Flash) installed on your router, refer to the Memory Requirements section of How to Choose a Cisco IOS Software Release.

   Tips:

   • If you want to keep the same features as the version that is currently running on your router, but don't know which feature set you are using, enter the show version command on your router and paste it into the Output Interpreter (registered customers only) to find out. It is important to check for feature support, especially if you plan to use recent software features.

   • If you need to upgrade the Cisco IOS software image to a new version or feature set, refer to How to Choose a Cisco IOS Software Release for more information.

3. If you determine that a Cisco IOS software upgrade is required, follow the Software Installation and Upgrade Procedures for the Cisco 7400 Series Router.

   Tip: For information on how to recover a Cisco 7400 series router stuck in ROMmon (rommon # > prompt), refer to the ROMmon Recovery Procedure.

Background

The Cisco 7400 Application Specific Router (ASR) combines the Network Services Engine (NSE) and Input/Output (I/O) controller card into a single unit. With a single Port Adapter (PA) slot and two fixed 10/100/1000 Ethernet ports, the 7400 takes up only one Rack Unit (RU) of space.

Conventions

For more information on document conventions, refer to the Cisco Technical Tips Conventions.

Identifying the Issue

The Cisco 7400 Series Router can reboot or reload for various reasons, several of which are potential hardware issues. Below are the most common symptoms resulting from a potential hardware issue seen on this platform. The troubleshooting steps for each symptom are listed in the Step-by-Step Troubleshooting section.

Capturing Information

In order to determine what is causing the issue, the first step is to capture as much information about the problem as possible. The following information is essential for determining the cause of the problem:

• Console logs - For more information, refer to Applying Correct Terminal Emulator Settings for Console Connections.

• Syslog information - If the router is set up to send logs to a syslog server, you may be able to obtain information on what happened. For details, refer to the How to Configure Cisco Devices for Syslog section of Resource Manager Essentials and Syslog Analysis: How-To.

• show technical-support command output - The show technical-support command is a compilation of many different commands including show version, show running-config, and show stacks. TAC engineers usually ask for this information to troubleshoot hardware issues. It is important to collect the show technical-support information before doing a reload or power-cycle as these actions can cause all information about the problem to be lost.

• The complete bootup sequence if the router experiences boot errors.

• Crashinfo File (if available) - Information on obtaining the crashinfo file can be found at Retrieving Information from the Crashinfo File.

If you have the output of a show command from your Cisco device (including show technical-support), you can use the Output Interpreter (registered customers only) to display potential issues and fixes. To use the Output Interpreter (registered customers only) , you must be logged in and have JavaScript enabled.

Misleading Symptoms

There are a few issues that can be misinterpreted as hardware problems when, in fact, they are not. For instance, a failure following a new hardware installation is not always a hardware issue. Another example is when the router stops responding or "hangs". The table below provides symptoms, explanations, and troubleshooting steps for these commonly misinterpreted issues:

Router uptime is 2 days, 21 hours, 30 minutes
System restarted by bus error at PC 0x30EE546, address 0xBB4C4
System image file is "flash:igs-j-l.111-24.bin", booted via flash 
.........

*** System received a Bus Error exception *** 
signal= 0xa, code= 0x8, context= 0x608c3a50
PC = 0x60368518, Cause = 0x20, Status Reg = 0x34008002

Router uptime is 1 minute 
System restarted by abort at PC 0x802737BC 
System image file is "flash:c2600-i-mz.120-4.T"

Router uptime is 2 minutes 
System restarted by trace trap at PC 0x3171310 
System image file is "flash:c2500-jos56i-l.120-9.bin" 

For more information, refer to Less Common Types of System Crashes.

Step-by-Step Troubleshooting

• Parity errors - Parity errors can occur on the Cisco 7400 Series Router, including:

  • PCI Bus Parity Errors: These can be caused by a mis-seated or faulty port adapter (PA) or a faulty main board. The error messages should look something like this:

       %ERR-1-GT64120A (PCI0):Fatal error, Parity error on master read
       GT=B4000000, cause=0x0110E083, mask=0x0ED01F00, real_cause=0x00100000   
       Bus_err_high=0x00000000, bus_err_low=0x00000000,
    
       addr_decode_err=0x00000470
       %ERR-1-SERR: PCI bus system/parity error
       %ERR-1-FATAL: Fatal error interrupt, No reloading
       Err_stat=0x81, err_enable=0xFF, mgmt_event=0x40
    

    Do not be concerned if your error message contains "GT64010" or "GT64120A". These are the same components, but with different revisions. Because of the similarities between the Cisco 7200 Series Routers and the Cisco 7400 Series Routers, it is recommended that you review the Cisco 7200 Parity Error Fault Tree page (section GT64120 System Parity Error Master Read) to determine the potential component causing this issue.

  • Processor Memory Parity Errors: Follow the applicable instructions on the Cisco 7200 Parity Error Fault Tree page to troubleshoot this error message.

• System Restarted By Bus Error Exception: This can be either hardware- or software-related. Below is an example of such an error message:

     *** System received a Bus Error exception ***
     signal= 0xa, code= 0x18, context= 0x6206b820
     PC = 0x606e356c, Cause = 0x6020, Status Reg = 0x34008002

  For potential hardware-related issues, follow these steps:

  1. Power down the router and remove the Port Adapter (PA) from the unit. Power the system back up and see if the problem continues.

  2. If the system reloads correctly, place the PA back into the router, power the system back up and see if the problem continues. The purpose of this step is to remove the possibility of the PA being mis-seated.

  3. If the system does NOT reload correctly, and continues to reboot or display the Bus Error Exception message, further investigation is necessary to determine the root cause of the errors. The issue might be within the chassis or it could be a software error. You can open a TAC case for further troubleshooting. Ensure that you include all relevant information (for example, troubleshooting logs, troubleshooting steps taken, and so on).

• Continuously Rebooting: If the Cisco 7400 Series Router is continuously rebooting, even after a power-cycle of the router, follow these steps:

  1. Remove the PA, then power-cycle the router.

  2. If it still fails, check if there is a valid image on the Compact Flash Disk. In order to do this, you must be directly connected to the console port of the router. Send the break key within the first 60 seconds of bootup to go into ROMmon. From there, you can follow the procedures in the ROMmon Recovery Procedure to try to recover.

  3. If the router still does not boot, and you are sure that there is a valid image on it, then further investigation is necessary to determine the root cause of the errors. The issue might be within the chassis or it could be a software error. You can open a TAC case for further troubleshooting. Ensure that you include all relevant information (for example, troubleshooting logs, troubleshooting steps taken, and so on).

Information to Collect if You Open a TAC Service Request

Related Information

• Standard Break Key Sequence Combinations During Password Recovery
• Retrieving Information from the Crashinfo File
• ROMmon Recovery Procedure
• Troubleshooting Router Hangs
• Troubleshooting High CPU Utilization on Cisco Routers
• Troubleshooting Memory Problems
• Troubleshooting Router Crashes
• Cisco 7200 Parity Error Fault Tree
• Technical Support - Cisco Systems