Cisco Systems Cisco 12816 Manuale Utente

This section describes the methods used in troubleshooting the router. The 
troubleshooting methods are organized according to the major subsystems in the 
router.

If you are unable to solve a problem on your own, you can contact a Cisco 
customer service representative for assistance. When you call, have the following 
information ready:

Date you received the router and the chassis serial number (located on a label 
on the back of the chassis). 

Installed line cards. 

Use the show hardware command to determine which line cards are 
installed if possible.

Cisco IOS software release number. 

Use the show version command to determine this information if 
possible.

Brief description of the symptoms and steps you have taken to isolate and 
solve the issue.

Maintenance agreement or warranty information.

To solve a system problem, try to isolate the problem to a specific subsystem. 
Compare current router behavior with expected router behavior. Because a startup 
issue is usually attributable to one component, it is most efficient to examine each 
subsystem, rather than trying to troubleshoot each router component.

For troubleshooting purposes in this chapter, the router consists of the following 
subsystems:

Power subsystem—Includes the following components:

AC-input or DC-input power supplies, also called power entry modules 
(PEMs). The router chassis is shipped with fully-redundant PEMs 
installed in the chassis.