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Cisco 12006 and Cisco 12406 Router Installation and Configuration Guide
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Field Diagnostics for the Cisco 12000 Series Router
Field diagnostics are available for all Cisco 12000 Series Routers to help you
isolate faulty hardware to the level of a field-replaceable unit (FRU), without
disrupting the operation of the system. After you identify the faulty unit, you can
replace it with a spare unit.
Field diagnostics are not designed to identify specific components within the
router. They simply determine whether a particular card is operational or
defective.
Note Starting with Cisco IOS Release 12.0(22)S, the line card field diagnostics image
is unbundled from the main Cisco IOS image. Line card field diagnostics are now
stored and maintained as a separate image that must be available on a Flash
memory card or TFTP boot server before the diagnostics commands can be used.
Route processor and switch fabric card field diagnostics continue to be bundled
and do not need to be launched from a separate image.
Unbundled field diagnostics offer the following benefits:
• In-service testing—Field diagnostics can be run on an in-service router
running Cisco IOS and only take the card being tested out of service. If the
tested card passes the diagnostic tests, it is returned to normal operation. If
there is a hardware fault, the card remains out of service after the testing is
completed.