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Chapter 4
Cisco's Diagnostic Commands
As you can see, the output contains a great deal of information. Let's move
through it field by field. The first field indicates the revision of software that
is actively running on the router. In this case, it is Cisco IOS11.1(25)CC.
The next field is the bootstrap version, which indicates the Cisco IOS that
is used in case the IOS isn't found. This IOS is stored on the PROMS or
FLASH memory of the router. The router boots by using 11.1(8)CA. This
allows the router to actually boot so that you may fix software problems.
Current router status information is located in the field following the
bootstrap information. This output tells you the length of time the router has
been up and the last date it was reloaded. If an error caused the router to
reload, the error message is included in this field. Finally, the file that was
used while booting is listed.
The final field describes the route processor and amount of RAM. At the
end of the field, all interface processors are listed, followed by the number of
interfaces. The last three lines indicate the different amounts and types of
memory.
Because this output is from a Cisco 7513 that contains two RSP4 proces-
sor boards, the show version command also lists information about the
slave board. (In routers with two RSP boards, one board takes the role of the
master, and the other becomes the slave.)
startup-config and running-config
These two commands are used to view the syntax of the router's configura-
tion. The show startup-config command displays the contents of the
configuration that was written to NVRAM. The show running-config,
show config
, and write term commands are all equivalent commands.
The results of these commands display the configuration that was loaded
into memory and is running on the router.
Although you should already be familiar with these commands, it is a very
good troubleshooting tip to compare the two configurations when working
on network problems. It is always possible that configuration changes were
made to the running configuration and were not copied to the start-up
configuration. There may be extra or missing commands in the different con-
figuration versions. You may be able to solve the problem of missing com-
mands in the running configuration quickly by copying the startup-
config
to the running-config.
These commands provide you with global, protocol, and interface informa-
tion. You can analyze them for proper configuration and make changes, if
needed. Many problems can be isolated by viewing the configuration. Most of
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