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Chapter 5
Applying Cisco's Diagnostic Tools
(fc1)
Router_B uptime is 3 hours, 11 minutes
System restarted by reload
Running default software
cisco 2500 (68030) processor (revision A) with 4096K/2048K
bytes of memory.
Processor board ID 01229726, with hardware revision
00000000
X.25 software, Version 2.0, NET2, BFE and GOSIP compliant.
Cisco-ET Extended Temperature platform.
1 Ethernet/IEEE 802.3 interface.
2 Serial network interfaces.
32K bytes of non-volatile configuration memory.
8192K bytes of processor board System flash (Read/Write)
Configuration register is 0x2101
Router_B(boot)#
The response is that it is running a bootstrap version of IOS, which displays
in the first few fields. From these two outputs, it can be deduced that the IOS
contained in flash memory was not used to boot the router.
As previously mentioned, the IOS image could be corrupt, or the router is look-
ing for the IOS in the wrong place. The router uses a configuration register to point
to the location of the IOS image that it should load during the boot process.
For a full description of config-register settings, refer to CCO. To briefly
explain, the config-register is a 16-bit number that controls the router's boot
sequence. The lowest four bits indicate from where the system image, or IOS, will
be loaded. If the value is 0000, then the router enters into ROM monitor mode. If
the register is set to 0001, then the IOS will be loaded from the boot ROM.
In this case, the configuration register was set to the hex value of
0x2101, which tells the router to look for the system image on the boot
ROM. Remember that it is only the first four bits that indicate the system
image location.
The action plan for this scenario is to change the configuration register
on Router B to load the image from system flash. The configuration
changes follow. After the router reloads, a quick check can be made by
issuing a show version command.
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