Information Technology Reference
In-Depth Information
The Order of
boot system
Commands Determines Which IOS Is Loaded
Example 3-7
boot system flash mc3810-a2isv5-mz.120-7.XK1.bin
boot system tftp mc3810-a2isv5-mz.120-7.XK1.bin 1.1.1.1
boot system rom
1.1.1.1
Sample Boot Sequence
This section covers a sample boot sequence for a MC3810 router. For the test, you must have a
high level of familiarity with the boot sequence of a router. Following are the four stages:
•
System bootstrap
•
Bootloader
•
Booting of the system IOS image
•
Initialization of interfaces/System Restart
The first stage of the boot sequence is the loading of bootstrap software. The bootstrap software
initializes the CPU and launches the bootloader:
System Bootstrap, Version 11.3(1)MA1, MAINTENANCE INTERIM SOFTWARE
Copyright (c) 1998 by cisco Systems, Inc.
Compiled Sat 24-Jan-98 14:55 by krunyan
PPC860 PowerQUICC, partnum 0x0000, version A03(0x0013)
MC3810 platform with 32768 Kbytes of main memory
The second stage of the boot sequence is the bootloader. The bootloader is not a full router
image. It contains minimal functionality for reading the configuration and accessing the flash
file system (highlighted). The router at this point can act as an end host with no routing
functionality. If the bootloader is not present, the router attempts to load the first file present in
the flash file system. The system identifies which messages are from the bootloader:
System Bootstrap
program load complete, entry point: 0x23000, size: 0x11437c
Self decompressing the image : #################################################
############################################################### [OK]
Slot 3 OK. Configured as T1 TEB CSU Serial #08076360 Version 4.70
Initialize Flash file system
Initialize Flash file system.....
total size = 8388608
flashfs[4]: 1 files, 1 directories
flashfs[4]: 1 orphaned files, 1 orphaned directories
flashfs[4]: Total bytes: 8128000
flashfs[4]: Bytes used: 6757888
flashfs[4]: Bytes available: 1370112flashfs[4]: flashfs fsck took 18 seconds.
flashfs[4]: Initialization complete.
Readfile
(flash:mc3810-a2isv5-mz.120-7.XK1.bin) into ram (0x41E0E0) ...
flashfs[4]: dostat, unable to lookup filemap for fileid 0!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!
Finished - 6697836 bytes
%SYS-6-BOOT_MESSAGES: Messages above this line are from the boot loader.
boot loader
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