ccnax exam

ccnax exam.A multimedia demonstration of booting a Cisco router is included in the digital resources that accompany this book.For the above output, there are a few things to note. First, note that the router is loading the bootloader ( System Bootstrap, Versionll.O(lOc)), followed by loading the IOS image ( IOS (tm) 2500 Software (C2500-LL), Version 12.0(5)). o During the boot process, you do not see the POST process (this is different from the Catalyst switches). However, you will see a message about interface enable and disable, which is the IOS loading the configuration and enabling the interfaces that you have previously activated. If the router has a lot of interfaces, the message PressRETURN toget started! may be mixed in with the interface messages. When the message is displayed, pressRETURN to enter user EXEC mode. At this point, the router startup process is complete.At startup, the router runs POST, loads the bootloader, finds and loads the IOS, and loads the configuration file, in that order.Chapter 15 Router Initial Configuration 35915.2.1 BootloaderAs you can see from the previous boot example, the bootloader finds and loads the IOS. the bootloader takes the following steps to find and load the IOS image.1. Check the configuration register value. This value is a 4-bit hexadecimal number, where the last bit is the one that affects the boot process. If the last bit is 0x2.OxF, the router will proceed to step 2; otherwise, the router will decide what to do next according to Table 15.1.Look in the configuration file in NVRAM for boot system commands that tell the bootloader where to look for the I0S. These commands are listed later.3. If the boot system command is not found in theNVRAM the boot system command is not found in the configuration file, the first valid I0S image in flash memory will be used.