2MANAGING CISCO IOSDetermine how a Cisco device locates and loads the Cisco IOSUse the boot system commandIdentify the configuration register valuesBriefly describe the files used by the Cisco IOS and their functionsList the locations on the router of the different file typesBriefly describe the parts of the IOS nameSave and restore configuration files using TFTP and copy-and-pasteLoad an IOS image using TFTPLoad an IOS image using XModemVerify the file system using show commands
3Identify the stages of the router boot sequence MANAGING CISCO IOSIdentify the stages of the router boot sequenceThe startup routines must do the following:Test the router hardware.Find and load the Cisco IOS software.Find and apply configuration statements, including protocol functions and interface addresses
5MANAGING CISCO IOS How a Cisco device locates and loads IOS The default source for Cisco IOS software depends on the hardware platform, but most commonly the router looks to the boot system commands saved in NVRAMCisco IOS software allows several alternatives to be used. Other sources can be specified for the software, or the router can use its own fallback sequence to load the software
7MANAGING CISCO IOSROM – If flash memory is corrupted and the network server fails to load the image, booting from ROM is the final bootstrap option in software. However, the system image in ROM will likely be a subset of the Cisco IOS that lacks the protocols, features and configurations of the full Cisco IOS
8MANAGING CISCO IOS Troubleshooting IOS boot failure In the event that the router does not boot properly, there are several things that could be wrong:Configuration file has missing or incorrect boot system statementIncorrect configuration register valueCorrupted flash imageHardware failure
9MANAGING CISCO IOSWhen the router boots, it looks in the configuration file for a boot system statement. This boot system statement can force the router to boot from another image instead of the IOS in flash.An incorrect configuration register setting will prevent the IOS from loading from flash
10MANAGING CISCO IOSThe value in the configuration register tells the router where to get the IOSThis can be confirmed by using the show version command and looking at the last line for the configuration register
14MANAGING CISCO IOSTo identify the different versions, Cisco has a naming convention for IOS files. This IOS naming convention uses different fields in the name. Among the fields are the hardware platform identification, the feature set identification, and the numerical release
16MANAGING CISCO IOSThe first part of the Cisco IOS file name identifies the hardware platform for which this image is designed.The second part of the IOS file name identifies the various features that this file contains. There are many different features to choose from. These features are packaged in "software images". Each feature set contains a specific subset of Cisco IOS features
17MANAGING CISCO IOSThe third part of the file name indicates the file format. It specifies if the IOS is stored in flash in a compressed format and whether the IOS is relocatableThe fourth part of the file name identifies the release of the IOS. As Cisco develops newer versions of the IOS, the numerical version number increases.
18MANAGING CISCO IOS Managing configuration files using TFTP Enter the command copy running-config tftp.At the prompt, enter the IP address of the TFTP server to store the configuration file.Enter the name to assign to the configuration file or accept the default name.Confirm the choices by typing yes each time.
20MANAGING CISCO IOS Enter the command copy tftp running-config. At the prompt, select a host or network configuration file.At the system prompt, enter the IP address of the TFTP server where the configuration file is located.At the system prompt, enter the name of the configuration file or accept the default name.Confirm the configuration filename and the server address that the system supplies.
22MANAGING CISCO IOS Managing configuration files using copy and paste Perform the following to capture the configuration using the text displayed on the HyperTerminal screen to a text file
23MANAGING CISCO IOS Select Transfer Select Capture Text Specify the name for the text file to capture the configurationSelect Start to start capturing textDisplay the configuration to the screen by entering show running-configPress the space bar when each "-More -" prompt appearsWhen the complete configuration has been displayed, stop the capture by:Select Stop
25MANAGING CISCO IOSAfter the capture is complete, the configuration file needs to be edited to remove extra text. To create this in a form to be “pasted” back into the router, remove any unnecessary information from the captured configuration
26MANAGING CISCO IOSThe configuration file can be edited from a text editor such as Notepad. To edit the file from Notepad click on File > Open. Find the captured file and select it. Click Open.The lines that need to be deleted contain
27MANAGING CISCO IOS show running-config Building configuration... Current configuration:- More -Any lines that appear after the word "End"
28MANAGING CISCO IOSHyperTerminal can be used to restore a configuration. The clean backup of the configuration can be copied into the router.
29MANAGING CISCO IOS Enter router global configuration mode. From HyperTerminal, click on Transfer > Send Text File.Select the name of the file for the saved backup configuration.The lines of the file will be entered into the router as if they were being typed.Observe any errors.After the configuration is entered, press Ctrl-Z key to exit global configuration mode.Restore the startup configuration with copy running-config startup-config.
30MANAGING CISCO IOS Managing IOS images using TFTP Occasionally the router will need to have the IOS upgraded or restoredThis server should have a TFTP service running. The IOS backup can be initiated from the privileged EXEC mode with the copy flash tftp command
31MANAGING CISCO IOS Managing IOS images using Xmodem If the IOS image in flash has been erased or corrupted, the IOS may need to be restored from the ROM monitor mode (ROMmon).In many of the Cisco hardware architectures, the ROMmon mode is identified from the rommon 1 > prompt.
32MANAGING CISCO IOS ROMMON Mode When the Router starts showing “System Bootstrap, Version … “ on the Hyper terminal screen, Press the CTRL key and the Break key togetherThe Router will enter the Rommon modeRommon 1>
33MANAGING CISCO IOSIf an image is located that appears to be valid, an attempt should be made to boot from that image. This is done using boot flash: command. For example if the image name was “c2600-is-mz.121-5”, the command would be:rommon 1>boot flash:c2600-is-mz.121-5
34MANAGING CISCO IOSIf the router will not properly boot from the image or there is no IOS image, a new IOS will need to be downloaded. The IOS file may be recovered using either Xmodem to restore the image through the console, or downloading the image using TFTP from the ROMmon mode.