1 / 29

CCNA 2 v3. 1 Module 5

CCNA 2 v3. 1 Module 5. CCNA 2. Module 5 Managing IOS Software. Router Boot Sequence and Verification. Stages of the router power-on boot sequence. Cisco Router cannot operation without CISCO Internetwork Operating System (IOS) The startup routines must do the following:

shen
Download Presentation

CCNA 2 v3. 1 Module 5

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CCNA 2 v3.1 Module 5

  2. CCNA 2 Module 5 Managing IOS Software

  3. Router Boot Sequence and Verification

  4. Stages of the router power-on boot sequence • Cisco Router cannot operation without CISCO Internetwork Operating System (IOS) • The 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

  5. The sequence: Try the interactive media CCNA 2 Module 5 Page 5.1.1

  6. How a device locates and loads IOS • Normally the router looks to the NVRAM • Router can use fallback sequence to load the software • Search for boot system commands in NVRAM • If boot system commands are not found • Search FLASH for IOS • Search for TFTP Server with IOS • Limited IOS from ROM • Configuration register enable alternatives Try interactive media lab CCNA 2 Module 5 Page 5.1.2

  7. Configuration Register • Saved in NVRAM • Identify where to boot the IOS image from • To set the configuration register manually • Router#config terminal • Router(config)#boot system flash ios-filename • Router(config)#boot system tftp ios-filename tftp-address • Router(config)#boot system ROM

  8. To manually boot IOS from Flash • Advantage of booting from FLASH • Information is not vulnerable to network failures that can occur when loading system images from TFTP servers • Steps • Router#config terminal • Router(config)#boot sytem flash gsnew-image • Router(config)#Ctrl-Z • Router#copy running-config startup-config

  9. TFTP Network Server • Used in case flash memory becomes corrupted • Steps • Router#config terminal • Router(config)#boot system tftp IOS_image 172.16.13.111 • Router(config)#Ctrl-Z • Router#Copy running-config startup-config

  10. ROM • Used when • Flash memory is corrupted • And Network server fails to load the image • System image in ROM • Is a subset of the Cisco IOS • Lacks protocols, features and configurations of the full Cisco IOS • Software may be an older version • Steps • router#config t • Router(config)#boot system rom • Router(config)#Ctrl-Z • Router#copy run start

  11. Configuration register • 16-bit register in NVRAM • The lowest four bits is for the boot field • To find the current configuration register values • Router#show version • To change the boot field in configuration register • Use config register command

  12. Note When I use nnn it means use the numbers identified when using show version • To set to ROM monitor mode • Router#config t • Router(config)#config register 0Xnnn0 • Boot from ROM • Router#config t • Router(config)#config register 0Xnnn1 • Examine NVRAM for boot system • Router(config)#config register 0Xnnn2 to F • 2 represents boot from Flash Try interactive lab CCNA 2 Module 5 Page 5.1.4

  13. Troubleshooting IOS boot failure • What could be wrong if the Router does not boot: • Configuration file has missing or incorrect boot system statement • Incorrect configuration register value • Corrupted flash image • Hardware failure

  14. How to identify problems • An incorrect configuration register setting will prevent the IOS from loading from flash • Confirm this using show version • Correct this by changing the configuration register in the configuration and saving this as the start-up configuration • Corrupted flash image file • Error message • open: read error...requested 0x4 bytes, got 0x0 • trouble reading device magic number • boot: cannot open "flash:" • boot: cannot determine first file name on device "flash:"ú • If the flash image is corrupt, a new IOS should be uploaded into the router

  15. Managing the CISCO File System

  16. Files in Memory • Operating system files - IOS…MBs • Configuration files - …KBs

  17. IOS • Stored in Flash memory - non-volatile storage • IOS can be upgraded or have multiple copies • IOS is copied into RAM and run from RAM • Startup configuration (startup config) • Stored in Non-volatile RAM - NVRAM • Copied into RAM at boot time • Running Configuration (running config) • Stored in RAM • Used to operate the router Try interactive lab CCNA 2 Module 5 Page 5.2.1

  18. IOS naming conventions

  19. First part identifies the hardware platform • Second part identifies the features the file contains • Basic – A basic feature set for the hardware platform, e.g.IP • Plus – Basic features ..IP/FW Plus, and Enterprise Plus • Encryption – • k8 > Less than or equal to 64-bit encryption in IOS version 12.2 and up • k9 > Greater than 64-bit encryption (on 12.2 and up) • Third part indicates the file format • Is the IOS is stored in flash in a compressed format or not • Is the IOS relocatable(can be copied into RAM) or not(run from flash) • Fourth part identifies the release of the IOS Try interactive media lab CCNA 2 Module 5 Page 5.2.2

  20. Managing configuration files using TFTP • Your configuration file should be backed up on a TFTP server. • Router#copy running-config tftp • Enter the IP address of the TFTP server • Enter the configuration file name or press enter to accept the default name • Confirm the choices by typing yes each time

  21. Retrieving or using TFTP config backup: • Router#copy tftp running-config • Select a host or network configuration file • Enter the IP address of the TFTP server • Enter configuration file name or press enter to accept the default name

  22. Managing configuration files using copy and paste • Another way to create a backup of the configuration • Capture the output of show running-config • Select the output in the HyperTerminal screen and paste it into a text file. • Things that have to be deleted: • show running-config • Building configuration... • Current configuration: • - More - • Any lines that appear after the word "End" • Add comments • Use an exclamation mark (!) at the beginning of the line

  23. Note at the end of each of the interface • Add the no shutdown command • HyperTerminal can be used to restore a configuration. • Erase the startup configuration file • Router#erase startup-config • Restart the router • Router#reload • Enter router global configuration mode • Router#config t • Transfer the configuration data • From HyperTerminal, click on Transfer > Send Text File. • Select the name of the file for the saved backup configuration • Observe any errors • Return to privilaged mode • Ctrl-Z • Save running configuration files to backup configuration • Router#copy running-config startup-config

  24. Managing IOS images using Xmodem • If IOS image in flash is erased or corrupted • Restore IOS from the ROM monitor mode (ROMmon) • Reasons are a corrupt or missing image • Examine flash with the dir flash: command • If an image is located that appears to be valid, an attempt should be made to boot from that image.

  25. rommon 1>boot flash:c2600-is-mz.121-5 • Why would it boot correctly from ROM not flash? • show version • checks the configuration register to ensure that it is configured for the default boot sequence • If configuration register is correct • show startup-config • See if there is a boot system command instructing the router to use the IOS for ROM monitor • If router will not properly boot from the image or there is no IOS image • Download a new IOS using • Xmodem to restore the image through the console • or TFTP from the ROMmon mode

  26. Download using XModem from ROMmon • To restore the IOS through the console • PC needs a copy of the IOS file to restore and a terminal emulation program (HyperTerminal) • The IOS can be restored using • default console speed of 9600 bps • baud rate can be changed to 115200 bps to speed up the download • Use Xmodem in ROMmon to restore IOS software image from the PC • Format xmodem -cimage_file_name • E.g., xmodem -c c2600-is-mz.122-10a.bin • -c instructs Xmodem to use Cyclic Redundancy Check (CRC) for error checking during the download

  27. Environment variables • Fasted way to download IOS image • using TFTP from ROMmon • ROMmon has very limited functions • No configuration file loaded during boot • Set environmental variables (set) • IP_ADDRESS – The IP address on the LAN interface • IP_SUBNET_MASK – The subnet mask for the LAN interface • DEFAULT_GATEWAY – Default gateway for the LAN interface • TFTP_SERVER – The IP address of the TFTP server • TFTP_FILE – The IOS filename on the server • Use the tftpdnld command • When new image is written to flash restart router using i

  28. File system verification Router#show version checks • The current image • The total amount of flash. • The source of the IOS image the router used to boot and displays the configuration register • Configuration register • Determines where the router is to load the IOS from

  29. Router#show flash command identifies • IOS image(s) in flash • The amount of flash memory • Used to confirm that there is ample space to store a new IOS image

More Related