In preparation of our CCNA exam, we want to make sure we cover the various concepts that we could see on our Cisco CCNA exam. So to assist you, below we will discuss Cisco Configuration.

Managing Your Cisco Configuration
Altering the Configuration Register
 
Before changing the configuration register, use the show version command to determine the current setting. The last line contains the register value. Changing the value changes the location of the Cisco IOS load. The reload command must be used for the new configuration to be set. The register value is checked only during the boot process.
 
 
When the Cisco IOS Software is loaded, the router must be configured. Configurations in NVRAM are executed. If one does not exist in NVRAM, the router initiates an auto-install or setup utility. The auto-install routine downloads the config file from a TFTP server.
 
There are other sources of configurations. The Cisco IOS copy commands are used to move configurations from one component or device to another. The syntax is copy object < source> < dest>. Here’s an example:
router#copy running-config startup-config
 
 
Note: When a configuration is copied into RAM, it merges with the existing configuration in RAM. It does not overwrite the existing configuration.
 
 
The show running-config and show startup-config commands are useful troubleshooting aids. These commands allow you to view the current configuration in RAM or the startup configuration commands in NVRAM.
In NVRAM:
router#show startup-config
Using 1359 out of 32762 bytes
!
version 12.0
!
–More—
 
You know that you are looking at the startup configuration file when you see a message at the top telling you how much nonvolatile memory has been used.
 
In RAM:
router#show running-config
Building configuration…
Current configuration:
!
version 12.0
!
–More—
 
You know that you are looking at the current configuration file when you see the words “Current configuration” at the top of the display.
 
Key Feature of IFS
 
The Cisco IOS File System (IFS) feature provides an interface to the router file systems. The universal resource locator (URL) convention allows you to specify files on network devices. Here are the URL prefixes for Cisco network devices:
  •  
    		•  Bootflash—Boot Flash memory
  •  
    		•  Flash—Available on all platforms
  •  
    		•  Flh—Flash load helper log files
  •  
    		•  ftp—File Transfer Protocol network server
  •  
    		•  nvram—NVRAM
  •  
    		•  rcp—Remote copy protocol network server
  •  
    		•  slot0—First PCMCIA Flash memory card
  •  
    		•  slot1—Second PCMCIA Flash memory card
  •  
    		•  System—Contains the system memory and the running configuration
  •  
    		•  tftp—Trivial File Transfer Protocol (TFTP) network server
     
    How to Manage Cisco IOS Images
     
    It is always prudent to retain a backup copy of your Cisco IOS Software image in case your router software becomes corrupted. Here’s a Cisco IOS upgrade example:
    router#show flash
    router#copy flash tftp
    router#copy tftp flash
     
    When using the copy flash command, you must enter the IP address of the remote host and the name of the source and destination system image file. The router prompts you for this information. If no free Flash memory space is available, or if the Flash memory has never been written to, the erase routine is required.
     
    Router Boot Sequence and Verification Summary
  •  
    		•  The major components of the router are RAM, ROM, Flash memory, NVRAM, the configuration register, and the interfaces.
  •  
    		•  The four major areas of microcode contained in ROM are bootstrap code, POST code, ROM monitor, and a mini Cisco IOS Software.
  •  
    		•  The router configuration can come from NVRAM, a terminal, or a TFTP server.
  •  
    		•  You can back up your software image on the network server by using the copy flash
    [location] command.
     

    I hope you found this article to be of use and it helps you prepare for your Cisco CCNA certification. Achieving your CCNA certification is much more than just memorizing Cisco exam material. It is having the real world knowledge to configure your Cisco equipment and be able to methodically troubleshoot Cisco issues. So I encourage you to continue in your studies for your CCNA exam certification.