Cisco IOS & Router ConfigSemester 2V2

Chapter 7

Chapter 8

Routers boot Cisco IOS software from:

• Flash memory

• TFTP server

• ROM (not full Cisco IOS software)

Cisco IOS software allows you to use several alternatives to loading your system. (router)

•You can specify other sources for the router to look for software.

•The router can use its own fallback sequence, as necessary, to load the software.• •The settings in the configuration register enable the alternatives.

Router Fallback Sequence

• It can use default Cisco IOS in Flash memory.

• If Flash memory is empty, the router can try its next TFTP alternative.

The router uses the configuration register value to form a filename from which to boot a default system image stored on a network server.

• ROM may contain an older version of IOS

To check the boot field setting, and to verify the config-register command, use the show version command.

[Router(config)# config-register]

Show Version Command

• Displays information about the Cisco IOS software version

that is currently running on the router. • This includes the configuration register and the boot field

setting .

• The highlighted line at the bottom of the graphic shows the system image file. You will learn about Cisco IOS software Release 11.2 image naming conventions later in this lesson. For now, notice the portion of the filename that indicates that this image is for a Cisco 4500 platform.

• As it continues to output, the show version command displays information about the type of platform on which the version of Cisco IOS software is currently running.

Boot System Commands to Specify the Fallback Sequence

• Flash memory - You can copy a system image by changing the electrically erasable programmable read-only memory (EEPROM). The information stored in Flash memory is not vulnerable to network failures that can occur when loading system images from TFTP servers.

• Network server - In case Flash memory becomes corrupted, you provide for a backup by specifying that a system image should be loaded from a TFTP server.

• ROM - 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 Cisco IOS software, that lacks the protocols, features, and configurations of full Cisco IOS software. Also, if you have updated the software since you purchased the router.

it may bean older version of Cisco IOS software,

Boot system flash “name”

Boot from a Server

Boot from a ROM

First step when preparing to copying between TFTP and Flash

Preparing For TFTP

Copying software between the TFTP host and Flash memory in the router. However, before you do this, you must prepare for the TF server by checking the following

preliminary conditions: • On the router, check to make sure that you can see and write into Flash memory.

Verify that the router has sufficient room in Flash memory to accommodate the Cisco IOS software image.

• From the router, check to make sure that you can access the TFTP server over the TCP/IP network. The ping command is one method that can help you check this.

• On the TFTP server, check to make sure you know the file or file space for the Cisco IOS software image. For upload and download operations, you need to specify a path or filename.

If there is insufficient free memory, you will not be able to copy or load the image, which means that you can either try to obtain a smaller Cisco IOS software image or increase the available memory on the router.

The naming convention for Cisco IOS Release 11.2 contains three parts:

1. the platform on which the image runs (cpa25)

2. a letter or series of letters identifies the special capabilities and feature sets supported in the image ( cg )

3. specifies where the image runs and whether it has been zipped, or

compressed

One reason for this upload to the server would be to provide a fallback copy of the current image prior to updating the image with a new version. Then, if problems develop with the new version, the administrator can download the backed-up image and return to the image that was running before the update attempt.

copy flash tftp -- send image to server

show flash --- to view name of system image file

After you have provided for a backup copy of the current Cisco IOS software image, you can load a new image.

You download the new image from the TFTP server by using the command copy tftp flash.

Configuration register for password recovery for a 2500 router? -- 0x2142

Command to configure a Ethernet port? --

•Router (config)# int E0 ip address subnet mask

•Routing Protocol -- Router(config)# router rip

8.1.2.1. Make a flowchart showing the router configuration process.

8.1.3.1. Describe and perform the router password recovery procedure on 1600 and 2500 series routers.