Transcript Semester 2 Chapter 7 & 8 - Institute of Technology Sligo

Institute of Technology Sligo - Dept of Computing
Cisco IOS & Router Config
Semester 2V2
Chapter 7
Chapter 8
Institute of Technology Sligo - Dept of Computing
Routers boot Cisco IOS software from:

Flash memory

TFTP server

ROM (not full Cisco IOS software)
Institute of Technology Sligo - Dept of Computing
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.
Institute of Technology Sligo - Dept of Computing
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
Institute of Technology Sligo - Dept of Computing
To check the boot field setting, and to verify the
config-register command, use the show version command.
[Router(config)# config-register]
Institute of Technology Sligo - Dept of Computing
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.
Institute of Technology Sligo - Dept of Computing
Institute of Technology Sligo - Dept of Computing
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,
Institute of Technology Sligo - Dept of Computing
Boot system flash “name”
Boot from a Server
Boot from a ROM
Institute of Technology Sligo - Dept of Computing
First step when preparing to copying between TFTP and Flash
Institute of Technology Sligo - Dept of Computing
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.
Institute of Technology Sligo - Dept of Computing
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.
Institute of Technology Sligo - Dept of Computing
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
Institute of Technology Sligo - Dept of Computing
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
Institute of Technology Sligo - Dept of Computing
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.
Institute of Technology Sligo - Dept of Computing
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
Institute of Technology Sligo - Dept of Computing
8.1.2.1. Make a
flowchart
showing the
router
configuration
process.
Institute of Technology Sligo - Dept of Computing
8.1.3.1. Describe and perform
the router password recovery
procedure on 1600 and 2500
series routers.