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NETWORK BASICS

Network A system of interconnected computers and computerized peripherals such as printers is called computer network. This interconnection among computers facilitates information sharing among them. Computers may connect to each other by either wired or wireless media. A computer network consists of a collection of computers, printers and other equipment that is connected together so that they can communicate with each other.  


Network application
A Network application is any application running on one host and provides a communication to another application running on a different host, the application may use an existing application layer protocols such as: HTTP(e.g. the Browser and web server), SMTP(e.g. the email-client). And may be the application does not use any existing protocols and depends on the socket programming to communicate to another application. So the web application is a type of the network applications. 
There are lots of advantages from build up a network, but the th…

Managing Cisco Devices

The following ICND2 exam topics are covered in this chapter :
IP Routing Technologies
Image result for cisco devices"
■ Describe the boot process of Cisco IOS routers
■ POST
■ Router bootup process
■ Manage Cisco IOS Files
■ Boot preferences
■ Cisco IOS image(s)
■ Licensing
■ Show license
■ Change license

Here in Chapter 2, I’m going to show you how to manage Cisco 
routers on an internetwork. The Internetwork Operating System 
(IOS) and configuration files reside in different locations in a 
Cisco device, so it’s really important to understand both where these files are located and how 
they work.
You’ll be learning about the main components of a router, the router boot sequence, and the 
configuration register, including how to use the configuration register for password recovery.
Finally, I’ll cover how to verify licenses on the ISRG2 routers as well as how to install a 

permanent license and configure evaluation features in the latest universal images.
The Internal Components of a Cisco Router
To configure and troubleshoot a Cisco internetwork, you need to know the major components of Cisco routers and understand what each one does. Table 16.1 describes the major 
Cisco router components.
Table 16.1 Cisco router components
Component Description
Bootstrap Stored in the microcode of the ROM, the bootstrap is 
used to bring a router up during initialization. It will boot 
the router and then load the IOS.
POST (power-on self-test) Stored in the microcode of the ROM, the POST is used to 
check the basic functionality of the router hardware and 

determines which interfaces are present
Component Description
ROM monitor Stored in the microcode of the ROM, the ROM monitor is 
used for manufacturing, testing, and troubleshooting. In 
older routers it could load what was called a mini-IOS.
Mini-IOS Called the RX-BOOT or boot-loader by Cisco, the mini￾IOS is a small IOS in ROM that can be used to bring up 
an interface and load a Cisco IOS into flash memory. 
The mini-IOS can also perform a few other maintenance 
operations, but not many.
RAM (random access memory) Used to hold packet buffers, ARP caches, routing 
tables, and also the software and data structures that 
allow the router to function. Running-config is stored 
in RAM, and most routers expand the IOS from flash 
into RAM upon boot.
ROM (read-only memory) Used to start and maintain the router. Holds the POST 
and the bootstrap program as well as the mini-IOS.
Flash memory Stores the Cisco IOS by default. Flash memory is not 
erased when the router is reloaded. It is EEPROM (electronically erasable programmable read-only memory) 
created by Intel.
NVRAM (nonvolatile RAM) Used to hold the router and switch configuration. 
NVRAM is not erased when the router or switch is 
reloaded. Does not store an IOS. The configuration 
register is stored in NVRAM.
Configuration register Used to control how the router boots up. This value can 
be found as the last line of the show version command 
output and by default is set to 0x2102, which tells the 

router to load the IOS from flash memory as well as to 

load the configuration from NVRAM.
The Router Boot Sequence
When a router boots up, it performs a series of steps, called the boot sequence, to test the 
hardware and load the necessary software. The boot sequence consists of the following 
steps, as shown in Figure 16.1:
1. The router performs a POST. The POST tests the hardware to verify that all components 
of the device are operational and present. For example, the POST checks for the different 

interfaces on the router. The POST is stored in and run from ROM (read-only memory).
2. The bootstrap then looks for and loads the Cisco IOS software. The bootstrap is a program in ROM that is used to execute programs. The bootstrap program is responsible 
for finding where each IOS program is located and then loading the file. By default, the 
IOS software is loaded from flash memory in all Cisco routers, but only after the configuration register is read and NVRAM is checked for the boot sequence.
The default order of an IOS loading from a router is: flash, TFTP server, 
then ROM.
3. After the IOS is expanded into RAM, the IOS software looks for a valid configuration 
file stored in NVRAM. This file is called startup-config and is only there if an administrator copies the running-config file into NVRAM.
4. If a startup-config file is in NVRAM, the router will copy this file and place it in 
RAM and call the file running-config. The router will use this file to run the router. 
The router should now be operational. If a startup-config file is not in NVRAM, the 
router will broadcast out any interface that detects carrier detect (CD) for a TFTP 
host looking for a configuration, and when that fails (typically it will fail—most 
people won’t even realize the router has attempted this process), it will start the setup 
mode configuration process.
Managing Configuration Register
All Cisco routers have a 16-bit software register that’s written into NVRAM. By default, 

the configuration register is set to load the Cisco IOS from flash memory and to look for and load the startup-config file from NVRAM. In the following sections, I am going to dis￾cuss the configuration register settings and how to use these settings to provide password 
recovery on your routers.
Understanding the Configuration Register Bits
The 16 bits (2 bytes) of the configuration register are read from 15 to 0, from left to right. The 
default configuration setting on Cisco routers is 0x2102. This means that bits 13, 8, and 1 
are on, as shown in Table 16.2. Notice that each set of 4 bits (called a nibble) is read in binary 
with a value of 8, 4, 2, 1.
Table 16. 2 The configuration register bit numbers
Configuration 
Register 2 1 0 2
Bit number 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Binary 0 0 1 0 0 0 0 1 0 0 0 0 0 0 1 0
Add the prefix 0x to the configuration register address. The 0x means that 
the digits that follow are in hexadecimal.
Table 16.3 lists the software configuration bit meanings. Notice that bit 6 can be used 
to ignore the NVRAM contents. This bit is used for password recovery—something I’ll go 
over with you soon in the section “Recovering Passwords,” later in this chapter.
Remember that in hex, the scheme is 0–9 and A–F (A = 10, B = 11, C = 12, 
D = 13, E = 14, and F = 15). This means that a 210F setting for the configuration register is actually 210(15), or 1111 in binary.
Table  16. 3 Software configuration meanings
Bit Hex Description
0–3 0x0000–0x000F Boot field (see Table 16.4).
6 0x0040 Ignore NVRAM contents.
7 0x0080 OEM bit enabled.
Bit Hex Description
8 0x101 Break disabled.
10 0x0400 IP broadcast with all zeros.
5, 11–12 0x0800–0x1000 Console line speed.
13 0x2000 Boot default ROM software if network boot fails.
14 0x4000 IP broadcasts do not have net numbers.
15 0x8000 Enable diagnostic messages and ignore NVRAM contents.
The boot field, which consists of bits 0–3 in the configuration register (the last four 
bits), controls the router boot sequence and locates the Cisco IOS. Table 16.4 describes 
the boot field bits.
Table 16. 4 The boot field (configuration register bits 00–03)
Boot Field Meaning Use
00 ROM monitor mode To boot to ROM monitor mode, set the configuration register to 2100. You must manually boot the 
router with the b command. The router will show 
the rommon> prompt. 
01 Boot image from ROM To boot the mini-IOS image stored in ROM, set the 
configuration register to 2101. The router will show 
the Router(boot)> prompt. The mini-IOS is not 
available in all routers and is also referred to 
as RXBOOT. 
02–F Specifies a default boot 
filename
Any value from 2102 through 210F tells the router 
to use the boot commands specified in NVRAM.
Checking the Current Configuration Register Value
You can see the current value of the configuration register by using the show version
command (sh version or showver for short), as demonstrated here:
Router>sh version

Cisco IOS Software, 2800 Software (C2800NM-ADVSECURITYK9-M), 
Version 15.1(4)M6, RELEASE SOFTWARE (fc2)
[output cut]
Configuration register is 0x2102
The last information given from this command is the value of the configuration register. 
In this example, the value is 0x2102—the default setting. The configuration register setting 
of 0x2102 tells the router to look in NVRAM for the boot sequence.
Notice that the show version command also provides the IOS version, and in the preceding 
example, it shows the IOS version as 15.1(4)M6.
The show version command will display system hardware configuration 
information, the software version, and the names of the boot images on 
a router.
To change the configuration register, use the config-register command from global 
configuration mode:
Router(config)#config-register 0x2142
Router(config)#do sh ver
[output cut]
Configuration register is 0x2102 (will be 0x2142 at next reload)
It’s important that you are careful when you set the configuration register!
If you save your configuration and reload the router and it comes up in 
setup mode, the configuration register setting is probably incorrect.
Boot System Commands
Did you know that you can configure your router to boot another IOS if the flash is corrupted? 
Well, you can. You can boot all of your routers from a TFTP server, but it’s old school, and 
people just don’t do it anymore; it’s just for backup in case of failure. 
There are some boot commands you can play with that will help you manage the way 
your router boots the Cisco IOS—but please remember, we’re talking about the router’s 
IOS here, not the router’s configuration!
Router>en
Router#config t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#boot ?

 bootstrap Bootstrap image file
config Configuration file
 host Router-specific config file
 network Network-wide config file
 system System image file
The boot command truly gives you a wealth of options, but first, I’ll show you the typical 
settings that Cisco recommends. So let’s get started—the boot system command will allow you 
to tell the router which system IOS file to boot from flash memory. Remember that the router, 
by default, boots the first system IOS file found in flash. You can change that with the following 
commands as shown in the output: 
Router(config)#boot system ?
 WORD TFTP filename or URL
 flash Boot from flash memory
 ftp Boot from a server via ftp
 mop Boot from a Decnet MOP server
 rcp Boot from a server via rcp
 rom Boot from rom
 tftp Boot from a tftp server
Router(config)#boot system flash c2800nm-advsecurityk9-mz.151-4.M6.bin
Notice I could boot from FLASH, FTP, ROM, TFTP or another useless option. The 
preceding command I used configures the router to boot the IOS listed in it. This is a helpful command for when you load a new IOS into flash and want to test it, or even when you
want to totally change which IOS is loading by default.
The next command is considered a fallback routine, but as I said, you can make it a permanent way to have your routers boot from a TFTP host. Personally, I wouldn’t necessarily 
recommend doing this (single point of failure); I’m just showing you that it’s possible:
Router(config)#boot system tftp ?
 WORD System image filename
Router(config)#boot system tftp c2800nm-advsecurityk9-mz.151-4.M6.bin?
 Hostname or A.B.C.D Address from which to download the file
 <cr>
Router(config)#boot system tftp c2800nm-advsecurityk9-mz.151-4.M6.bin 1.1.1.2
Router(config)#
As your last recommended fallback option—the one to go to if the IOS in flash doesn’t 
load and the TFTP host does not produce the IOS—load the mini-IOS from ROM like this:
Router(config)#boot system rom
Router(config)#do show run | include boot system

boot system flash c2800nm-advsecurityk9-mz.151-4.M6.bin

boot system tftp c2800nm-advsecurityk9-mz.151-4.M6.bin 1.1.1.2
boot system rom
Router(config)#
If the preceding configuration is set, the router will try to boot from the TFTP server if 
flash fails, and if the TFTP boot fails, the mini-IOS will load after six unsuccessful attempts 
of trying to locate the TFTP server. 
In the next section, I’ll show you how to load the router into ROM monitor mode so you 
can perform password recovery.
Recovering Passwords
If you’re locked out of a router because you forgot the password, you can change the config￾uration register to help you get back on your feet. As I said earlier, bit 6 in the configuration 
register is used to tell the router whether to use the contents of NVRAM to load a router 
configuration.
The default configuration register value is 0x2102, meaning that bit 6 is off. With 
the default setting, the router will look for and load a router configuration stored in 
NVRAM (startup-config). To recover a password, you need to turn on bit 6. Doing this 
will tell the router to ignore the NVRAM contents. The configuration register value to 
turn on bit 6 is 0x2142.
Here are the main steps to password recovery:
1. Boot the router and interrupt the boot sequence by performing a break, which will 
take the router into ROM monitor mode.
2. Change the configuration register to turn on bit 6 (with the value 0x2142).
3. Reload the router.
4. Say “no” to entering Setup mode, the enter privileged mode.
5. Copy the startup-config file to running-config, and don’t forget to verify that your 
interfaces are re-enabled.
6. Change the password.
7. Reset the configuration register to the default value.
8. Save the router configuration.
9. Reload the router (optional).
I’m going to cover these steps in more detail in the following sections. I’ll also show you 
the commands to restore access to ISR series routers.
You can enter ROM monitor mode by pressing Ctrl+Break or Ctrl+Shift+6 then b, during 
router bootup. But if the IOS is corrupt or missing, if there’s no network connectivity available 
to find a TFTP host, or if the mini-IOS from ROM doesn’t load (meaning the default router 

fallback failed), the router will enter ROM monitor mode by default.
Interrupting the Router Boot Sequence
Your first step is to boot the router and perform a break. This is usually done by pressing 
the Ctrl+Break key combination when using Hyper-terminal (personally, I use Secure-CRT 
or PuTTY) while the router first reboots.
System Bootstrap, Version 15.1(4)M6, RELEASE SOFTWARE (fc2)
Copyright (c) 1999 by cisco Systems, Inc.
TAC:Home:SW:IOS:Specials for info
PC = 0xfff0a530, Vector = 0x500, SP = 0x680127b0
C2800 platform with 32768 Kbytes of main memory
PC = 0xfff0a530, Vector = 0x500, SP = 0x80004374
monitor: command “boot” aborted due to user interrupt
rommon 1 >
Notice the line monitor: command “boot” aborted due to user interrupt. At this 
point, you will be at the rommon 1> prompt, which is called the ROM monitor mode.
Changing the Configuration Register
As I explained earlier, you can change the configuration register from within the IOS by 
using the config-register command. To turn on bit 6, use the configuration register 
value 0x2142.
Remember that if you change the configuration register to 0x2142, the 
startup-config will be bypassed and the router will load into setup mode.
To change the bit value on a Cisco ISR series router, you just enter the following command 
at the rommon 1> prompt:
rommon 1 >confreg 0x2142
You must reset or power cycle for new config to take effect
rommon 2 >reset
Reloading the Router and Entering Privileged Mode
At this point, you need to reset the router like this:
uu From the ISR series router, type I (for initialize) or reset.
uu From an older series router, type I.
The router will reload and ask if you want to use setup mode (because no startup-config 
is used). Answer no to entering setup mode, press Enter to go into user mode, and then type 

enable to go into privileged mode.
Viewing and Changing the Configuration
Now you’re past the point where you would need to enter the user-mode and privileged-mode 
passwords in a router. Copy the startup-config file to the running-config file:
copy startup-config running-config
Or use the shortcut:
copy start run
The configuration is now running in random access memory (RAM), and you’re in 
privileged mode, meaning that you can now view and change the configuration. But you 
can’t view the enable-secret setting for the password since it is encrypted. To change the 
password, do this:
config t
enable secret todd
Resetting the Configuration Register and Reloading the Router
After you’re finished changing passwords, set the configuration register back to the default 
value with the config-register command:
config t
config-register 0x2102
It’s important to remember to enable your interfaces after copying the configuration 
from NVRAM to RAM.
Finally, save the new configuration with a copy running-config startup-config and 
use reload to reload the router.
If you save your configuration and reload the router and it comes up in 
setup mode, the configuration register setting is probably incorrect.
To sum this up, we now have Cisco’s suggested IOS backup routine configured on our 
router: flash, TFTP host, ROM.
Backing Up and Restoring the Cisco IOS
Before you upgrade or restore a Cisco IOS, you really should copy the existing file to a TFTP 

host as a backup just in case the new image crashes and burns.

And you can use any TFTP host to accomplish this. By default, the flash memory in a router 
is used to store the Cisco IOS. In the following sections, I’ll describe how to check the amount 
of flash memory, how to copy the Cisco IOS from flash memory to a TFTP host, and how to 
copy the IOS from a TFTP host to flash memory.
But before you back up an IOS image to a network server on your intranet, you’ve got to 
do these three things:
uu Make sure you can access the network server.
uu Ensure that the network server has adequate space for the code image.
uu Verify the file naming and path requirements.
You can connect your laptop or workstation’s Ethernet port directly to a router’s 

Ethernet interface, as shown in Figure 16.2. 
• TFTP server software must be running on the PC.
• The PC must be on the same subnet as the router’s E0 interface.
• The copy flash tftp command must be supplied the IP address of the PC.
Router# copy flash tftp
E0
Console
• IP address of the TFTP server
• IOS filename
You need to verify the following before attempting to copy the image to or from 
the router:
uu TFTP server software must be running on the laptop or workstation.
uu The Ethernet connection between the router and the workstation must be made with a 
crossover cable.
uu The workstation must be on the same subnet as the router’s Ethernet interface.
uu The copy flash tftp command must be supplied the IP address of the workstation if 
you are copying from the router flash.
uu And if you’re copying “into” flash, you need to verify that there’s enough room in flash 

memory to accommodate the file to be copied.

Verifying Flash Memory
Before you attempt to upgrade the Cisco IOS on your router with a new IOS file, it’s a good 
idea to verify that your flash memory has enough room to hold the new image. You verify 
the amount of flash memory and the file or files being stored in flash memory by using the 
show flash command (sh flash for short):
Router#sh flash
-#- --length-- -----date/time------ path
1 45392400 Apr 14 2013 05:31:44 +00:00 c2800nm-advsecurityk9-mz.151-4.M6.bin
18620416 bytes available (45395968 bytes used)
There are about 45 MB of flash used, but there still about 18 MB available. If you 
want to copy a file into flash that is more than 18 MB in size, the router will ask you if 
you want to erase flash. Be careful here!
The show flash command will display the amount of memory consumed 
by the current IOS image, as well as, tell you if there’s enough room available to hold both current and new images. You should know that if there’s 
not enough room for both the old and new image you want to load, the old 
image will be erased!
The amount of RAM and flash is actually easy to tally using the show version command 
on routers:
Router#show version
[output cut]
System returned to ROM by power-on
System image file is "flash:c2800nm-advsecurityk9-mz.151-4.M6.bin"
[output cut]
Cisco 2811 (revision 1.0) with 249856K/12288K bytes of memory.
Processor board ID FTX1049A1AB
2 FastEthernet interfaces
2 Serial(sync/async) interfaces
1 Virtual Private Network (VPN) Module
DRAM configuration is 64 bits wide with parity enabled.
239K bytes of non-volatile configuration memory.
62720K bytes of ATA Compact-flash (Read/Write)
The first highlighted line shows us that this router has about 256 MB of RAM, and you can 
see that the amount of flash shows up on the last line. By estimating up, we get the amount of 

flash to 64 MB.
 Notice that the filename in this example is c2800nm-advsecurityk9-mz.151-4.M6.bin. 
The main difference in the output of the show flash and show version commands is that 
the show flash command displays all files in flash memory and the show version command 
shows the actual name of the file used to run the router and the location from which it was 
loaded, which is flash memory. 
Backing Up the Cisco IOS
To back up the Cisco IOS to a TFTP server, you use the copy flash tftp command. It’s a 
straightforward command that requires only the source filename and the IP address of the 
TFTP server.
The key to success in this backup routine is to make sure you’ve got good, solid connectivity to the TFTP server. Check this by pinging the TFTP device from the router console 
prompt like this:
Router#ping 1.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.2, timeout
 is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max
 = 4/4/8 ms
After you ping the TFTP server to make sure that IP is working, you can use the copy 
flash tftp command to copy the IOS to the TFTP server as shown next: 
Router#copy flash tftp
Source filename []?c2800nm-advsecurityk9-mz.151-4.M6.bin
Address or name of remote host []?1.1.1.2
Destination filename [c2800nm-advsecurityk9-mz.151-4.M6.bin]?[enter]
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
45395968 bytes copied in 123.724 secs (357532 bytes/sec)
Router#
Just copy the IOS filename from either the show flash or show version command and 
then paste it when prompted for the source filename.
In the preceding example, the contents of flash memory were copied successfully to the 
TFTP server. The address of the remote host is the IP address of the TFTP host, and the source 
filename is the file in flash memory.
Many newer Cisco routers have removable memory. You may see names 
for this memory such as flash0:, in which case the command in the preceding example would be copy flash0: tftp:. Alternately, you may see it as 
usbflash0:.
Restoring or Upgrading the Cisco Router IOS
What happens if you need to restore the Cisco IOS to flash memory to replace an original file 
that has been damaged or if you want to upgrade the IOS? You can download the file from 
a TFTP server to flash memory by using the copy tftp flash command. This command 
requires the IP address of the TFTP host and the name of the file you want to download.
But before you begin, make sure the file you want to place in flash memory is in the 
default TFTP directory on your host. When you issue the command, TFTP won’t ask you 
where the file is, so if the file you want to use isn’t in the default directory of the TFTP host, 
this just won’t work.
Router#copy tftp flash
Address or name of remote host []?1.1.1.2
Source filename []?c2800nm-advsecurityk9-mz.151-4.M6.bin
Destination filename [c2800nm-advsecurityk9-mz.151-4.M6.bin]?[enter]
%Warning: There is a file already existing with this name
Do you want to over write? [confirm][enter]
Accessing tftp://1.1.1.2/ c2800nm-advsecurityk9-mz.151-4.M6.bin...
Loading c2800nm-advsecurityk9-mz.151-4.M6.bin from 1.1.1.2 (via
 FastEthernet0/0): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 21710744 bytes]
45395968 bytes copied in 82.880 secs (261954 bytes/sec)
Router#
In the preceding example, I copied the same file into flash memory, so it asked me if I 
wanted to overwrite it. Remember that we are “playing” with files in flash memory. If I had 
just corrupted my file by overwriting it, I won’t know for sure until I reboot the router. Be 
careful with this command! If the file is corrupted, you’ll need to do an IOS-restore from 
ROM monitor mode.
If you are loading a new file and you don’t have enough room in flash memory to 
store both the new and existing copies, the router will ask to erase the contents of flash 
memory before writing the new file into flash memory, and if you are able to copy the IOS 
without erasing the old version, then make sure you remember to use the boot system 
flash:ios-file command.
As I demonstrated in the Real World Scenario, a Cisco router can become a 
TFTP server host for a router system image that’s run in flash memory. The 

global configuration command is tftp-server flash:ios-file.

It’s Monday Morning and You Just Upgraded Your IOS
You came in early to work to upgrade the IOS on your router. After the upgrade, you 
reload the router and the router now shows the rommon> prompt.
It seems that you’re about to have a bad day! This is what I call an RGE: a resume-generating 
event! So, now what do you do? Just keep calm and chive on! Follow these steps to save 
your job:
rommon 1 > tftpdnld
Missing or illegal ip address for variable IP_ADDRESS
Illegal IP address.
usage: tftpdnld [-hr]
 Use this command for disaster recovery only to recover an image via TFTP.
 Monitor variables are used to set up parameters for the transfer.
 (Syntax: "VARIABLE_NAME=value" and use "set" to show current variables.)
 "ctrl-c" or "break" stops the transfer before flash erase begins.
 The following variables are REQUIRED to be set for tftpdnld:
 IP_ADDRESS: The IP address for this unit
 IP_SUBNET_MASK: The subnet mask for this unit
 DEFAULT_GATEWAY: The default gateway for this unit
 TFTP_SERVER: The IP address of the server to fetch from
 TFTP_FILE: The filename to fetch
 The following variables are OPTIONAL:
[unneeded output cut]
rommon 2 >set IP_Address:1.1.1.1
rommon 3 >set IP_SUBNET_MASK:255.0.0.0
rommon 4 >set DEFAULT_GATEWAY:1.1.1.2
rommon 5 >set TFTP_SERVER:1.1.1.2
rommon 6 >set TFTP_FILE: flash:c2800nm-advipservicesk9-mz.124-12.bin

rommon 7 >tftpdnld
From here you can see the variables you need to configure using the set command; be 
sure you use ALL_CAPS with these commands as well as underscore (_).From here, you 
need to set the IP address, mask, and default gateway of your router, then the IP address 
of the TFTP host, which in this example is a directly connected router that I made a TFTP 
server with this command:
Router(config)#tftp-server flash:c2800nm-advipservicesk9-mz.124-12.bin

And finally, you set the IOS filename of the file on your TFTP server. Whew! Job saved. 

There is one other way you can restore the IOS on a router, but it takes a while. You 
can use what is called the Xmodem protocol to actually upload an IOS file into flash memory 
through the console port. You’d use the Xmodem through the console port procedure if you 
had no network connectivity to the router or switch. 
Using the Cisco IOS File System (Cisco IFS)
Cisco has created a file system called Cisco IFS that allows you to work with files and directo￾ries just as you would from a Windows DOS prompt. The commands you use are dir, copy, 
more, delete, erase or format, cd and pwd, and mkdir and rmdir.
Working with IFS gives you the ability to view all files, even those on remote servers. 
And you definitely want to find out if an image on one of your remote servers is valid before 
you copy it, right? You also need to know how big it is—size matters here! It’s also a really 
good idea to take a look at the remote server’s configuration and make sure it’s all good 
before loading that file on your router.
It’s very cool that IFS makes the file system user interface universal—it’s not platform 
specific anymore. You now get to use the same syntax for all your commands on all of your 
routers, no matter the platform!
Sound too good to be true? Well, it kind of is because you’ll find out that support for all 
commands on each file system and platform just isn’t there. But it’s really no big deal since 
various file systems differ in the actions they perform; the commands that aren’t relevant to 
a particular file system are the very ones that aren’t supported on that file system. Be assured 
that any file system or platform will fully support all the commands you need to manage it.
Another cool IFS feature is that it cuts down on all those obligatory prompts for a lot 
of the commands. If you want to enter a command, all you have to do is type all the necessary info straight into the command line—no more jumping through hoops of prompts! So, 
if you want to copy a file to an FTP server, all you’d do is first indicate where the desired 
source file is on your router, pinpoint where the destination file is to be on the FTP server, 
determine the username and password you’re going to use when you want to connect to 
that server, and type it all in on one line—sleek! And for those of you resistant to change, 
you can still have the router prompt you for all the information it needs and enjoy entering 

a more elegantly minimized version of the command than you did before.
But even in spite of all this, your router might still prompt you—even if you did everything 
right in your command line. It comes down to how you’ve got the file prompt command con￾figured and which command you’re trying to use. But no worries—if that happens, the default 
value will be entered right there in the command, and all you have to do is hit Enter to verify 
the correct values.
IFS also lets you explore various directories and inventory files in any directory you want. 
Plus, you can make subdirectories in flash memory or on a card, but you only get to do that 
if you’re working on one of the more recent platforms.
And get this—the new file system interface uses URLs to determine the whereabouts 
of a file. So just as they pinpoint places on the Web, URLs now indicate where files are 
on your Cisco router, or even on a remote file server! You just type URLs right into your 
commands to identify where the file or directory is. It’s really that easy—to copy a file 
from one place to another, you simply enter the copy source-url destination-url
command—sweet! IFS URLs are a tad different than what you’re used to though, and 
there’s an array of formats to use that vary depending on where, exactly, the file is that 
you’re after.
We’re going to use Cisco IFS commands pretty much the same way that we used the 
copy command in the IOS section earlier:
uu For backing up the IOS
uu For upgrading the IOS
uu For viewing text files
Okay—with all that down, let’s take a look at the common IFS commands available to 
us for managing the IOS. I’ll get into configuration files soon, but for now I’m going to get 
you started with going over the basics used to manage the new Cisco IOS.
dir Same as with Windows, this command lets you view files in a directory. Type dir, hit 
Enter, and by default you get the contents of the flash:/ directory output.
copy This is one popular command, often used to upgrade, restore, or back up an IOS. 
But as I said, when you use it, it’s really important to focus on the details—what you’re 
copying, where it’s coming from, and where it’s going to land.
more Same as with Unix, this will take a text file and let you look at it on a card. You can 
use it to check out your configuration file or your backup configuration file. I’ll go over it 
more when we get into actual configuration.
show file This command will give you the skinny on a specified file or file system, but 
it’s kind of obscure because people don’t use it a lot.
delete Three guesses—yep, it deletes stuff. But with some types of routers, not as well 
as you’d think. That’s because even though it whacks the file, it doesn’t always free up the 
space it was using. To actually get the space back, you have to use something called the 

squeeze command too.
erase/format Use these with care—make sure that when you’re copying files, you say no 
to the dialog that asks you if you want to erase the file system! The type of memory you’re 
using determines if you can nix the flash drive or not.
cd/pwd Same as with Unix and DOS, cd is the command you use to change directories. 
Use the pwd command to print (show) the working directory.
mkdir/rmdir Use these commands on certain routers and switches to create and delete 
directories—the mkdir command for creation and the rmdir command for deletion. Use 
the cd and pwd commands to change into these directories.
The Cisco IFS uses the alternate term system:running-config as well 
as nvram:startup-config when copying the configurations on a router, 
although it is not mandatory that you use this naming convention. 
Using the Cisco IFS to Upgrade an IOS
Let’s take a look at some of these Cisco IFS commands on my ISR router (1841 series) with 
a hostname of R1.
We’ll start with the pwd command to verify our default directory and then use the dir
command to verify its contents (flash:/):
R1#pwd
flash:
R1#dir
Directory of flash:/
 1 -rw- 13937472 Dec 20 2006 19:58:18 +00:00 c1841-ipbase-
 mz.124-1c.bin
 2 -rw- 1821 Dec 20 2006 20:11:24 +00:00 sdmconfig-18xx.cfg
 3 -rw- 4734464 Dec 20 2006 20:12:00 +00:00 sdm.tar
 4 -rw- 833024 Dec 20 2006 20:12:24 +00:00 es.tar
 5 -rw- 1052160 Dec 20 2006 20:12:50 +00:00 common.tar
 6 -rw- 1038 Dec 20 2006 20:13:10 +00:00 home.shtml
 7 -rw- 102400 Dec 20 2006 20:13:30 +00:00 home.tar
 8 -rw- 491213 Dec 20 2006 20:13:56 +00:00 128MB.sdf
 9 -rw- 1684577 Dec 20 2006 20:14:34 +00:00 secure-desktop-
 ios-3.1.1.27-k9.pkg
 10 -rw- 398305 Dec 20 2006 20:15:04 +00:00 sslclient-win-1.1.0.154.pkg

32071680 bytes total (8818688 bytes free)
What we can see here is that we have the basic IP IOS (c1841-ipbase-mz.124-1c.bin). 
Looks like we need to upgrade our 1841. You’ve just got to love how Cisco puts the IOS type 
in the filename now! First, let’s check the size of the file that’s in flash with the show file
command (show flash would also work):
R1#show file info flash:c1841-ipbase-mz.124-1c.bin
flash:c1841-ipbase-mz.124-1c.bin:
 type is image (elf) []
 file size is 13937472 bytes, run size is 14103140 bytes
 Runnable image, entry point 0x8000F000, run from ram
With a file that size, the existing IOS will have to be erased before we can add our new 
IOS file (c1841-advipservicesk9-mz.124-12.bin), which is over 21 MB. We’ll use the 
delete command, but remember, we can play with any file in flash memory and nothing 
serious will happen until we reboot—that is, if we made a mistake. So obviously, and as I 
pointed out earlier, we need to be very careful here!
R1#delete flash:c1841-ipbase-mz.124-1c.bin
Delete filename [c1841-ipbase-mz.124-1c.bin]?[enter]
Delete flash:c1841-ipbase-mz.124-1c.bin? [confirm][enter]
R1#sh flash
-#- --length-- -----date/time------ path
1 1821 Dec 20 2006 20:11:24 +00:00 sdmconfig-18xx.cfg
2 4734464 Dec 20 2006 20:12:00 +00:00 sdm.tar
3 833024 Dec 20 2006 20:12:24 +00:00 es.tar
4 1052160 Dec 20 2006 20:12:50 +00:00 common.tar
5 1038 Dec 20 2006 20:13:10 +00:00 home.shtml
6 102400 Dec 20 2006 20:13:30 +00:00 home.tar
7 491213 Dec 20 2006 20:13:56 +00:00 128MB.sdf
8 1684577 Dec 20 2006 20:14:34 +00:00 secure-desktop-ios-3.1.1.27-k9.pkg
9 398305 Dec 20 2006 20:15:04 +00:00 sslclient-win-1.1.0.154.pkg
22757376 bytes available (9314304 bytes used)
R1#sh file info flash:c1841-ipbase-mz.124-1c.bin
%Error opening flash:c1841-ipbase-mz.124-1c.bin (File not found)
R1#
So with the preceding commands, we deleted the existing file and then verified the deletion by using both the show flash and show file commands. We’ll add the new file with 
the copy command, but again, we need to make sure to be careful because this way isn’t 
any safer than the first method I showed you earlier:
R1#copy tftp://1.1.1.2/c1841-advipservicesk9-mz.124-12.bin/ flash:/

 c1841-advipservicesk9-mz.124-12.bin
Source filename [/c1841-advipservicesk9-mz.124-12.bin/]?[enter]
Destination filename [c1841-advipservicesk9-mz.124-12.bin]?[enter]
Loading /c1841-advipservicesk9-mz.124-12.bin/ from 1.1.1.2 (via
 FastEthernet0/0): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[output cut]
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 22103052 bytes]
22103052 bytes copied in 72.008 secs (306953 bytes/sec)
R1#sh flash
-#- --length-- -----date/time------ path
1 1821 Dec 20 2006 20:11:24 +00:00 sdmconfig-18xx.cfg
2 4734464 Dec 20 2006 20:12:00 +00:00 sdm.tar
3 833024 Dec 20 2006 20:12:24 +00:00 es.tar
4 1052160 Dec 20 2006 20:12:50 +00:00 common.tar
5 1038 Dec 20 2006 20:13:10 +00:00 home.shtml
6 102400 Dec 20 2006 20:13:30 +00:00 home.tar
7 491213 Dec 20 2006 20:13:56 +00:00 128MB.sdf
8 1684577 Dec 20 2006 20:14:34 +00:00 securedesktop-ios-3.1.1.27-k9.pkg
9 398305 Dec 20 2006 20:15:04 +00:00 sslclient-win-1.1.0.154.pkg
10 22103052 Mar 10 2007 19:40:50 +00:00 c1841-advipservicesk9-mz.124-12.bin
651264 bytes available (31420416 bytes used)
R1#
We can also check the file information with the show file command:
R1#sh file information flash:c1841-advipservicesk9-mz.124-12.bin
flash:c1841-advipservicesk9-mz.124-12.bin:
 type is image (elf) []
 file size is 22103052 bytes, run size is 22268736 bytes
 Runnable image, entry point 0x8000F000, run from ram
Remember that the IOS is expanded into RAM when the router boots, so the new IOS 
will not run until you reload the router.
I really recommend experimenting with the Cisco IFS commands on a router just to 
get a good feel for them because, as I’ve said, they can definitely give you some grief if 
not executed properly!
I mention “safer methods” a lot in this chapter. Clearly, I’ve caused 
myself some serious pain by not being careful enough when working in 
flash memory! I cannot stress this enough—pay attention when messing 

around with flash memory!
One of the brilliant features of the ISR routers is that they use the physical flash cards 
that are accessible from the front or back of any router. These typically have a name like 
usbflash0:, so to view the contents you’d type dir usbflash0:, for example. You can pull 
these flash cards out, put them in an appropriate slot in your PC and the card will show up 
as a drive. You can then add, change, and delete files. Just put the flash card back in your 
router and power up—instant upgrade. Nice!
Licensing
IOS licensing is now done quite differently than it was with previous versions of the IOS. 
Actually, there was no licensing before the new 15.0 IOS code, just your word and honor, 
and we can only guess based on how all products are downloaded on the Internet daily 
how well that has worked out for Cisco! 
Starting with the IOS 15.0 code, things are much different—almost too different. I can 
imagine that Cisco will come back toward the middle on its licensing issues, so that the 
administration and management won’t be as detailed as the new 15.0 code license is now; 
but you can be the judge of that after reading this section.
A new ISR router is pre-installed with the software images and licenses that you ordered, 
so as long as you ordered and paid for everything you need, you’re set! If not, you can just 
install another license, which can be a tad tedious at first—enough so that installing a license 
was made an objective on the Cisco exam! Of course, it can be done, but it definitely requires 
some effort. As is typical with Cisco, if you spend enough money on their products, they tend 
to make it easier on you and your administration, and the licensing for the newest IOS is no 
exception, as you’ll soon see.
On a positive note, Cisco provides evaluation licenses for most software packages and 
features that are supported on the hardware you purchased, and it’s always nice to be able 
to try it out before you buy. Once the temporary license expires after 60 days, you need to 
acquire a permanent license in order to continue to use the extended features that aren’t 
available in your current version. This method of licensing allows you to enable a router to 
use different parts of the IOS. So, what happens after 60 days? Well, nothing—back to the 
honor system for now. This is now called Right-To-Use (RTU) licensing, and it probably 
won’t always be available via your honor, but for now it is.
But that’s not the best part of the new licensing features. Prior to the 15.0 code release, 
there were eight different software feature sets for each hardware router type. With the IOS 
15.0 code, the packaging is now called a universal image, meaning all feature sets are available 
in one file with all features packed neatly inside. So instead of the pre-15.0 IOS file packages of 
one image per feature set, Cisco now just builds one universal image that includes all of them 
in the file. Even so, we still need a different universal image per router model or series, just not 
a different image for each feature set as we did with previous IOS versions.
To use the features in the IOS software, you must unlock them using the software 
activation process. Since all features available are inside the universal image already, 

you can just unlock the features you need as you need them, and of course pay for these features when you determine that they meet your business requirements. All routers 
come with something called the IP Base licensing, which is the prerequisite for installing 
all other features.
There are three different technology packages available for purchase that can be installed 
as additional feature packs on top of the prerequisite IP Base (default), which provides entry￾level IOS functionality. These are as follows:
Data: MPLS, ATM, and multiprotocol support
Unified Communications: VoIP and IP telephony
Security: Cisco IOS Firewall, IPS, IPsec, 3DES, and VPN
For example, if you need MPLS and IPsec, you’ll need the default IP Base, Data, and 
Security premium packages unlocked on your router.
To obtain the license, you’ll need the unique device identifier (UDI), which has two 
components: the product ID (PID) and the serial number of the router. The show license 
UDI command provides this information in an output as shown:
Router#sh license udi
Device# PID SN UDI
-------------------------------------------------------------------------
*0 CISCO2901/K9 FTX1641Y07J CISCO2901/K9:FTX1641Y07J
After the time has expired for your 60-day evaluation period, you can either obtain the 
license file from the Cisco License Manager (CLM), which is an automated process, or use 
the manual process through the Cisco Product License Registration portal. Typically only 
larger companies will use the CLM because you’d need to install software on a server, which 
then keeps track of all your licenses for you. If you have just a few licenses that you use, you 
can opt for the manual web browser process found on the Cisco Product License Registration 
portal and then just add in a few CLI commands. After that, you just basically keep track of 
putting all the different license features together for each device you manage. Although this 
sounds like a lot of work, you don’t need to perform these steps often. But clearly, going with 
the CLM makes a lot of sense if you have bunches of licenses to manage because it will put 
together all the little pieces of licensing for each router in one easy process.
When you purchase the software package with the features that you want to install, 
you need to permanently activate the software package using your UDI and the product 
authorization key (PAK) that you received with your purchase. This is essentially your 
receipt acknowledging that you purchased the license. You then need to connect the license 
with a particular router by combining the PAK and the UDI, which you do online at the 
Cisco Product License Registration portal (www.cisco.com/go/license). If you haven’t 
already registered the license on a different router, and it is valid, Cisco will then email 
you your permanent license, or you can download it from your account.
But wait! You’re still not done. You now need to activate the license on the router. 
Whew… maybe it’s worthwhile to install the CLM on a server after all! Staying with the 
manual method, you need to make the new license file available to the router either via a 
USB port on the router or through a TFTP server. Once it’s available to the router, you’ll 
use the license install command from privileged mode. Assuming that you copied the file into flash memory, the command would look like 
something like this: 
Router#license install ?
 archive: Install from archive: file system
 flash: Install from flash: file system
 ftp: Install from ftp: file system
 http: Install from http: file system
 https: Install from https: file system
 null: Install from null: file system
 nvram: Install from nvram: file system
 rcp: Install from rcp: file system
 scp: Install from scp: file system
 syslog: Install from syslog: file system
 system: Install from system: file system
 tftp: Install from tftp: file system
 tmpsys: Install from tmpsys: file system
 xmodem: Install from xmodem: file system
 ymodem: Install from ymodem: file system
Router#license install flash:FTX1628838P_201302111432454180.lic
Installing licenses from "flash::FTX1628838P_201302111432454180.lic"
Installing...Feature:datak9...Successful:Supported
1/1 licenses were successfully installed
0/1 licenses were existing licenses
0/1 licenses were failed to install
April 12 2:31:19.786: %LICENSE-6-INSTALL: Feature datak9 1.0 was 
installed in this device. UDI=CISCO2901/K9:FTX1628838P; Store-index=1:Primary 
License Storage
April 12 2:31:20.078: %IOS_LICENSE_IMAGE_APPLICATION-6-LICENSE_LEVEL: Module name 
=c2800 Next reboot level = datak9 and License = datak9
You need to reboot to have the new license take effect. Now that you have your license 
installed and running, how do you use Right-To-Use licensing to check out new features on 
your router? Let’s look into that now.
Right-To-Use Licenses (Evaluation Licenses)
Originally called evaluation licenses, Right-To-Use (RTU) licenses are what you need 
when you want to update your IOS to load a new feature but either don’t want to wait 
to get the license or just want to test if this feature will truly meet your business requirements. This makes sense because if Cisco made it complicated to load and check out a feature, they could potentially miss out on a sale! Of course if the feature does work for 
you, they’ll want you to buy a permanent license, but again, this is on the honor system 
at the time of this writing.
Cisco’s license model allows you to install the feature you want without a PAK. The 
Right-To-Use license works for 60 days before you would need to install your permanent 
license. To enable the Right-To-Use license you would use the license boot module com￾mand. The following demonstrates starting the Right-To-Use license on my 2900 series 
router, enabling the security module named securityk9: 
Router(config)#license boot module c2900 technology-package securityk9
PLEASE READ THE FOLLOWING TERMS CAREFULLY. INSTALLING THE LICENSE OR LICENSE KEY 
PROVIDED FOR ANY CISCO PRODUCT FEATURE OR USING 
SUCHPRODUCT FEATURE CONSTITUTES YOUR FULL ACCEPTANCE OF THE 
FOLLOWING TERMS. YOU MUST NOT PROCEED FURTHER IF YOU ARE NOT WILLING 
TO BE BOUND BY ALL THE TERMS SET FORTH HEREIN.
[output cut]
Activation of the software command line interface will be evidence of 
your acceptance of this agreement.
ACCEPT? [yes/no]: yes
% use 'write' command to make license boot config take effect on next boot
Feb 12 01:35:45.060: %IOS_LICENSE_IMAGE_APPLICATION-6-LICENSE_LEVEL: 
Module name =c2900 Next reboot level = securityk9 and License = securityk9
Feb 12 01:35:45.524: %LICENSE-6-EULA_ACCEPTED: EULA for feature 
securityk9 1.0 has been accepted. UDI=CISCO2901/K9:FTX1628838P; 
StoreIndex=0:Built-In License Storage
Once the router is reloaded, you can use the security feature set. And it is really nice that 
you don’t need to reload the router again if you choose to install a permanent license for this 
feature. The show license command shows the licenses installed on the router:
Router#show license
Index 1 Feature: ipbasek9
 Period left: Life time
 License Type: Permanent
 License State: Active, In Use
 License Count: Non-Counted
 License Priority: Medium
Index 2 Feature: securityk9
 Period left: 8 weeks 2 days

Period Used: 0 minute 0 second
 License Type: EvalRightToUse
 License State: Active, In Use
 License Count: Non-Counted
 License Priority: None
Index 3 Feature: uck9
 Period left: Life time
 License Type: Permanent
 License State: Active, In Use
 License Count: Non-Counted
 License Priority: Medium
Index 4 Feature: datak9
 Period left: Not Activated
 Period Used: 0 minute 0 second
 License Type: EvalRightToUse
 License State: Not in Use, EULA not accepted
 License Count: Non-Counted
 License Priority: None
Index 5 Feature: gatekeeper
 [output cut]
You can see in the preceding output that the ipbasek9 is permanent and the securityk9
has a license type of EvalRightToUse. The show license feature command provides 
the same information as show license, but it’s summarized into one line as shown in the 
next output:
Router#sh license feature
Feature name Enforcement Evaluation Subscription Enabled RightToUse
ipbasek9 no no no yes no
securityk9 yes yes no no yes
uck9 yes yes no yes yes
datak9 yes yes no no yes
gatekeeper yes yes no no yes
SSL_VPN yes yes no no yes
ios-ips-update yes yes yes no yes
SNASw yes yes no no yes
hseck9 yes no no no no
cme-srst yes yes no yes yes
WAAS_Express yes yes no no yes

UCVideo yes yes no no yes

The show version command also shows the license information at the end of the 
command output:
Router#show version
[output cut]
License Info:
License UDI:
-------------------------------------------------
Device# PID SN
-------------------------------------------------
*0 CISCO2901/K9 FTX1641Y07J
Technology Package License Information for Module:'c2900'
-----------------------------------------------------------------
Technology Technology-package Technology-package
 Current Type Next reboot
------------------------------------------------------------------
ipbase ipbasek9 Permanent ipbasek9
security None None None
uc uck9 Permanent uck9
data None None None
Configuration register is 0x2102
The show version command shows if the license was activated. Don’t forget, you’ll 
need to reload the router to have the license features take effect if the license evaluation 
is not already active.
Backing Up and Uninstalling the License
It would be a shame to lose your license if it has been stored in flash and your flash files 
become corrupted. So always back up your IOS license!
If your license has been saved in a location other than flash, you can easily back it up to 
flash memory via the license save command:

Router#license save flash:Todd_License.lic

The above command will save your current license to flash. You can restore your license 
with the license install command I demonstrated earlier.
There are two steps to uninstalling the license on a router. First, to uninstall the license 
you need to disable the technology package, using the no license boot module command 
with the keyword disable at the end of the command line:
Router#license boot module c2900 technology-package securityk9 disable
The second step is to clear the license. To achieve this from the router, use the license 
clear command and then remove the license with the no license boot module command.
Router#license clear securityk9
Router#config t
Router(config)#no license boot module c2900 technology-package securityk9 disable
Router(config)#exit
Router#reload
After you run through the preceding commands, the license will be removed from 
your router.
Here’s a summary of the license commands I used in this chapter. These are important commands to have down and you really need to understand these to meet the Cisco 
objectives:
uu show license determines the licenses that are active on your system. It also displays 
a group of lines for each feature in the currently running IOS image along with several status variables related to software activation and licensing, both licensed and 
unlicensed features.
uu show license feature allows you to view the technology package licenses and feature 
licenses that are supported on your router along with several status variables related to 
software activation and licensing. This includes both licensed and unlicensed features.
uu show license udi displays the unique device identifier (UDI) of the router, which 
comprises the product ID (PID) and serial number of the router.
uu show version displays various information about the current IOS version, including 
the licensing details at the end of the command’s output.
uu license install url installs a license key file into a router.
uu license boot module installs a Right-To-Use license feature on a router.
Summary
You now know how Cisco routers are configured and how to manage those configurations.
This chapter covered the internal components of a router, which included ROM, RAM, 

NVRAM, and flash.
In addition, I covered what happens when a router boots and which files are loaded at 
that time. The configuration register tells the router how to boot and where to find files. You 
learned how to change and verify the configuration register settings for password recovery 
purposes. I also showed you how to manage these files using the CLI and IFS.
Finally, the chapter covered licensing with the new 15.0 code, including how to install a 
permanent license and Right-To-Use license to install features for 60 days. I also showed you 
the verification commands used to see what licenses are installed and to verify their status.
Exam Essentials
Define the Cisco router components. Describe the functions of the bootstrap, POST, ROM 
monitor, mini-IOS, RAM, ROM, flash memory, NVRAM, and the configuration register.
Identify the steps in the router boot sequence. The steps in the boot sequence are: POST, 
loading the IOS, and copying the startup configuration from NVRAM to RAM.
Understand configuration register commands and settings. The 0x2102 setting is the 
default on all Cisco routers and tells the router to look in NVRAM for the boot sequence. 
0x2101 tells the router to boot from ROM, and 0x2142 tells the router not to load the 
startup-config in NVRAM to provide password recovery.
Perform password recovery. The steps in the password recovery process are: interrupt the 
router boot sequence, change the configuration register, reload the router and enter privi￾leged mode, copy the startup-config file to running-config and verify that your interfaces 
are re-enabled, change/set the password, save the new configuration, reset the configuration 
register, and reload the router.
Back up an IOS image. By using the privileged-mode command copy flash tftp, you 
can back up a file from flash memory to a TFTP (network) server.
Restore or upgrade an IOS image. By using the privileged-mode command copy tftp 
flash, you can restore or upgrade a file from a TFTP (network) server to flash memory.
Describe best practices to prepare to back up an IOS image to a network server. Make 
sure that you can access the network server, ensure that the network server has adequate 
space for the code image, and verify the file naming and path requirement.
Understand and use Cisco IFS file system management commands. The commands to use 
are dir, copy, more, delete, erase or format, cd and pwd, and mkdir and rmdir, as well as
system:running-config and nvram:startup-config.
Remember how to install a permanent and Right-To-Use license. To install a permanent 
license on a router, use the install license url command. To install an evaluation feature, 

use the license boot module command.

Remember the verification commands used for licensing in the new ISR G2 routers. The
show license command determines the licenses that are active on your system. The show 
license feature command allows you to view the technology package licenses and feature 
licenses that are supported on your router. The show license udi command displays the 
unique device identifier (UDI) of the router, which comprises the product ID (PID) and serial 
number of the router, and the show version command displays various information about 

the current IOS version, including the licensing details at the end of the command’s output.

Written Labs
The answers to these labs can be found in Appendix A, “Answers to Written Labs.”
In this section, you’ll complete the following labs to make sure you’ve got the information 
and concepts contained within them fully dialed in:
Lab 2.1: IOS Management
Lab 2.2: Router Memory
Written Lab 2.1: IOS Management
Write the answers to the following questions:
1. What is the command to copy a Cisco IOS to a TFTP server?
2. What do you set the configuration register setting to in order to boot the mini-IOS 
in ROM?
3. What is the configuration register setting to tell the router to look in NVRAM for the 
boot sequence? 
4. What do you set the configuration register setting to in order to boot to ROM moni￾tor mode?
5. What is used with a PAK to generate a license file?
6. What is the configuration register setting for password recovery?
7. Which command can change the location from which the system loads the IOS?
8. What is the first step of the router boot sequence?
9. What command can you use to upgrade a Cisco IOS?
10. Which command determines the licenses that are active on your system?
Written Lab 2.2: Router Memory
Identify the location in a router where each of the following files is stored by default.
1. Cisco IOS
2. Bootstrap
3. Startup configuration
4. POST routine
5. Running configuration
6. ARP cache
7. Mini-IOS
8. ROM monitor
9. Routing tables

10. Packet buffers
Hands-on Labs
To complete the labs in this section, you need at least one router (three would be best) and at 
least one PC running as a TFTP server. TFTP server software must be installed and running 
on the PC. For these labs, it is also assumed that your PC and the router(s) are connected 
together with a switch or hub and that all interfaces (PC NIC and router interfaces) are in the 
same subnet. You can alternately connect the PC directly to the router or connect the routers 
directly to one another (use a crossover cable in that case). Remember that the labs listed here 
were created for use with real routers but can easily be used with the LammleSim IOS version 
or Cisco’s Packet Tracer program.
Here is a list of the labs in this chapter:
Lab 2.1: Backing Up Your Router IOS
Lab 2.2: Upgrading or Restoring Your Router IOS
Hands-on Lab 2.1: Backing Up Your Router IOS
In this lab, we’ll be backing up the IOS from flash to a TFTP host.
1. Log into your router and go into privileged mode by typing en or enable.
2. Make sure you can connect to the TFTP server that is on your network by pinging the 
IP address from the router console.
3. Type show flash to see the contents of flash memory.
4. Type show version at the router privileged-mode prompt to get the name of the IOS cur￾rently running on the router. If there is only one file in flash memory, the show flash and 
show version commands show the same file. Remember that the show version command 
shows you the file that is currently running and the show flash command shows you all 
of the files in flash memory.
5. Once you know you have good Ethernet connectivity to the TFTP server and you also 
know the IOS filename, back up your IOS by typing copy flash tftp. This command 
tells the router to copy a specified file from flash memory (this is where the IOS is 
stored by default) to a TFTP server.
6. Enter the IP address of the TFTP server and the source IOS filename. The file is now 
copied and stored in the TFTP server’s default directory.
Hands-on Lab 2.2: Upgrading or Restoring 
Your Router IOS
In this lab, we’ll be copying an IOS from a TFTP host to flash memory.
1. Log into your router and go into privileged mode by typing en or enable.
2. Make sure you can connect to the TFTP server by pinging the IP address of the server 
from the router console.
Hands-on Labs 693
3. Once you know you have good Ethernet connectivity to the TFTP server, type the 
copy tftp flash command.
4. Confirm that the router will not function during the restore or upgrade by following 
the prompts provided on the router console. It is possible this prompt may not occur.
5. Enter the IP address of the TFTP server.
6. Enter the name of the IOS file you want to restore or upgrade.
7. Confirm that you understand the contents of flash memory will be erased if there is not 
enough room in flash to store the new image.
8. Watch in amazement as your IOS is deleted out of flash memory and your new IOS is 
copied to flash memory.
If the file that was in flash memory is deleted but the new version wasn’t copied to flash 
memory, the router will boot from ROM monitor mode. You’ll need to figure out why the 
copy operation did not take place.
694 Chapter 16 u Managing Cisco Devices
Review Questions
The following questions are designed to test your understanding of this 
chapter’s material. For more information on how to get additional ques￾tions, please see this book’s introduction.
The answers to these questions can be found in Appendix B, “Answers to Review 
Questions.”
1. What does the command confreg 0x2142 provide?
A. It is used to restart the router.
B. It is used to bypass the configuration in NVRAM.
C. It is used to enter ROM monitor mode.
D. It is used to view the lost password.
2. Which command will copy the IOS to a backup host on your network?
A. transfer IOS to 172.16.10.1
B. copy run start
C. copy tftp flash
D. copy start tftp
E. copy flash tftp
3. What command is used to permanently install a license on an ISR2 router?
A. install license
B. license install
C. boot system license
D. boot license module
4. You type the following into the router and reload. What will the router do?
Router(config)#boot system flash c2800nm-advsecurityk9-mz.151-4.M6.bin
Router(config)#config-register 0x2101
Router(config)#do sh ver
[output cut]
Configuration register is 0x2102 (will be 0x2101 at next reload)
A. The router will expand and run the c2800nm-advsecurityk9-mz.151-4.M6.bin
IOS from flash memory.
B. The router will go into setup mode.
C. The router will load the mini-IOS from ROM.
D. The router will enter ROM monitor mode.
Review Questions 695
5. A network administrator wants to upgrade the IOS of a router without removing the 
image currently installed. What command will display the amount of memory consumed by the current IOS image and indicate whether there is enough room available 
to hold both the current and new images?
A. show version
B. show flash
C. show memory
D. show buffers
E. show running-config
6. The corporate office sends you a new router to connect, but upon connecting the console cable, you see that there is already a configuration on the router. What should be 
done before a new configuration is entered in the router?
A. RAM should be erased and the router restarted.
B. Flash should be erased and the router restarted.
C. NVRAM should be erased and the router restarted.
D. The new configuration should be entered and saved.
7. Which command loads a new version of the Cisco IOS into a router?
A. copy flash ftp
B. copy nvram flash
C. copy flash tftp
D. copy tftp flash
8. Which command will show you the IOS version running on your router?
A. sh IOS
B. sh flash
C. sh version
D. sh protocols
9. What should the configuration register value be after you successfully complete the 
password recovery procedure and return the router to normal operation?
A. 0x2100
B. 0x2101
C. 0x2102
D. 0x2142
696 Chapter 16 u Managing Cisco Devices
10. You save the configuration on a router with the copy running-config startup-con￾fig command and reboot the router. The router, however, comes up with a blank configuration. What can the problem be?
A. You didn’t boot the router with the correct command.
B. NVRAM is corrupted.
C. The configuration register setting is incorrect.
D. The newly upgraded IOS is not compatible with the hardware of the router.
E. The configuration you saved is not compatible with the hardware.
11. Which command will install a Right-To-Use license so you can use an evaluation version 
of a feature?
A. install Right-To-Use license feature feature
B. install temporary feature feature
C. license install feature
D. license boot module
12. Which command determines the licenses that are active on your system along with 
several status variables?
A. show license
B. show license feature
C. show license udi
D. show version
13. Which command allows you to view the technology package licenses and feature 
licenses that are supported on your router along with several status variables?
A. show license
B. show license feature
C. show license udi
D. show version
14. Which command displays the unique device identifier that comprises the product 
ID and serial number of the router?
A. show license
B. show license feature
C. show license udi
D. show version
Review Questions 697
15. Which command displays various information about the current IOS version, including 
the licensing details at the end of the command’s output?
A. show license
B. show license feature
C. show license udi
D. show version
16. Which command backs up your license to flash memory?
A. copy tftp flash
B. save license flash
C. license save flash
D. copy license flash
17. Which command displays the configuration register setting?
A. show ip route
B. show boot version
C. show version

D. show flash

18. What two steps are needed to remove a license from a router? (Choose two.)
A. Use the erase flash:license command.
B. Reload the system.
C. Use the license boot command with the disable variable at the end of the command line.
D. Clear the license with the license clear command.
19. You have your laptop directly connected into a router’s Ethernet port. Which of the 
following are among the requirements for the copy flash tftp command to be successful? (Choose three.)
A. TFTP server software must be running on the router.
B. TFTP server software must be running on your laptop.
C. The Ethernet cable connecting the laptop directly into the router’s Ethernet port 
must be a straight-through cable.
D. The laptop must be on the same subnet as the router’s Ethernet interface.
E. The copy flash tftp command must be supplied the IP address of the laptop.
F. There must be enough room in the flash memory of the router to accommodate the 
file to be copied.
698 Chapter 16 u Managing Cisco Devices
20. The configuration register setting of 0x2102 provides what function to a router?
A. Tells the router to boot into ROM monitor mode
B. Provides password recovery
C. Tells the router to look in NVRAM for the boot sequence
D. Boots the IOS from a TFTP server

E. Boots an IOS image stored in ROM

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