The router components enable the boot up process and loading of the operating system. The bootstrap program loads the IOS image, while the flash memory stores IOS. NVRAM stores configuration files and the configuration register controls the booting process. The chapter discusses router installation, boot sequence, IOS, CLI, initial configuration, hostname, banners and passwords configuration.
2. Chapter Objectives
Explain router components
Explain router installation
Discuss router boot sequence
Define Internetwork Operating System (IOS)
Explain Command Line Interface (CLI)
Perform initial router configuration
Set hostname, banners and passwords for the
router
Manage the configuration register
Chapter 4 2
3. Recall - I
Different network devices include:
Hubs
Routers
Switches
Bridges
Repeaters
Different types of hubs include:
Active
Passive
Hybrid
Chapter 4 3
4. Recall - II
Different WAN devices include:
WAN Switch
Access Server
Modem
Channel Service Unit
ISDN Terminal Adapter
Chapter 4 4
5. Router Components
Router components allow the router to enter the
bootup process, load its operating system, and
configuration files
Router
Components
Configuration
Processor ROM RAM Flash NVRAM
Register
Chapter 4 5
6. Router Boot Sequence
The router requires all the router components during
its bootup
Chapter 4 6
7. Internetwork Operating System
IOS acts as an interface between the network
devices and the user
It is stored in the flash memory of the router
The Cisco IOS software requires the processor of
the system for configuring and maintaining the
network devices
Different features of IOS include:
Support for different technologies
Scalability
Security
Chapter 4 7
8. Router Ports
Router ports help to configure the router, verify its
configuration and access Cisco IOS
Router Ports
Console Port Auxiliary Port
Chapter 4 8
11. CLI Prompts
CLI prompts allow you to navigate and recognize
the mode that you have entered
CLI prompts include:
Interfaces
Sub-Interfaces
Line
Router
Chapter 4 11
12. Accessing Help and History
Command Description
? Help for all available commands in the mode
Command ? Describes all the first parameters of the command
com? Lists the commands that begin with com
command parm? Lists the characters that begin with parm
command When the tab is pressed in between the word, the CLI
parm<Tab> completes the word. If the CLI is idle, it indicates that the
typed characters can form more possible words
command parm1 ? Lists all the next parameters and their description
Chapter 4 12
13. Enhanced Editing Commands - I
The enhanced editing commands include:
Ctrl + A - Moves the cursor to the beginning of a
line
Ctrl+E - Moves the cursor to the end of the line
Esc+B - Move the cursor back by one word
Ctrl+B - Move the cursor back by one character
Ctrl+F - Move the cursor forward by one character
Esc+F - Move the cursor forward by one word
Ctrl+D - Deletes one character
Chapter 4 13
14. Enhanced Editing Commands - II
Backspace - Deletes one character
Ctrl+R - Recalls a line
Ctrl+U - Deletes a line
Ctrl+W - Deletes a word
Ctrl+Z - Returns to EXEC from the configuration
mode
Tab - Finishes typing a word
Chapter 4 14
15. Router History Commands
Command Description
Ctrl+P or Up arrow Displays the last command entered
Ctrl+N or Down arrow Displays the previously entered commands
show history Displays the last 10 command entered
show terminal Displays terminal configuration and size of history
buffer
terminal history size Allows to change the buffer size
Chapter 4 15
17. Banners
Banner is a message displayed to all the users when
they access the router through Telnet, console and
auxiliary ports
It can be used to display information about the router
itself or nay kind of security message
Four types of banners available for the Cisco routers
are:
Message of the day banner
Exec process creation banner
Incoming terminal line banner
Login banner
Chapter 4 17
18. Summary - I
The router components enable the router to start the
boot up process, load its operating system, and load
its configuration files
The Power-On-Self-Test or the POST component
provides a series of diagnostic tests for the router
The POST is a series of 14 tests that run in the
reverse numerical order
The bootstrap program or the ROM Monitor
component enables you to initialize the processor
hardware when the router boots
Chapter 4 18
19. Summary - II
The bootstrap program loads the IOS image for the
router
The different values for the image in the
configuration register are:
0x0 - Boots the router into ROM monitor mode
0x1 - Boots the router using the Mini-IOS
0x2–0xF - Boots the router using the default boot
sequence
Chapter 4 19
20. Summary - III
The boot system commands in the startup-config file
are:
boot system flash IOS filename - Enables you to
boot from flash memory
boot system tftp IOS filename tftp server ip
address - Enables you to boot from a TFTP server
boot system rom - Enables you boot from system
ROM
Chapter 4 20
21. Summary - IV
The bootstrap program offers a console-based
interface or monitor for working with the program
Mini-IOS component provides an alternate file for
the router boot up, if the existing image file is
unavailable
ROM monitor is a component stored in the
microcode of RAM
The flash memory contains IOS using which the
router can boot
Chapter 4 21
22. Summary - V
NVRAM or Non-Volatile RAM is a type of random
access memory that stores the configuration files for
the router
Configuration register is a component that controls the
booting process of a router
The router can be connected through console port,
auxillary port or Telnet program
CLI is a character or text based interface that allows
manual configuration of the router
User Exec Mode enables you to work with the router
and execute very simple commands
Chapter 4 22