CN2668
Routers and Switches
Kemtis Kunanuraksapong
MSIS with Distinction
MCTS, MCDST, MCP, A+
Agenda
• Chapter 5: Router and IOS Basics
• Exercise
• Quiz
Benefits of Routing
• Routers provide
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Packet filtering
Connections between local networks
Traffic control
Wide area network (WAN) connections
• Routers operate at the Network layer of the OSI
reference model
▫ Because of Network layer addressing, routers can
direct packets to both local and remote segments
Cisco Router User Interface
• Cisco Internetwork Operating System (IOS)
▫ Provides a command-line interface (CLI)
• You can access a router in several different ways
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Console port (also known as the console)
Auxiliary port (AUX)
Virtual terminals (VTY)
Trivial File Transfer Protocol (TFTP) server
See Figure 5-1 on Page 119
System Configuration Dialog
• If the router has not been configured previously,
or if the startup file has been erased
▫ The Cisco IOS will prompt you to run the initial
configuration dialog after the router boots
▫ You also can type Setup to configure as well
• A series of prompts that guide you through the
initial configuration for the router
• If IOS 12.0, you have two setups
▫ Basic management
▫ Extended setup
User Interface
• The initial prompt:
▫ The host name of the router followed by the
greater than symbol (>)
▫ Default: router>
• User EXEC mode (User mode)
▫ When the prompt displayed is the greater than
symbol
▫ User mode does not allow you to configure the
router only to check status and review settings
User Interface (continued)
• The question mark activates context-sensitive
Help on the Cisco router
• Privileged EXEC mode
▫ To enter privileged EXEC, you can type the
enable command at the user mode prompt
▫ Next, you may be prompted for a password
▫ Greater than symbol (>) changes to a pound sign
(#)
User Interface (continued)
• The question mark activates context-sensitive
Help on the Cisco router
• Privileged EXEC mode
▫ To enter privileged EXEC, you can type the
enable command at the user mode prompt
▫ Next, you may be prompted for a password
▫ Greater than symbol (>) changes to a pound sign
(#)
User Interface (continued)
• In Privileged EXEC mode
▫ Setup command will cause the router to enter the
system configuration dialog
▫ Copy configurations can be copied from TFTP
servers to the router and therefore change the
router configuration
▫ Erase configuration files as well as the entire IOS
can be erased
Configuration Modes
• Global configuration mode
▫ Accessed by typing configure terminal at the
enable mode prompt
• Interface configuration mode
▫ Allows you to configure the Ethernet and serial
interfaces on your router
• Line configuration mode
▫ Allows you to configure the virtual terminals,
console, and AUX lines that let you access the
router
Configuration Modes (continued)
• Typing exit will take you back one level
• Typing end or pressing the Ctrl+Z keys will take
you all the way back to the enable prompt
• Abbreviated commands
▫ Such as conf t, en, sh ru
• The router will show you the point at which you
entered an incorrect character
Plethora of Passwords
• 5 passwords you can set
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▫
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Enable
Enable Secret
Console
Aux
Virtual Terminal (VTY)
• Use service password-encryption if you want to
encrypt all passwords
Plethora of Passwords
• Enable Password and Enable Secret Password
configuration
▫ You can set both passwords from the global
configuration mode prompt
▫ You can type no enable secret and no
enable password at the global configuration
mode prompt
 To remove the enable secret and enable passwords
Plethora of Passwords (continued)
• Setting Line passwords
▫ You can set passwords for each line used to
configure the router
▫ Configure the console line password
 Enter line con 0
▫ You can also configure passwords on the five
virtual terminal lines that exist on every router
 Enter line vty 0 4
Enhanced Editing
• The enhanced editing commands let you jump to
the beginning or end of a command line
▫ You can also jump forward or back, character by
character, or word by word
• You can turn off the enhanced editing features
by typing terminal no editing at either the
user EXEC or the privileged EXEC prompts
▫ You can turn on terminal editing by typing
terminal editing
• See Table 5-3 on Page 129
Command History
• Command history
▫ Allows you to retrieve previously typed commands
▫ You can see up to 10 previously typed commands
by typing show history
• To modify the number of commands stored by
the router, you can use the terminal command
▫ Up to 256 previous commands
▫ Type terminal history size n
Configuring Router
• Router host name
▫ Default host name is router
▫ To set the router host name, type hostname followed
by the name that you want to set
• Configure a banner
▫ A banner is a message that you can configure to
display each time someone attempts to log in to the
router
▫ Enter global configuration mode by typing config t
 Then type banner motd, followed by a space and a
delimiting character
Configuring Router (Cont.)
• Configure an interface description
▫ Use the description command
▫ The interface description helps you remember
which network the interface services
• Use the clock set command in enable mode
to configure the time
▫ You must be in global configuration mode to
configure the time zone
▫ See Figure 5-14 on Page 132
Router Components
• ROM
▫ Contains the bootstrap
▫ Not modified during normal operations, but it can
be upgraded with special plug-in chips
• Flash memory (EPROM)
▫ Contains the working copy of the current Cisco
IOS
▫ Is the component that initializes the IOS for
normal router operations
Router Components (Cont.)
• NVRAM
▫ Contain the startup configuration file for the
router and IOS uses it during boot process
• RAM/DRAM
▫ Changes to the router’s running configuration take
place in RAM/DRAM
• Interfaces
Assignment
• Review Questions
▫ 1 – 24
• Case Projects
▫5
• Lab 5.1, 5.3 – 5.5