1. CCNA Guide to Cisco Networking Fundamentals Fourth Edition
Chapter 5
Router and IOS Basics

2. Objectives Describe the benefits of network segmentation with routers
Understand the elements of the Cisco router user interface
Configure the HyperTerminal program to interface with the Cisco router
Describe the various router configuration modes
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

3. Objectives (continued)
Describe the various router passwords
Understand the enhanced editing features of the Cisco IOS
Compare router components to typical PC components
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

4. Benefits of Routing Routers provide
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
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

5. Cisco Router User Interface
Cisco Internetwork Operating System (IOS)
Provides a command-line interface (CLI)
Allows network operators to check the status of the router and network administrators to manage and configure the router
You can access a router in several different ways
Console port (also known as the console)
Auxiliary port (AUX)
Virtual terminals (VTY)
Trivial File Transfer Protocol (TFTP) server
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

6. CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

7. CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

8. Connecting via Terminal Programs
When configuring the router through the console or AUX ports
You must first make the physical connection
Then, you can access the router through a terminal program
Steps to configure HyperTerminal:
Open the HyperTerminal application
Click File on the menu bar, and then click New Connection
Enter a name for the connection
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

9. Connecting via Terminal Programs (continued)
Steps to configure HyperTerminal: (continued)
Configure how you will connect to the router via the Connect To dialog box
If you are connecting to the router through the AUX port, you would provide the router phone number here
If connecting to the router through the console port, click the “Connect using” list box and choose the COM port to which the RJ-45 to DB-9 connector is attached
Configure the following settings for the COM port: Bits per second, 9600; Data bits, 8; Parity, None; Stop bits, 1; Flow control, None
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

10. 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
The system configuration dialog presents a series of prompts that guide you through the initial configuration for the router
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

11. CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

12. User Interface The initial prompt consists of two parts:
The host name of the router followed by the greater than symbol (>)
Default: router>
User EXEC mode (or user mode)
When the prompt displayed is the greater than symbol
Network operator can check router status and review several of the router settings
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

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14. User Interface (continued)
The question mark activates context-sensitive Help on the Cisco router
User mode does not allow you to configure the router
To do this, you must go into the 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 (#)
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

15. User Interface (continued)
You can do a few things at this prompt
Setup: the 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
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

16. 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
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

17. CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

18. 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
Often, you can discover abbreviated commands by simply trying them
The router will show you the point at which you entered an incorrect character
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

19. Configuration Modes (continued)
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

20. Plethora of Passwords
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

21. Plethora of Passwords (continued)
Enable Password and Enable Secret Password configuration
You can set both passwords from the global configuration mode prompt
Because it is encrypted, the enable secret password is more secure than the enable password
You can type no enable secret and no enable password at the global configuration mode prompt
To remove the enable secret and enable passwords
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

22. Plethora of Passwords (continued)
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

23. CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

24. Plethora of Passwords (continued)
Setting Line passwords
Line passwords are the first line of defense against unauthorized intrusion into the router
You can set passwords for each line used to configure the router
Configure the console line password
Enter line configuration mode
You can also configure passwords on the five virtual terminal lines that exist on every router
In much the same way as on the console port
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

25. Plethora of Passwords (continued)
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

26. Plethora of Passwords (continued)
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

27. Plethora of Passwords (continued)
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

28. Enhanced Editing
By default, the router supports enhanced editing features that allow you to modify lengthy commands
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
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

29. Enhanced Editing (continued)
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

30. Command History Command history
Allows you to retrieve previously typed commands
You can see up to 10 previously typed commands by typing show history
From either the user EXEC or privileged EXEC mode
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
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

31. Configuring Router Identification
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
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

32. Configuring Router Identification (continued)
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

33. Configuring Router Identification (continued)
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

34. Configuring Router Identification (continued)
Configure an interface description
Use the description command
The interface description helps you remember which network the interface services
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

35. Configuring the Time and Date
Use the clock set command in enable mode to configure the time
You must be in global configuration mode to configure the time zone
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

36. Router Components
This section discusses the hardware elements of the router:
ROM
Flash memory
NVRAM
RAM/DRAM
Interfaces
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

37. ROM Read-only memory (ROM)
Loads the bootstrap program that initializes the router’s basic hardware components
Not modified during normal operations, but it can be upgraded with special plug-in chips
The content of ROM is maintained even when the router is rebooted
The ROM monitor firmware runs when the router is turned on or rebooted
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

38. Flash Memory Flash memory
A type of erasable, programmable, read-only memory (EPROM)
Not typically modified during normal operations
However, it can be upgraded or erased when necessary
The content of flash memory is maintained even when the router is rebooted
Contains the working copy of the current Cisco IOS
Is the component that initializes the IOS for normal router operations
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

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40. NVRAM Nonvolatile random access memory (NVRAM)
A special type of RAM that is not cleared when the router is rebooted
The startup configuration file for the router is stored in NVRAM by default
This is the first file created by the person who sets up the router
The Cisco IOS uses the configuration file in NVRAM during the router boot process
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

41. RAM/DRAM Random access memory (RAM)
Also known as dynamic random access memory (DRAM)
A volatile hardware component
Its information is not maintained in the event of a router reboot
Changes to the router’s running configuration take place in RAM/DRAM
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

42. RAM/DRAM (continued)
The IOS contains commands to view each of the router’s components
show running-config
show memory
show buffers
show startup-config
Copy running-config startup-config
Abbreviated as Copy run start
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

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44. Interfaces A router can ship with a variety of configurable interfaces
A common interface is Ethernet0
Other types of interfaces include:
Token Ring
Basic Rate Interface (BRI)
Asynchronous Transfer Mode (ATM)
Fiber Distributed Data Interface (FDDI)
Channel Interface Processor (CIP) for Systems Network Architecture (SNA)
High-Speed Serial Interface (HSSI)
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

45. CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

46. Summary
Cisco routers use the Cisco IOS to provide an interface for network operators and administrators
The first mode entered is user EXEC (router> prompt) and the next mode is privileged EXEC (router# prompt)
In user EXEC, you can accomplish basic tasks
To actually configure the router, privileged EXEC mode must be accessed
The privileged EXEC mode is often called enable mode
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

47. Summary (continued)
The enable, enable secret, and VTY passwords are set during initial configuration if the system configuration dialog is used
When configured, the enable secret password supersedes the enable password
The components of a router include ROM, flash memory, NVRAM, RAM/DRAM, and interfaces
ROM stores a limited version of the Cisco IOS and routines for checking the hardware during system boot
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

48. Summary (continued)
Flash memory stores the Cisco IOS that is loaded by default during system boot
NVRAM stores the startup copy of the router configuration file that is loaded by default during system boot
RAM/DRAM stores the working copy (running configuration) of the router configuration
Interfaces provide connectivity to various types of LANs and WANs
CCNA Guide to Cisco Networking Fundamentals, Fourth Edition