CCNA Router and IOS Basics

CCNA Guide to Cisco Networking Fundamentals Chapter 5 Router and IOS Basics

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

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

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

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

CCNA Guide to Cisco Networking Fundamentals, Fourth Edition

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

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

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

User Interface CCNA Guide to Cisco Networking Fundamentals, Fourth Edition 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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 Flash memory 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

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

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

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

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

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

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

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

CCNA Router and IOS Basics

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CCNA Router and IOS Basics