INTRODUCTION TO IOS AND CISCO ROUTERS
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Transcript of INTRODUCTION TO IOS AND CISCO ROUTERS
INTRODUCTION TO IOS AND CISCO ROUTERS
ByAnil Kumar VishwakarmaMCA,MCTS,CCNA
CISCO ROUTER IOS
oThe Cisco IOS (Internetwork Operating System) was created to deliver network services and enable networked applications. It runs on most Cisco routers.
oSome of the important things that the Cisco router IOS software is responsible for includeo Carrying network protocols and functions.o Connecting high-speed traffic between devices.o Adding security to control access and stop unauthorized
network use.o Supplying network reliability for connecting to network
resources.
CISCO ROUTER Router uses to connect: -
Subnet with another Subnet (By LAN Interface).
LAN with another LAN (By WAN Interface).LAN with WAN (By WAN Interface).WAN with another WAN (By WAN
Interface).
Router Consist of External Components (Interfaces) and Internal Components
INTERNAL COMPONENT
CONNECTING TO A CISCO ROUTER You can connect to a Cisco router to configure it, verify its configuration, and check statistics.
There are Three ways to do that: - Console Session. Auxiliary Session. Telnet Session can’t use this method after
router has taken valid IP address.
COMPUTER CONSOLE CONNECTION
MODEM CONNECTION
BRINGING UP A ROUTER When you first bring up a router, it will takes this Boot Sequence: - Perform POST (Power On Self Test) which
is small program stored in ROM to check router components.
Load IOS image from Flash memory and decompress it into RAM.
Display the information from POST. Running Valid Configuration (Startup Conf). If no configuration router will go into
Setup mode.
MEMORY ARCHITECTURE
MEMORY TYPES RAM
Used to store working tables as well as running IOS image
ROMStores a bootable IOS image that provides
basic functionality as well as a barebones interface called the ROM Monitor (ROMMON)
Flash MemoryStores the full function IOS image and is
the default location for IOS at boot NVRAM
Stores startup configuration file
MEMORY TYPES
RAM(Working Memory)
Flash(IOS)
ROM(Basic IOS)
NVRAM(Startup Config)
CONFIGURATION AND IOS IMAGES
CONFIGURATION FILE The configuration is a text file that
contains configuration commands that are executed at startup
When the router boots a copy of the config in NVRAM (startup-config) is executed to establish the initial configuration
Configuration commands entered while the router is running are entered into the temporary configuration stored in RAM (running-config)
SAVING A CONFIGURATION
RAM(Running-Config)
NVRAM(Startup-Config)
Copy running-config startup-config
Copy startup-config running-config
Merged
Replaces
SYNTAX OF THE COPY COMMAND
Copy From-Location To-Location Where:
From- and To-Location - {tftp|running-config|startup-config}
tftp – a trivial ftp server located somewhere on the network
ENTERING THE CONFIGURATION Setup Mode
If no configuration exists when the router boots, it enters setup mode Router hasn’t been configured before Someone used the ‘Erase Startup-Config’ then
rebooted NVRAM was damaged
Setup mode is a question and answer process that can be used to create basic configurations
Command Line Interface (CLI)Configuration commands entered at
command prompt then saved to NVRAM
SETUP MODE Setup Mode allows configuration of:
Interface summaryRouter hostnamePasswordsSNMPVarious network protocols
DECnet, Appletalk, IP, IPXRouting protocols Interfaces
When finished setup mode gives the user the option of copying the configuration to NVRAM and RAM
VIEWING CONFIGURATIONS
Show {running-config|startup-config}
THE CLI AND GETTING HELP
COMMAND LINE INTERFACE Most Cisco devices use a command
line interface Commands can be entered and edited
before they are executed by hitting the enter key
Commands can be abbreviated as long as they are not ambiguous
e.g. Show Interface => sh int
COMMAND LINE INTERFACE
If a command has an error the command will be repeated and a “^” will mark the location of the error
access-list 110 permit host 1.1.1.1 ^%Invalid input detected at ‘^’ marker.
COMMAND HISTORY
Up and Down arrows scroll through command history Also ctrl+p (up) and ctrl+n (down) Command history commands
Show history – shows commands in history Show terminal – shows terminal configurations and terminal
history size (default = 10) Terminal history size – changes history buffer size up to a max
of 256
GETTING HELP Typing ? at any point will cause IOS to show
what options exist at that point Just ? on a line will list all commands available in
that mode Typing one letter followed by ? will show all
commands that begin with the letter Adding ? after a command will show what
arguments are available for the command
CONNECTING TO THE ROUTER
CONNECTING TO THE ROUTER
ConsoleConnect directly to console port and use a terminal
program like Windows Hyperterminal or Linux’s Minicom AUX
The auxiliary port is port you can attach a modem toCan also be used as a backup connection dial on
demand circuit TTY
Can use Telnet to connect to TTY once router has been configured initially
Most routers have 5 TTY connections
IOS MODES
IOS MODES
User ModeRouter>
Privileged (Enable) ModeRouter#
disable enable
Telnet Aux Console
IOS CONFIGURATION MODES
Configuration ModeRouter(config)#
Privileged ModeRouter#
Config terminal (config t)
Interface Configuration ModeRouter(config-if)#
Interface <interface>(interface ethernet 0)
Router Configuration ModeRouter(config-router)#
Router <protocol> (Router rip)
ROUTER INTERFACES
INTERFACES LANs
Ethernet (Ethernet 0, E0, E1, etc.)FastEthernet (FastEthernet 0, F0, F1, etc.)Token Ring (TokenRing 0, TO0, TO1, etc.)
WANsSerial 0, S0, S1, etc.
INTERFACES ON EXPANSION CARDS Interfaces on add in expansion cards include
the slot number followed by a slash then the interface number The first FastEthernet interface on a card in the
first slot would be FastEthernet 0/0 On 7500 series routers three values are
required (slot/port-adapter/port) so it would be FastEthernet 0/0/0 for example
LOOPBACK INTERFACES Loopback interfaces are internal interfaces
and treated like other interfaces Loopback interfaces are never shutdown
Loopback interfaces are useful when you need an interface that will never go down
INTERFACE CONFIGURATION MODE Use the Interface command in configuration
or interface configuration mode to enter configuration mode Router(config)#interface e0 Router(config-if)#interface Lo0 Router(config)#interface s0/1
BRINGING UP AN INTERFACE By default, all interfaces (except loopback
interfaces) are in administrative shutdown mode
To activate the interface use the no shutdown command in the interface configuration mode
ASSIGNING AN IP ADDRESS IP addresses are assigned in interface
configuration mode
Router#config tRouter(config)#interface s0Router(config-if)#ip address 129.130.32.1 255.255.224.0Router(config-if)#no shutdownRouter(config-if)#exit
SETTING THE CLOCK RATE
On serial connections the DCE must set a clock rate to synchronize communication
In the lab the 2501 that is a router is a DCE because the cable attached is a DCE cable so the clock rate must be set on this router
The 2501 that is a Frame Relay switch is also a DCE but you do not configure this one
Router(config)#int s0Router(config-if)#clockrate 2000000
SETTING THE SERIAL ENCAPSULATION We’ll discuss this in more detail later in the
semester but the data link layer protocol must be set for the Frame Relay link using the encapsulation command
Router(config)#interface s0Router(config-if)#encapsulation frame-relay
PASSWORDS
PRIVILEGED MODE PASSWORDS Enable password
Enable password <password> Enable password is shown in clear text Not used if enable secret password is set
Enable secret password Enable secret <password> Enable secret password is encrypted
USER MODE PASSWORDS Console
Line console 0LoginPassword <password>
AuxiliaryLine aux 0Login Password <password>
TelnetLine vty 0 4LoginPassword <password>
Enter configuration mode
Require login
Set password
Most routers have 5 telnetlines. This command setsall five.
ENCRYPTING PASSWORDS User mode passwords are normally
stored in the configuration file in clear text
To encrypt them use the following sequence of commands
service password-encryptionline console 0
login password <password> no service password-encryption
IOS COMMANDS TO KNOW Enable/disable
Enable secret/password Config Editing commands Show history Show terminal Terminal history size Line
How to require login and set password for console, vty and aux
IOS COMMANDS TO KNOW Service password-encryption Banner Interface
ShutdownKnow the interfaces commands for
ethernet, fast ethernet, serial, token ring and loopback
Description Hostname Show running/startup-config Copy <running-config/startup-
config,tftp> <running-config/startup-config,tftp>
IOS COMMANDS TO KNOW Show interface Show controllers Clock rate Ip address Show Version Show flash
Thank You