ccna bec v4 02 cisco ios

1Introduction to Cisco IOS

Introduction to Cisco IOS

LogicaCMG CCNA course

Global Training department


Objectives

• Introduction to Cisco Routers

– Memory

– Interfaces

– Initializing

• Managing Cisco Routers

– Access Modes

– User Interface

• Configuring Cisco Routers

• Cisco Discovery Protocol


Memory on Cisco routers

• RAM– Is used during normal operation

• NVRAM– Stores configuration

• Flash– Stores image(s)

• ROM– Stores ROM-image (BIOS)

RAM NVRAM Flash ROM


Memory on Cisco routers

CoreRouter2#sh verCisco Internetwork Operating System SoftwareIOS (tm) C2600 Software (C2600-I-M), Version 12.2(23), RELEASE SOFTWARE (fc2)Copyright (c) 1986-2004 by cisco Systems, Inc.Compiled Wed 28-Jan-04 17:48 by kellmillImage text-base: 0x8000808C, data-base: 0x80A1C284

ROM: System Bootstrap, Version 11.3(2)XA4, RELEASE SOFTWARE (fc1)

CoreRouter2 uptime is 1 week, 2 hours, 55 minutesSystem returned to ROM by power-onSystem image file is "flash:c2600-i-mz.122-23.bin"

cisco 2611 (MPC860) processor (revision 0x203) with 45056K/4096K bytes of memory.Processor board ID JAD04370AXG (3468462565)M860 processor: part number 0, mask 49Bridging software.X.25 software, Version 3.0.0.2 Ethernet/IEEE 802.3 interface(s)2 Serial network interface(s)16 terminal line(s)32K bytes of non-volatile configuration memory.8192K bytes of processor board System flash (Read/Write)

Configuration register is 0x2102


Initializing

RUN RXbootImage

Enter ROMMonitor Mode

not found

CHECKCONFIG

REG

Load fromTFTP

Load fromROM

Loadconfig

LoadIOS

Load IOS

Subset

Run auto setup

SEARCHCONFIG

FILE

Load fromflash

ReadNVRAM

CHECKCONFIG

REG

POST


Configuration-register

• 16-bit register

– Normal value is 0x2102

– Ignore startup-configuration (pw-recovery) value is 0x2142

• Other combinations; to specify system boot order–0x2100 - Rommon

–0x2101 - RxBoot

–0x2102 - Normal IOS

• Use ‘show version’ to display value config register

• Use ‘config-register’ global configuration command to set the value from a running system


Configuring the system boot file

• Specify boot options in ‘startup-config’, e.g. to boot from:– flash: boot system flash:filename– tftp: boot system tftp filename tftp-server-ip– rom: boot system rom

• Examples:boot system flash:

boot system tftp c2600-ip-plus 255.255.255.255

boot system tftp c2600-ip-plus 172.16.10.2

boot system rom

• Use ‘copy tftp flash’ to copy IOS to a Cisco device• Use ‘show flash:’ to display stored files in flash


Access to the router

• Console

– COM port on computer to RJ45 Console port router

– Roll-over console cable

• Telnet

– Interface must be reachable via IP

– Using a Terminal Emulator

• Auxiliary port

– Often used for Asynchronous dial access

– Can also be used as a normal console port


Access Modes

• User Exec Mode– limited control

– Router>

• Privileged Exec Mode– full control

– Router#

• Setup mode– When there is no startup-config

• Rxboot mode– if IOS load failure

– Router(boot)>

• ROM monitor mode– rommon 1 >


Access Modes diagram

User EXEC Mode

Privileged EXEC Mode

RT1>enableRT1#

RT1#disableRT1>

• Console/AUX• Telnet

Global configuration

Mode

RT1#config tRT1(config)#

RT1(config)#exitRT1#

Line configuration ModeInterface configuration mode

RT1(config)#int fa0/0RT1(config-if)#RT1(config)#line con 0RT1(config-line)#

RT1(config-if)#exitRT1(config)#RT1(config-line)#exitRT1(config)#


User Interface

•? - gives (sub)command explanation/parameter options

•Ctrl+p - or arrow up, recalls last command(s)

•Ctrl+n - or arrow down, recalls next command

•tab - entry completion

•Ctrl+a - cursor to (command)line start

•Ctrl+e - cursor to (command)line end

•show history - shows previously used commands

•terminal history size lines - sets recall buffer (default=10)

•Ctrl+r - recall current command

•Ctrl+shift+6,x break sequence, returns to the first session

•Ctrl+shift+6,xx returns to previous session, instead of the first


Viewing Router/Switch Status

RAM

Internetwork Operating System

RunningPrograms

Tables and

Buffers

DynamicConfigurationInformation

NVRAM Flash

BackupConfiguration

File

OS imagesand stored

routingtables

Interfaces

Router#show interfaces

Router#show memRouter#show ip route

Router#show flash

Router#show startup-configRouter#show running-config

Router#show processes CPURouter#show protocols

Router#show version


Switch# show interface fa0/1

FastEthernet0/1 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 000d.653b.4341 (bia 000d.653b.4341)

MTU 1500 bytes, BW 100000 Kbit, DLY 1000 usec, reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 100Mb/s

input flow-control is unsupported output flow-control is unsupported

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:01, output 00:00:04, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 1000 bits/sec, 1 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

922345 packets input, 141140805 bytes, 0 no buffer

Received 854152 broadcasts (0 multicast)

0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 715978 multicast, 0 pause input

0 input packets with dribble condition detected

102307 packets output, 10217308 bytes, 0 underruns

0 output errors, 0 collisions, 2 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier, 0 PAUSE output

0 output buffer failures, 0 output buffers swapped out


Understanding show interface

Switch#sh int fa0/1

FastEthernet0/1 is up, line protocol is up (connected)….

• Layer 1 working then FastEthernet0/1 is up

• Layer 2 working then Line protocol is up

THENIF

Interface is up, line protocol is up (connected)

Working

Interface is up, line protocol is downLine protocol (L2) /Datalink layer problem

Interface is down, line protocol is down(not connected)

Interface (L1) /Physical layer problem

Interface is administratively down, line protocol is down

Administratively disabled


Router/Switch configuration

• Start configuring by typing in privileged mode (#)

– ‘configure terminal‘ (or short: ‘conf t‘)

• Use ‘no <command>’ to remove configuration commands• Commands are effectuated/executed directly after pressing ‘Enter’• Use ‘^z’ or ‘end ‘ or ‘exit ‘ to exit (sub)config mode• Display active configuration

– ‘show running-config ‘

• Display saved startup configuration– ‘show startup-config‘

• Save active (modified) configuration using– ‘copy running-config startup-config‘ (preferred)– ‘write memory‘ (or short: ‘wr’ , is outdated command!)


Managing configuration files

TFTP

RAM

NVRAM

Copy tftp running-config(merge) Copy running-config startup-conf

Copy startup-config running-config (merge)

Copy running-config tftp

Copy tftp startup-config

Copy startup-config tftp


Configuring Comments

• Give the device a name–Router(config)# hostname Router5

–Router5(config)#

• Use descriptions on interfaces–description Frame Relay line to Amsterdam

• Use banners–banner motd #

Unauthorized access is rewarded!

#

–banner exec

–banner login


Configuring Ethernet Interfaces

router#configure terminal

router(config)# interface Ethernet 0

router(config-if)# description connection to router1

router(config-if)# ip address 10.1.1.1 255.255.255.0

router(config-if)# no shut

router(config-if)# exit

router(config)# interface FastEthernet 0/1

router(config-if)# description VLAN 2 Ethernet


router(config-if)# duplex full

router(config-if)# speed 100


router(config-if)# exit


Configuring Serial Interfaces (1/2)

• Serial lines require a clock signal

• The DCE side provide the clock signal

• When using a null-modem cable, then specify a clock on the DCE side (normally only used in lab environments)

• To check if a serial interface is DTE or DCE:

–show controllers serial 0router5#show controllers serial 0/0Interface Serial0/0Hardware is PowerQUICC MPC860DTE V.35 TX and RX clocks detected.idb at 0x811C0484, driver data structure at 0x811C7F18SCC Registers:General [GSMR]=0x2:0x00000030, Protocol-specific [PSMR]=0x8Events [SCCE]=0x0000, Mask [SCCM]=0x001F, Status [SCCS]=0x06Transmit on Demand [TODR]=0x0, Data Sync [DSR]=0x7E7EInterrupt Registers: ……………………


Configuring Serial Interfaces (2/2)

DTE Cable:


router(config)# interface serial 0

router(config-if)# description connection to Amsterdam


router(config-if)# bandwidth 64


DCE cable:


router(config)# interface serial 0

router(config-if)# description connection to Utrecht


router(config-if)# bandwidth 64

router(config-if)# clock rate 64000



Configuring DNS

• DNS lookups are enabled by default, to disable type:

– no ip domain-lookup

• Specify DNS server:–ip name-server <address 1> {<address2>, }

• Create a local hosts table:–ip host <name> [tcp port] <ip address>


Cisco Discovery Protocol

• Cisco proprietary protocol

• Used to discover directly connected Cisco devices

• Provides additional information like:– device id

– address list

– port id

– capabilities list

– version

– platform

– layer 3

– addressing


Cisco Discovery Protocol

router4>sh cdp neigh detail-------------------------Device ID: Router1Entry address(es): IP address: 172.16.2.6Platform: cisco 2500, Capabilities: RouterInterface: Serial0/0, Port ID (outgoing port): Serial0Holdtime : 156 sec

Version :Cisco Internetwork Operating System SoftwareIOS (tm) 2500 Software (C2500-AJS40-L), Version 11.3(6), RELEASE SOFTWARE (fc1)

Copyright (c) 1986-1998 by cisco Systems, Inc.Compiled Tue 06-Oct-98 23:17 by kpma


Other Useful troubleshooting tools

• ping

• traceroute

• debug


Ping

router4>ping

% Incomplete command.

router4#ping

Protocol [ip]:

Target IP address: 172.16.10.3

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]:

Extended commands [n]: y

Source address or interface: 172.16.10.4

Type of service [0]:

Set DF bit in IP header? [no]: yes

Validate reply data? [no]:

Data pattern [0xABCD]:

Loose, Strict, Record, Timestamp, Verbose[none]:

Sweep range of sizes [n]:

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.16.10.3, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms


ICMP echo response codes

• . – Nothing was received before echo request timed-out

• ! – ICMP echo reply received (0)

• ? – Unknown packet received

• M – ICMP can’t fragMent message received

• N – ICMP Network unreachable message received

• P – ICMP Port unreachable message received

• Q – ICMP source Quench message received

• U – ICMP destination Unreachable message received


Traceroute

CoreRouter2#traceroute

Protocol [ip]:

Target IP address: 192.168.1.1

Source address:

Numeric display [n]:

Timeout in seconds [3]:

Probe count [3]:

Minimum Time to Live [1]:

Maximum Time to Live [30]:

Port Number [33434]:

Loose, Strict, Record, Timestamp, Verbose[none]:

Type escape sequence to abort.

Tracing the route to 192.168.1.1

1 router1 (10.0.0.1) 4 msec 4 msec 4 msec

2 * * *

3 * *


Debug

• Debug is CPU intensive

• Use ‘un all’ to disable debugging

• Be very specific in what you want to debug

CoreRouter3#debug isdn q921

ISDN Q921 packets debugging is on

CoreRouter3#

1w0d: ISDN BR1/0: RX <- RRp sapi=0 tei=82 nr=0


1w0d: ISDN BR1/0: TX -> RRf sapi=0 tei=82 nr=0



1w0d: ISDN BR1/3: TX -> RRp sapi=0 tei=82 nr=0


1w0d: ISDN BR1/3: RX <- RRf sapi=0 tei=82 nr=0

CoreRouter3#un all

All possible debugging has been turned off

CoreRouter3#


Summary

• In this chapter you learned how to:

– Identify different pieces of hardware within Cisco devices

– Navigate through different levels of the Operating environment

– Learned how to use the various troubleshooting tools inside IOS

ccna bec v4 02 cisco ios

Documents

routerconfigure

configuring

type escape

target ip

check config

shut router

line protocol

isdn br13