CLI - CCNA

CLI ( COMMAND LINE INTERFACE )

* this is used for configuring the router.

ROUTER:

--> network layer device or layer 3 device

--> forwards the packet based on IP address

--> maintains routing table

--> builds routing table, either static routing or dynamic routing

* router is a device used to interconnect different networks.

AUI ( ATTACHMENT UNIT INTERFACE )

* used for LAN connections

SERIAL

* used for WAN connection

* mainly used for leased line connection

BRI ( BASIC RATE INTERFACE )

* used for WAN connection

* its connection type is ISDN connection

CONSOLE

* it is used to configure bthe router for the first time

CABLING TYPES:

* straight through ( used for connecting dissimilar devices )

* cross - over ( used for connecting similar devices )

* roll - over or console ( to configure the router )

ROUTER BOOT SEQUENCE

CLI

there are four modes in CLI

* user execution mode

* privilege execution mode

* global configuration mode

* specific configuration mode

USER EXECUTION MODE:

by default, it will show as

Router>

this is called as user execution

PRIVILEGE EXECUTION MODE:

to enter into this mode, enter

Router>enable

once enable is given, it will start showing as

Router#

Router#

GLOBAL CONFIGURATION MODE:

to enter into this mode, enter

Router#configure terminal

after entering this command, it will show like this

Router(config)#

Router(config)#

Router(config)#

in this mode, we can rename the router name by giving

EX: Router(config)#hostname RA

RA(config)#

RA(config)#

RA(config)#

SPECIFIC CONFIGURATION MODE:

here we can enter the interface lik

RA(config)interface serial 1

RA(config-if)#

RA(config-if)#

RA(config-if)#

RA(config-if)#

TOPOLOGY:

there are 3 Routers given in the above diagram..

* this topology is used for configuring 3 routers, which is need for three systems..

* to configure multiple routers from one location, we need term server...

for getting termserver, press CTRL+SHIFT+6 and x....which will show as

TERMSERVER>

TERMSERVER>

TERMSERVER>

TERMSERVER>

static routing:

topics discussed are,

* static routing

* serial ( clock rate )

* static routers

* ICMP

* route cache forwarding

* adding static route

here, ICMP consist of

--> sending and receiving

--> sending

--> unroutable

--> encapsulation failed

--> forward

DYNAMIC ROUTING:

different classes of dynamic routing protocol:

* distance vector

* link state

* hybrid

DISTANCE VECTOR:

it exchanges routing table information with neighbors.

PROTOCOL:  RIP & IGRP ( Routing Information Protocol & Interior Gateway Routing Protocol )

LINK STATE:

it excahnges information about links

PROTOCOL:  OSPF

HYBRID:

it has the characteristics of both distance vectors and link state.

PROTOCOL:  EIGRP ( Enhanced Interior Gateway Routing Protocol )

commom characterisitcs of routing protocol:

* first RIP protocol is enabled.

* if there are two routers, having two routing protocol ( RIP & IGRP )

ADMINISTRATIVE DISTANCE:

--> rate of trust worthiness

                                   

                                             DISTANCE

RIP                                   :       120

IGRP                                 :       100

EIGRP                               :       90

OSPF                                 :       110

STATIC                              :        1

CONNECTED                     :        0

* based on metric values, it select the best route.

metric parameters are :

* HOP COUNT

* BANDWIDTH

* DELAY

* RELIABILITY

* LOAD

* MTV

* COST

here, cost alone works with OSPF and the rest are with IGRP & EIGRP...

RIP:

* it comes under distance vector routing protocol.

* it exchanges routing table information with neighbors.

* administrative distance : 120

* metric calculation : HOP count

* broadcast updates.