Wans and Routers.ppt

7/25/2019 Wans and Routers.ppt

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Module 1WANs and

Routers


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WANS

WAN operates at the physical layer and the data

link layer of the OSI reference model.

Provide connectivity over a large geographic area

Use regional Bell companies Serial connections

Userouters, switches, modems(SU!"SU#,

communication servers(dial$in, dial$out#


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Routers & PCs

A router is a special type of computer.

It has the same basic components as a standarddesktop PC.

It has a CPU memory a system bus and !ariousinput"output interfaces.

#outers connect and allo$ communicationbet$een t$o net$orks and determine the best

path for data to tra!el throu%h the connectednet$orks.

#outers need the Internet$ork Operatin% System&IOS' soft$are to run con(%uration (les.


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Router Internal Components

)he main internal components of the router arerandom*access memory A+' non!olatilerandom*access memory &N,#A+' -ash memory

read*only memory O+' and interfaces.


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Router Internal Components

RA% is used &or

routing ta'le

in&ormation and it

holds the running

con&iguration

N)RA% is used to

store the'ac*up!startup

con&iguration &ile +lash memory is

used &or storage o&

&ull isco -S

so&tware images

R-% is used &or

permanently

storing startup

diagnostic code

.he console port

provides physicalaccess &or initial

con&iguration

.he inter&aces

provide /AN andWAN connectivity


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Routers

#outers are mainly used as WAN de!ices.

#outers use WAN connections to communicate $itheach other.

#outers are the backbone de!ices of lar%eintranets and of the Internet.

)hey operate at ayer / of the OSI model makin%decisions based on net$ork addresses.


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Functions of a Router

)he t$o main functions of a router are to select thebest path for packets and to route packets to theproper interface.

#outers build routin% tables and e0chan%e net$orkinformation $ith other routers.

Routers segment local area networ*s


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Functions of a Router Initiated !

Router Confi"uration Files

Selection o& B0S. PA.1 &or data

ontrolling the &low o& tra&&ic in and out o& the router

(switching pac*ets to appropriate inter&ace#

Speci&ying the correct set up and use o& routed and routing

protocols

Routers do this 'y 'uilding a routin" taleand sharing thatin&ormation with other routers


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An Internet#or$

A correctly con(%ured internet$ork pro!ides thefollo$in%1

2 Consistent end*to*end addressin%

2Addresses that represent net$ork topolo%ies

2 3est path selection

2 4ynamic or static routin%

2 S$itchin%


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WAN %ata in$ Protocols

)he primary functions of a WAN operate at thephysical layer and at the data link layer.

)he WAN physical layer describes the interfacebet$een the data terminal e5uipment &4)6' and the

data circuit*terminatin% e5uipment &4C6'.WAN data link protocols include the follo$in%1

2 7i%h*le!el data link control &74C'

2 8rame #elay

2 Point*to*Point Protocol &PPP'


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Academ! Approac' to WANs

In the academy lab all the net$orks $ill beconnected $ith serial or 6thernet cables.

In the real $orld serial cables are not connectedback to back.

In a real $orld situation one router could be in Ne$9ork $hile another router could be in SydneyAustralia.

In the academy lab de!ices that make up the WAN

cloud are simulated by the connection bet$een theback*to*back 4)6*4C6 cables.


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WAN Connections

We use

Academ! trainin"

simulates t'is

%() to %C)

connection


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Connectin" WAN interfaces

A WAN uses many di:erent technolo%ies to makedata connections across a broad %eo%raphic area.

WAN communication ser!ices are usually leasedfrom ser!ice pro!iders.


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Router Interfaces

AN interfaces allo# routers to connect to t'e

AN media. ('is is usuall! some form of )t'ernet.

WANs pro*ide connections t'rou"' a ser*ice

pro*ider to a distant site or to t'e Internet.


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Router Mana"ement Ports

Console

2 +sed for initial confi"uration

2 (roules'ootin"

2%eu""in"2 Monitorin" t'e s!stem

2 %ispla!s startup and error messa"es ! default,console onl!-

2 %o not depend on net#or$ connections

2 Actuall! as!nc'ronous serial ports

Auiliar! ,A+/-

2 Auiliar! for dial0in access


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Initial Connection to t'e Router

A rollo*er cale #it' a %02 to R045 adapter

Connect to t'e console port of t'e router

Connect to to t'e C6M port of a PC #it' terminal

emulation soft#are suc' as 7!per(erminal


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Confi"urin" 7!per(erminal

Confgure terminal emulation sotware onthe PC or the ollowing:

Wans and Routers.ppt

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