pbl wan tech

8/15/2019 Pbl WAN Tech

1/22

GERMAN MALAYSIAN INSTITUTEWAN TECHNOLOG

INTRODUCTION

A wide area network or WAN, spans a lare eorap!i"al area, o#ten a

"o$ntr% or "ontinent& WAN 'Wide Area Network( "onne"ts two or )ore LANs

and ot!er networks so t!at "o)p$ters at one lo"ation "an "o))$ni"ate to

t!e "o)p$ters at #arawa% so)e ot!er lo"ation& It "ontains a "olle"tion o#

)a"!ines intended #or r$nnin $ser appli"ation prora)s& We "all t!ese

)a"!ines as !osts&

A WAN is a data "o))$ni"ations network t!at operates *e%ond t!e

eorap!i" s"ope o# a LAN& WAN "onne"t de+i"es t!at are separated *% a

*roader eorap!i"al area t!an a LAN& T!at are $sin "arriers 'p!one

"o)panies, "a*le "o)panies, network pro+iders(& It also $se serial

"onne"tions o# +ario$s t%pes&

WANs enerall% #$n"tion at La%er - . /ri)aril% "on"erned wit!

)o+in data *etween LANs Use leased0line, "ir"$it0swit"!ed, and pa"ket0

swit"!ed te"!nolo% $s$all% "apa*le o# !andlin +oi"e, +ideo, and data

si)$ltaneo$sl%&


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Types of Switching

Swit"!in is a pro"ess o# )o+in t!e data t!ro$! a series o# inter)ediate

steps rat!er t!an )o+in #ro) t!e start point dire"tl% to t!e end point&

Swit"!in Cir"$it Swit"!in Messae Swit"!in /a"ket Swit"!in

.

SWITCHING

MESSAGE

SWITCHING

/AC1ET

SWITCHING

CIRCUIT

SWITCHING


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GERMAN MALAYSIAN INSTITUTEWAN TECHNOLOGCircuit Switching

2ire"t p!%si"al "onne"tion esta*lis!ed *etween sender and re"ei+er *e#ore

data trans)ission& Allows a 34ed rate o# trans)ission& Ma5or draw*a"ks are

$n$sed trans)ission is wasted $n$sed *andwidt! "annot *e $sed *% an%

ot!er trans)ission&

Message Switching

No dire"t p!%si"al "onne"tion esta*lis!ed *etween sender and re"ei+er&

Messae ro$ted t!ro$! t!e inter)ediate nodes &T!is te"!nolo% is also

known as store and #orward )et!od&

6


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Pacet Switching

Messae to *e trans)itted *roken into $nits "alled pa"kets& /a"ket "ontains

addressin in#or)ation /a"kets are "arried on +irt$al "ir"$its& 7irt$al "ir"$its

are te)porar% "onne"tions o+er w!i"! t!e sendin and re"ei+in stations

"o))$ni"ate&

8


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Connection!ess Ser"ices

Conne"tionless does not re9$ire a session "onne"tion *etween

sender and re"ei+er& T!e sender si)pl% starts sendin pa"kets '"alled

datara)s( to t!e destination& T!is ser+i"e does not !a+e t!e relia*ilit% o#

t!e "onne"tion0oriented )et!od, *$t it is $se#$l #or periodi" *$rst trans#ers&

Neit!er s%ste) )$st )aintain state in#or)ation #or t!e s%ste)s t!at t!e%

send trans)ission to or re"ei+e trans)ission #ro)& A "onne"tionless network

pro+ides )ini)al ser+i"es&

:e#ore trans)ittin t!e pa"kets, a"t$al "onne"tion not

esta*lis!ed *etween t!e sender and t!e re"ei+er, Ea"! pa"ket "onsidered as

an independent $nit ,Ea"! pa"ket treated as a "o)plete )essae /a"kets

#ollow di;erent ro$tes to rea"! destination&


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Connection#oriente$ Ser"ices

Conne"tion0oriented re9$ires a session "onne"tion 'analoo$s to

a p!one "all( *e esta*lis!ed *e#ore an% data "an *e sent& T!is )et!od is

o#ten "alled a =relia*le= network ser+i"e& It "an $arantee t!at data will

arri+e in t!e sa)e order& Conne"tion0oriented ser+i"es set $p +irt$al links

*etween end s%ste)s t!ro$! a network, as s!own in >i$re & Note t!at t!e

pa"ket on t!e le#t is assined t!e +irt$al "ir"$it n$)*er ?& As it )o+es

t!ro$! t!e network, ro$ters 9$i"kl% send it t!ro$! +irt$al "ir"$it ?&

:e#ore trans)ittin pa"kets, "o))$ni"ation link esta*lis!ed

pa"kets #ollow sa)e ro$te to rea"! destination #or trans)ission, $ses eit!er

Swit"!ed 7irt$al Cir"$it 'S7C( or /er)anent 7irt$al Cir"$it '/7C(&

@


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PSTN %pu&!ic switche$ te!ephone networ'

/STN 'p$*li" swit"!ed telep!one network( is t!e worlds

"olle"tion o# inter"onne"ted +oi"e0oriented p$*li" telep!one networks, *ot!

"o))er"ial and o+ern)ent0owned& Its also re#erred to as t!e /lain Old

Telep!one Ser+i"e '/OTS(& Its t!e areation o# "ir"$it0swit"!in telep!one

networks t!at !as e+ol+ed #ro) t!e da%s o# Ale4ander Gra!a) :ell &Toda%, it

is al)ost entirel% diital in te"!nolo% e4"ept #or t!e 3nal link #ro) t!e

"entral 'lo"al( telep!one oB"e to t!e $ser&

Structure of Te!ephone Syste(

& 2iital trans)ission is )ore relia*le t!an analo and less prone to

noise and inter#eren"e and also it is "!eaper and easier to )aintain

Telep!one s%ste) "onsists o# #ollowin )a5or "o)ponents&.& T%pi"al "ir"$it ro$te #or a )edi$)0distan"e "all&

6& Swit"!in "enter is known as a toll oB"e• 2i;erent tolls "o))$ni"ate wit! ea"! ot!er $sin t!e !i!

*andwidt! intertoll tr$nks&• Lo"al loop is so)eti)es re#erred to as last )ile Uses analo

sinalin&


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Mu!tip!e)ing

M$ltiple4in 'or )$4in( is a wa% o# sendin )$ltiple sinals or

strea)s o# in#or)ation o+er a "o))$ni"ations link at t!e sa)e ti)e in t!e

#or) o# a sinle, "o)ple4 sinalD t!e re"ei+er re"o+ers t!e separate sinals,

a pro"ess "alled de)$ltiple4in 'or de)$4in(&

Networks $se )$ltiple4in #or two reasons to )ake it possi*le #or

an% network de+i"e to talk to an% ot!er network de+i"e wit!o$t !a+in to

dedi"ate a "onne"tion #or ea"! pair& T!is re9$ires s!ared )edia to )ake a

s"ar"e or e4pensi+e reso$r"e stret"! #$rt!erD e& to send )an% sinals down

ea"! "a*le or 3*er strand r$nnin *etween )a5or )etropolitan areas, or

a"ross one satellite $plink&

T!ree t%pes o# )$ltiple4in, Ti)e 2i+ision M$ltiple4in 'T2M(

$sed #or diital data, >re9$en"% 2i+ision M$ltiple4in '>2M(, Wa+elent!2i+ision M$ltiple4in 'W2M(, $sed #or opti"al "arrier sinals&


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PPP %Point#to#Point Protoco!'

/// '/oint0to0/oint /roto"ol( is a proto"ol #or "o))$ni"ation

*etween two "o)p$ters $sin a serial inter#a"e, t%pi"all% a personal

"o)p$ter "onne"ted *% p!one line to a ser+er& >or e4a)ple, %o$r Internet

ser+er pro+ider )a% pro+ide %o$ wit! a /// "onne"tion so t!at t!e pro+iders

ser+er "an respond to %o$r re9$ests, pass t!e) on to t!e Internet, and

#orward %o$r re9$ested Internet responses *a"k to %o$& /// $ses t!e Internet

proto"ol 'I/( 'and is desined to !andle ot!ers(& It is so)eti)es "onsidered a

)e)*er o# t!e TC/FI/ s$ite o# proto"ols& Relati+e to t!e Open S%ste)s

Inter"onne"tion 'OSI( re#eren"e )odel, /// pro+ides la%er . 'data0link la%er(

ser+i"e& Essentiall%, it pa"kaes %o$r "o)p$ters TC/FI/ pa"kets and #orwards

t!e) to t!e ser+er w!ere t!e% "an a"t$all% *e p$t on t!e Internet&

/// is a #$ll0d$ple4 proto"ol t!at "an *e $sed on +ario$s p!%si"al

)edia, in"l$din twisted pair or 3*er opti" lines or satellite trans)ission& It

$ses a +ariation o# Hi! Speed 2ata Link Control 'H2LC( #or pa"ket

en"aps$lation&

/// is $s$all% pre#erred o+er t!e earlier de #a"to standard Serial

Line Internet /roto"ol 'SLI/( *e"a$se it "an !andle s%n"!rono$s as well as

as%n"!rono$s "o))$ni"ation& /// "an s!are a line wit! ot!er $sers and it

!as error dete"tion t!at SLI/ la"ks& W!ere a "!oi"e is possi*le, /// is

pre#erred&


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Physica! *ayer

To a""o)plis! point0to0point "onne"tion *etween two de+i"es at t!e p!%si"al

la%er, t!at are $sin Mode) te"!nolo% '


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GERMAN MALAYSIAN INSTITUTEWAN TECHNOLOGConne"tion0oriented pa"ket0swit"!in proto"ol at t!e network la%er de3nes

t!e wa% in w!i"! t!e "onne"tions *etween t!e $ser de+i"es and t!e network

de+i"es are esta*lis!ed and )aintained& &.< $sed in t!e pa"ket0swit"!ed

networks '/SNs( s$"! as t!e telep!one "o)panies&

+,-. networ $e"ices

• 2ata ter)inal e9$ip)ent '2TE(

• 2ata "ir"$it0ter)inatin e9$ip)ent '2CE(

• /a"ket0swit"!in e4"!ane '/SE(

• Session esta*lis!)ent J a #$ll d$ple4 "o))$ni"ation is esta*lis!ed

*etween two de+i"es and "an *e ter)inated *% eit!er o# t!e two

de+i"es&• /a"ket Asse)*lerF2isasse)*ler '/A2( J )ain #$n"tion is *$;erin and

adds an &.< !eader to t!e pa"ket&

+,-. /irtua! Circuits


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GERMAN MALAYSIAN INSTITUTEWAN TECHNOLOG• Swit"!ed 7irt$al Cir"$its 'S7Cs(

• /er)anent 7irt$al Cir"$its '/7Cs(

CONT0$

•

M$ltiple +irt$al "ir"$its also "alled as loi"al "onne"tors• So$r"e 2TE de+i"es spe"i3es t!e +irt$al "ir"$its to *e $sed in t!e

!eaders o# t!e o$toin data pa"kets

C1T 2ra(e Re!ay

• Hi! per#or)an"e WAN proto"ol, #aster t!an &.< Operates at t!e

p!%si"al and data link la%er o# t!e OSI re#eren"e )odel does notin+ol+e error "orre"tion and network ow "ontrol operations&

• >ra)e rela% +irt$al "ir"$its are Swit"!ed 7irt$al Cir"$its 'S7Cs( and

/er)anent 7irt$al Cir"$its '/7Cs(

2ra(e Re!ay De"ices

• T!e de+i"es atta"!ed to t!e >ra)e Rela% WAN #or trans)ission o# data

pa"kets are, 2ata ter)inal e9$ip)ent '2TE( and 2ata "ir"$it0

ter)inatin e9$ip)ent '2CE(&

.


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3TM %asynchronous transfer (o$e'

S!ort #or As%n"!rono$s Trans#er Mode, a network te"!nolo% *ased on

trans#errin data in "ells or pa"kets o# a 34ed siKe& T!e "ell $sed wit! ATM is

relati+el% s)all "o)pared to $nits $sed wit! older te"!noloies& T!e s)all,

"onstant "ell siKe allows ATM e9$ip)ent to trans)it +ideo, a$dio, and

"o)p$ter data o+er t!e sa)e network, and ass$re t!at no sinle t%pe o#data !os t!e line&

So)e people t!ink t!at ATM !olds t!e answer to t!e Internet *andwidt!

pro*le), *$t ot!ers are skepti"al& ATM "reates a 34ed "!annel, or ro$te,

*etween two points w!ene+er data trans#er *eins& T!is di;ers #ro) TC/FI/,

in w!i"! )essaes are di+ided into pa"kets and ea"! pa"ket "an take a

di;erent ro$te #ro) so$r"e to destination& T!is di;eren"e )akes it easier to

tra"k and *ill data $sae a"ross an ATM network, *$t it )akes it less

adapta*le to s$dden s$res in network traB"&

Types of ser"ice

6


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GERMAN MALAYSIAN INSTITUTEWAN TECHNOLOG• Constant *it rate 'C:R( spe"i3es a 34ed *it rate so t!at data is sent in

a stead% strea)& T!is is analoo$s to a leased line&• 7aria*le *it rate '7:R( pro+ides a spe"i3ed t!ro$!p$t "apa"it% *$t

data is not sent e+enl%& T!is is a pop$lar "!oi"e #or +oi"e and

+ideo"on#eren"in data&• A+aila*le *it rate 'A:R( pro+ides a $aranteed )ini)$) "apa"it% *$t

allows data to *e *$rstedat !i!er "apa"ities w!en t!e network is #ree&

Unspe"i3ed *it rate 'U:R( does not $arantee an% t!ro$!p$t le+els&

T!is is $sed #or appli"ations, s$"! as 3le trans#er, t!at "an tolerate

dela%s&

3TM De"ices

ATM network "onsists o# two de+i"es

• ATM Swit"!

• ATM endpoint

3TM Networ Interface

Uses two t%pes o# inter#a"es #or inter"onne"tion

• User Network Inter#a"e 'UNI(

8


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GERMAN MALAYSIAN INSTITUTEWAN TECHNOLOG• Network to Network Inter#a"e 'NNI(

• T!e UNI and NNI are "lassi3ed on t!e *asis o# w!et!er t!e swit"! is

owned and lo"ated at t!e "$sto)ers pre)ises or are p$*li"l% owned

and operated *% t!e telep!one "o)pan%&

3TM Reference Mo$e!Re#eren"e )odel "o)prises o# t!e #ollowin

• ATM la%ers

• ATM planes


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Integrate$ Ser"ices Digita! Networ %ISDN'

'Interated Ser+i"es 2iital Network( is a diital "o))$ni"ations line t!at

allows #or t!e trans)ission o# +oi"e, data, +ideo and rap!i"s, at +er% !i! speeds,

o+er standard "o))$ni"ation lines& IS2N pro+ides a sinle, "o))on inter#a"e wit!

w!i"! to a""ess diital "o))$ni"ations ser+i"es t!at are re9$ired *% +ar%in

de+i"es, w!ile re)ainin transparent to t!e $ser&

IS2N is a "ir"$it0swit"!ed telep!one network s%ste), w!i"! also pro+ides

a""ess to pa"ket swit"!ed networks, desined to allow diital trans)ission o# +oi"e

and data o+er ordinar% telep!one "opper wires '/lain0Old Telep!one Ser+i"e 0

/OTS (, res$ltin in potentiall% *etter +oi"e 9$alit% t!an an analo p!one "an

pro+ide& It o;ers "ir"$it0swit"!ed "onne"tions '#or eit!er +oi"e or data(, and pa"ket0

swit"!ed "onne"tions '#or data(, in in"re)ents o# @8 kilo*itFs&

ISDN De"ices

@


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ISDN Ser"ices

T!e in#or)ation trans)itted o+er t!e IS2N network tra+els t!ro$! t!e

t!ree loi"al diital "o))$ni"ation "!annels• :0C!annel 0 Carries $ser ser+i"e in#or)ation t!at in"l$des diital

data, +ideo and +oi"e& It is t!e *asi" $ser "!annel and operates

at @8 k*ps• 20C!annel 0 Carries sinals and data *etween t!e $ser and t!e

network&• H0C!annel 0 /er#or)s t!e sa)e #$n"tions as t!at o# t!e :0

C!annels and operates at data rate o# @8 1*ps&• IS2N :RI ser+i"e J operates . k*ps

• IS2N /RI ser+i"e J operates at &


18/22

GERMAN MALAYSIAN INSTITUTEWAN TECHNOLOG*oca! Manage(ent Interface %*MI'

LMI is a set o# en!an"e)ents to t!e *asi" >ra)e Rela%

spe"i3"ation& T!e LMI was de+eloped in ? *% Cis"o S%ste)s, StrataCo),

Nort!ern Tele"o), and 2iital E9$ip)ent Corporation& It o;ers a n$)*er o#

#eat$res '"alled e4tensions( #or )anain "o)ple4 internetworks& 1e% >ra)e

Rela% LMI e4tensions in"l$de lo*al addressin, +irt$al "ir"$it stat$s

)essaes, and )$lti"astin&

T!e LMI lo*al addressin e4tension i+es >ra)e Rela% data0link

"onne"tion identi3er '2LCI( +al$es lo*al rat!er t!an lo"al sini3"an"e& 2LCI

+al$es *e"o)e 2TE addresses t!at are $ni9$e in t!e >ra)e Rela% WAN& T!e

lo*al addressin e4tension adds #$n"tionalit% and )anaea*ilit% to >ra)e

Rela% internetworks& Indi+id$al network inter#a"es and t!e end nodes

atta"!ed to t!e), #or e4a)ple, "an *e identi3ed *% $sin standard address0

resol$tion and dis"o+er% te"!ni9$es& In addition, t!e entire >ra)e Rela%

network appears to *e a t%pi"al LAN to ro$ters on its perip!er%&

LMI +irt$al "ir"$it stat$s )essaes pro+ide "o))$ni"ation and

s%n"!roniKation *etween >ra)e Rela% 2TE and 2CE de+i"es& T!ese

)essaes are $sed to periodi"all% report on t!e stat$s o# /7Cs, w!i"!

pre+ents data #ro) *ein sent into *la"k !oles 't!at is, o+er /7Cs t!at no

loner e4ist(&

T!e LMI )$lti"astin e4tension allows )$lti"ast ro$ps to *e

assined& M$lti"astin sa+es *andwidt! *% allowin ro$tin $pdates and

address0resol$tion )essaes to *e sent onl% to spe"i3" ro$ps o# ro$ters&

T!e e4tension also trans)its reports on t!e stat$s o# )$lti"ast ro$ps in

$pdate )essaes&


19/22


20/22


The maximum signaling rate of (&&I is 52 Mbps) *t this rate+ (&&I can han'le

the T, spee's .5 Mbps/ of many of to'ays fast $*N technologies+ as !ell as the

1ptical Channel-# 1C-#/ spee's 52 Mbps/ of the synchronous 'igital hierarchy &D(/)

In a''ition+ (&&I easily can proi'e high-spee' connectiity bet!een *Ns+ such as

To3en 4ing an' Ethernet)

The use of 'ifferential emitter-couple' logic EC/ helps (&&I achiee high 'ata

rates an' lo! noise leels) EC has been use' in Cray computer system interfaces for

years an' is specifie' by the *N&I (igh-%erformance %arallel Interface (I%%I/

communications stan'ar' for supercomputer *N communications) EC is an off-the-

shelf technology that permits excellent retiming on the receier+ resulting in reliable

timing margins)

.?


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CONC*USION

WAN "o+ers a lare eorap!i"al area #or e4a)ple, a "o$ntr% or a

"ontinent& Its data trans#er data is $s$all% low as "o)pared to LAN, *$t it is

"o)pati*le wit! a +ariet% o# a""ess lines and !as an ad+an"ed se"$rit%&

T!e wide area network !as )ade it possi*le #or "o)panies to

"o))$ni"ate internall% in wa%s ne+er *e#ore possi*le& :e"a$se o# WANs, t!e

"ons$)ers "an en5o% *ene3ts #ro) "o)panies t!at wo$ldnt !a+e *een a*le

to in t!e past&

.


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R424R4NC4S

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/resentation&!t)l2) http66'oc!i3i)cisco)com6!i3i6Intro'uction7to7$*N7Technologies,) http66searchnet!or3ing)techtarget)com6'efinition6(igh-&pee'-&erial-Interface.) http66searchnet!or3ing)techtarget)com6'efinition6%%%

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