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Dahlan AbdullahEmail : dahlan@unimal.ac.id

Web: http://dahlan.unimal.ac.id

Pengenalan Wireless LANPengenalan Wireless LAN

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Pasar Wireless LANPasar Wireless LAN

Terlihat seperti fashion dalam industri network

Pertumbuhan sangat pesat

Wireless LAN sangat fleksibel dlm implementasi

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Sejarah Wireless LANSejarah Wireless LAN

Spread spektrum wireless network Spread spectrum dapat diartikan sebagai teknik pengiriman

sinyal informasi yang menggunakan suatu kode untuk

menebarkan spectrum energi sinyal informasi dalam

bandwidth yang jauh lebih lebar dibanding bandwidth sinyal

informasi.

arga teknologi wireless semakin turun dan kualitas semakin

bagus

!enawarkan koneksi yang tidak mahal bagi

perusahaan"kampus untuk menghubungkan antar gedung

Sekarang# banyak bisnis yang mengimplementasikan wireless

dalam networknya

!ampu menghemat waktu dan uang perusahaan ketikamemerlukan fleksibilitas perpindahan

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Standart Wireless LANStandart Wireless LAN

$%%% &'(.)) Standart asli wireless LAN Transfer data paling lambat

$%%% &'(.)) b Transfer data lebih cepat

*ikenalkan sebagai Wi+,iT!oleh W%-A $%%% &'(.)) a Transfer data lebih cepat lagi Tidak kompatibel dengan lainnya# frekuensi /0

$%%% &'(.)) g Transfer data sama cepat dengan $%%% &'(.)) a 1ompatibel dengan $%%% &'(.)) b

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Dasar Radi !re"uensi #R!$ %Dasar Radi !re"uensi #R!$ %

/ain 2

digambarkan sebagai sebuah penambahan amplitudo signal 3,

Loss 2digambarkan sebagai sebuah pengurangan amplitudo

signal 3,

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&ltage Standing Wa'e Rati&ltage Standing Wa'e Rati

#&SWR$#&SWR$

Apa kah 4SW3 2suatu keadaan dimana terjadi ketidaksamaan impedansi antar

peralatan dalam sistem 3,

Penyebab 4SW3 2

disebabkan oleh sebuah signal 3, yang ter+refleksi pada titik dari

impedansi dalam path signal

Akibat 4SW3return loss kemorosotan energi yang melalui sistem

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&ltage Standing Wa'e Rati&ltage Standing Wa'e Rati

#&SWR$#&SWR$

5kuran 4SW3 direpresentasikan ( angka sebagai perbandingan

A67 8).6)9# A adalah impedansi dari peralatan# 7 impedansi

yang seharusnyaSolusi 4SW3 /unakan semua kabel# konektor dan peralatan mempunyai

impedansi yang sama atau paling tidak hampir sama untuk

semua peralatan.

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!resnel (ne ) Line * Sight!resnel (ne ) Line * Sight

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Antenna /ain 22ukuran kekuatan antena dalam memancarkan signal

$ntentional 3adiatorperalatan 3, yang secara khusus dirancang untuk menghasilkan

dan memancarkan signal 3,# dalam hardaware meliputi peralatan3,# semua pengkabelan# konektor dan antena

%:ui;alent $sotropically 3adiated Power 8%$3P9power yang dipancarkan oleh elemen antena#dan menentukan gain

dari antena

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Perbandingan u,uranPerbandingan u,uran

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Spread spectrumSpread spectrum

Teknik komunikasi dimana karakternyaditentukan oleh lebar bandwith dan low peakpower+nya

Signalnya hampir sama dengan noise1elebihan Susah di deteksi Susah di modulasi tanpa alat khusus

Narrow 7and Transmission dan SpreadSpectrum Technology

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Spread SpectrumSpread Spectrum

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Narr- and ransmissinNarr- and ransmissin

Teknologi komunikasi yang menggunakan cukup

spektrum frekuensi untuk membawa signal data

igh peak power

3ange frekuensi kecil

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Spread Spectrum echnlg0Spread Spectrum echnlg0

!enggunakan range frekuensi yang lebar

!engurangi kemungkinan data corrupt

atau jammedLow peak power

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Penggunaan Spread SpectrumPenggunaan Spread Spectrum

*apat dikirim dibawah komunikasi klasik

Wireless Local Area Networks

Wireless Personal Area Networks

Wireless !etropolitan Area Networks

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% e,nlgi Spread Spectrum% e,nlgi Spread Spectrum

). *irect Se:uence Spread Spectrum 8*SSS9

(. ,re:uency opping Spread Spectrum

8,SS9

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Wireless LANWireless LAN1n*rastructure De'ices1n*rastructure De'ices

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Access Pint

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1nstall AP dalam -ired net-r,

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2 3de 4n*igurasi AP

3oot !ode

3epeater !ode

7ridge !ode

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Rt 3de

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ridge 3de

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Repeater 3de

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Wireless ridge

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Penggunaan Wireless ridge

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5 mde ,muni,asi -ireless

bridge

3oot !ode Salah satu bridge harus diset sebagai root bridge 7isa berkomunikasi dengan non+root bridge lainnya Tidak bisa berkomunikasi dengan root bridge lainnya

Non+root !ode 1omunikasi bisa ke root bridge

Access Point !ode Punya kemampuan memperbolehkan client connect

3epeater !ode 7erada diantara ("lebih bridge !emperpanjang segmen wireless bridge

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Peralatan 0ang berhubungan

dengan -ireless bridge

,i

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Wireless Wr,grup ridges

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Penggunaan Wireless

Wr,grup ridges

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Wireless LAN client de'ices

P-!-$A > compact flash cards

%thernet > serial con;erters

5S7 AdaptersP-$ > $SA Adapters

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P6361A ) 6n'erter

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Wireless Adapters

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Wireless LANs: 6haracteristics

Types

$nfrastructure based

Adhoc

Ad;antages

,le

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1n*rastructure 's. Adhc

Net-r,sinfrastructurenetwork

ad+hoc network

APAP

AP

wired network

AP6 Access Point

Source6 Schiller

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ransmissin: 1n*rared 's. Radi $nfrared

uses $3 diodes# diffuse light#

multiple reflections 8walls#

furniture etc.9

Ad;antages

simple# cheap# a;ailable in

many mobile de;ices

no licenses needed

simple shielding possible *isad;antages

interference by sunlight# heat

sources etc.

many things shield or absorb $3

light

low bandwidth %

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Di**erence et-een Wired and

Wireless

$f both A and - sense the channel to be idle at the same time#

they send at the same time. -ollision can be detected at senderin %thernet.

alf+duple< radios in wireless cannot detect collision at sender.

A 6

A

6

Ethernet LAN Wireless LAN

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3bile 1P #R!6 %77%$:

3ti'atin Traditional routing

based on $P destination address network prefi< determines physical subnet change of physical subnet implies

change of $P address 8conform to new subnet9# or special routing table entries to forward packets to new subnet

-hanging of $P address *NS updates take to long time T-P connections break security problems

-hanging entries in routing tables

does not scale with the number of mobile hosts and fre:uentchanges in the location

security problems Solution re:uirements

retain same $P address# use same layer ( protocols authentication of registration messages# @

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3bile 1P: asic 1dea

Ruter

8

Ruter

2

Ruter

%

S 3N

9me

agent

Source6 4aidya

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3bile 1P: asic 1dea

Ruter

8

Ruter

2

Ruter

%

S 3N

9me agent

!reign agent

m'e

Pac,ets are tunneled

using 1P in 1P

Source6 4aidya

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3bile 1P: erminlg0

!obile Node 8!N9 node that mo;es across networks without changing its $P address ome Agent 8A9

host in the home network of the !N# typically a router registers the location of the !N# tunnels $P packetsto the -=A

,oreign Agent 8,A9 host in the current foreign network of the !N# typically a router forwards tunneled packets to the !N# typically the default router for

!N -are+of Address 8-=A9

address of the current tunnel end+pointfor the !N 8at ,A or !N9

actual location of the !N from an $P point of ;iew -orrespondent Node 8-N9

host with which !N is correspondingB 8T-P connection9

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Data trans*er t the mbile s0stem

$nternet

sender

!A

9A

3N

hme net-r,

*reign

net-r,

recei;er

8

%

2

). Sender sends to the $P address of !N# A intercepts packet 8pro

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Data trans*er *rm the mbile s0stem

$nternet

recei;er

!A

9A

3N

hme net-r,

*reign

net-r,

sender

8

). Sender sends to the $P address

of the recei;er as usual#

,A works as default router

Source6 Schiller

6N

Re'erse tunneling #R!6 %255$

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Re'erse tunneling #R!6 %255$

Source6 Schiller

$nternet

recei;er

!A

9A

3N

hme net-r,

*reign

net-r,

sender

2

%

8

). !N sends to ,A

(. ,A tunnels packets to Aby encapsulation

C. A forwards the packet to the

recei;er 8standard case9

6N

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3bile 1P: ther 1ssues

3e;erse Tunneling

firewalls permit only topological correct addresses a packet from the !N encapsulated by the ,A is now topological correct

Agent Ad;ertisement A",A periodically send ad;ertisement messages into their physical subnets !N listens to these messages and detects# if it is in home"foreign network !N reads a -=A from the ,A ad;ertisement messages

3egistration !N signals -=A to the A ;ia the ,A A acknowledges ;ia ,A to !N limited lifetime# need to be secured by authentication

=ptimi0ations Triangular 3outing

A informs sender the current location of !N -hange of ,A

new ,A informs old ,A to a;oid packet loss# old ,A now forwards remainingpackets to new ,A

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3ulti;9p Wireless Net-r,s

!ay need to tra;erse multiple links to reach destination

!obility causes route changes

Source6 4aidya

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3bile Ad 9c Net-r,s #3ANE$

ost mo;ement fre:uent Topology change fre:uent

No cellular infrastructure. !ulti+hop wireless links.

*ata must be routed ;ia intermediate nodes.

A B A

B

Source6 4aidya

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Ruting in 3ANE

!obile $P needs infrastructure ome Agent",oreign Agent in the fi

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raditinal RutingA routing protocolsets up a routing tablein routers

A node makes a local choice depending on global

topology Source6 1esha;

Di t t ) Li , t t

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Distance;'ectr ) Lin,;state

Ruting

7oth assume router knows

address of each neighbor

cost of reaching each neighbor

7oth allow a router to determine global routinginformation by talking to its neighbors

*istance ;ector+ router knows cost to each destination

Link state+ router knows entire network topology and

computes shortest path

Distance &ectr Ruting:

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Distance &ectr Ruting:

E

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Lin, State Ruting: E

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3ANE Ruting Prtcls

3eacti;e protocols

*etermine route if and when needed

Source initiates route disco;ery

%

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D0namic Surce Ruting #DSR$

=>hnsn?

When source S wants to send a packet to destination *# but does not knowa route to *# S initiates a route disco;ery

S floods 3oute 3e:uest 833%F9

%ach node appends its own identifierwhen forwarding 33%F

* on recei;ing the first 33%F# sends a 3oute 3eply 833%P9 33%Psent on route obtained by re;ersingthe route appended in 33%F

33%Pincludes the routefrom S to *# on which 33%Fwas recei;ed by *

S on recei;ing 33%P# cachesthe route included in the 33%P

When S sends a data packet to *# entire route is included in the header $ntermediate nodes use the source route in the packetheader to determine

to whom a packet should be forwarded

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Rute Disc'er0 in DSR

A

S E

!

9

>

D

6

B

1

4

(

C

Represents a nde that has recei'ed RRE *r D *rm S

3

N

L

Source6 4aidya

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Rute Disc'er0 in DSR

A

S E

!

9

>

D

6

B

1

4

Represents transmissin * RRE

(

C

radcast transmissin

3

N

L

=S

=FC Represents list * identi*iers appended t RRE

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Rute Disc'er0 in DSR

A

S E

!

9

>

D

6

B

1

4

GNde 9 recei'es pac,et RRE *rm t- neighbrs:

ptential *r cllisin

(

C

3

N

L

=SFE

=SF6

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Rute Disc'er0 in DSR

A

S E

!

9

>

D

6

B

1

4

GNde 6 recei'es RRE *rm B and 9F but des nt *r-ard

it againF because nde 6 has alread0 *r-arded RREnce

(

C

3

N

L

=SF6FB

=SFEF!

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Rute Disc'er0 in DSR

A

S E

!

9

>

D

6

B

1

4

(

C

3

GNdes > and 4 bth bradcast RRE t nde DGSince ndes > and 4 are hidden *rm each therF their

transmissins ma0 cllide

N

L

=SF6FBF4

=SFEF!F>

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Rute Disc'er0 in DSR

A

S E

!

9

>

D

6

B

1

4

(

C

GNde D des nt *r-ardRREF because nde D

is the intended target* the rute disc'er0

3

N

L

=SFEF!F>F3

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Rute Repl0 in DSR

A

S E

!

9

>

D

6

B

1

4

(

C

3

N

L

RREP =SFEF!F>FD

Represents RREP cntrl message

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Data Deli'er0 in DSR

A

S E

!

9

>

D

6

B

1

4

(

C

3

N

L

DAA =SFEF!F>FD

Pac,et header siGe gr-s -ith rute length

DSR 1

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DSR 1ssues =ptimi0ations6 cacheroutes learnt by any means When S finds route HS#%#,#I#*Jto *# S also learns route HS#%#,J to , When 1 recei;es 33%FHS#-#/J for /# 1 learns route H1#/#-#SJ to S When , forwards 33%P HS#%#,#I#*J# , learns route H,#I#*J to * When % forwards *ata HS#%#,#I#*J# % learns route H%#,#I#*J to *

Ad;antages 3outes maintained only between nodes who need to communicate 3educes o;erhead of route maintenance -aching 8at intermediate nodes9 can further reduce route disco;ery

o;erhead

*isad;antages Packet header si0e grows with route length due to source routing ,lood of route re:uests may potentially reach all nodes in the network 3oute 3eply Stormproblem6 !any intermediate nodes reply from local

cache Stale caches will lead to increased o;erhead

Destinatin;Se"uenced Distance;&ectr #DSD&$

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" # $

=Per,ins?5Sigcmm

%ach node maintains a routing table which stores ne

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Destinatin;Se"uenced

Distance;&ectr #DSD&$

When K recei;es information from about a route to E

Let destination se:uence number for E at K be S8K9# S89 is sent

from

$f S8K9 M S89# then K ignores the routing information recei;ed

from

$f S8K9 S89# and cost of going through is smaller than the

route known to K# then K sets as the ne

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Reacti'e '/s Practi'e rade;

**s

3eacti;e protocols Lower o;erhead since routes are determined on demand Significant delay in route determination %mploy flooding 8global search9 -ontrol traffic may be bursty

Proacti;e protocols Always maintain routes Little or no delay for route determination -onsume bandwidth to keep routes up+to+date !aintain routes which may ne;er be used

Which approach achie;es a better trade+off depends on the traffic andmobility patterns

(ne Ruting Prtcl #(RP$

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(ne Ruting Prtcl #(RP$

=9aas?H

E3P combines proacti;e and reacti;e approaches

All nodes within hop distance at most d from a node K are

said to be in the routing 0oneof node K

All nodes at hop distance e

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(RP: E