concepts.ppt

8/18/2019 concepts.PPT

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1

Some basic concepts review


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What is the Internet?

Terdiri dari jutaan perangkat computing :hosts, end-systems pc’s workstations, servers

phones, toasters

Yang menjalankan network applications

communication links i!er, copper, radio, satellite

routers: memorward paket data melalui jaringan


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3

What is the Internet?

protocols : mengendalikan pengiriman dan

penerimaan messages mis : T"#, I#, $TT#, %T#, ###

Internet: &network o networks' loosely hierarchical

pu!lic Internet versus private intranet

Internet standards (%": (e)uest or comments

I*T%: Internet *ngineering Task %orce


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What is the Internet: a service view

+uatu inrastruktur komunikasi yangmemungkinkan adanya aplikasi terditri!usi:

WWW, email, games, e-commerce, data!ase,

more?

ayanan komunikasi yang disediakan:

connectionless

connection-oriented


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What is a protocol?

+emua aktivitas komunikasi di Internet diatur olehprotokol

#rotokol : turan-aturan dan perjanjian yangmengatur pertukaran inormasi antar komputer di

jaringan

#rotokol mendeinisikan : ormat, urutanmessage yang dikirim dan yang diterima oleh

entitas jaringan, serta tindakan .action/yang harus diam!il !ila mengirimkan ataumenerima message

- mendeinisikan synta0 dan semantic


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What is a protocol?

a human protocol and a computer network protocol:

$i

$i

1ot thetime?

2:33

T"# connection

re)4T"# connectionreply4

1et http:55gaia4cs4umass4edu5inde04htm

6ile7time


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+truktur jaringan

network edge: hosts

applications

network core: routers

network o networks

access networks, physical media: communication links


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The network edge:

end systems .hosts/: 8enjalankan program aplikasi mis: WWW, email at &edge o network'

client5server model client host mengirimkan re)uest ke server, dan

menerima layanan .service/ dari server mis : WWW client .!rowser/5server9 email

client5server

peer-peer model: Interaksi antar host yang simetri mis: teleconerencing


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1oal: Transer data antar end systems: idahului proses handshaking

#em!entukan koneksi se!elum transer data

dilakukan "ontoh :

T"# - Transmission "ontrol #rotocol

Internet’s connection-oriented service

;etwork edge: connection-oriented service


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T"# service


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;etwork edge: connectionless service

1oal: transer data antar end systems no handshakingA

"ontoh : B# - Bser atagram #rotocol


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;etwork edge

pp’s using T"#: $TT# .WWW/, %T# .ile transer/, Telnet

.remote login/, +8T# .email/

pp’s using B#: streaming media, teleconerencing,

Internet telephony


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The ;etwork "ore

Interkoneksi !er!entuk mesh dari sejumlah

routers

#ertanyaan mendasar: !agaimana dataditranser melalui jaringan ?

circuit switching: dedicated circuit per call:

telephone net

packet-switching: data dikirimkan dalam

!entuk paket-paket


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;etwork "ore: "ircuit +witching

*nd-end resources reserved or &call'

link !andwidth, switch capacity

dedicated resources: no sharing circuit-like .guaranteed/ perormance

call setup re)uired


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;etwork "ore: "ircuit +witching

network resources .mis4!andwidth/ di!agi-!agi

+etiap !agian dialokasikanuntuk suatu call

+uatu !agian resource akanidle jika tidak digunakan olehpemiliki .call/ !agian terse!ut.no sharing/

"ara mem!agi !andwidth dari

suatu link re)uency division time division


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;etwork "ore: #acket +witching

+etiap aliran data end-to-enddikirimkan dalam !entuk paket

#aket dari user dan E memakaisecara !ersama .share / networkresources

+etiap paket menggunakan!andwidth link secara penuh

resources hanya digunakan jikaperlu

Farakteristik resource contention:

#ermintaan pemakaianresource dapat mele!ihi jumlah resource yang

tersedia store and orward: paket

dikirimkan per hop transmit over link

wait turn at ne0t link congestion: ada antrian

paketEandwidth division into &pieces'

edicated allocation

(esource reservation


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;etwork "ore: #acket +witching

E

"G3 8!s*thernet

G4H 8!s

H 8!s

*

statistical multiple0ing

)ueue o packetswaiting or output

link


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;etwork "ore: #acket +witching#acket-switching:

store and orward !ehavior


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#acket switching versus circuit switching

8isalkan sejumlah userterhu!ung kepada suatu link G8!it4 Eila sedang &akti',

setiap user mengirimkaninormasi dengan kecepatanG33 F!ps4 +etiap user aktiselama G3J dari waktu

#ada circuit-switching:

;KG3 users #ada packet switching:

engan ;K H users, peluang7 G3 user akti le!ih kecildaripada 433

#acket switching memungkinkan le!ih !anyak user yangmenggunakan jaringanA

; users

G 8!ps link


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#acket switching versus circuit switching

"ocok untuk !ursty data resource sharing

no call setup 8emiliki kemungkinan terjadinya kongesti:

mengaki!atkan ter-delay-nya paket atau !ahkanmenye!a!kan hilangnya paket .loss/

i!utuhkan protokol congestion control untukrelia!le data transer , 8asalah : Eagaimana menyediakan kualitas seperti

pada circuit-switching?

Ladi packet switching adalah sang juara ?


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2

#acket-switched networks: routing

1oal: mentranser paket antar router dari source kedestination

#ada datagram network : destination address determines ne0t hop routes may change during session

#ada virtual circuit network: each packet carries tag .virtual circuit I/, tag

determines ne0t hop

i0ed path determined at call setup time , remains i0edthrough the call

routers maintain per-call state


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ccess networks and physical media

Eagaimana cara menghu!ungkan end systems ke edgerouter ?

residential access nets

institutional access networks .school, company/ mo!ile access networks

Important issues:

!andwidth .!its per second/ o access network shared or dedicated


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(esidential access: point to point access

ialup via modem

up to HCF!ps direct access to router.conceptually/

I+;: integrated services digital network: G2DF!psall-digital connect to router

+: asymmetric digital su!scri!er line

%8

up to G 8!ps home-to-router

up to D 8!ps router-to-home


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(esidential access: ca!le modems

$%": hy!rid i!er coa0 ca!le modems

asymmetric: up to G38!ps

upstream, G 8!ps

downstream

network o ca!le and i!er

attaches homes to I+#

router

shared access to routeramong houses

issues: congestion,

dimensioning


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Institutional access: local area networks

company5univ local area network .;/ connects

end system to edge router

*thernet:

shared or dedicated ca!le connects end system

and router

G3 8!s, G338!ps, 1iga!it *thernet


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Wireless access networks

shared wireless access network connects end

system to router

wireless ;s:

radio spectrum replaces wire e4g4, ucent Wavelan G3 8!ps

wider-area wireless access "#: cellular digital packet data

wireless access to I+# router via cellular network

1#(+


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#hysical 8edia

physical link: transmitted data !it propagates across link

guided media: signals propagate in solid media: copper, i!er

unguided media: signals propagate reely, e4g4, radio


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#hysical 8edia: twisted pair

Twisted #air .T#/ two insulated copper wires

"ategory : traditional phone wires, G3 8!ps*thernet "ategory H T#: G338!ps *thernet


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#hysical 8edia: coa0, i!er

"oa0ial ca!le: wire .signal carrier/

within a wire .shield/ !ase!and

!road!and

!idirectional

common use in G38!s

*thernet

%i!er optic ca!le: glass i!er carrying

light pulses high-speed operation:

G338!ps *thernet high-speed point-to-point

transmission .e4g4, H 1ps/

low error rate


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#hysical media: radio

signal carried inelectromagneticspectrum

no physical &wire'

!idirectional propagation

environment eects: relection

o!struction !y o!jects intererence

(adio link types: microwave e4g4 up to H 8!ps channels

; .e4g4, wave;/ one to tens o 8!ps

wide-area .e4g4, cellular/ e4g4 "#, G3’s F!ps

satellite !andwidth in the 1!ps range 2=3 8sec end-end delay


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elay in packet-switched networks

#aket-paket mengalamidelay pada saatmenempuh perjalananend-to-end

da empat sum!erdelay pada setiap hop.lihat gam!ar/

nodal processing: check !it errors determine output link

)ueueing time waiting at output

link or transmission depends on congestion

level o router

E

propagation

transmission

nodalprocessing )ueueing


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elay in packet-switched networks

Transmission delay: (Klink !andwidth .!ps/ Kpacket length .!its/ time to send !its into

link K 5(

#ropagation delay: d K length o physical link s K propagation speed in

medium .M20G3D m5sec/

propagation delay K d5s

E

propagation

transmission

nodal

processing )ueueing

;ote: s and ( are verydierent )uantititesA


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Nueueing delay

(Klink !andwidth .!ps/ Kpacket length .!its/ aKaverage packet

arrival ratetraic intensity K a5(

a5( M 3: average )ueueing delay small a5( -7 G: delays !ecome large a5( 7 G: more &work' arriving than can !e

serviced, average delay ininiteA


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#rotocol &ayers'

;etworks are comple0A many &pieces':

hosts routers links o various

media applications protocols hardware,

sotware

Nuestion: Is there any hope oorganiOing structure o

network?


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PrganiOation o air travel

a series o steps

ticket .purchase/

!aggage .check/

gates .load/

runway takeo

airplane routing

ticket .complain/

!aggage .claim/

gates .unload/

runway landing

airplane routing

airplane routing


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PrganiOation o air travel: a dierent view

ayers: +etiap layer menerapkan layanan 8elalui tindakan-tindakan yang dilakukan pada layer itu sendiri 8engandalkan layanan yang disediakan oleh layer yang ada di!awahnya

ticket .purchase/

!aggage .check/

gates .load/

runway takeo

airplane routing

ticket .complain/

!aggage .claim/

gates .unload/

runway landing

airplane routing

airplane routing


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ayered air travel: services

"ounter-to-counter delivery o personQ!ags

!aggage-claim-to-!aggage-claim delivery

people transer: loading gate to arrival gate

runway-to-runway delivery o plane

airplane routing rom source to destination


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istri!uted implementation o layer unctionality

ticket .purchase/

!aggage .check/

gates .load/

runway takeo

airplane routing

ticket .complain/

!aggage .claim/

gates .unload/

runway landing

airplane routing

airplane routing

d e p a r t i n

g

a i r p o r t

a r r i v i n g

a i r p o r t

intermediate air traic sites

airplane routing airplane routing


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Why layering?

Bntuk menanggulangi masalah pada sistem yang kompleks: +truktur yang eksplisit memungkinkan identiikasi

hu!ungan antara !agian-!agian pada sistem yangkompleks

8odularitas memudahkan maintenance danupdating sistem #eru!ahan implementasi layanan pada suatu

layer transparan terhadap komponen sistem

yang lainR mis4, peru!ahan ke!ijakan pada prosedur pemeriksaan

di airport gate tidak mempengaruhi komponen sistemairline yang lain


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Ppen +ystem Interconnection .P+I/Ppen +ystem Interconnection .P+I/(eerence 8odel(eerence 8odel ikem!angkan oleh International PrganiOation or

+tandardiOation .I+P/ pada tahun G>D 8odel reerensi P+I adalah suatu model

konseptual yang terdiri atas tujuh layer, masing-masing layer mempunyai ungsi tertentu

+etiap layer adalah sel-contained ungsi yangdi!erikan ke setiap layer dapat diimplementasikansecara independent Bpdating ungsi suatu layer

tidak akan mempengaruhi layer yang lain


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4

Physical

Application

Presentation

Session

Transport

Network

Data Link

1

2

7

6

5

4

3

• Upper layers application isses pa!a ""nya !ii"ple"entasikan secara so#tware• Application oriente!

• Lower layers !ata transport isses Layer 1 $ 2 %h&w $ s&w i"ple"ente!

Layer 3 !an 4 % s&w i"ple"ente!•

Network oriente!


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8odel P+I dan komunikasi antar sistem8odel P+I dan komunikasi antar sistem

Physical

Application

Presentation

Session

Transport

Network

Data Link

Physical

Application

Presentation

Session

Transport

Network

Data Link

Prosesaplikasi

Prosesaplikasi

Siste" A Siste" '

Physical

Network

Data Link

(nter"e!iate no!e )repeater* +ri!,e* roter-

Peer.to.peer co""nications


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Physical

Application

Presentation

Session

Transport

Network

Data Link

Physical

Application

Presentation

Session

Transport

Network

Data Link

Interaksi antar layer OSI: Interaksi dengan layer di atasnya Interaksi dengan layer di bawahnya Interaksi dengan layer peer di sistem yang berbeda

Siste"A N

N/1

N.1

Siste"'


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Layer dan pertukaran informasi

Siste" A Siste" '

0ea!er 4 Data

Data0ea!er 3

1

76

4

3

2

5

1

76

4

3

2

5

enkapslasi

Data0ea!er 2

Data

Network

Protocol Data Unit = PDU


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4

Internet .T"#5I#/ protocol stack

application: mendukung aplikasi jaringan tp, smtp, http

transport: transer data antar aplikasi tcp, udp

network: merutekan datagrams dari sum!er

ke tujuan ip, routing protocols

link: transer data antar elemen jaringan ppp, ethernet

physical: pengiriman !it-!it pada mediumtransmisi

application

transport

network

link

physical


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identicalmessage

identicalpacket

identicaldatagram

identicaldatagram

identical

frame

identical

frame

Application Application

Transport Transport

Internet Internet

N-Interface

Host A Host B

Router R

Internet

Physical Net 1 Physical Net 2

N-InterfaceN-Interface


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ayering: logical communication

applicationtransportnetwork

linkphysical


linkphysical

application

transportnetworklink

physical

application


physical

network

linkphysical

+etiap layer: terdistri!usi +etiap entitas

menerapkanungsi layerpada setiapnode

+etiap entitasmelakukan

pertukaranmessagesdengan peer-nya


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ayering: logical communication


linkphysical


linkphysical

application


physical

application


physical

network

linkphysical

data

data

8is4: transport 8enerima data

dari aplikasi 8enam!ahkan

pengalamatan, dan

mekanismepengujian sehinggater!entuk&datagram'

8engirimkandatagram ke peer

layer 8enunggu ack dari

peer

data

transport

transport

ack


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ayering: physical communication


linkphysical


linkphysical

application

transportnetwork

linkphysical

application

transportnetwork

linkphysical

networklink

physical

data

data


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#rotocol layering and data

+etiap layer menerima data dari layer yang !erada di atasnya 8enam!hakan header untuk mem!entuk unit data !aru 8engirimkan unit data !aru ke layer yang ada di!awahnya


linkphysical


linkphysical

source destination

8

8

8

8

$t

$t$n

$t$n$l

8

8

8

8

$t

$t$n

$t$n$l

message

segment

datagram

rame

TCPIP ! OSITCPIP ! OSI


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TCPIP ! OSITCPIP ! OSI

alam terminologi model reerensi P+I, T"#5I#protocol suite meliputi network dan transport layers

T"#5I# dapat diterapkan pada !ermacam data-linklayers .mampu mendukung !ermacam implementasihardware jaringan/

Physical

Application

Presentation

Session

Transport

Network

Data Link

1

2

7

6

5

4

3

Network inte#ace

Application

Transport

(P

1

3

4

2

TP&(PS(

Host A Host B


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Application Application

Transport Transport

Internet Protocol Internet Protocol

Net. Interface

Physical Net

identical

message

identical

packet

identical

frame

identical

datagram

Host A Host B

Net. Interface


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Internet structure: network o networks

roughly hierarchical national5international

!ack!one providers .;E#s/ e4g4 EE;51T*, +print,

TST, IE8, BB;et interconnect .peer/ with

each other privately, or atpu!lic ;etwork ccess #oint.;#s/

regional I+#s connect into ;E#s

local I+#, company connect into regional I+#s

;E#

;E# E

;# ;#

regional I+#

regional I+#

localI+#

localI+#


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;ational Eack!one #rovider

e4g4 EE;51T* B+ !ack!one network


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T8: synchronous Transer 8ode nets

Internet: today’s de acto

standard or glo!aldata networking

G>D3’s: telco’s develop T8:

competing networkstandard or carryinghigh-speed voice5data

standards !odies: T8 %orum ITB

T8 principles: small .D !yte payload, H

!yte header/ i0ed lengthcells .like packets/

ast switching small siOe good or voice

virtual-circuit network:switches maintain state oreach &call'

well-deined interace!etween &network' and&user' .think o telephonecompany/


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T8 layers

T8 daptationayer ./: interace to upperlayers end-system segmentation5rea

ssem!ly T8 ayer: cell

switching #hysical

T8

physical

T8

physical

T8

physical

T8

physical

T8physical

Where’s the application? T8: lower layer

unctionality only I#-over T8: later

applicationT"#5B#

I#

applicationT"#5B#

I#

applicationT"#5B#

I#

applicationT"#5B#

I#

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