chapter1 Redes de computadoras

8/9/2019 chapter1 Redes de computadoras

1/84

Introduction 1-1

Introduccin a las

Redes deComputadoras

Introduccin

Nota acerca de las transparencias del curso:

Estas transparencias estn basadas en el sitio web que acompaa el libro, y

han sido modificadas por los docentes del curso.

All material copyright 1!"#$1#

%.& 'urose and '.(. )oss, All )ights )eser*ed


2/84


3/84

Introduction 1-3

Aspectos administrativos:

Aprobacin

%aboratorio

na tarea introductoria)

*res +bligatorios (entrega obligatoria)Grupos de tres estudiantes)

&onitoreos cada semana con un docente en grupos

reducidos (, o - grupos a la ve".

De/ensa en m01uina con el mismo docente.

(reglamento completo de aprobacin en el EVA)2arcial

*erico (da puntos para el e3amen.


4/84

Introduction 1-4

Recursos

&oodle

eva./ing.edu.u4 5ibliogra/a

Computer Networking: A Top Down Approach)6t' edition. #im 7urose) 7eit' Ross) Addison89esle4) #ul4 -;. IS5;;?.

@t' edition. #im 7urose) 7eit' Ross) Addison89esle4) &arc' ->. IS5;>.

t' edition. #im 7urose) 7eit' Ross) Addison89esle4) &arc' -,-. IS5


5/84

C'apter ,: Introduction

+ur goal: get /eel and

terminolog4

more dept') detail

later in course approac':

use Internet ase3ample

+vervieB: B'atFs t'e Internet

B'atFs a protocol

netBorH edge 'osts) access net)

p'4sical media

netBorH core: pacHetJcircuit

sBitc'ing) Internet structure

per/ormance: loss) dela4)

t'roug'put

securit4

protocol la4ers) service models

'istor4 +ntroduction 1"


6/84

C'apter ,: roadmap

,., 9'at is t'e Internet

,.-


7/84

9'atFs t'e Internet: nuts and bolts vieB

millions o/ connectedcomputing devices:

'osts K end s4stems

running netBorH appsome netBorH

Institutional netBorH

&obile netBorH

Global IS2

Regional IS2

router

2C

server

Birelesslaptop

cellular'and'eld

BiredlinHs

accesspoints

communication linHs

/iber) copper)

radio) satellite

transmission rateK bandBidt'

routers:/orBard pacHets

(c'unHs o/ data

+ntroduction 1"-


8/84

+t'er Internet appliances

+nternet phones

+ntroduction 1"


9/84

Internet Si"e


10/84

9'atFs t'e Internet: nuts and bolts vieB

protocols control sending)receiving o/ msgs e.g.) *C2) I2) **2) SH4pe)

Et'ernet

Internet: netBorH o/netBorHs loosel4 'ierarc'ical

public Internet versus private

intranet

Internet standards R!C: Re1uest /or comments

IE*!: Internet Engineering

*asH !orce

ome netBorH

Institutional netBorH

&obile netBorH

Global IS2

Regional IS2

+ntroduction 1"1$


11/84

9'atFs t'e Internet: a service vieB

communication in/rastructureenables distributed

applications:

9eb) $oI2) email) games)

e8commerce) /ile s'aring

communication services

provided to apps:

reliable data deliver4 /rom

source to destination

best e//ort (unreliable

data deliver4

+ntroduction 1"11


12/84

9'atFs a protocol

'uman protocols: B'atFs t'e time

I 'ave a 1uestion

introductions

L speci/ic msgs sent

L speci/ic actions taHen

B'en msgs received)

or ot'er events

netBorH protocols: mac'ines rat'er t'an

'umans

all communication

activit4 in Internetgoverned b4 protocols

protocols de/ine /ormat) order

o/ msgs sent and received

among netBorH entities)and actions taHen on msg

transmission) receipt

+ntroduction 1"1#


13/84

9'atFs a protocol

a 'uman protocol and a computer netBorH protocol:

M:+t'er 'uman protocols

/i

/i

0ot the

time

#:$$

234 connectionresponse

0ethttp:55www.awl.com56urose"ross

7file8time

+ntroduction 1"19

234 connectionrequest


14/84

C'apter ,: roadmap

,.,9'at is t'e Internet

,.-


15/84

A closer looH at netBorH structure:

netBorH edge:applications and

'osts access netBorHs)

p'4sical media:Bired) Bireless

communication linHs

netBorH core: interconnected

routers

netBorH o/ netBorHs

+ntroduction 1"1


16/84

*'e netBorH edge:

end s4stems ('osts: run application programs

e.g. 9eb) email

at edge o/ netBorH

clientJserver

peer8peer

clientJserver model client 'ost re1uests) receives

service /rom alBa4s8on server

e.g. 9eb broBserJserver email

clientJserver

peer8peer model: minimal (or no use o/ dedicated

servers

e.g. SH4pe) 5it*orrent

+ntroduction 1"1!


17/84

Access netBorHs and p'4sical media

M: oB to connect ends4stems to edge router

residential access nets

institutional access

netBorHs (sc'ool)compan4

mobile access netBorHs

7eep in mind:

bandBidt' (bits per

second o/ access

netBorH

s'ared or dedicated+ntroduction 1"1-


18/84

telephone

network Internet

home

dial-up

modem

ISP

modem

(e.g., AO!

home

P"

central

o##ice

uses e3isting telep'on4 in/rastructure

'ome directl48connected to central o//ice

up to @7bps direct access to router (o/ten less

canFt sur/) p'one at same time: not alBa4s on

Dial8up &odem

+ntroduction 1"1


19/84


20/84

Residential access: cable modems

uses cable *$ in/rastructure) rat'er t'an

telep'one in/rastructure

!C: '4brid /iber coa3

as4mmetric: up to =&bps doBnstream) -&bps upstream

netBorHo/ cable) /iber attac'es 'omes to IS2

router

'omes s'are access to router unliHe DS%) B'ic' 'as dedicated access

+ntroduction 1"#$


21/84

Residential access: cable modems

;iagram: http:55www.cabledatacomnews.com5cmic5diagram.html +ntroduction 1"#1


22/84

home

cable headend

cable distribution

networ6


23/84

home

cable headend

cable distribution

networ6

ser*er


24/84

Cable


25/84

home

cable headend

cable distribution

networ6

3hannels

>

+

;

E

?

>

+

;

E

?

>

+

;

E

?

>

+

;

E

?

>

+

;

E

?

>

+

;

E

?

;

A

2

A

;

A

2

A

3

?

N

2

)?

@

1 # 9 ! -

!D& (more s'ortl4:

+ntroduction 1"#

Cable


26/84

O0

O

central o##iceopticalplitter

O0

O0

optical

#ier

optical#ier

Internet

!iber to t'e ome

optical linHs /rom central o//ice to t'e 'ome

tBo competing optical tec'nologies: 2assive +ptical netBorH (2+


27/84

, &bps

, &bps

, &bps

, Gbps

server

Et'ernet

sBitc'

institutional

routerto institutionFs

IS2

Et'ernet Internet access

t4picall4 used in companies) universities) etc , &bps) ,&bps) ,Gbps) ,Gbps Et'ernet

toda4) end s4stems t4picall4 connect into Et'ernet

sBitc'

+ntroduction 1"#-


28/84

9ireless access netBorHs

s'ared Bireless access netBorHconnects end s4stem to router via base station aHa access point

Bireless %A


29/84

ome netBorHs

*4pical 'ome netBorH components: DS% or cable modem

routerJ/ireBallJ


30/84

2'4sical &edia

bit:propagates betBeen

transmitterJrcvr pairs

p'4sical linH:B'at lies

betBeen transmitter Q

receiver

guided media: signals propagate in solid

media: copper) /iber) coa3

unguided media: signals propagate /reel4) e.g.)

radio

*Bisted 2air (*2 tBo insulated copper

Bires Categor4 =: traditional

p'one Bires) , &bps

Et'ernet Categor4 @:

,&bps Et'ernet

+ntroduction 1"9$


31/84

2'4sical &edia: coa3) /iber

Coa3ial cable: tBo concentric copper

conductors

bidirectional

baseband: single c'annel on cable legac4 Et'ernet

broadband: multiple c'annels on

cable !C

!iber optic cable: glass /iber carr4ing lig'tpulses) eac' pulse a bit

'ig'8speed operation:

'ig'8speed point8to8pointtransmission (e.g.) ,Fs8

,Fs Gpbs

loB error rate: repeaters

spaced /ar apart immune

to electromagnetic noise

+ntroduction 1"91


32/84

2'4sical media: radio

signal carried inelectromagnetic

spectrum

no p'4sical Bire

bidirectionalpropagation environment

e//ects: re/lection

obstruction b4 obects inter/erence

Radio linH t4pes: terrestrial microBave

e.g. up to 6@ &bps c'annels

%A


33/84

C'apter ,: roadmap

,.,9'at is t'e Internet

,.-


34/84

*'e


35/84


36/84


37/84

Circuit SBitc'ing: !D& and *D&

&;

frequency

time

2;

frequency

time

users

EBample:

+ntroduction 1"9-


38/84


39/84


40/84

2acHet SBitc'ing: Statistical &ultiple3ing

se1uence o/ A Q 5 pacHets 'as no /i3ed timing pattern bandBidt' s'ared on demand: statistical multiple3ing.

*D&: eac' 'ost gets same slot in revolving *D& /rame.

A

5

C, &bJs

Et'ernet

,.@ &bJs

D E

statisticalmultiple3ing

1ueue o/ pacHetsBaiting /or output

linH

+ntroduction 1"$


41/84

2acHet8sBitc'ing: store8and8/orBard

taHes %JR seconds totransmit (pus' out

pacHet o/ % bits on to linHat R bps

store and /orBard: entirepacHet must arrive atrouter be/ore it can be

transmitted on ne3t linH dela4 K =%JR (assuming

"ero propagation dela4

E3ample:

% K ;.@ &bits

R K ,.@ &bps transmission dela4 K ,@

sec

R R R%

more on dela4 s'ortl4 L

+ntroduction 1"1


42/84

2acHet sBitc'ing versus circuit sBitc'ing

E3ample:

, &bJs linH

eac' user: , HbJs B'en active

active ,T o/ time

circuit8sBitc'ing: , users

pacHet sBitc'ing: Bit' =@ users) probabilit4 U

, active at same time is

less t'an .6

2acHet sBitc'ing alloBs more users to use netBorH

6:5aran 8 pacHet8

sBitc'ing in militar4 nets ,>;:AR2Anet conceived

b4 Advanced Researc'

2roects Agenc4

,>>:/irst AR2Anet node

operational

,>;-:

AR2Anet public demonstration


80/84

Internet istor4

,>;:A%+Anet satellitenetBorH in aBaii

,>;6:Cer/ and 7a'n 8arc'itecture /or interconnectingnetBorHs

,>;:Et'ernet at Pero3 2ARC late;Fs:proprietar4

arc'itectures: DECnet) S:AR2Anet 'as - nodes

Cer/ and 7a'nFs internetBorHingprinciples: minimalism) autonom4 8

no internal c'anges

re1uired to interconnectnetBorHs

best e//ort service model stateless routers decentrali"ed control

de/ine toda4Fs Internetarc'itecture

,>;-8,>?: InternetBorHing) neB and proprietar4 nets

+ntroduction 1"$

Internet istor4


81/84

Internet istor4

,>?=:deplo4ment o/

*C2JI2

,>?-:smtp e8mail

protocol de/ined ,>?=:D?@:/tp protocolde/ined

,>??:*C2 congestion

control

neB national netBorHs:

Csnet) 5I*net)


82/84

Internet istor4

earl4 ,>>Fs:AR2Anet

decommissioned

,>>,:@ earl4 ,>>s:9eb

'4perte3t Z5us' ,>6@) Fs[

*&%) **2: 5erners8%ee

,>>6: &osaic) later >Fs: commerciali"ationo/t'e 9eb

late ,>>Fs \ -Fs: more Hiller apps: instant

messaging) 2-2 /ile s'aring

netBorH securit4 to /ore/ront

est. @ million 'ost) ,

millionW users

bacHbone linHs running at

Gbps

,>>) -Fs: commerciali"ation) t'e 9eb) neB apps

+ntroduction 1"#

Internet istor4


83/84

Internet istor4

-,: O;@ million 'osts

voice) video over I2

2-2 applications: 5it*orrent

(/ile s'aring SH4pe ($oI2)22%ive (video

more applications: You*ube)

gaming) *Bitter

Bireless) mobilit4

+ntroduction 1"9

Introduction: Summar4


84/84

Introduction: Summar4

Covered a ton o/ material Internet overvieB

B'atFs a protocol

netBorH edge) core) accessnetBorH pacHet8sBitc'ing versus

circuit8sBitc'ing Internet structure

per/ormance: loss) dela4)

t'roug'put la4ering) service models securit4

'i

You noB 'ave: conte3t) overvieB)

/eel o/ netBorHing

more dept') detail to/olloB

chapter1 Redes de computadoras

Documents

Transcript of chapter1 Redes de computadoras