1

Kommunikatsiooniteenuste arendusIRT0080

Loeng 2/2008

Avo Otstelekommunikatsiooni õppetool,

TTÜ raadio- ja sidetehnika inst.avo.ots@ttu.ee

The Internet

Every machine transparently connected to

every other

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Kasutuskava muutus

One computer/phone,many users

One computer/phone,one user

Many computers/phones,one user

anywhere,any time

any media

right place (device),right time,right media

~ ubiquitous computing embedded VoIP

mainframe erahome phone

party line

PC eracell phone era

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Implementation

Applications

OS

Applications

OS

Multi layer implementation-Breaking down into smaller components-Easier to implement

Single layer implemen-tation

Applications

OS

Co

mm

un

icat ion

Applications

OS

Co

mm

un

icat ion

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Densely Connected Heterogeneous Network

Terrestrial Fiber

Terrestrial Copper

Regional Wireless

Free-Space Lasercomm

Satcomm

Võrgu tipptase

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Datagramm vs Virtuaalahel

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Multiple Access Protocols

Multiple access protocols

Contention-based Conflict-free

Random access Collision resolution

FDMA,

TDMA,

CDMA,

DQDB, etc

ALOHA,

CSMA

WINDOW, etc

DQDB: Distributed Queue Dual Bus

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Throughput

G86420

0.5

0.4

0.3

0.2

0.1

0

Slotted Aloha

Aloha

0.368

0.184

G

S

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Vastastikused häired

Interference Margin (dB) and Load Factor

0

5

10

15

20

25

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Load Factor

Inte

rfer

ence

Mar

gin

(d

B)

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E-Mail Standards (3)

SendingE-MailClient

ReceivingE-MailClient

Sender’s MailServer

Receiver’s MailServer

MessageRFC 822 or 2822HTML bodyUNICODE

Message Body Format Standard

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Internet

IP Network

Tugijaam

Võrgu ülesehitus

Gateway

Raadioliides

Telefonivõrk

Gateway

End-to-End IP

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MMC (Measure, Model, and Control)

Ülesehitus Liiklus

Muutuste tegemine

Käigusolev võrk

Models, tools, scripts,

databases

measure

control

Võrguhaldus

AndmehõiveHäälestus

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ApplicationsApplicationsApplicationsApplications

Call Call ProcessingProcessing

Call Call ProcessingProcessing

InfrastructureInfrastructureInfrastructureInfrastructure

ClientsClientsIP SoftPhone

• PSTN gateways• Analog phone supportIP

Network

PSTN

Directory

Call Processing

Voice Mail, UMS

Intelligent Contact Manager

IP IVR, IP AAApps Engine

Voice Portal

ICMICM

Collaboration

Video

Paketipõhine telefonilahendus

GKGK

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Message Transmission Example

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TCP

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The Problem• only nodes on the same physical/link layer

network could communicate

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Solution

Gateways

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E-Mail Standards (1)

SMTPTo Send

SMTPTo Send

SendingE-MailClient

ReceivingE-MailClient

Sender’s MailServer

Receiver’s MailServer

Simple Mail Transfer Protocol (SMTP) to transmit mail in real time to a user’s mail server or between mail servers

Sender-initiated

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E-Mail Standards (2)

Sending E-MailClient

ReceivingE-MailClient

Sender’s MailServer

Receiver’s MailServer

POP orIMAP

To Receive

POP or IMAP to download mail to receiver when the receiver is next capable of downloading mail.

Receiver-initiated

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Lingidhttp://en.wikipedia.org/wiki/Client_server

http://en.wikipedia.org/wiki/Application_server

ftp://ftp.prenhall.com/pub/esm/sample_chapters/cs/stallings/index.html

http://www.williamstallings.com