1

Kommunikatsiooniteenuste arendusIRT0080Loeng 5

Avo Otstelekommunikatsiooni õppetool,

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

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Teenusetase (SLA)

3

PõhiparameetridViide Ülekandekiirus TöökindlusViide Ülekandekiirus Töökindlus

Foon

E-postalla-laadimine

Interaktiivne

veebVoog

videoloeng

Vestlus

kõne

Lub

atav

vii

de

Liiklusklassid viite järgi

Reaalajas (Real-time) Parim võimalik (best effort)

4

I n t

e r

a k

t I I

v s

u s

Digitaalne sisu

S E

A D

M E

D

INTERNET

DIGI TV

MOBIIL

Kättesaadavus

5

Edastuse kvaliteet (QoS)

6

Kõneviite piirid

One WayOne WayDelay (Delay (mmsec)sec) DescriptionDescription

00––150150 Acceptable for most user applicationsAcceptable for most user applications

150150––400400Acceptable provided that administrations are aware Acceptable provided that administrations are aware of the transmission time impact on the transmission of the transmission time impact on the transmission quality of user applicationsquality of user applications

400 +400 +Unacceptable for general network planning Unacceptable for general network planning purposes—however—It is recognized that in some purposes—however—It is recognized that in some exceptional cases this limit will be exceededexceptional cases this limit will be exceeded

• ITU G.114 soovitus

7

Telefoni vs datagrammi teenus• Ainult üks teenus:

kõne• Host on telefon

• Palju teenuseid• Host tekitab mitu

voogu

ApplicationLayer

TelephoneNetwork

(Data) LinkLayer

Telephone

Telephone numbering, signaling, routing

TDMA

ApplicationLayer

TransportLayer

NetworkLayer

(Data) LinkLayer

telnet, ftp, email

TCP, UDP

IP

802.3, 802.11

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Liikluse (de)multipleksimine

IP

TCP Transport

A B C

p1 p2 p1 p2 p3 p1 p2

portsApplication

HTTP sshtelnet

In TCP, a data stream is identified by a set of numbers:(Source Address, Destination Address, Source Port, Destination Port)

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Transpordiprotokolli funktsioonid• Multiplexing/demultiplexing for multiple applications.

– Port abstraction

• Connection establishment.– Logical end-to-end connection– Connection state to optimize performance

• Error control.– Hide unreliability of the network layer from applications– Many types of errors: corruption, loss, duplication,

reordering.

• End-to-end flow control.– Avoid flooding the receiver

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Transmission Control Protocol (TCP)• Reliable bidirectional in-

order byte stream– Socket: SOCK_STREAM

• Connections established & torn down

• Multiplexing/ demultiplexing– Ports at both ends

• Error control– Users see correct, ordered

byte sequences

• End-end flow control

Source PortSource Port Dest. PortDest. Port

Sequence NumberSequence Number

Acknowledgment NumberAcknowledgment Number

HL/FlagsHL/Flags Advertised Win.Advertised Win.

ChecksumChecksum Urgent PointerUrgent Pointer

Options..Options..

0 16 32

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TCP lisaomadused ja lipud• Sliding window protocol

– Use sequence numbers

• Bi-directional– Each host can be a receiver and a sender simultaneously

• SYN: Synchronize– Used when setting up connection

• FIN: Finish– Used when tearing down connection

• ACK– Acknowledging received data

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Võrgujõudluse kasutus

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Ummistusest tekkinud viide

14

Ummistuste haldamine

15

Värin (jitter)ja sünkroniseerimine

• Värin – saabumisaja erinevus• Sünkroniseerimine – tegevuste ajastamine

saatjavastuvõtja

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Andmevoog (stream)

• Paketid peavad jõudma kohale kindlal ajal kindlas järjestuses

• Kui ei jõua, siis vastu ei võeta

89saatjavastuvõtja

7 6 5 4 2 1

3

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RTP (Real Time Protocol)

Len. CRC

SP (554) DP (554)

Data

Data

Payload type Seq. No

Timestamp

Syncro Source

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Leviedastus (Broadcast)

Tra

nsm

itte

r

Rece

iver

Eesmärgid1. Otstarbekas ressursikasutus2. Kõrge tunnetatav edastuse (ja

kohaletoimetamise) kvalteet

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TV stuudio täna

Kaamera juht-seade

SDI saatja

SDI vastu-võtja

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Digitaalne ülekanne ja seadmed

Video serverid

Võrk Vastuvõtja Meediaseadmed

OnlineOnline OfflineOffline (salvestatud) (salvestatud)

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Kujutise mahud (pikselites)

QSIF(19Kp)

SIF (82Kp)

601 (300Kp)

SVGA (500Kp)

A_TV (1Mp)

Workstation (1Mp)

HDTV (2Mp)

120

240

483

600

720

900

1080

160 352 720 800 1152 1280 1920

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Kvaliteedi tagamineP

akki

mis

e te

gur

Keerukus Latentsus

Parem kvaliteet

Halvem kvaliteetHalvem

kvaliteet

Parem kvaliteet P

akki

mis

e te

gur

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Infomahu vähendamine (MPEG)

PuhverEntroopia

kodee-rimine

Kvan-timine

DCTTeisendus4:2:2 ->

8-bit 4:2:0

Pakitudandmed

Täis-kiiru-sega

andmed

Kvanditud andmed

Edastuse juhtimine

Info kaduAndme-

hulkvähenes

Poleinfo kaduAndme-

hulksama

Andme-hulk

vähenes(info kadu)

Andme-hulk

vähenes(pole

info kadu)

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Multipleks

PAT

MUX

Audio

Video

PTS/DTS

Audio

Audio

Video

Video

PTS/DTS

PTS/DTS

PMT

NIT

Programm 1

Programm 2

Programm 3

TranspordivoogTransport stream

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MPEG-2• ISO/IEC 13818-1 Systems (transport and

programs streams), PES, T-STD buffer model and the basic PSI tables: CAT, PAT, PMT and NIT.

• ISO/IEC 13818-2 video coding.

• ISO/IEC 13818-3 audio coding.

• ISO/IEC 13818-4 MPEG test and conformance.

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MPEG-4

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MPEG-4 lahendusi• MPEG-4 on objektipõhine

• Panoraamkujutised – ülisuure pakkimistihedusega – 1000:1

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Networks

Provider

PVR

service providerscontent providers

In-home Network

Gate

way

In-home Network

removable media

Gate

way

storage

NDR

Provider

PVR

DVD

control/contentcontrol

Networks

TV-Anytime

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Universal Home API

• Defined by the UHAPI Forum

• Simplifying software development for CE products

• Application portability over multiple HW/SW platforms

• Open Source implementation: UHAPI4Linux

Operating System and UNIVERSAL HOME API

streaming A/V software

Architecture 3

Company C

web-DVD

OCAP PVR Memory Card InternetBrowsing MHP

Videoediting

Pictures discs

PictureBrowsing MHEG

contentmanager EPGISDB-BML

streaming A/V software

Architecture 2

streaming A/V software

Architecture 4

Company B Company D

streaming A/V software

Architecture 1

Company A

…

•Application portability over multiple HW/SW platforms

•Open Source implementation: UHAPI4Linux

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IP tv (ülesanne) 100 Mbit FOC4 Mbit DSLDVB-C + IP

100 Mbit TPPOTSISDNVOIP

100 Mbit TP

TV Telefon PC

Scartkabel

CPE (Access-Switch)

Settop Box

4-8 Mbit

1.5-3.0 Mbit 8-12 Mbit

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

Protocol

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

http://en.wikipedia.org/wiki/H.264

http://en.wikipedia.org/wiki/Real-time_Transport_Protocol

http://geocities.com/intro_to_multimedia/RTP/

http://www.cs.columbia.edu/~hgs/rtp/

http://en.wikipedia.org/wiki/MPEG-2