8/6/2019 18675388-IETF

1/43

1

IETF Standard Protocols for

Multimedia Transport

Gio vin hng dn : TS. L Nht Thng

Hc vin : Nguyn Chnh Hng QuangHong Dng S

HHc vic vin Cng nghn Cng ngh Bu chBu chnh Vinh Vin thng Vin thng Vit Namt NamKhoa HKhoa Hp tp tc Quc Quc tc tvvo to to sau o sau i hi hcc

8/6/2019 18675388-IETF

2/43

2

Ni dung

Gii thiu v chng giao thc sdng cho

Multimedia v t chc IETF

RTP - Real Time Transport Protocol

SIP Session Initiation Protocol

SDPSession Description Protocol

SAPSession Announcement Protocol

RTSPReal Time Streaming Protocol

Kt lun

8/6/2019 18675388-IETF

3/43

3

IETF (Internet Engineering Task Force)

L mt nhm chuyn trch nghin cu v pht trin InterNet

nh ngha v ra cc tiu chun tch hp hoc s dng trong mng IP

(TCP/IP, SMTP, FTP, RTP)

Thnh phn tham gia : M, lnh vc D liu, Vin thng,

Trong nhng nm gn y : Ti c cu, m rng quy m, quy ch tham

gia

Quan tm pht trin lnh vc RAI :

Real-time Applications and Infrastructure

8/6/2019 18675388-IETF

4/43

4

Chng giao thc a phng tin - IETF

8/6/2019 18675388-IETF

5/43

5

RTP - Real Time Transport Protocol

Giao thc cung cp cc dch v truyn cc s liu vi c tnh v thi

gian thc tu cui n u cui

RTP pha trn giao thc UDP thc hin ghp lung v kim tra li,

c hai giao thc ny (RTP v UDP) kt hp nhau thc hin vai tr l giao

thc truyn ti.

RTP v c bn c thit k nhm p ng vic truyn d liu cho cc

hi ngha dch v vi nhiu ngi tham gia, khng gii hn s dng vi

mt dch v c th no

RTP : Truyn cc d liu yu cu thi gian thc

RTCP : Theo di + iu khin + QoS

8/6/2019 18675388-IETF

6/43

6

Vng tiu cnh RTP

V=2 P X CC M PT Sequence number

Timestamp

Synchronization Source (SSRC) Identifier

Contributing Source (CSRC) Identifiers

2 1 1 4 1 7 16

4 Octet

4 Octet

4 Octet

4 Octet

. Version : Xc nh Version ca RTP

. Padding (P) : Chth cho vic chn

. Extension (X) : Cho bit vic chn phn m rng

. CSRC count (CC) : S CSRC cho bit s nhn dng CSRC sau phn tiu cnh

. Marker (M) : S dng nh du gii hn ca khung trong lung gi.

. Payload Type : Xc nh loi ti RTP.

. S th t :c tng thm 1 khi mi gi tin RTP c gi i,

. Nhn thi gian : Phn nh thi im ly mu ca octet u tin

. SSRC : xc nh tn hiu ng b

. CSRC list : Xc nh cc ngun ca ti trng trong gi tin

8/6/2019 18675388-IETF

7/43

7

Giao thc iu khin RTP - RTCP

Cung cp phn hi v cht lng

ca vic phn pht d liu

Kt hp nhiu lung d liu t mt

ngi tham gia bit trc vo mt tp

cc phin RTP lin quan nhau. V d

nh vic ng b gia Video v Audio

iu khin tc

iu khin phin, c tnh ty chn,

8/6/2019 18675388-IETF

8/43

8

TrnKch bn s dng ca RTP

end system 1

end system 2

transl.1

from ES1: SSRC=6

from ES2: SSRC=23

transl.2

from ES2: SSRC=23

from ES1: SSRC=6

authorized tunnel

firewall

from ES2: SSRC=23

from ES1: SSRC=6

Chuyn i

8/6/2019 18675388-IETF

9/43

9

SIP SESSION INITIATION PROTOCOL

SIP l tiu chun ca t chc IETF s dng cho kt ni hi ngha

phng tin trong mi trng IP

SIP l mt giao thc da trn bng m ASCII, iu khin lp ng dng

( c nh ngha trong RFC 2543 )

SIP c dng thit lp, duy tr v kt thc cc cuc gi gia haihoc nhiu u cui.

Bo hiu : cho php cc thng tin cuc gi c truyn qua cc ng

bin ca mng

Qun l phin trong mt mng thoi chuyn mch gi

iu khin thuc tnh ca mt cuc gi tu cui n u cui.

8/6/2019 18675388-IETF

10/43

10

Cc thnh phn ca SIP

Khch UA ( User Agent Client ) : Mt ng dng khch, ng vai trkhi to yu cu SIP

Server UA ( User Agent Server ) : ng dng Server s kt ni vingi dng khi mt yu cu SIP c nhn v tr v mt phc p cangi dng.

8/6/2019 18675388-IETF

11/43

11

Hot ng ca SIP

Cc Yu cu v Phc p

. Vn bn, phi nh phn, c khun dng

. Rt gn vi HTTP/1.1

. Yu cu v Phc p tng t nhau, ngoi tr dng u tin

. Cc Yu cu v Phc p c th cha cc khi tin

M t phin thng thng, c th l ASCII hoc HTML

8/6/2019 18675388-IETF

12/43

12

Cc phng thc ca SIP

INVITE Khi to cuc gi

ACK Phn hi cui cng

BYE Kt thc ( v chuyn ) cuc gi

CANCEL Hy tm kim v chung

OPTIONS Cc c tnh h tr bi i phng

REGISTER ng k dch vnh v

INFO Thng tin cuc goi trung gian

COMET Cuc gp c iu kin tin quyt

PRACK Chp nhn tm thi

SUBCRIBE ng d kin

NOTIFY Thng bo cho cc khch hng

REFER Yu cu ngi nhn pht yu cu SIP (chuyn tip chuc gi)

8/6/2019 18675388-IETF

13/43

13

Cc phc p SIP

8/6/2019 18675388-IETF

14/43

14

M t hot ng ca SIP

S dng mt Servery nhim

Long@vtn.vn

Long

Sy@v

npt.qti

Sy@vnpt.qti

Sy@vnpt.qti

Quang@vtn3.vn

dng.vn

vtn.vn

8/6/2019 18675388-IETF

15/43

15

S dng Server Ti nh hng

Long@vtn.vnLong@vtn.vn

Long

Long@vtn.vn

vtn.vn

Sy@vnpt.qti

Sy

vnpt.qtiSy@vnpt.qti

Sy@vnpt.qti

vtn.vn

Quang@dng.vn

8/6/2019 18675388-IETF

16/43

16

So snh gia SIP v H.323

8/6/2019 18675388-IETF

17/43

17

SDPSESSION DESCRIPTION PROTOCOL

SDP n thun l mt khun dng m t phin

Khng phi l mt giao thc truyn

ti

Truyn thng bo cc phin

Truyn cc thng tin v thit lp hi

ngh

Cc thng tin v cc cng c h tr

SDP c th dng vo nhiu mch

ch, s dng rng ri trong cc mi

trng mng

Link and Physical Layer

IP

UDP TCP

Signaling Layer (SIP)

Session Description (SDP)

Key Exchange (SDES, MIKEY)

RTPZRTP

SRTP

Audio Application

8/6/2019 18675388-IETF

18/43

18

M t SDP

Vn bn, s dng b kt ISO 10646, UTF-8

=

. : 1 k t, c xt n

c tnh ch hoa hay chthng.

. : L mt chui vn

bn c cu trc c khun

dng ph thuc vo

8/6/2019 18675388-IETF

19/43

19

M tphin

V = Version ca giao thcO = Nhn dng phin v ch nhn ca

phin

S = Tn ca phin

I = Thng tin v phin

U = URI ca m t

e =a chEmail

c = Thng tin kt ni

b = thng tin v bng thng

z = siu chnh vng thi gian

k = kha m ha

a = Zero hoc nhiu thuc tnh phin

M t thi gian

t = nh thi cho phin c thitlp

r = Zero hoc nhiu thi gian lp

M t phng tin

m = tn phng tin v a chtruyn ti

i = tiu

c =Thng tin kt ni

b = thng tin v bng thngk = Kha m ha

a = Zero hoc nhiu thuc tnh

phng tin

M t phin

8/6/2019 18675388-IETF

20/43

20

Mt v d m t SDP nh sau :

v=0

o=mhandley 2890844526 2890842807 IN IP4 126.16.64.4s=SDP Seminar

i=A Seminar on the session description protocol

u=http://www.cs.ucl.ac.uk/staff/M.Handley/sdp.03.ps

e=mjh@isi.edu (Mark Handley)c=IN IP4 224.2.17.12/127

t=2873397496 2873404696

a=recvonly

m=audio 49170 RTP/AVP 0m=video 51372 RTP/AVP 31

m=application 32416 udp wb

a=orient:portrait

8/6/2019 18675388-IETF

21/43

21

Chnh sch i vi thng tin iu khin hi ngh

Khai bo n

Vng thuc tnh hi ngh (phin) -> quyt nh chnh sch iu khinhi ngh

V d 1 phin ITU-H.332

c=IN IP4 224.5.6.7

a=type:H332

m=audio 49230 RTP/AVP 0

m=video 49232 RTP/AVP 31m=application 12349 udp wb

m=control 49234 H323 mc

c=IN IP4 134.134.157.81

hi ngh (loi H332)

a chngi iukhin

cng ciu khin

8/6/2019 18675388-IETF

22/43

22

ng dng SDP

Thng bo a chiu

. Pht a hng gi thng bo, nh k -> a cha hng, cng

s dng SAP

Thng bo Email v WWW

. S dng loi ni dung MIME application/sdp -> kch hot vic

khi to ng dng tng t khch hng WWW hoc chng trnh c

Mail

. Khi to ng dng tng

8/6/2019 18675388-IETF

23/43

23

Cc yu cu v khuyn ngh

Thng tin v dch v

. Loi dch v (Video, Audio)

. Giao thc truyn ti (RTP/UDP/IP, H.320)

. Khun dng ca dch v (H.261 Video, MPEG Video)

. IP a hng :

-a cha hng ca dch v

- Cng truyn ti ca dch v. IP n hng

-a cht xa cho dch v

- Cng truyn ti cho a chlin h

Thng tin vnh thi

. Mt danh sch v thi gian bt u v kt thc ca phin

.i vi mi phin c gii hn -> thi gian lp li

8/6/2019 18675388-IETF

24/43

24

Thng tin c nhn

. M ha m t phin

Cc thng tin m rng ca phin

. Nhn dng Ti nguyn thng thng - URI m t thm v phin.

Phn loi. Lc cc thng bo khng cn c quan tm

Quc t ha

. Khuyn ngh s dng b k t ISO 10646 m ha UTF-8 (RFC2044)

8/6/2019 18675388-IETF

25/43

25

SAPSESSION ANNOUNCEMENT PROTOCOL

H tr cho vic thng

bo cc hi ngh (phin)

a phng tin

Truyn ti cc thng

tin thit lp phin cn

thit

Gip ngi (s tham

gia phin) xa kch hot

cc cng c cn thit

tham gia phin

8/6/2019 18675388-IETF

26/43

26

Thng bo phin

SAP nh k gi mt gi thng bo n cc a chv cng truyn a

hng

Thng bo cha s m t phin v phi mang tiu cho vic xc

thc

Mt phin ton cc trong Ipv4 : 222.2.128.0 n 224.2.225.255, thng

bo SAP c gi n 224.2.127.254

a chtruyn a hng thng bo : a chcao nht trong vng gim

st tng ng. VD nu vng gii hn trong khong t 239.16.32.0 n239.16.33.255, a ch239.16.33.255 s dng cho SAP.

8/6/2019 18675388-IETF

27/43

27

Xa phin

Ti trng m t thi gian gii hn r : cha thng tin v nhn thi

gian cho bit thi gian bt u v kt thc ca phin. Nu thi gian hinti l tr hn thi gian kt thc ca phin, lc phin s b xa ti b

nhm phin pha ngi nhn.

Bn tin thng bo thi gian gii hn n :sc nhn mt cchnh k i vi mi m t phin trong b nhm phin pha ngi

thu

Gi tin xa phin :nhn c xc nh phin s b xa. Gi tin xaphin phi c tiu xc thc c hiu lc. Nu khng c xc thc bn

tin xa phin s b b qua

8/6/2019 18675388-IETF

28/43

28

Thay i phin

Thng bo thay i phi cha tiu xc thc, c nh ducng mt kha nh thng bo phin n m n ang thay i

Thng bo phin n phi khng cha cha tiu xc thc v

thng bo thay i phin phi bt ngun t cng mt my ch nh

phin m n ang thay i.

Nu mt thng bo c nhn cha tiu xc thc v thng bo

o khng cha tiu xc thc hoc cha mt tiu xc thc khc,

thng bo thay i phi c x l nh l mt thng bo mi.

8/6/2019 18675388-IETF

29/43

29

Kch bn SAP

8/6/2019 18675388-IETF

30/43

30

Khun dng gi

V: S Version.

A : Kiu a ch.

R : D tr.T : Kiu bn tin.

E : Bit m ha :.

C : Bit nn :

di xc thc : 8 bit. Cho bit d liu

xc thc

D liu xc thc :nh s cho gi

Nhn dng tin : cung cp mt nhn dng duy

nhtTi nguyn gc : Cho bit a chIP ca bn tin

gc

Loi ti trng ty chn : B m t kiu ni dung

MIME, m t khun dng ca ti trng

R

8/6/2019 18675388-IETF

31/43

31

Thng bo c m ha

Trong tiu SAP c bit m ha cho php m ha thng bo

Ngi nhn khng c kha m ->khng th s dng ->hao ph bngthng

Khng khuyn khch s dng.

Thng bo xc thc

Kim tra m t phin xa phin

Xc thc nhn dng ca ngi to phin

8/6/2019 18675388-IETF

32/43

32

V : S Version

P : Bit chn

Auth : Loi xc thc

V=1 P Auth

M t khun dng cho tiu xc thc ph

3 1 4 24

Khun dng d liu xc thc trong tiu SAP

8/6/2019 18675388-IETF

33/43

33

RTSPREAL TIME STREAMING PROTOCOL

Thit lp v iu khin mt hoc nhiu lung tin ng b Video v

Audio

Xen k cc lung tn hiu iu khin gia cc lung tin lin tc

iu khin servera phng tin t xa

RTSP khng ph thuc vo k thut truyn ti

RTSP tng t nh HTTP v c php v hot ng

8/6/2019 18675388-IETF

34/43

34

RTSP v khi nim Dng chy

Dng chy l mt mt qu trnh chy mt file trong khi n vn

ang c ti ( vd nh tn hiu Video, Audio trc tuyn)

St ph ca Dng chy : Khng cn lu ton b v b nh

ni b ( PC, Softphone, Palmtop, PDA) trc khi chy n

Cng ngh Dng chy cho php khch hng xem hoc nghe cc

dch v tc thi m khng phi chi

8/6/2019 18675388-IETF

35/43

35

Cc ng dng

Nhn dch v truyn thng t server dch v. M t trnh din thng qua HTTP hoc mt s phng php khc

Kt ni mt server dch v vo mt hi ngh

. C th s dng cc phin n cc nt iu khin t xa

Tch hp cc dch v vo mt trnh din hin hnh

8/6/2019 18675388-IETF

36/43

36

Cc tnh cht ca giao thcC th m rng

. Mt phng php hoc tham s mi rt d tch hp vo RTSP

D dng phn tch ng php. RTSP c thc phn tch theo HTTP tiu chun hoc cc

b phn tch MIME

Bo mt. RTSP s dng li k thut bo mt Web

Tnh c lp vi truyn ti. RTSP c th s dng UDP (theo RFC 768 ), RDP (RFC 1151);

TCP (RFC 793) khi to tin cy cho lp ng dng

Kh nng a server. Mi lung dch v trong mt trnh din c th nm mt server

khc nhau.

8/6/2019 18675388-IETF

37/43

37

Hot ng tng qut

Iris

Web browser

Media player

Tower box

Tower box

Web

server

Streaming

server

Client

(1)

HTTP request/

response,

description file

(3)

Audio/video file

requested and

sent

(2)

Descrip-

tion file

Internet

Trnh din lung dch v xc nh bi mt RTSP URL

Khch hng gi m t qua HTTP, Email

Lung dch vc iu khin ring bit qua RTSP

8/6/2019 18675388-IETF

38/43

38

Hot ng tng qut

UserInterface RTSPPlayer RTSPServerOpenURLSETUP

response1

PLAY

response2Audio

PAUSE

response3

Quit TEARDOWN

response10

Activate RTP

PLAY

PAUSE

Activate RTP

Supplier : VTC, FPT, VCTVPlayer : TV, PC,

SoftPhone, Palmtop

Interface : WWW, 3rd

Party Soft

8/6/2019 18675388-IETF

39/43

39

Hot ng tng qut

8/6/2019 18675388-IETF

40/43

40

RTP v RTSP

RTP v RTSP u l phng thc truyn ti, cn phn bit RTP v

RTSP. RTSP c s dng khi cc ngi xem kt ni vi mt server

truyn n hng

RTSP cho php truyn hai chiu : Ngi xem c th kt ni vi Server

(Audio,Video), tua li, nhy n mt on

RTP l giao thc mt chiu, s dng cc lung dch v trc tip

hoc pht li t Servern Khch hng

RTSP c th xem nh l mt s ci tin RTP -> nn tiu RTP

8/6/2019 18675388-IETF

41/43

41

RTSP

header

M tng khung RTSP

8/6/2019 18675388-IETF

42/43

42

Kt lunTiu lun gii thiu mt cch tng qut v cc c s, vai tr v

nguyn l hot ng ca mt s giao thc chnh trong chng giao thc h

tr cho Multimedia ca IETF B cc giao thc trn ngy cng c s dng rng ri trong cc dch

v Multimedia, c bit trong mi trng InterNet

Do cc gi tin, cc lung dch v - Dng chy c iu khin bi

nhiu lp trong chng giao thc nn i hi qu trnh x l kh ln

c th mang li cht lng dch v cao, p ng cc yu cu ca

cc ng dng cn c c s h tng (ng thu bao, mng trc) thng

tin p ng cc tc v cc tham s li t ra Vi cu trc mng NGN ang c hon thin v pht trin nh hin

nay, gp phn thc y pht trin lnh vc RAIang c nhu cu ngy

cng cao

8/6/2019 18675388-IETF

43/43

43

Fine

Thank for attention !