-41
.323 SIP
.323. .323.
H.323 ITU-T, - . .323 ISDN, IP-. H.323 . H.323, .
H.323 :
- , , , . H.323 . , H.323. . H.323 .
H.323 (, IP ISDN, IP PSTN).
H.323 , . , .
H.323 . MCU ( ), .
H.323 , (, IGMP). . , - .
H.323 - . . , , , . , , .
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, . H.323 , .
H.323 , . , - , / .
IP- H.323 .
.1. H.323
H.323 IP-, ( / ) , . . , IP- . . .323 , - .
.323 IP . , ( ) , , IP . , , / RTP/UDP/IP. IP .
(Gatekeeper):
- H.323;
- ( , .) (IP- + TCP);
- , ;
- .
IP , , . . H.323 , .
.2. H.323
. .. , .
(MCU Multipoint Control Unit)
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IP . H.323 .
. - (MCU), , .
. - , , .
. .
.3. .323
. , .
IP (IP multicasting). , -, .
MCU , (Multipoint controller, MC). MCU - - (Multipoint processor, MP).
ITU-T H IP-. (H.320) 1990 -, ISDN.
H , , , .
- H.320 ISDN;
- H.321 - ATM;
- H.322 ;
- H.323 ;
- H.324 ;
- H.324/C .
H.323 , , .
.4. .323
H.323 3 :
- RAS (Registration Admission Status) ;
- H.225;
- H.245.
, RAS, :
- ;
- ;
- ;
- ;
- .
.5. .323
H.323- :
H.245 - ,
Q.931 - ,
RAS (Registration/Admission/Status) - (Gatekeeper),
RTP/RTCP - .450, G.711 . H.261 / H.263. T.120.
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, . H.323 G.711 ( 3,1- 48, 56 64 /), G.722 (7 ; 48, 56 64 /), G.723 (3,1 ; 5,3 6,3 /), G.728 (3,1 ; 16 /) G.729 (3,1 ; 8 /). .
RAS (, ) . RAS- , , , . RAS .
Q.931 H.323, . TCP.
H.245 :
- ;
- ;
- ;
- ( );
- .
H.245 H.245- . 0, , -, . , . .
H.225.0 H.323, (ITU-T).
H.225.0 :
- : .. , H.323. H.225.0 ISDN Q.931.
- RAS: , , , H.323 (H.323 Gatekeeper). RAS , (Registration), (Admission) (Status), RAS.
- - RTP , G.711, H.261 H.263.
RTP (RFC 1889) IP- - . H.323, - , RAS User Datagram Protocol (UDP). (IP Multicast) . IP Multicast RTP, .
RTP , . , , . RTP .
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RTCP (RFC 1889) RTP. , .
:
1) .., .. SOFTSWITCH. .: -, 2006. 368 .
2) http://interexc.com/113
3) http://iptop.net/tech/h323_1.html
SIP
SIP (Session Initiation Protocol ) , -, (- , , -).
SIP .
, (, ) , , , , . , (, RTP). , ( -). .
IETF MMUSIC Working Group. 1996 . 2000 SIP 3GPP IMS ( 3GPP TS.24.229). c H.323, SIP , Voice over IP.
MMUSIC :
: ()
, UDP, TCP, ATM ..
. . . . REGISTER.
. SIP .
. .
. SIP , IETF. SIP, RSVP, RTP, RTSP, SDP.
. SIP IP-, , .
SIP 5060 TCP UDP SIP-. , SIP . , , , , . RFC, SIP . , RTP.
SIP IP, , . SIP , . , - (Proxy Servers) (User Agents). : , , .
SIP , -7, . -7 , , , ( ). SIP , (, , ) , (, ).
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SIP . SIP SDP, , IP . SIP RTP. RTP .
IP- , SIP , . URI, SIP URI. [sip ":"] ["@" ], , , IP-.
SIP 4 :
@,
@ (sip:[email protected]),
@IP- (sip:[email protected]),
@ (tel:[email protected]).
. , . - , . , IP-.
- . IP-, , () / . , , 2-3-4-.
, , , . (IP- ) -, .
SIP - .
. 1 -
, , . , , , , .
SIP. , , . , .
SIP :
. 2 SIP.
, User Agent Client (UAC) User Agent Server (UAS). UAC, UAS, User Agent (UA), SIP.
UAS UAC . SIP .
, UAC-UAS.
-
- ( . proxy ) . ( SS). , . - , , . - , Via.
-
(stateful). .
(stateless). . , .
. , -. .
, , .
SIP, . . , , SIP ( , MS Exchange, RADIUS- ..).
, . SIP- LDAP, RWHOIS, .
B2BUA
B2BUA (. back-to-back user agent, : --) , SIP. , B2BUA - SIP, . B2BUA, ( , ) , -. B2BUA , UAS UAC , . . , ( ), B2BUA, , , . ( From, To Contact) , B2BUA. , B2BUA - . , , , .
B2BUA :
(, , . .)
( , , )
( , . .)
B2BUA - , - . , / B2BUA.
‑
.
INVITE (1) - 5060, ( 7.10). . - (2), (3). - INVITE (4). , Via - , . , 180 Ringing (5), To, From, Call‑ID, CSeq Via. 200 (6),
SDP. (7). .
BYE (8), 200 (9). -, .
.3 ,
SIP
SIP ( ), , RFC 2279. SIP HTTP. SIP:
SIP-. , , . , , .
, ( , , .)
.
. ( BYE). , .
SIP (RFC 3261) . , , , . . .
1. INVITE . SDP- .
2. ACK INVITE.
3. BYE . , .
4. CANCEL , , .
5. REGISTER .
6. OPTIONS .
, , :
1. PRACK (RFC 3262)
2. SUBSCRIBE (RFC 3265)
3. NOTIFY (RFC 3265)
4. PUBLISH (RFC 3903)
5. INFO , (RFC 2976)
6. REFER SIP (RFC 3515)
7. MESSAGE SIP (RFC 3428)
8. UPDATE (RFC 3311)
. SIP HTTP. , . , , :
SIP-T SIP-I
, -7, SIP : Session Initiation Protocol for Telephones (SIP-T) Session Initiation Protocol Internetworking (SIP-I). , SIP-I ITU-T, SIP-T IETF RFC 3372. SIP ISUP IP-. SIP. SIP:
SIP-T | |
ISUP | ISUP SIP |
SIP ISUP | ISUP SIP |
INFO |
SIP NGN
1) IP- ( ) .., .., .. .: , 2006. - 336 .: . ISBN 5-256-01585-0 2) .., .., .. . - .: , 2004. 272 . 3) http://uk.wikipedia.org/wiki/Session_Initiation_Protocol |