h.323 packet-based multimedia communications systems
DESCRIPTION
H.323 Packet-based multimedia communications systems. Speaker: Yi-Lei Chang Advisor: Dr. Kai-Wei Ke 2012/11/28. Outline. Introduction Protocol Stack Elements Call signalling procedures. Introduction. 1996 - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/1.jpg)
Speaker: Yi-Lei ChangAdvisor: Dr. Kai-Wei Ke
2012/11/28
H.323 Packet-based multimedia communications systems
1
![Page 2: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/2.jpg)
Outline
• Introduction• Protocol Stack• Elements• Call signalling procedures
2
![Page 3: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/3.jpg)
Introduction
• 1996 • ITU-T
(Telecommunication Standardization sector of International Telecommunication Union)
• Packet-based multimedia communications systems
3
![Page 4: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/4.jpg)
Protocol Stack
4
![Page 5: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/5.jpg)
Additional Documents
• H.235 Security within H.245-based systems• H.450.x Supplementary services• H.460.x Various H.323 protocol extensions• H.501 Protocol for mobility management
and inter/intra-domain communication
• H.510 User, terminal, and service mobility• H.530 Security specification for H.510
5
![Page 6: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/6.jpg)
Elements
• Terminals• Gateways• Gatekeeper• MC, MP, MCU– Multipoint controller– Multipoint processor– Multipoint control unit
6
![Page 7: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/7.jpg)
Terminals
• Telephones, Video phones, etc.• Soft phones• G.711 (voice)• H.261 (video, optional)
7
![Page 8: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/8.jpg)
Gateway
• Interface H.323 to other networks– PSTN– H.320 systems– other H.323 networks (proxy)– etc.
8
![Page 9: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/9.jpg)
Gatekeeper
• Optional element• H.225.0 RAS– Address Translation– Admissions Control– Bandwidth Control– Zone Management– Optional• Call Control signalling• Call Management
9
![Page 10: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/10.jpg)
MC, MP, MCU• Multipoint controller– Provides control functions to support conferences
between three or more endpoints in a multipoint conference
• Multipoint processor– Handle media mixing, switching, or other media
processing• Multipoint control unit– An endpoint which provides support for multipoint
conferences– The MCU shall consist of an MC and zero or more MPs
10
![Page 11: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/11.jpg)
MC, MP, MCU
11
![Page 12: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/12.jpg)
H.255.0 RAS• Registration, Admission, and Status• Used between the endpoint and its Gatekeeper• RAS Port
– 1719 (unicast)– 1718 (multicast) for GRQ, LRQ
• RAS messages generally have three types– Request (xRQ)– Reject (xRJ)– Confirm (xCF)– x can be
• G:Gatekeeper R:Registration• A:Admissions L:Location• D:Disengage U:Unregistration
• IRQ (Information Request), IRR (Information Request Response)
12
![Page 13: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/13.jpg)
Call signalling procedures
• Phase A: Call setup.– H.225.0/Q.931 Call control , H.225.0 RAS (if reg. to a gatekeeper)
• Phase B: Initial communication and capability exchange– H.245 Multimedia control, H.225.0/Q.931 Call control
• Phase C: Establishment of audiovisual communication– H.245 Multimedia control, RTP, RTCP
• Phase D: Call services– Status, Bandwidth changes, Conference expansion
• Phase E: Call termination– H.225.0/Q.931 Call control, H.245 Multimedia control (optional),
H.225.0 RAS (if reg. to a gatekeeper)
13
![Page 14: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/14.jpg)
Phase A: Call setup• Notify user, setup H.245 channel• Caller/Callee registered to Gatekeeper?• Routed/direct call? (if reg. to a Gatekeeper)• Simple call setup:
14
![Page 15: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/15.jpg)
Phase A: Call setupCaller/Callee registered to Gatekeeper
15
![Page 16: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/16.jpg)
Phase A: Call setupCaller routed call
16
![Page 17: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/17.jpg)
Phase A: Call setupCallee routed call
17
![Page 18: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/18.jpg)
Phase A: Call setupAn example
• Endpoint 1 – registered to gatekeeper 1
• Gatekeeper 1– use direct call
• Endpoint 2– registered to gatekeeper 2
• Gatekeeper 2– use routed call
18
![Page 19: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/19.jpg)
19
![Page 20: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/20.jpg)
20
![Page 21: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/21.jpg)
Phase B: Initial communication and capability exchange
• Capability exchange• Master Slave Determination
21
![Page 22: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/22.jpg)
Phase C: Establishment of audiovisual communication
22
![Page 23: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/23.jpg)
Phase D: Call services• Status– IRQ, IIR– Interval > 10 sec.
• Bandwidth changes– BRQ, BCF, BRJ– closeLogicalChannel, openLogicalChannel,
flowControlCommand• Conference expansion– Create– Invite– Join
23
![Page 24: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/24.jpg)
Phase E: Call termination• Terminate a call– Discontinue transmission of video, data, audio and then
close all logical channels for them– Transmit the H.245 endSessionCommand (optional)– Close H.245 Control Channel– Transmit a Release Complete message and close the
H.225.0 call signalling channel• Terminate a conference– H.245 message dropConference– Wait for MC to terminate calls
• Call clearing with a gatekeeper• Call clearing by gatekeeper
24
![Page 25: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/25.jpg)
Phase E: Call terminationCall clearing with a gatekeeper
25
![Page 26: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/26.jpg)
Phase E: Call terminationCall clearing by gatekeeper
26
![Page 27: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/27.jpg)
Reference[1] International Telecommunication Union, "Packet-based Multimedia Communications Systems," Recommendation H.323, Telecommunication Standardization Sector of ITU, December 2009.
[2] International Telecommunication Union, "Call signalling protocols and media stream packetization for packet-based multimedia communication systems," Recommendation H.225.0, Telecommunication Standardization Sector of ITU, December 2009.
[3] International Telecommunication Union, "Control protocol for multimedia communication," Recommendation H.245, Telecommunication Standardization Sector of ITU, May 2011.
27
![Page 28: H.323 Packet-based multimedia communications systems](https://reader035.vdocuments.us/reader035/viewer/2022081517/56815409550346895dc204a1/html5/thumbnails/28.jpg)
Thanks for Listening
Q&A
28