H.323 - Multimedia over IP Technology Overview (VoIP).ppt

Voz sobre ip

1. H.323 -Multimedia over IP
Technology Overview

2. H.323 Overview
2
What is H.323?
LAN
ATM
ISD
N
P
OT
S
An ITU standard for interoperability:
•Works over existing infrastructures
(LAN/WAN, Internet, ISDN, POTS)
Can be deployed wherever IP is used:
•Ethernet, Token Ring, FDDI,
Frame Relay (RFC1490), ATM etc
Supports Multimedia Applications:
•Data (and data conferencing)
•Audio (typically packetised speech)
•Video

3. H.323 Overview
3
H.323 Network Components
H.323
Endpoint
H.323
Gatekeeper
H.323
Endpoint
H.323
MCU
H.323
Gateway
Switched Circuit
Network(s)
H.320
Endpoint
H.324
Endpoint
Analogue
Telephone
ISDN
POTS
POTS

4. H.323 Overview
4
The H.323 Endpoint
H.323
Endpoint
H.323
Endpoint
H.323 Mandatory Requirements:
•G.711(PCM audio codec, 64Kbps)
•H.245(for identifying and controlling media exchanges, such as
voice and video)
•Q.931(a signaling protocol for establishing and releasing
connections)
•Registration/Admission/Status (RAS) ChannelA data stream used
to communicate with a Gatekeeper (RAS only needed if a
Gatekeeper exists within the endpoint zone)
•Real-Time Protocol/ Real-Time Control Protocol (RTP/RTCP)
IETF application level protocol for transporting real-time
media on IP networks

5. H.323 Overview
5
ITU Recommendations -H.32X
H.320 H.321 H.322 H.323v1
H323v2
H.324
Network Narrowband
ISDN
Broadband
ISDN/ATM
Guaranteed
B/W
Non-
Guaranteed
B/W
PSTN/POTS
Approval 1990 1995 1995 1996/1998v21996
Audio G.711
G.722
G.728
G.711
G.722
G.728
G.711
G.722
G.728
G.711
G.722
G.728
G.723.1
G.729, 729A
G.723
Video H.261
H.263
H.261
H.263
H.261
H.263
H.261
H.263
H.261
H.263
Data T.120 T.120 T.120 T.120 T.120
Control H.230
H.243
H.242 H.230
H.242
H.245 H.245

6. H.323 Overview
6
H.323 Environment
Gateway
Gatekeeper
H.323
Terminal
Multipoint
Control
Unit

7. H.323 Overview
7
H.323 Terminals (Endpoints)
•Audio
•Video
•Data
•Control

8. H.323 Overview
8
Gateway Functions
PSTN Intranet/Extranet
P
B
X
•Portal between Switched Circuit Network (e.g.
PSTN) and Intranet/Extranet
Gateway

9. H.323 Overview
9
Gatekeeper Functions
•May perform call control functions
for terminals/gateways in an area/zone
Gateway
Gatekeeper
MCU

10. H.323 Overview
10
H.323 Protocol Stack
T.12X
RAS
Q.931
H.245
TCP
IP
G.723.1
G.729
G.729A
H.261
H.263
LAN
UDP
RTP/
RTCP
RTP/
RTCP
ControlAudioVideoData

11. H.323 Overview
11
H.323 Call Procedures
Audio/
Video
Codecs
Packet
Processing
RTP/
RTCP
Audio/Video Streams Module
U
D
P
I
P
T
C
P
RAS (if GK present)
Call Signaling -Q.931 (if GK present)
Control Channel -H.245
System Control Unit

12. H.323 Overview
12
RAS
RAS
•Registration, Admission, and Status
Endpoint Gatekeeper

13. H.323 Overview
13
RAS Support -
With and Without GK
VANGUARD34
H.323
6400 Gateway
PSTN
With
Gatekeeper
RASRAS
VANGUARD34
H.323
6400 Gateway
PSTN
Without
Gatekeeper
No RASNo RAS

14. H.323 Overview
14
Call Signaling Channel -Q.931
RAS
Call Signaling

15. H.323 Overview
15
Q.931 Call Signaling -
With GK
VANGUARD34
H.323
6400 Gateway
PSTN
With
Gatekeeper
RAS
RAS
1 1
2
Call Signaling

16. H.323 Overview
16
Q.931 Call Signaling -
Without GK
VANGUARD34
H.323
6400 Gateway
PSTN
Without
Gatekeeper
Call Signaling

17. H.323 Overview
17
Basic Call Setup (Direct Endpoint)
VANGUARD34
H.323
Setup
Call Proceeding
Alerting
Connect
Call Signaling
Q.931

18. H.323 Overview
18
Basic Call Setup
With Gatekeeper
VANGUARD34
Setup
Call Proceeding
Alerting
Connect
ARQ
ACF
ARQ
ACF
RAS
RAS
Call Signaling
Gatekeeper
Q.931

19. H.323 Overview
19
Basic Call Setup
With Gatekeeper
VANGUARD34
Setup
Call Proceeding
Alerting
Connect
ARQ
ACF
ARQ
ACF
RAS
RAS
Call Signaling
Setup
Call Proceeding
Alerting
Connect
Gatekeeper
Q.931

20. H.323 Overview
20
H.245 Control Channel
RAS
CallSignaling
Control Channel

21. H.323 Overview
21
H.245 Control Channel
With GK
VANGUARD34
H.323
6400 Gateway
PSTN
Gatekeeper
RAS
RAS
1 1
2
Control Channel

22. H.323 Overview
22
H.245 Control Channel
Without GK
VANGUARD34
H.323
6400 Gateway
PSTN
Without
Gatekeeper
Control Channel

23. H.323 Overview
23
Audio
G.723.1/G.729

24. H.323 Overview
24
Video
H.261/H.263

25. H.323 Overview
25
T.120 Data Conferencing
•Provides support for real-time multipoint data
communications
Shared Whiteboarding
File Transfer

26. H.323 Overview
26
Audio and Video Synchronization
•RTP and RTCP
+

27. H.323 Overview
27
Quality of Service (QOS)
Say again, you’re
breaking up…..

28. H.323 Overview
28
Resource Reservation Protocol (RSVP)
RSVP request
level of service
Router
Router with reserved
capacity for RSVP flow
•Bandwidth reservation done on a link-by-link basis
•All routers in path must support RSVP
•Problems of scalability

29. H.323 Overview
29
Differentiated Services
•Traffic forwarding priority determined by IPv4 TOS bits
(6 bits used as Differentiated Service bits)
•TOS set at edge of the network
•Transit nodes interrogate TOS and forward packets
accordingly

30. H.323 Overview
30
Multipoint Control Unit (MCU)
•Facilitates Desktop Conferencing
Can y’all
hear me?
MCU

31. H.323 Overview
31
Multipoint Control Unit
Can y’all
hear me?
MCU
M
C
M
P

32. H.323 Overview
32
Centralized Conferencing
Can y’all
hear me?
Conference Control
Audio/Video Streams
Unicast
MCU

33. H.323 Overview
33
Decentralized Conferencing
Can y’all
hear me?
Conference Control
Unicast
Audio/Video Streams
Multicast
MCU

34. H.323 Overview
34
H.323 version 2
•Address deficiencies in version 1
•Adds functionality to existing protocols
–Security
–Fast call setup
–Supplemental services
–Clarifies T.120/H.323 integration
–and more…..

35. H.323 Overview
35
ETSI PROJECTTIPHON
Telecommunications and Internet
Protocol Harmonization over Networks

36. H.323 Overview
36
WWW Background Resources
•www.data.com/Tutorials/Multimedia_Over_IP
•www.data.com/roundups/decision
•www.data.com/roundups/ip_telephony
•www.data.com/roundups/rsvp
•www.databeam.com/h323/h323primer
•www.databeam.com/ccts/t120primer
•www.pcwebopedia.com/Internet_telephony