H.323 Revisited

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Agenda

• H.323 and related protocols
• Ready for right products
• Design Considerations
• Experiences and Suggestions

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What is H.323?

• A multimedia communication protocol suite
• Includes voice, video, and data conferencing
• For use over packet-switched networks

H.323 is ITU-T Recommendation H.323
Packet-based multimedia communications systems
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Elements of an H.323 System

• Terminals
• Multipoint Control Units (MCUs)
• Gateways
• Gatekeeper
• Border Elements

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H.323 Network Elements
H.323 MCU
H.323 Terminal
H.323 Gatekeeper
H.323 Gateway
H.323 Terminal
H.323 Terminal
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Terminals
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MCUs

• For managing multipoint conferences
• Contains
• Multipoint Controller (MC) - manages the call
  signaling
• Multipoint Processors (MPs) - handle media
  mixing, switching, or other media processing

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Gateways

• Interface H.323 to other networks,
• including the PSTN, H.320 systems, other H.323
  networks (proxy), etc.
• Composed of
• a Media Gateway Controller (MGC)
• a Media Gateway (MG)
• MGC handles
• call signaling , non-media-related functions
• MG handles the media

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Gatekeeper

• Admission control
• Address resolution
• e.g.,Phone number to IP address

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Border Elements

• Exchange addressing information and participate
  in call authorization between administrative
  domains
• Often co-located with a Gatekeeper,

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An H.323 Stack
H.323 Application
RAS
RTP / RTCP
H.245
H.225.0 Call Signaling
Packet-switched Network
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H.323 basic protocols
Gatekeeper
Gatekeeper
Annex G
Q.931/H.245
RAS
RAS
Q.931/ H.245
Q.931/ H.245
Signalling (Q.931)
Endpoint
Endpoint
H.245
RTP/RTCP
Gatekeeper Routed Signaling Direct Routed
Signaling
Source Lior Moscovici
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H.323 related standards

• RTP/RTCP Streaming
• T.120 - Data conferencing
• Audio Codecs G.711, G.722, G.723.1, G.728,
  G.729, GSM
• Video Codecs H.261, H.263, H.264

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Past to Present

• H.323 v.1 was published in 1996
• was designed for LANs

Or was it?
Local Area Network
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Past to Present

• But, it was used in WANs, large private VoIP
  networks, and the Internet
• It worked very well

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Past to Present

• H.323 proved that
• RTP is able to carry real-time audio and video
  over IP networks that span the globe
• Indeed, H.323 was much more than a LAN protocol

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Past To Present

• Recognizing the fact that H.323 was much more
  than a LAN protocol, the name was changed in
  H.323 Version 2 (1998)
• Enhancements were made, including
• Security
• Performance
• Supplementary Services
• Scalability

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Strength in Numbers
Accord Networks Aethra AG Communications Agilent Anatel Aspect Atlantic Avaya Axent Brooktrout Technology CUseeMe Callserve Catapult CheckPoint China Netcom China Telecom China Unicom Cirilium Cisco Systems Clarent Comverse Data Connection Delta Information Systems Dialogic Dialpad E-Tech Canada Ltd. Elemedia Equivalence e-tel eZenia! FVC Genuity HearMe Huawei Hughes Software Systems iBasis IBM Inalp Networks Inari Inc. Innovaphone Intel ISPhone ITXC Ji-Tong Communications Komodo Technology Lotus Lucent Macchina Madge Networks Microsoft Motorola MultiTech Systems Natural MicroSystems NetSpeak WebPhone Netergy Networks Network Associates NexTone Nuera Communications Nx Networks OKI Packetizer Pagoo PictureTel Polycom RADCom RADVision Ridgeway Systems Siemens Smith Micro Sorenson Vision Swyx Symbol Technologies Telxon TINY Teles Trillium Unylogix VCON VegaStream VIVE Technologies VTEL VocalTec WowRing Zydacron
Partial Listing
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The Market Today

• Today, the biggest market for H.323 applications
  is Voice over IP. Why?
• Lack of right video terminals to address
• Low bit-rate Internet connections make video and
  data intensive applications less appealing
• Its a young industry and with all such
  industries, it takes time to mature good products
• Companies can provide VoIP services today at a
  low cost and provide new competition to the
  incumbent carriers

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Video Communication Era

• Future, expect to see video and data
  communication to become more pervasive
• Broadband connectivity is making it possible
• Video and data are logically the next services
  customers expect to find in conference rooms, at
  home and on their computer screens

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Why current H.323 products is not good?

• Unstable Video Quality
• Good over dedicated lines or in demo room
• Deteriorates significantly over Internet
• Difficult to install
• Not easy to use
• Too expensive
• Business model

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Design Considerations

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Networking environment

• Backbone band-width oversupply
• Last-mile bandwidth getting better
• gt 384K bps at lt NT2,000/m
• xDSL, ADSL, VDSL
• Cable
• WLAN / WiMax
• 3G

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IP Network Issues

• Lack of IP addresses
• Dynamic IP
• Virtual IP
• Use of NAT
• Adds difficulties to address resolution
• Firewall
• Blocks media packets
• Make plug play less possible

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Codec Issues

• Standard algorithms
• Implementations
• Computation speed
• Bit rate vs picture quality
• Hardware vs Software
• DSP
• No longer a dominating issue

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Performance bottlenecks

• Not at computation unit (DSP or CPU)
• Systems
• Buffers
• Internal bus
• Memory speed
• Graphics display

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Right prices for right users

• Corporate users
• Large conference room NT1.0M
• Small conference room NT50k NT100k
• Desk top with PC NT3K
• Soho users lt NT50k
• Home users lt NT10k
• Personal users lt NT6k

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Common Requirements

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Common requirements

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Suggested HW architecture

• HW
• P4 for corporate and soho users
• SOC DSP RSIC
• for home and personal/mobile users
• Camera
• VGA resolution at 30 fps
• High-end webcam is good enough
• Display
• VGA monitor vs TV
• Speaker and Microphone
• Headphone is uncomfortable
• Conference phone is a good choice
• Full duplex and echo cancellation

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Suggested SW Architecture

• Embedded Linux
• Spport P4 RISC platforms
• Complete TCP/IP stack
• Embedded Windows and GUI
• Small but rich
• Interoperable vs compatible
• Standard H.323
• Optimized implementation

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Data Conference

• Work with PC / MS Windows
• RDP
• Graphical terminal
• Network Neighbor Samba
• Network file system
• Multi-point screen sync
• T.120
• H.323 whiteboard standard

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More than Data Conference

• Distance Collaboration
• Run programs
• Co-design
• Life demonstrations
• Scratch paper notepad
• etc

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Results

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• More than a H.323 system
• At an affordable price

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Product Varieties

• Stand-alone
• Embedded in LCD monitor/HDTV
• Embedded in xDSL
• Built-in PDA/PPC/PMP/DSC
• Must have in mobile phone

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Remarks

• Internet is ready for video communication
• H.323 is a valid protocol, SIP simplifies call
  setup
• Multimedia communication with Voice, video, text,
  graphics, 3D,
• Design issues are on the system integration, HW
  and SW
• Embedded in various products