VCON | Cruiser | H.323: Technical Specifications

H.323: Technical Specifications
H.323: The emerging TCP/IP
Videoconferencing Solution
The intent of this document is threefold. First a brief overview of the International Technology
Union (ITU) H.323 standard will be addressed. Following the overview, an enumeration of
products (both hardware and software solutions) supporting the H.323 standard will be listed.
Finally, a comparison of a number of H.323 products listing features, advantages and
disadvantages will be presented as derived from objective studies and reviews reported via the
Internet. Appropriate citations and URL references will be provided throughout the document
and at the conclusion of the report. An overview of the H.323 standard will now follow.
H.323 Standard Overview
The following information was derived from DataBeams H.323 Developer s Toolkit web site. It
can be found at: DataBeam begins their Primer
by saying:
The H.323 standard provides a foundation for audio, video, and data communications
across IP-based networks, including the Internet. By complying to H.323, multimedia
products and applications from multiple vendors can interoperate, allowing users to
communicate without concern for compatibility.
In other words, a standardized agreed upon set of protocols, codecs, and network bandwidth
management tools have been developed which when implemented according to the specifications
outlined, should allow desktop video/audio conferencing and application collaboration between
different applications via the Internet or a TCP/IP Local Area Network (LAN). With the
increasing speed, specialized chip instruction sets and multimedia capabilities of computers,
Desktop video conferencing (DVC) is now becoming a possible alternative to expensive, high
bandwith, switched digital telephoney networks. Prior to the emergence of the ITU H.323
standard, TCP/IP multimedia conferencing was severely limited in fidelity and interoperability
between software platforms.
By its very nature, the IP (Internet Protocol) standard sends information in packets over the
Internet, which are then transmitted and reassembled for the end user. When sending control
commands or data, lossless transmission is needed over the IP packet network. Transmission
control protocol (TCP) runs atop the IP network guaranteeing that the data packets are lossless,
arriving error free and in their proper sequence. Hence the connotation TCP/IP. A drawback to
this TCP protocol is that transmissions may be delayed to ensure accuracy. Thus TCP/IP or LAN
networks may induce latency effects. This standard, while good for data transmission is bad for
sending continuous video or audio data streams over the Internet.
To allow more contiguous flow of audio and video data over IP networks a lossy, unreliable
(versus reliable TCP) protocol has been developed called User Datagram Protocol. Under the
H.323 standard the IP stack uses the unreliable User Datagram Protocol for audio and video
that promises nothing more than best effort delivery . This means that video and audio will
be transmitted with possible gaps in the data stream (creating possible jumps or delayed video
with audio that may briefly drop out or modulate). The quality of DVC depends on the size of
the network pipline, the speed of the network, the current load on the network, and the speed and
efficiency of the desktop terminal. Within the networking community the H.323 standard then
does not provide a guaranteed Quality of Service (QoS). While this may sound less than perfect,
the advantage is that networks can now support DVC without changing the current network
In essence the H.323 standard is comprised of several protocol standards. The audio codec that
compresses and decompresses the transmission of audio is G.711. Several other audio codecs are
supported in H.323 dependent on network traffic; some like G.723 which transfer audio at bit
rates lower than 56 kbs (preferred for <56K connectivity). For a more indepth description of
audio codecs as a function of connectivity or quality transmission refer to Intel’s description at:
The video codec for the H.323 standard is H.263. This video codec ensures that video will not be
transmitted higher then determined via the capability exchange between endpoints (terminals).
Thus the video is sent at the rate of the slowest link in the chain. Finally, all data that is shared
between H.323 conference collaborators (whiteboard, shared and collaborative applications, file
transfer, etc.) meet the T.120 standard which uses the reliable, lossless method of transmission
discussed above. See the imamge above for a pictorial representation of H.323 codecs.
A breakdown of the multimedia component that fall within the H.323 protocol will next be
Network Components:
The H.323 network in comprised of four major components: Terminals, Gateways, Gatekeepers,
and Multipoint Control Units. A brief definition of each will follow. For a more detailed
overview with supporting graphics please refer to the URL cited at the beginning of the report.
Terminals are the client endpoints on the LAN that provide real-time, two-way
communications. All terminals must support voice communications; video and data are
The Gateway is an optional element in an H.323 conference. Gateways provide many services,
the most common being a translation function between H.323 conferencing endpoints and other
terminal types. Gateways are required if connections to other networks are needed. In addition,
the Gateway also translates between audio and video codecs and performs call setup and clearing
on both the LAN side and the switched-circuit network side. Basically, gateways allow different
types of networks (ISDN, LAN, PSTN, etc.) to communicate via multimedia conferencing
A Gatekeeper is the most important component of an H.323 enabled network. It acts as the
central point for all calls within its zone and provides call control services to registered
endpoints. In many ways, an H.323 gatekeeper acts as a virtual switch. One important function
of the Gatekeeper concerns the function of bandwidth management. A network manager can use
the Gatekeeper component of the H.323 network to control in advance the number of
simultaneous users conferencing over the network. This control allows the manager to keep the
network from becoming clogged or delayed due to the transmission of excessive audio and video
conferencing data. Finally, Gatekeepers may also
The Multipoint Control Unit (MCU) supports conferences between three or more endpoints.
Under H.323, an MCU consists of a Multipoint Controller (MC), which is required, and zero or
more Multipoint Processors (MP). The MC handles H.245 negotiations between all terminals to
determine common capabilities for audio and video processing. The MC also controls conference
resources by determining which, if any, of the audio and video streams will be multicast. Thus
"MCU s provide a more powerful and flexible architecture for hosting multipoint conferences."
With a brief overview of the H.323 network, a look at the different software and hardware
technologies utilizing the H.323 standard will now be addressed.
A special note from Intel (
dealing with deployment difficulties of H.323 network should close out the discussion on this
H.323 Deployment Obstacles
In order to achieve H.323 deployment in real networks, limitations at both the network
level and the client platform level must be resolved at the H.323 client. The client should
scale performance based on the available bandwidth. Given the inconsistencies of
networks with best effort traffic, (i.e., no guaranteed Quality of Sevice (QoS), the
Internet), it is extremely important to provide mechanisms for fault tolerance and error
resiliency at the client platform, if it is to be used on an unmanaged network such as the
Internet. At the network level, broad connectivity, policy management, and security are
considered the major issues in the deployment of a new technology such as H.323.
Switched Circuit Network connectivity is achieved in the H.323 context by using
gateways for H.320, H.324, H.323, POTS, and other endpoints on other networks. Policy
management is achieved using gatekeepers to provide call admission, authentication, and
zone management. Deployment of QoS protocols such as RSVP can also help with policy
management. The security of media streams is another important factor in the success of
H.323 deployment, especially in unsecured environments such as the Internet.
H.323 Software and Hardware Solutions
The Intel system displayed above is a single card solution which requires at least a 233 MHz
Intel Pentium II processor (optimal performance requires a 400 MHz or higher Intel Pentium II).
The system requires at least 49 MB RAM (64 MB recommneded) and one available PCI slot and
one IRQ for the ISDN/audio/video capture card. The computer must also have an adequate video
graphics card (preferable settings at 16 bit depth with 800X600 resolution). Higher settings may
cause Intel’s Proshare card to lag (complete description of graphic card compatibility can be
found at: Also Netmeeting 3.0
cannot be installed on the system if the ProShare card/software is installed.
The Intel Proshare system above includes:
Single PCI ISDN/aduio/video capture card
Headset with microphone
Composite color video camera
Boom microphone
Color-coded connectors and cables
Language installation options: English, French, German, Italian, or Spanish
Quick Install Guide
Cost: anywhere from $660 to $700 (discount applies to purchases of two or more). Retail price
for ProShare 500 is $799
Online Review
Online ZD Net review:,4161,368084,00.html
Video Improves its image:,4153,372437,00.html
Product Description:
The Sorsenson system displayed above is a single card solution which requires at least a P90 or
faster processor. The system requires only 16 MB RAM (32 MB recommneded) and one
available PCI slot and one IRQ for the ISDN/audio/video capture card. The computer must also
have an adequate video graphics card (preferable settings at 16 bit depth with 800X600
resolution). Sorenson EnVision claims they are able to create good quality video (15 fps) over
low bandwidth connections (56 K modem).
The Sorenson EnVision system above includes:
NTSC camera with video cable
PCI card with audio/video processors
H.323 desktop video conferencing software CD
Audio headset with microphone and earphone
Stand-alone microphone
Jumper cable for use with existing sound cards, microphones and speakers
Collaboration software compatible with Microsoft’s NetMeeting
Full Installation Guide
Cost: anywhere from $799 to 899 (depending on it you order kit with higer price camera).
Online Review
Sorenson Video Codec-Articles and Magazine Reviews
Product Description:
The PictureTel system displayed above is a single card solution which requires at least a Pentium
133 (or higher) processor. The system requires a minimum of 32MB and one available PCI slot.
The computer must also have a PCI video graphics card with a least 2 MB VRAM (4 preferred).
The LiveManager & LiveGateway components are interoperability and mulitipoint connectivity
products that Virginia Tech already has a working solution for. The product described below
refers only to the LiveLan desktop system.
The PictureTel LiveLan 3.1 system above includes:
• PCI Video/Audio codec board
• Color composite camera
• Multimedia speakers, microphone, and headset for privacy
• LiveLAN videoconferencing software on CD-ROM including T.120 data collaboration
• Online documentation
• Optional FlipCam (cost an additional $950, allowing manual control of zoom, pan, 90o Tilt)
Cost: anywhere from $1,195 to $2,145 (depending on if you order kit with higher price camera).
Online Review
TechWeb-Network Computing:
Corporate.Net -H.323: Videoconferencing Approaches The Millennium
(great article comparing PictureTel to NetMeeting 2.0 to Intel BVS to CuSeeMe (Meeting Point)
Product Description:
The VCON Cruiser 150 system is a single card solution which requires at least a Pentium 200 (or
higher) processor. The system requires a minimum of 64MB and one available PCI slot. The
computer must also have a PCI video graphics card with a least 2 MB of video ram. The 150
system has the capability of connecting an ISDN line to the system to contact those outside of an
IP system. The lower scalable card, the Escort 25 Pro, is for network connectivity only and does
not have an additional ISDN slot.
The VCON Curiser 150/Escort 25 Pro system above includes:
PCI Video/Audio codec board
ISDN Cable/Port (only Cruiser 150 system)
Audio Ca ble to Sound Card
Installation Guide
Desktop software
Cost: Escort 25 PRO: $899 retail/no outside ISDN connectivity possible
Aramada Cruiser 150: $1,495 (allows 30 frames per second quality)
Online Review
Computer Telephony’s "People’s Choice Award for H.323 Client" was awarded to the Escort 25
desktop videoconferencing system and was presented to VCON at the DVC’98 Fall Conference
& Exhibition in Boston, MA, in October 1998.
"The Cruiser 75 is a real business solution for companies that need a consolidated, consistent
way to provide videoconferencing. The product’s $995 per user price tag is high, but if high
quality video is what your company needs, the Cruiser is a good solution."
PC Today, September 1998
"You can slap the [VCON] Cruiser 150 on those133MHz Pentiums you installed for your
customers last year, but you’ll have to purchase a recommended big and beefy 400 MHz Pentium
machine for the ProShare. Both products are excellent but the Cruiser 150’s support for adding
an extra camera and third-party board for higher bandwidth, as well as support for Windows 98,
offers the reseller excellent opportunities for value-add. That’s why the VCON Cruiser 150 is a
Sm@rt choice." SM@RT RESELLER, November 2, 1998
"VCON’s units show between 15 and 30 frames a second, 30 frames being equivalent to the
speed of television images. The dominant players .provide products that are more expensive
and offer fewer frames a second than VCON."
Dow Jones News Services, November 17, 1998
Regarding VCON’s interoperability and support for Cisco IP/TV clients, Jack Bradley, General
Manager - Video Internet Services Unit, Cisco Systems comments, "Cisco is excited about
VCON’s support of multicast technology and the ease with which Cisco IP/TV can be integrated
for a total video solution. We believe customers are requiring a mixture of streaming video,
video-on-demand, and interactive videoconferencing. VCON’s interactive multicast combines
the reach and low-cost benefits associated with multicasted video with the personal interactivity
of videoconferencing".
April 1999
Product Description:
The VTEL 128 Smart Station is a single card solution which requires at least a Pentium
processor. The system requires a minimum of 32MB hard disk space and one available PCI slot.
The computer must also have a PCI video graphics card with a least 2 MB of video ram and 16
MB of SDRAM. The Smart Station has the capability of connecting an ISDN line to the system
to contact those outside of an IP system and can support up to 800X600 resoultion full screen
video. A listing of PC specifications can be found at:
The VTEL Smart Station above includes:
PCI Video/Audio codec board
Fixed Camera with built in microphone
Pan/Tilt/Zoom Camera (add an additional $2,000 to price)
Desktop Software
Cost: $2,995 retail with fixed camera; $4,995.00 with Pan/Tilt/Zoom camera.
The 384 bandwidth series supports a higher encoding frame rate and cost $5495 with
fixed camera and $7495 retail with Pan/Tilt/Zoom camera.
Online Review
Comparison of Intel Business Systems, PictureTel and VTEL specifications as reported from VTEL:
RadVision H.323 Products
Radvision sells several scaleable and stackable hardware solutions for creating H.323 networks.
RADVision builds the following H.323 hardware components: Gateway, H.323 IP adapter and
Multipoint Control Unit. The contact information for RADVision US is:
Dan Acquafredda
Office: 201-529-4300 X227
CellPhone: 201-642-0829
RadVision is sold through Cisco Systems which may qualify VT for a discount should they already have an existing
purchasing agreement. Cisco calls the RADVision unit, unit number 3510. Dan Acquadredda said the closest
competing product is a software solution: Meeting Point running atop a Sun Spark Server (which also cost $30,000
just for the Spark machine). The MCU from RADVision is a hardware solution that is run off a stand alone RISC
processor and cost $19,000 list for the15 port scalablecomponent shown below.
Multipoint Control Unit:
The RADVision’s MCU-323 was designed as a unique solution to
allow users to spontaneously initiate voice-only or full multimedia
multipoint conferences. It runs unattended there is no need to
configure conferences in advance (as is the case in the traditional
model of scheduled resource usage utilized by H.320 based
systems). A user can simply dial a number and the MCU-323 will
automatically set up the conference anyone else who dials that
number can join the conference. The MCU-323 will also allow
users to "invite" others to join the conference in a similar fashion
to the way some telephones now allow users to set up their own
conference calls without an operator.
Online Reviews/NEWS:
• November 2, 1999 - Tandberg Chooses RADVision Technology to Provide its Customers
with a Complete H.323 Videoconferencing Solution
• October 25, 1999 - Cisco To Integrate RADVision Networking Products Into New
IP/VCTM Product Family for Internet-Based Videoconferencing
• Intelect Leverages RADVision’s H.323 Enabling Software for its Full-Motion Video
• Technology Today: RADVision Featured Guest-H.323 Product Review
• MultiPoint Control Unit (listing of hardware, software choices)
RADVision MCU Features
Modular and Stackable:
• Each unit supports up to 15 simultaneous multimedia calls or up to 24 voice-only calls
• Multiple MCUs may be used to transparently increase the number of concurrent
conferences . MCUs may be centralized or distributed.
• Cascading of units provides a solution for very large conferences, conference panels
with many remote viewers, and joining remote groups of participants to a conference
through narrow communication channels. MCUs may be centralized or distributed.
Bandwidth Support:
• A wide range of call bandwidths starting from 64Kbps (for voice-only calls),
128Kbps and up to 1.5Mbps (for multimedia calls).
Web Interface:
Enables easy conference monitoring
Chair control including disconnecting parties and locking video streams
Spontaneous invitation of new participants during ongoing conferences
Data collaboration initiation
• Optional password protection for conference to ensure privacy
• Each unit is password protected
Call Control:
• Built-in gatekeeper
• Robust design based on RISC architecture to ensure high reliability
• Designed to meet rigorous requirements needed for network infrastructure products
Call Control: Optional built-in GateKeeper.
Easy Installation, Configuration, and Management:
• SNMP-based administration and configuration utility
• Remote configuration via the LAN port
• Field software upgradable
• Built-in Test CPU, peripherals and memories are tested at "Power On"
• Front panel LED indications
Optional Gatekeeper:
• RADVision’s Windows NT-based NGK-100 H.323 Version 2-compliant Gatekeeper
application supports 300 registrations and 60 concurrent calls.
LAN Interface: 10BaseT - IEEE 802-3 Ethernet port
Terminal Port: RS232, 9-pin D-type, DCE
Protocols: H.323, H.225, H.245, RTP/RTCP
Video coding: H.261, QCIF/CIF.
Audio Coding: G.711, A/ Law
Panel LEDs: Power, Test, Link, Session, CPU Load
Dimensions: 43.2cm x 35.0cm x 4.3cm
Power Supply: 100-240VAC auto sense, 50/60Hz
Product Description:
DC-Share is for UNIX platforms and is the first T.120 and H.323 data, audio and video
conferencing product compatible with Microsoft’s NetMeeting. UNIX users may now
participate in conferences over the Internet and intranets with Windows 95, 98 and NT users
running NetMeeting and across Sun, SGI and HP unix platforms. Data Connection also allows
users running other T.120 / H.323 compliant products from companies such as Netopia and
PictureTel to collaborate. For example, Macintosh users using Netopia’s Timbuktu Pro
(T.120/T.128 application sharing compliant) may now share applications and audio conference
with Windows systems running NetMeeting and Unix systems running DC-Share softare.
• NetMeeting 3.0
• White Pine ClassPoint/Meeting Point
• DC Share-Sun, Unix and NT desktop confernecing solution from Data Connection.
• Timpuktu Pro (mac/windows collaborative tool) from Netopia.
(Not all have been addressed at this point in the generation of this report)
H.323 Primer
Making H.323-To-H.320 Connections with Two Videoconferencing Solutions
Visual Connections Computer Corporation
H.323 RadVision
Desktop Video Communications: H.323 Desktop Videoconferencing Clients
Internet.Com: Webopedia-H.323
TechWeb: Network Computing-Corporate.Net H.323: Videoconferencing approaches the
H.323 solutions for Sun, Unix and NT
Fundamental of Desktop Videconferencing: Seminar
Intel Business Video Products (desktop/room)
Intel H.323 Overview: Considerations for Deployment
Tech Papers
Simplicity H.323 1.0
Sorenson Envision:
Picuture Tel-LiveLan
The Problem of getting H.323 Safely through Firewalls
Intel White Paper on H.323
Data Connection Share for Unix
Sun SunForum 3.0 (unix collaboration tool):
Silicon Graphics SGIMeeting 1.1
Timbukto Pro (for windows)
Timbukto Pro(for macintosh)
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