VioMeeting is designed from the ground up to provide seamless collaboration
over the Internet and private IP networks. Our unique technology base is built
around the concept of real-time sharing of PC-based content (Microsoft
PowerPoint, Microsoft Word, Microsoft Excel, Software Demonstrations, custom
applications, etc.), Voice over IP, and Video. These capabilities are delivered
through a secure, reliable, and firewall friendly infrastructure designed to
easily integrate into any environment.
This paper is designed to describe the technological foundation for the
VioMeeting product offering. Please refer to the links below for information
about a specific aspect of the VioMeeting technology base.
TECHNOLOGY
MEETING MODEL
VIOMEETING COMPONENTS
SERVER LOCATIONS AND
HOSTING
NETWORK MODEL
PRIMARY FEATURES
TECHNOLOGY BASE
PC
Content Sharing
Voice Over
IP
Video
COMPATIBILITY
FIREWALL SUPPORT
VioMeeting was designed to closely simulate a physical meeting that involves
multiple presentations and dynamic interaction among participants during the
meeting. VioMeeting employs the Presenter <-> Viewers model to deliver
its online meeting capabilities. At any particular moment one user is designated as a
Presenter while all other users are designated as Viewers. The Presenter is the
primary source of content during the meeting. He or she sources their PC
desktop, voice, and video to the other users. The Viewers receive the content
that is sourced by the Presenter and interact with the Presenter through text
messaging (chat) or via a parallel telephone conference.
Although there can be only one Presenter in a VioMeeting at any particular moment, the
user who is designated as the presenter can be changed at any time during the
meeting. This allows multiple participants in a meeting to become presenters
and share their content.
VioMeeting also allows secure remote control of a Presenter's computer by one
of the Viewers. With Presenter's approval a Viewer can be designated as a
remote controller. Once designated, all keyboard and mouse input to the
Presenter's computer is sourced over the VioMeeting network from the Viewer
allowing active remote control and enabling remote presentations.
The VioMeeting system is based on three components: Control Servers, Player,
and Meeting Servers:
Control Servers provide the standard, web-based control functionality
available on VioMeeting. These servers host the VioMeeting web site and are
used by clients to authenticate, schedule meetings, join meetings, configure
preferences, etc. These servers also host the custom VioMeeting portals that
are available to clients who wish to customize the look and feel of VioMeeting
for their users. The meeting host or a presenter can share files with other
meeting participants. The files can be copies of the presentation, lecture
notes, associated documents, or any other files that would be useful for the
meeting.
Player provides end-user functionality for VioMeeting. The Player is a
small component that transparently runs on the workstations of all VioMeeting
users. The Player is automatically downloaded and configured when a user starts
a meeting from the VioMeeting site (hosted on the Control Servers) and does not
require any installation. It is responsible for acquiring meeting content (PC,
voice, or video) from meeting presenters and rendering this content for the
meeting viewers. Internally, the player is a small browser plug-in that runs
natively on the end-user's machine. For users with highly restrictive browser
security settings that do not allow plug-ins, the Player can be directly
downloaded via a link on the Support page of the VioMeeting web site.
Meeting Servers provide the network transmission functionality within
VioMeeting. They are directly responsible for transmitting the presentation
content (PC, voice, or video) from the presenter to the viewers. The VioMeeting
player for each meeting participant connects to a Meeting Server. After player
connections Meeting Servers create virtual circuits between the presenter and
each of the viewers. Once the circuits are established, all presenter content
is multiplexed and transmitted to each viewer. Viewer feedback content is
similarly multiplexed through the virtual circuits and transmitted to the
presenter and other viewers. Primary Meeting Servers are located on a major
Internet backbone for maximum network throughput. Secondary meeting servers can
be installed on local client networks to insure optimal network performance.
VioMeeting components described in the section above are designed to support 3
hosting options as described below:
All servers can be hosted at VioWorks facilities. Under this option, the
Control and Meeting servers are located at VioWorks facilities and all content
delivery is performed through the public Internet.
All servers can be located at client facilities. Under this option, Control and
Meeting servers are located in client data centers. Primary content delivery is
performed through the high-speed client network (WAN); unless a meeting
involves an outside party, in which case the public Internet is used to connect
to the outside party.
A hybrid solution where the Control servers are located at VioWorks facilities
while the Meeting servers are located at client facilities. This allows content
delivery to be performed through the high-speed client network (WAN), while
leaving the management complexity associated with Control servers at VioWorks.
VioMeeting depends on a standard IP network for all data transmission. This
makes our technology compatible with both the public Internet and private
networks. All VioMeeting transmissions use either direct TCP or HTTP
transmissions (TCP transmissions are significantly more efficient than HTTP,
but may not be possible in a proxy/firewall environment). When first
establishing a connection from an end-user to a VioMeeting server, the
VioMeeting player running on the end-user's PC, attempts to connect through a
range of standard TCP/IP ports (20, 21, 23, 25, 80, 443). If all TCP/IP
connection attempts are unsuccessful, the player connects through HTTP or HTTPS
using the proxy configuration of the web browser that launched the meeting.
PC Content Sharing is one of the central components of the VioMeeting offering.
Content sharing allows all participants in a meeting to see a view of the
presenter's desktop. Essentially, all meeting participants see what the
presenter sees on his or her desktop in real time. As the presenter makes
changed on his or her screen (e.g.: advances a PowerPoint presentation) all
viewers see the screen changes on their own PCs.
VioMeeting provides PC content sharing at either the Desktop level (where the
presenter's entire desktop is shared) or the Application level (where a single
application window is shared). In both sharing situations, the VioMeeting
operates by replicating the presenter's screen content on the clients'
workstations. The VioMeeting player running on the presenter's workstation
monitors the presenter's screen, detects changes, compresses the changed screen
areas, and transmits the changes through an encrypted channel to all viewers.
The VioMeeting system is optimized on the presenter, distribution, and viewer
levels to insure maximum performance.
Voice over IP functionality allows VioMeeting to deliver voice for meetings and
presentations over standard IP networks such as the Internet or private WANs.
In VioMeeting the presenter's voice is acquired by either through a PC
microphone on his or her computer, or, optionally, through a telephone
connection. Once acquired, the voice signal is digitized and encoded using a
standard G.729 voice encoder and transmitted through VioMeeting virtual
circuits to presentations viewers. All voice transmissions are packetized and
transmitted using an adaptive algorithm to insure minimum end-to-end
transmission delay through each virtual circuit. As a result of human voice
perception studies, voice packets in VioMeeting are given maximum transmission
priority in the infrastructure and arrive at each destination ahead of any
other content transmitted in parallel.
Video support is the newest feature of VioMeeting (this feature is not yet
available, but is due in an upcoming release). Video support is designed to
allow all meeting participants to view presenter video in real-time. Presenter
video is primarily acquired from a camera (or web-cam) connected to the
presenter's PC, but can also be sourced from any video source interfaced to a
PC acquisition card. Once acquired, the video signal is encoded using a variant
of an H.263 algorithm, packetized and transmitted to all viewers through the
VioMeeting virtual circuits.
VioMeeting is currently supported on all Windows platforms starting with
Windows 95. Macintosh and PocketPC support is currently under development and
will be available in the future.
VioMeeting is designed to be firewall friendly and does not require any changes
to the end-user's firewall configuration. Please refer to the
Network Model section for more information on details of network
transmission model used by VioMeeting.
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