WORKSTATION-BASED VTC AND WHITEBOARD FOR DEPLOYMENT
OVER THE DSI AND GCCS LES
DRAFT - DECEMBER 30, 1994
THE MITRE CORPORATION
AUTHORS:
Christopher O'Donnell
Charles King
Alok Nigam
Elden George - Space Applications Corporation
EXECUTIVE SUMMARY
By request of the Advanced Information Technology Services Joint Program
Office (AITS-JPO), MITRE conducted a review of available desktop commercial
off-the-shelf (COTS) products that support collaborative computing (shared
whiteboards and desktop video teleconferencing (VTC)) over packet networks.
The primary review criteria were interoperability between products, support
of standards-based VTC, and availability on UNIX platforms. MITRE also conducted
demonstrations of UNIX-based VTC capabilities to AITS-JPO representatives.
Communications support for video teleconferencing requires the following
three characteristics: (1) guaranteed throughput to ensure integrity of
motion video and intelligible audio; (2) fast data forwarding to assure
minimum latency (the time from video capture to video display); and (3)
multiple data streams to permit more than one simultaneous VTC.
Our research indicated that the use of real-time face-to-face video over
local area networks (LANs) will remain an immature technology for at least
the next two years. Some technologists suggest that this technology will
not mature until around the year 2000. Reasons for this immaturity include
both standards issues and network technology limitations. These issues suggest
that interoperability between different manufacturers' products will not
be achievable in the near term, and thus, users must deploy proprietary
products, and expect to upgrade to an interoperable standards-based capability
in the future.
Only one packet-network COTS VTC product was identified during this review
that offers standards-based (H.261) desktop VTC on UNIX platforms. There
was limited availability of standards-based desktop VTC on personal computers
(PCs) over packet networks. As discussed in this report, there are some
VTC products that have implemented a portion of the H.320 international
standard that provide compressed video and audio over LANs using Internet
Protocols without use of special interface units. However, these implementations
still provide VTC only among users of a single manufacturer's products,
with no interoperability to other vendors' products.
Based on our evaluation criteria, the leading COTS product for UNIX-based
desktop VTC is InSoftõs Communique, which supports a proprietary
approach to VTC over packet networks. This product was evaluated in MITREõs
labs. VTC was conducted between two workstations at data rates that varied
between 800 kilobits per second (Kbps), supporting a frame rate of 27 frames
per second, to 150 Kbps, supporting a frame rate of approximately 4 frames
per second. Insoft has indicated their intent to move to standards-based
VTC once formatting standards for communication packets have been ratified
by the International Telecommunications Union (ITU) committee.
The InSoft product offers a capability for near-term support of collaborative
computing (video, whiteboard, and sharing of applications). However, the
user acceptance of the current product, using its proprietary capability
at a throttled speed, is uncertain. Lost or delayed communication packets
must be disregarded, video may freeze, and short phrases of audio may be
lost. In addition, product robustness and interoperability issues identified
by current users have not been resolved. For this reason, it is recommended
that tests be conducted using InSoftõs Communique product in a user
environment between two or more DSI nodes. If the DSI tests are satisfactory,
a limited initial deployment is suggested with user acceptance to drive
expanded use.