The document proposes a phased approach for ESnet to support expanded video conferencing capabilities across the Energy Research community. Phase I involves establishing a centralized management structure and migrating from the existing pilot program to an architecture using ISDN and dynamic bandwidth allocation to interconnect sites. This will improve efficiency and flexibility over the current fixed bandwidth approach. Future phases may incorporate emerging technologies like cell switching and packet video.

1. Report of the Task Force
for
ESnet Support of Video Conferencing
Greg Chartrand
Superconducting Super Collider Laboratory
Steve Elbert
Ames Laboratory
Jim Leighton
Lawrence Livermore National Laboratory
Bill Lidinsky
Fermi National Laboratory
Stu Loken
Lawrence Berkeley Laboratory
October 17, 1992

2. Illustrations ................................................................................................................................................................. ii
Introduction................................................................................................................................................................. 1
A Vision of the Future ...................................................................................................................................... 1
Figure 1......................................................................................................................................................................... 1
Video Conferencing Time/Cost Continuum.......................................................................................................... 1
Technical Video Coordination Group............................................................................................................2
Technical Implementations........................................................................................................................................3
Phase 0 .......................................................................................................................................................................... 3
ESnet Video Conferencing Pilot Project......................................................................................................... 3
Figure 2......................................................................................................................................................................... 3
Initial Pilot Project Configuration............................................................................................................................. 3
Figure 3......................................................................................................................................................................... 4
Current Video Conferencing Network (Expanded Pilot Project) ........................................................................4
Current Video Network Implementation...................................................................................................... 4
Figure 4 Video teleconferencing system in use at the SSCL ................................................................................5
Phase I...........................................................................................................................................................................6
Architecture........................................................................................................................................................6
ISDN For Video Conferencing ................................................................................................................6
Figure 5 Proposed ESnet Video Conferencing Architecture................................................................................7
Management and Operations.......................................................................................................................... 7
Personnel ....................................................................................................................................................8
Facilities ...................................................................................................................................................... 8
Coordination of Transmission Facilities ................................................................................................8
Video Branch Exchange Coordination...................................................................................................8
Reservations...............................................................................................................................................8
Consultation and Training.......................................................................................................................8
Interoperability: Video Systems and Networks...........................................................................................9
Codec's ........................................................................................................................................................9
Speed...........................................................................................................................................................9
Interoperability With Other Video Networks.......................................................................................9
Phase 2 ......................................................................................................................................................................... 10
Future Evolution............................................................................................................................................... 10
Cell Switching Transport for Digital Video .......................................................................................... 10
Packet Video and Desktop Multimedia Conferences ......................................................................... 10
Summary ..................................................................................................................................................................... 11
ii

3. Appendix A: Standards............................................................................................................................................ 12
iii

4. Illustrations
Figure 1, Video Conferencing Time/Cost Continuum ......................................................................................... 1
Figure 2, Initial Pilot Project Configuration ............................................................................................................4
Figure 3, Current Video Conferencing Network (Expanded Pilot Project)........................................................5
Figure 4, Video teleconferencing system in use at the SSCL ................................................................................6
Figure 5, Proposed ESnet Video Conferencing Architecture................................................................................7
iv

5. Report of the Task Force
for
ESnet Support of Video Conferencing
Introduction
Energy Research (ER) and the broader scientific community have made extensive use of electronic
communication through computer networking for over a decade. Now a new dimension, video
conferencing, has been added to the standard electronic communications repertoire. Technological
advances in video conferencing have made it economically feasible, and the growing size and dispersion of
scientific activities will almost certainly make it a necessity in the future conduct and management of large
projects and programs.
In the spring of 1992, a task force was assembled to look at defining a means by which ESnet could provide
support for the provision and operation of video conferencing across all Energy Research programs.
This report defines a general direction for the use of video conferencing to support ER-funded science
projects and associated Principal Investigators in improving program management and meeting scientific
needs. Topics addressed include the current status of video conferencing within ER, technical and
managerial issues, and a proposal designed to effect tightly coordinated, phased implementation of video
conferencing capability throughout the ER community.
A Vision of the Future
The trend in video conferencing is toward simplification. This trend has been fostered and sustained by
technological advances in the field, decreasing costs of video conferencing equipment, and the simultaneous
decrease of communications costs. (Fig. 1.0)
Conference Room
Conference Environment
Meeting
Today Office
S Video Workstation Environment
Emerging • •
Videophone
• • Home
Environment
Videophone
Time
Figure 1
Video Conferencing Time/Cost Continuum
Early video conferencing was based on large, expensive, studio-quality systems. The norm was one large
video conference room per institution with substantial advance notice required to schedule conferences.
The medium was reserved for important occasions attracting large audiences and was rarely available to
anyone other than top management.
The video conferencing systems of today can be, and therefore should be encouraged to be, housed in multi-
purpose meeting rooms for more common use and increased productivity as well as staff capability.
Systems are substantially less expensive and lead time required for scheduling has been reduced, primarily
because the resources are more common. The medium is available to a broader range of users for a wider
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6. Report of the Task Force
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ESnet Support of Video Conferencing
variety of purposes. Now, it is not unusual for a handful of scientists and researchers to conduct a working
meeting lasting several hours.
The development of office-based video conferencing will be the next logical step in this trend, making it
available to personnel at many levels, with instant access for two-person conferences and only modest
reservation and set-up time required for larger sessions. The combination of video conferencing and
windowing capability could allow two or more researchers to make contact quickly and easily, see one
another on workstation monitors in real time video, electronically share other relevant data, files, etc. and
even jointly work on and modify documents, engineering designs, spreadsheets, and other work related
products.
Planning that takes into account the following points should make it possible for the ER community to take
full advantage of opportunities provided by this technology during the coming decade.
• Cost-Effectiveness: Cost-effective choices in the design and implementation of the ER video
conferencing system will encourage extending it to productive everyday use among the
greatest number of workers.
• Leading Edge Technology: The trend in video conferencing technology has been a coincidence of
decreasing cost and expanding functionality. Incorporating leading edge technology into
developing ER video conferencing systems is deemed to be the most cost-effective approach.
• Access: Encouraging increased access by minimizing and eventually eliminating reservation
lead time is essential to providing maximum benefits to researchers and other ER
users/workers.
• Availability: Every effort should be made to continue expanding the number of people with
access to this important tool. (Through broader deployment and/or coordination on an ER-
wide basis.)
• Production-level Support: The quality of support will have a material effect on user interest in
the medium (a system cannot be cost-effective if no one is willing to use it). Production
support should include minimum mean time to failure (MTTF), mean time to repair (MTTR),
and a central point of contact for reservations, configuration, problem solving, and consulting.
Technical Video Coordination Group
Overall direction and coordination of ER video conferencing planning and activities will be required. A
Technical Video Coordination Group (TVCG) is proposed for this function. It will be a high-level group,
reporting directly to the ESnet Steering Committee (ESSC). Its purpose will be to foster cooperation and
compatibility among the ER laboratories, DOE Headquarters, and other federal installations. The TVCG
will serve as:
• a resource, providing information to the ESnet Steering Committee on the broad range of
video conferencing technical issues;
• a forum for establishing an overall direction and developing plans for ER community
teleconferencing activities involving ESnet;
• a clearing house for gathering requirements for video conferencing; and
• an advisory group, to analyze video conferencing needs and recommend courses of action
directly to both the ESSC and ER-7; and ultimately to ER-1 through ER-7.
The TVCG will consist of both program and technical representatives, designated by the ESSC, to provide as
broad and accurate a perspective as possible on requirements and potential technical solutions.
In carrying out its work, the TVCG will rely extensively on meetings (using video conferencing whenever
feasible) to gather and disseminate information which will become the basis of reports and briefings to the
ESSC.
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7. Report of the Task Force
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Technical Implementations
Phase 0
The following sections describe the history, current status, and short-term extendibility of the ESnet video
conferencing system for the period from mid FY-1990 through FY-1993. A great deal of progress has already
been made, but further growth during this period will probably be restricted by limitations on scalability of
the existing systems and funding constraints. Headquarters facilities, operations offices, and most major
research facilities are expected to be included within the scope of the implementation during this phase.
ESnet Video Conferencing Pilot Project
In early 1990 a limited video conferencing Pilot Project was established linking Lawrence Berkeley
Laboratory (LBL), Fermi National Accelerator Laboratory (FNAL), and the Superconducting Super Collider
Laboratory (SSCL). (See Figure 2.) Network Connectivity for the Pilot Project was provided by
multiplexing bandwidth using existing ESnet T-1 circuits running at 384 Kbps.
The Pilot Project produced a fuller understanding of ER video conferencing requirements and associated
management and technical issues, and demonstrated that video conferencing can often be a viable
alternative to travel. Most important, the Pilot Project clearly showed that frequent meetings among
collaborators have a positive impact on productivity, cost control, and effective coordination of large
projects.
LBL FNAL
TDM ESNET TDM VBX
384kb 384kb
TDM
SSCL
TDM ESNET
384kb
Figure 2
Initial Pilot Project Configuration
During FY-1991, the SSCL received approval from the DOE Office of Information Resources Management
for an Implementation Plan to procure video equipment to extend this pilot project and to move this project
into a production mode. Video Telecom Corporation (VTC) video conferencing systems were selected for
the Pilot Project for the following reasons:
• VTC had the only fully functional, multi-point video branch exchange (VBX) at that time, and
multi-point capability was considered essential for collaborative applications.
• VTC equipment is software driven, allowing for continuous upgrading without replacement of
hardware, timely compliance with developing standards, PC integration, and superior audio
technology.
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8. Report of the Task Force
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• VTC was committed to support of the Consultative Committee for International Telegraphy
and Telephony (CCITT) H.261 1 standard.
• The cost for VTC systems was less than half that of comparable systems in use at the time.
FNAL ANL
LBL HARVARD
VBX
TDM
TDM
TDM
TDM
T DM ESNET T DM (8 PORT) T DM ESNET T DM
T DM
ESNET
ORNL
SSCL ESNET T DM
T DM
T DM T DM
D ALLAS W A X A H A CH I E
VBX
(15 PORT)
U . M I C HI G A N
KEK INFN
(JAPAN) (ITALY)
ISDN
Figure 3
Current Video Conferencing Network (Expanded Pilot Project)
Current Video Network Implementation
The current ESnet video conferencing network is an extension of the system created for the Pilot Project.
The original system has been expanded using ESnet to include Argonne National Laboratory (ANL), Oak
Ridge National Laboratory (ORNL), and Harvard. Video conferencing to KEK (Japan) and INFN (Italy) is
provided through the Integrated Services Digital Network (ISDN) interface at the SSCL. See Figure 3,
Current Video Conferencing Network (Expanded Pilot Project). Additional ER Laboratory activities also
have ordered compatible video equipment at LLNL, BNL, Ames and other locations.
Hence, the video network has now been expanded to a point where further growth will require some
modifications in network and operations support.
The Pilot Project had two main purposes, to expand understanding of the potential role of video
conferencing in the ER community, and to identify any network and operations limitations in the system.
1 See Appendix A for a discussion of standards applicable to video conferencing.
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9. Report of the Task Force
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Two years experience with the Pilot Project in both its original and expanded configurations yielded the
following important conclusions.
• Multi-point conferencing is essential to support large experimental collaborations.
• The lowest acceptable speed acceptable for operation of the video systems to minimize the
costs associated with communications was determined to be 128 Kbps. This speed also was
chosen as the universal speed of operation because compatibility with ISDN will be important
in the long term. The 128 Kbps rate can be derived from ISDN by combining the two 64 Kbps
basic rate or B channels.
• As the number of sites increased, scheduling and operation became increasingly complicated
and time-consuming.
• Using multiplexed channels out of point-to-point ESnet circuits was cumbersome, difficult to
manage, and created inefficient utilization of VBX ports.
Figure 4 Video teleconferencing system in use at the SSCL
From a user and from an ESNet Steering Committee perspective, the Pilot Project was extremely successful.
Utilization of the video conferencing system reduced travel by providing an electronic meeting forum, and
greatly expanded the potential for collaborative efforts. Important technical and scientific projects now rely
extensively on the video conferencing system as a primary medium for cooperation and coordination.
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10. Report of the Task Force
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ESnet Support of Video Conferencing
Phase I
Architecture
The architecture for the next phase of the ER video conferencing system will be driven by two factors,
lessons learned (both positive and negative) from the operation of the expanded Pilot Project, and the
technical environment anticipated for the future.
In light of the goals outlined for this system (See A Vision of the Future, page 1) the following points will be
important in planning and implementing Phase I.
• Development should be operations-oriented, and provide for a central point of contact for
reservations, configuration, and problem resolution.
• Compatibility with equipment already in use will require adherence to the current make and
model until future enhancements and standards development allow vendor interoperability.
• The VBX is a critical interconnect resource, but it is not required for two party, i.e., point-to-
point, conferences.
• Dynamic assignment of VBX ports will prove more cost-effective than the current fixed
assignments.
• Dynamic assignment of bandwidth to conference sessions will be more cost-effective than the
current system (dedicated bandwidth), and will facilitate meeting requirements for
confidentiality as appropriate.
• In some instances, dedicated bandwidth will be more cost-effective, e.g., ESNet bandwidth
may be the best medium to link the VBXs on an ongoing basis to reduce scheduling, operations
overhead, and costs. Monitoring of actual usage will determine when dedicated bandwidth
should be used to lower operating costs.
• The current ESnet implementation (dedicated T-1 links) will best serve as a transitional path
and a federal site interconnect facility. It should be replaced where cost-effective by ISDN
services for DOE/ER and laboratory use. As cell-relay based infrastructure matures and
becomes widely used, it will be reconsidered as a vehicle for providing communications
support. Use of IP level services of ESnet as a follow-on step will also be considered.
ISDN For Video Conferencing
With the advent of Bellcore's ISDN-1 in early 1993, the ISDN facilities in the United States should finally be
unified. In addition, implementation of ISO/CCITT video and audio standards (H.261 and G.254,
respectively) in the same time frame should better facilitate the transmission of compressed video with
audio using ISDN. In January of 1992, the GSA FTS-2000 contract was extended to include ISDN. This
network is independent and isolated from all other ISDN networks, however gateway(s) may be established
to the unified commercial ISDN networks as they develop. In the meantime, the FTS-2000 ISDN network can
be used within the DOE/ER community and the ISDN gateway at the SSCL (and possibly at LLNL at a
future date), can provide the more global ISDN access. The FTS-2000 ISDN network is based upon dropping
an ISDN PRI onto the premise of the site. It is the responsibility of the site to provide the equipment
necessary to derive the "B" channels for use. Dedicated multiplexing equipment providing the interface
between the ISDN PRI and the teleconferencing equipment would allow for flexible bandwidth utilization
by enabling any number of "B" channels to be used for any given conferencing. It has been suggested that
three "B" channels (192 Kb.) be used for normal domestic teleconferences, and two "B" channels be used for
international teleconferences.
Implementation of this technology is imminent, and its potential is sufficiently important to merit close
tracking and the early design and operation of a Pilot Project. In fact, vendor surveys confirm that all
potential ESNet sites for video can be serviced by ISDN today very cost-effectively. Therefore, the VCC will
be responsible for complementing existing ESNet bandwidth to provide for bandwidth on demand ISDN
capabilities.
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11. Report of the Task Force
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Assumptions about Phase I architecture:
• Each participating site will have at least one compatible video conference facility, including a
meeting room, appropriate video conferencing equipment, including one or more Codec's, and
a connection to the video conferencing service provider.
• A small number of regional VBXs (3) is proposed. These will be available in the pool of centrally-
managed, shared resources. The VBXs will be sized so users will generally find ports available.
SITE M
FUTURE MEETING ROOM/OFFICE
BRIDGE BRIDGE CODEX
PHASE II VIDEO EQ
CELL-RELAY
SITE IV
FUTURE
GATEWAY IP GATEWAY MEETING ROOM/OFFICE
CODEX
VIDEO EQ
ATT
ACCUNET
SITE O
INTERNATIONAL SITE
SAN ISDN
CHI VBX (8) T1
• MUX
FOR GMTWN •
•
GTN FTS-2000
ISDN
LOCAL
• SITE A
VBX (8) • • SITE B
FNAL • MUX
• • SITE C
T1
SITE D
LOCAL
SITE E
VBX (14) •
MEETING ROOM
• MUX • CODEX
SSC • T1 VIDEO EQ
CONFIG
T1
VBX (14) •
NERSC • MUX
•
RESERVATION
&
LOCAL
CONFIGURATION RQ
CONFIG ENTITY
Figure 5 Proposed ESnet Video Conferencing Architecture
• A single authority is recommended for reservations and configuration coordination for multi-
point conferences. Its responsibilities include providing a central point of contact for user
reservation requests, reservation and configuration of resources, including equipment and
communication facilities, and problem resolution.
• Point-to-point conferences will be arranged between the two sites involved rather than
through the central reservation facility. The two sites will be responsible for establishing the
communications connection.
• The systems at DOE/OER sites will function independently; it will not be allocated as a central
facility. However, these systems will require compatibility to the VTC systems as well as to
other DOE video initiatives.
• Special conferencing capabilities will be made available, including links to international sites,
ISDN, and commercial vendors.
• Site contacts will be defined that will resolve technical and scheduling issues.
Management and Operations
Information technology in general, including video, is moving toward the distributed model for production
and dissemination of information and services. The distributed model is the central concept in the
development of the ER video conferencing system. Centralized administration of the distributed system is
essential to its successful operation.
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12. Report of the Task Force
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A video conferencing control center (VCC) will be the key element in managing this system. The VCC
would have primary responsibility for implementing policy established by the Technical Video
Coordination Group (TVCG) in concert with the ER/Scientific Computing Staff (SCS), the ESnet Steering
Committee and representatives of DOE Headquarters and field organizations. Therefore, the VCC should
be established and managed within the ESNet infrastructure framework of coordinated activities by the
ER/SCS.
The control center will provide access to approved Energy Research sites for multi-point conferences.
Although video conferencing equipment at individual sites (cameras, Codec's, etc.) will be owned and
maintained by them, the VCC will provide a single point of contact for video conferencing network issues
and provide management and coordination for network facilities .
These management and coordination components are needed to oversee network growth, facility
scheduling, conflict resolution, configuration coordination, documentation, and training.
Personnel
A manager and scheduler will be required at the VCC. The manager will be responsible for all aspects of
system implementation, management, operations and maintenance. High availability will be required,
although not necessarily 24 hours a day, 7 days a week. In addition, individual sites will require a half-time
technical support person capable of training users and participating in routine operations and maintenance.
These support people will be funded by the respective sites.
Facilities
The video conferencing network established by the VCC will be a combination of fully-owned, leased and
switched network services and equipment. The VCC will maintain an ongoing dialog with vendors to
ensure cost-effective acquisitions under the guidance of the ESSC.
Coordination of Transmission Facilities
The VCC will work with various transmission facility suppliers to provide Connectivity to all Energy
Research sites. In the beginning, suppliers will be private, dedicated network providers (e.g., ESnet,
NSFnet). As services become generally available, or where private dedicated network facilities are not
available, public dedicated network providers (e.g.,. AT&T, Sprint) and public switched network providers
(e.g. AT&T, Sprint) might be employed. Subject to the guidance of the TVCG, the VCC will work with all
suppliers to provide a cost-effective combination of public and private, switched and dedicated lines.
Video Branch Exchange Coordination
Video branch exchanges are the heart of the multi-point video conferencing system. For example, scalability
can be greatly increased through judicious reconfiguration or relocation of VBXs within a network.
The VCC would manage the VBXs currently owned by the ER community. In addition, the VCC could
expand capacity through purchase of additional VBXs or by working with commercial shared-VBX
providers (e.g. Sprint Meeting Channel). Responsibility for maintenance and management of VBXs would
fall mainly on the VCC with assistance provided by where VBXs are located.
Reservations
While every effort will be made to accommodate varied needs of a large number of users, resources in this
field are still too expensive to provide for instant response to all requests. An orderly reservation system
will be absolutely essential to the productive operation of the network facility.
TVCG guidance will be followed in drafting a procedure for prioritizing reservations, and the VCC will
respond to and process reservation requests electronically.
A designated local site manager will be responsible for coordinating the use of local video conference rooms
and facilities and for initiating requests for scheduling with the VCC.
Consultation and Training
The VCC will serve as a resource for information about video conferencing technology and techniques
within the Energy Research community. The VCC would provide a list of recommended equipment, work
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with vendors to coordinate purchasing in order to obtain favorable pricing, and provide coordination
among the video conferencing personnel at the separate Energy Research sites.
The VCC will provide documentation and tutorials to local sites so they can use the equipment effectively.
The documentation will include information on how to use all features of the equipment and scripts to
demonstrate typical use of those features. The VCC will work with specific site managers and other staff as
appropriate to assemble the necessary documentation and sample conference materials.
Interoperability: Video Systems and Networks
There are multiple interoperability issues associated with video conferencing systems. Provisions should be
made to overcome incompatibilities were interoperability will be required.
Codec's
Most Codec's in operation today are proprietary. Standards development and deployment will eventually
provide universal interoperability, but in the interim conversions may be required. Systems deployed in ER
programs will all be upgraded to H.261 standard interoperability. Current plans call for this upgrade to be
complete by mid-FY 1994. Because it is unclear if other systems in DOE will implement H.261 or convert in
a timely manner, it may be necessary to provide a gateway between the ER network and FTS-2000-based
video systems.
Speed
As stated previously, 128 Kbps was selected as the default operational speed for ER video conferencing, to
take advantage of international ISDN Connectivity and reduce communications costs. Current video
conferencing technology does not allow for mixing operational speeds within a conferencing group.
Interfacing with video networks running at incompatible speeds requires a gateway for speed conversions.
Interoperability With Other Video Networks
Some commercial video conferencing providers have systems deployed throughout the world, with
conference facilities and network support available for single events. Many corporations have established
connectivity to these providers and the ER community could use their services as well, to expand
communication to locations where no other systems are available. In any event, the ER federal sites should
incorporate compatibility for both the installed base of VTC systems as well as the FTS 2000 CVTS, as
approved in the ER HQ's video teleconferencing implementation plan.
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14. Report of the Task Force
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Phase 2
Future Evolution
Expanding technology will be the driving force in the evolution of the ER system and will impact the system
in two principal ways. First, changing technology will allow provision of existing video conference services
in newer and more cost-effective ways. Second, it will furnish additional capabilities and services to the
users. Change is taking place so rapidly that the Phase I architecture may only be viable for 18–24 months.
Obviously, in this dynamic environment, technology tracking and the implementation of pilot projects for
evaluation purposes will be very important. Several promising areas for exploration have already been
identified. The next major upgrade of ESnet will incorporate cell switching technology as the primary
network backbone at speeds of T-3 and greater. Due to the nature of this technology and increased speeds,
video conferencing is a promising application to support upon the cell switching structure.
Cell Switching Transport for Digital Video
Most recently there has been a major shift toward cell switching in transport technology within the
communications industry. Cells are very small packet-like units of information that are moved through a
network. Larger units such as packets or messages are decomposed into streams of cells before transmission
and reassembled into original form upon reception.
Cell switching has been designed for use with both the data transmission and transmission of digitized
voice, where timely delivery is crucial. Because cell switching is a new technology, we cannot predict when
we might be able to test using this technology for our video requirements. However, the deployment of this
technology by the common carriers argues for its evaluation for possible inclusion in the ER video
conference system as soon as the means to do so are available. (See Fig. 5.0)
Packet Video and Desktop Multimedia Conferences
Packet video can best be defined a transport mechanism which generally uses the IP suite of protocols to
encapsulate the data of a video teleconferencing system. The data, consisting of both audio and video,
normally uses circuit switched communications because it requires guaranteed throughput and delay to
assure the delivery of the audio such that the intelligibility is maintained. Most critical is the audio data
which carries virtually all of the "human" information of the teleconferencing session. Using IP packets as a
delivery mechanism introduces uncertainty of both orderly and timely reception of the data at the receiving
end. IP delivery on networks which have moderate levels of traffic can result in choppy or missing sound
which can render the audio unintelligible at times. Introducing delay can, to some extent, compensate for
network congestion by sacrificing the real-time efficiency of two-way conversations. The video data in
contrast to the audio, can be allowed to "float", in that the delivery of the video is far less critical than that of
the audio. Synchronization of the video to the audio however, is another factor that introduces delay and
potentially degrades the use ability of the system. For more reliable transmission of teleconferencing using
IP packets, a priority scheme for IP must be developed and deployed, which would provide for more
predictable delivery of the data.
Packet video, (i.e. packet delivery), by its self does not address the complications associated with multi-point
teleconferencing. Multi-point conferencing requires links to be established between all participants. This can
easily create network congestion as the number of required links and associated traffic increases N factorial.
Multi-casting is an obvious solution to this complication, however multi-cast servers must be established in
every sub-net, in and or between conferencing systems.
Commercial and public domain software is now becoming available to support packet video and
multimedia applications for PCs and workstations on popular desktop computers. These "desktop video"
products are maturing, but most of them do not have any method to support multi-casting or any
guaranteed delivery mechanism. The development of these systems should be tracked carefully to assure
that these systems do not adversely effect both our LAN's and WAN's, and that we can accommodate them
when they have sufficiently matured. A working group within the ESSC should be given the task to
investigate and test the various systems and software and determine the areas that require immediate
attention and exploration. (See Fig. 5.0)
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15. Report of the Task Force
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Summary
Video conferencing will become a very important communications means in the near future, particularly on
the desktop and eventually in the home. This report is not the "definitive" document on any aspect of video
conferencing, but is intended to provide the general direction which our collective efforts should be
directed. Existing within the ESnet umbrella are three working groups which should provide more detailed
strategic planning documents that will outline specific implementation and operational plans.
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16. Report of the Task Force
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Appendix A: Standards
Circuit switched video of the type used for remote video conferencing is rapidly moving toward a set of
standards jointly agreed to by the International Standards Organization (ISO) and the Consultative
Committee on International Telegraphy and Telephony (CCITT).
To date, the best known of these standards is H.261, which specifies uniform coding of signals. This
standard is sometimes referred to as the p x 64 standard because it defines the bit rates at which video is
transmitted in integer multiples of 64 Kbps. This standard was adopted in December 1990 and most
vendors claim to be designing their new offerings to this and related standards. The related video standards
also adopted on that date include:
• H.221, which defines video framing;
• H.230, specifying the protocol for Codec command communication;
• H.242, covering call establishment and termination; and
• H.320, which defines the technical requirements for low bit rate systems.
Of interest and adopted at the same time were two audio standards:
• G.711 defining 64 Kbps PCM audio, and
• G.722 which defined adaptive differential PCM for three different bit rates, 48, 56, and 64
Kbps.
These standards are designed to be used together to promote vendor interoperability for video conferencing
systems.
Of particular interest is the p x 64 option where p=2. In this case, the signal can be carried on two 64 Kbps
channels, the rate used to carry PCM voice outside of North America, and the rate toward which the United
States and Canada are moving. Thus, with p=2, the video can be carried on two voice-bit-rate digital lines.
Also, with p=2, Basic Rate ISDN (i.e., 2B + D) is capable of carrying video conferences. (This
implementation has gained worldwide acceptance and is being deployed in the United States as the
preferred means of providing voice communications.) All this portends the availability of very inexpensive
and ubiquitous video conferencing communications using H.261 and related standards with p=2.
However, there is still a problem with audio standards. Existing audio standards use between 48 Kbps and
64 Kbps, leaving insufficient remaining bit rate available for video. Consequently, many vendors have
chosen not to move to complete implementation of H.261 for p=2 operation at this time. Instead, they offer
proprietary schemes, usually using 32 Kbps for audio, leaving 96 Kbps (128 K-32 K) for video.
Recognizing the problem, ISO and CCITT are writing a new 16 Kbps audio standard (G.254) targeted for
adoption late this year. G.254 will allow two 64 Kbps lines or a BR_ISDN dial-up service to support video
conferencing where 112 Kbps is allocated for video, thus providing a much better video/audio ratio. All
major vendors have indicated that when this standard is adopted, they will offer H.261/G.254-compatible
equipment, probably in mid- to late 1993.
One remaining issue centers on the fact that, while 64 Kbps is the ubiquitous digital transmission standard
bit rate for most of the world, 56 Kbps is still widely deployed in North America. This raises the issue of
using 56 rather than 64 Kbps.
Choosing 64 Kbps is justified for several reasons:
• There is already movement away from 56 Kbps in the U.S., 64 Kbps will eventually become the
standard here, too.
• Existing and emerging standards are 64 Kbps.
• Vendors are moving toward 64 Kbps.
• 64 Kbps is used outside North America and one of the major benefits of ER video conferencing
to scientists will be ease of interaction with foreign sites.
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