Report of the Task Force
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ESnet Support of Video Conferencing




            Greg Chartrand
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Illustrations ...............................................................................................................
Appendix A: Standards........................................................................................................
Illustrations

Figure 1, Video Conferencing Time/Cost Continuum .............................................................
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Transcript of "Report of the Task Force for ESnet Support of Video Conferencing"

  1. 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. 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. 3. Appendix A: Standards............................................................................................................................................ 12 iii
  4. 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. 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 Page 1
  6. 6. Report of the Task Force for 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. Page 2
  7. 7. Report of the Task Force for ESnet Support of Video Conferencing 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. Page 3
  8. 8. Report of the Task Force for ESnet Support of Video Conferencing • 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. Page 4
  9. 9. Report of the Task Force for ESnet Support of Video Conferencing 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. Page 5
  10. 10. Report of the Task Force for 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. Page 6
  11. 11. Report of the Task Force for ESnet Support of Video Conferencing 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. Page 7
  12. 12. Report of the Task Force for ESnet Support of Video Conferencing 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 Page 8
  13. 13. Report of the Task Force for ESnet Support of Video Conferencing 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. Page 9
  14. 14. Report of the Task Force for ESnet Support of Video Conferencing 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) Page 10
  15. 15. Report of the Task Force for ESnet Support of Video Conferencing 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. Page 11
  16. 16. Report of the Task Force for ESnet Support of Video Conferencing 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. Page 12

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