Multipoint Connection Research Articles

The Evolution and Evaluation of Videoconferencing Technology for Graduate Nursing Education

The Integrated Services Digital Network H.323 (ISDN), which has been in use for the past 20 years often requires a dedicated telephone line and other equipment to implement. Consequently, expansion of ISDN-based videoconferencing requires infrastructure not always accessible in those areas that are most in need of technological connections. New H.323 technology using Internet Protocol H.320 (IP) connectivity can accommodate the use in a variety of videoconferencing software and fill this void as demonstrated by an experiment conducted live at the Syllabus Web '99 conference. When a faculty group were unable to secure ISDN connections to demonstrate their clinical evaluation of Family Nurse Practitioner (FNP) students using videoconferencing technology, an ad hoc group of computer experts, educators, instructional design specialists, and corporate sponsors collaborated to design a multipoint PC-based connection using IP connectivity. This article describes the first application of this technology, the evolution of ISDN and IP systems in nursing education and practice, and suggests appropriate future trends for their utility in nursing.

On optimal hyperuniversal and rearrangeable switch box designs

This paper explores theories on designing optimal multipoint interconnection structures, and proposes a simple switch box design scheme which can be directly applied to field programmable gate arrays (FPGAs), switch box designs, and communication switching network designs. We present a new hyperuniversal switch box designs with four sides and W terminals on each side, which is routable for every multipin net-routing requirement. This new design is proved to be optimum for W = 1, ..., 5 and close to optimum for W /spl ges/ 6 with 6.3 W switches. We also give a formal analysis and extensive benchmark experiments on routability comparisons between today's most well-known FPGA switch boxes like disjoint switch blocks (Xilinx XC4000 Type), Wilton's switch blocks, Universal switch blocks, and our Hyperuniversal switch boxes. We apply the design scheme to rearrangeable switching network designs targeting for applications of connecting multiple terminals (e.g., teleconferencing). Simply using a /spl kappa/-sided hyperuniversal switch block with a W /spl times/ W crossbar attached to each side, one can build a three-stage one-sided polygonal switching network capable of realizing every multipoint connection requirement on kW terminals. Besides, due to the fine-grained decomposition property of our design scheme, the new switch box designs are highly scalable and simple on physical layout and routing algorithm implementations.

A Standard-Compliant Virtual Meeting System with Active Video Object Tracking

This paper presents an H.323 standard compliant virtual video conferencing system. The proposed system not only serves as a multipoint control unit (MCU) for multipoint connection but also provides a gateway function between the H.323 LAN (local-area network) and the H.324 WAN (wide-area network) users. The proposed virtual video conferencing system provides user-friendly object compositing and manipulation features including 2D video object scaling, repositioning, rotation, and dynamic bit-allocation in a 3D virtual environment. A reliable, and accurate scheme based on background image mosaics is proposed for real-time extracting and tracking foreground video objects from the video captured with an active camera. Chroma-key insertion is used to facilitate video objects extraction and manipulation.We have implemented a prototype of the virtual conference system with an integrated graphical user interface to demonstrate the feasibility of the proposed methods.

Creating new businesses through a strategic innovation community—case study of a new interactive video service in Japan

In the past few years, the market for video terminals such as videoconferencing systems and video phones typified by multimedia and the market for multipoint connection services that use these devices have been growing rapidly in Japan. In the background to this growth is an innovation community with Nippon Telegraph and Telephone Corporation (hereafter referred to as NTT), Japan's largest telecommunications company, and NTT Phoenix Network Communications, Inc. (hereafter referred to as NTT Phoenix), a joint venture established by a strategic alliance between the United States and Japan. This innovation community has created a new market known as Interactive Video Communication and has been doing much to promote it. In this paper, we shall take up the world's largest multipoint connection video multimedia businesses. Project leaders of both NTT and NTT Phoenix will stand at the viewpoint of group corporate strategy, create a strategic innovation community, their innovative leadership will aim for resonance of values within the community, and by propagating knowledge within the community and enhancing their core competencies, we shall consider how to create a new market in Japan for new video multimedia services.

Business Innovation through Customer Value Creation-Type Businesses

In the last few years, Japan has seen rapid growth in the multipoint connection service market, which is associated with multimedia videoconferencing systems. Behind this trend was the birth and explosive growth of the multipoint video communications market, which was initiated by NTT, Japan's largest telecommunications carrier, in alliance with a joint venture business (NTT Phoenix Network Communication Inc.: hereafter, NTT Phoenix) comprised of heterogeneous U.S.-Japan joint businesses. This article takes up the case of the world's largest multi-point connection venture business, and considers how an NTT Phoenix's customer value creation-type business created a new video network service market in Japan.

Fair flow control for ATM-ABR multipoint connections

Multipoint-to-multipoint communication can be implemented by combining the point-to-multipoint and multipoint-to-point connection algorithms. In an ATM multipoint-to-point connection, multiple sources send data to the same destination on a shared tree. Traffic from multiple branches is merged into a single stream after every merge point. It is sometimes impossible for the network to determine any source-specific characteristics since all sources in the multipoint connection may use the same connection identifiers. The challenge is to develop a fair rate allocation algorithm without per-source accounting as this is inequivalent to per-connection or per-flow accounting in this case. We define fairness objectives for multipoint connections, and we design and simulate an O(1) fair ATM-ABR rate allocation scheme for point-to-point and multipoint connections sharing the same links. Simulation results show that the algorithm performs well and exhibits many desirable properties. We list key modifications necessary for any ATM-ABR rate allocation scheme to fairly accommodate multiple sources.

Creating new business through strategic community management: case study of a multimedia business

For the last few years, the videoconferencing system and multi-point connection service market represented by multimedia technology have enjoyed strong growth in Japan. Behind the recent upturn in this market was the strategic alliance of NTT, Japan's largest telecommunications carrier, and PictureTel of the US, followed by the birth of business communities centred around or outside NTT, thus intensively creating and boosting a new market referred to as interactive video communication. This article reviews the challenges that faced NTT, one of the big businesses in Japan, followed by PictureTel and other players within and outside NTT, all of which were lined up to create various strategic business communities. The article gives careful consideration to the measures taken by these players who achieved success in such a way as to alter employee consciousness, vitalize organizational morale, entrench the new NTT 'Phoenix' brand (videoconferencing system) in the Japanese market and create an emergent new video multi-point connection network service market. And it was under the innovative leadership of community leaders that communities' core competencies were elevated, and innovation of the multimedia business achieved, as a function of the creation and harmonization of new value outlooks within the business community, inside as well as outside the companies.

Customer value creation business through learning processes with customers: case studies of venture businesses in Japan

This article discusses business processes that are capable of creating new value with many new customers and in which enterprises and customers both achieve innovation through the provision of new services by the enterprise. Examples of innovation that venture companies providing IT‐based multimedia services have experienced over the past three years in Japan through mutual learning with customers are taken as case studies. In the last few years, Japan has seen rapid growth in the multipoint connection service market associated with multimedia videoconferencing systems. Behind this trend was the birth and explosive growth of the multipoint video communications market, which was initiated by NTT, Japan’s largest telecommunications carrier, in alliance with a joint venture business (NTT Phoenix Network Communication Inc.: hereafter, NTT Phoenix) comprised of heterogeneous US‐Japanese joint businesses. This article takes up the case of the world’s largest multipoint connection venture business, and considers how an NTT Phoenix’s customer value creation‐type business created a new video network service market in Japan.

Creating new business through strategic community management: case study of a multimedia business

For the last few years, the videoconferencing system and multi-point connection service market represented by multimedia technology have enjoyed strong growth in Japan. Behind the recent upturn in this market was the strategic alliance of NTT, Japan's largest telecommunications carrier, and PictureTel of the US, followed by the birth of business communities centred around or outside NTT, thus intensively creating and boosting a new market referred to as interactive video communication. This article reviews the challenges that faced NTT, one of the big businesses in Japan, followed by PictureTel and other players within and outside NTT, all of which were lined up to create various strategic business communities. The article gives careful consideration to the measures taken by these players who achieved success in such a way as to alter employee consciousness, vitalize organizational morale, entrench the new NTT 'Phoenix' brand (videoconferencing system) in the Japanese market and create an emergent new video multi-point connection network service market. And it was under the innovative leadership of community leaders that communities' core competencies were elevated, and innovation of the multimedia business achieved, as a function of the creation and harmonization of new value outlooks within the business community, inside as well as outside the companies.

Business innovation through joint ventures supported by major businesses

In the last few years, Japan has seen rapid growth in the multipoint connection service market involved in videoconferencing systems represented by multimedia. The trend depicts the background scenario of the birth and major growth of the multipoint video communications market initiated by NTT, Japan’s largest telecommunications carrier, in alliance with joint venture business (NTT Phoenix Network Communication Inc.) comprising heterogeneous US‐Japan joint businesses. This article introduces the world’s largest multipoint connection venture business followed by a review on how to create an emerging market for new video network services in Japan through partnerships bolstered by a close strategic alliance between the original investing businesses and the venture business plus the strategic assistance of the investing businesses.

Linear multicasting in dynamic networks

Multimedia services, available in wired infrastructure, can now be extended to the users of wireless networks. Emerging solutions make the integration of static and mobile networks applicable, with a guaranteed quality level, but new problems have to be faced in this kind of hybrid architecture. In integrated wired and wireless networks, characterized by a dynamic topology, flooding technique is typically utilized to disseminate information needed by node discovery mechanisms and routing maintenance facilities. As flooding is not efficient in the use of bandwidth, which can be a limiting factor in the successful deployment of multimedia applications, a different approach is proposed in this paper, based on the linear multicasting capabilities of the Depth-First Search (DFS) algorithm. Whenever network information has to be updated at the nodes, to preserve current connections against any occurring topology changes, DFS can be activated to operate in a new and unknown network configuration. In fact, DFS does not need any network information to support multicast communications. Furthermore, unlike flooding, DFS belongs to the family of linear multicast algorithms, that is to say, it provides a multipoint connection through a single path without bifurcations. Such a path, that implies the absence of any packet copying process, crosses hop by hop all the addressed nodes using a low cost route and by minimum use of network resources.

Optimal Routing for Dynamic Multipoint Connection

AbstractMultimedia applications are becoming increasingly important as networks are now capable to carry continuous media traffic, such as voice and video, to the end user. Most of the multimedia applications need multicast support too. In dynamic multicasting, destination nodes can join and leave the group during the communication period. Total or partial rerouting can optimize the tree cost to some extent. But rerouting for optimization is complex as cell‐ordering at ATM switches has to be preserved. Optimum Steiner tree is NP‐complete and therefore the present problem too. We propose a heuristic centralized routing algorithm, which optimize the total cost of the Steiner tree over the whole session period, where information about the joining and leaving of participants are available, at the time s/he actually joins. With this algorithm, the average hop‐length from source to destination has also reduced considerably. The efficiency of our algorithm and comparison with other proposed algorithms is shown by various simulation results.

Multicast address management and connection control based on hierarchical autonomous structure

Multicast capability, including multicast address and multicast routing mechanisms, at the network layer is necessary in order to reduce the bandwidth requirements of multiparty, multicast applications. Based on hierarchical autonomous structure in accordance with the self-organization topologies of Internet, the paper puts forward a multicast address management scheme that is shown to be robust and scalable. Connection control hierarchy (CCH) based on master/slave relationship and a simple efficient building algorithm of multi-point connection is also built. The paper also describes the normal operations of multicast address management and multi-point connection controller. Through simulation experiment, HAM, CM and DDM of Multicast Address Allocation are compared. HAM integrates the merits of CM and DDM, which is efficient as a whole, robust and scalable. CCH raises the efficiency of connection control, and is highly robust, flexible and scalable.

Feedback control mechanisms for real-time multipoint video services

While existing research shows that reactive congestion control mechanisms are capable of providing high video quality and channel utilization for point-to-point real-time video, there has been relatively little study of the reactive congestion control of point-to-multipoint video, especially in ATM networks. Problems complicating the provision of multipoint, feedback-based real-time video service include: (1) implosion of feedback returning to the source as the number of multicast destinations increases and (2) variance in the amount of available bandwidth on different branches in the multipoint connection. A new service architecture is proposed for real-time multicast video, and two multipoint feedback mechanisms to support this service are introduced and studied. The mechanisms support a minimum bandwidth guarantee and the best effort support of video traffic exceeding the minimum rate. They both rely on adaptive, multilayered coding at the video source and closed-loop feedback from the network in order to control both the high and low priority video generation rates of the video encoder. Simulation results show that the studied feedback mechanisms provide, at the minimum, a quality of video comparable to a constant bit rate (CBR) connection reserving the same amount of bandwidth. When unutilized network bandwidth becomes available, the mechanisms are capable of exploiting it to dynamically improve video quality beyond the minimum guaranteed level.

Architecture Design of an ATM Switch Based on a High Speed Network

One of the key issues that must be fulfilled to realize BISDN, is to develop high speed and high capacity ATM packet switches. For this, many technical problems must be investigated, such as design of switch architecture, development of switch protocols, and evaluation of the switch performance.In this paper we will propose an ATM switch with a shared medium architecture. The medium is a high speed fiber optic network with reservation based access protocol. The switch uses a novel interconnection topology between the switch units to reduce the fiber optics network aggregate data rate for a high dimensionality switch. The resultant switch dimensionality estimate shows that with a switch unit network bus rate of 4 Gb/s, a fully connected broadband switch with 16384 I/O STS-3C lines (155.52 Mb/s port bandwidth) can be realized. Moreover, the architecture of the switch allows a modular growth, meets the need for heterogeneous and dynamically changing mix of traffic, and provides multi-point connection capability.

Using destination set grouping to improve the performance of window-controlled multipoint connections

In conventional multicast communication, the source carries a single conversation with all destination nodes. If a node on the path to any destination becomes congested, the throughput to all destinations is reduced, thus treating some destination nodes unfairly. We consider a window-controlled multipoint connection and study the use of destination set grouping, where the destination set can be split into disjoint subgroups with the source carrying independent conversations with each subgroup. We present a static grouping heuristic that can obtain near optimum grouping for static network environments and a dynamic grouping protocol which can adjust the grouping and the window sizes per group in response to changing network conditions. The performance of the static grouping heuristic and the dynamic grouping protocol are studied using simulation and compared with single-group multicasting.

A promising application for broadband ISDN: Hypermedia teleconference

The optimum BISDN teleconference service for business, called hypermedia teleconference, is designed based on research into typical business activities and ATM, the most promising BISDN architecture. Service characteristics are determined by analysing the daily work practices of a large set of businessmen. It is shown that communication tasks occupy 44 per cent of the working day. The analysis further shows that some 60 per cent of all communication tasks could be performed through an advanced digital teleconference service. Hypermedia teleconference is designed to satisfy the needs of business through personal communication terminals and ATM public networks. The terminals effectively allocate the BISDN's high-speed transmission capability between a number of subchannels that realize distributed multipoint connection links and multimedia paths. The terminals use a new variable-bit-rate ATM codec created to realize high quality video. Users can easily create full featured teleconferences without a centralized connection facility. Terminals allow the synergistic combination of video, voice, telewriting, telepointing and document transmission services.

Multipoint connection routeing

AbstractAmong other potential services envisioned for broadband ISDN networks, multipoint connnection services have drawn much attention from the standards arena as well as research communities. These services include conference calls, video lectures, etc. where more than two endpoint CPEs are involved in communication. In this paper we investigate representative multipoint connection routeing algorithms from a number of viewpoints: computational complexity, call set‐up complexity, dynamic reconfiguration, robustness to node failures and bandwidth efficiency. These algorithms are either known in the literature or a simple generalization of point‐to‐point routeing algorithms. An interesting conclusion of our study is that the use of multiple point‐to‐point connections for multipoint calls is a viable solution in many cases of interest. This solution would eliminate much of the additional call‐handling complexity that may be otherwise introduced by more sophisticated multipoint routeing algorithms.

Design of a broadcast packet switching network

An overview is given of a system designed to handle a heterogeneous and dynamically changing mix of applications. It is based on fiber-optic transmission systems and high-performance packet switching and can handle applications ranging from low-speed data to voice to full-rate video. A novel feature is a flexible multipoint connection capability suitable for broadcast and conferencing applications. The architecture of a switching systems that can be used to support this network is described. >