telecom

THE BEAUTY OF ATM
Thao Mong Le
E-Mail: tle@eng.umd.edu

Abstract
A number of changes are occurring in the computing, data communications and telecommunications fields. As computing systems become increasingly powerful and versatile, data communications and telecommunications networks must evolve to support the performance of computing systems. Probably the best cell-base switching and multiplexing technology used to support the development of these types of high-performance communications and telecommunications networks is the Asynchronous Transfer Mode (ATM). ATM combines a user's data, voice, and video into fixed length cells, and multiplexes it into a single bit stream transmitted across a physical medium. ATM supports a wide range of high performance data communications and telecommunications services for local, national and international communities. In addition to providing a technical overview of ATM in terms understandable to the readers, this paper discuss the driving forces behind ATM, and various ATM applications for the "future" telecommunications.


A CARRIER BASED NETWORK ARCHITECTURE FOR MULTIPOINT VIDEO CONFERENCING SYSTEM
Luc T. Nguyen, Ph.D.
BellSouth Science & Technology
675 W. Peachtree Street
Room 41B50 SBC
Atlanta, GA 30375 USA
E-Mail: luc@snt.bellsouth.com

Abstract
Multipoint Video Conferencing is becoming the choice meeting arrangement for various industries, medical professions, government agencies, as well as the school systems. Many businesses have set up their own private video conferencing networks, other relied on networks built by various carriers either via dedicated connections or via ISDN dial-up. The main enabling equipment for Multipoint Video Conferencing is the MCU (Multipoint Control Unit). The MCU is usually expensive and needs to be used efficiently. In this paper we present a network based architecture for video conferencing that a carrier can use to provide this service to all of its customers. The architecture combines the traditional networking equipment, facilities, and operation systems together with the MCUs to allow for efficient sharing of MCUs among all of its customers. Moreover, together with a network Scheduling system, it greatly improves the reliability of the network and the service. This paper describes in detail this network architecture for video conferencing service. It also presents some of the applications that are being used or discussed to be used based on this type of service. The general idea of the network Scheduler will also be presented.


DISTANCE LEARNING AND THE INTERNET: EXPERIENCES AND LESSONS LEARNED
Tung Bui
The U.S. Naval Postgraduate School
Monterey, CA 93943 USA
E-Mail: tbui@nps.navy.mil

Abstract
The Internet, with its increasing popularity and it enhanced ability to provide other modes of information exchange beyond electronic mail and file transfer, such as voice conversation and video conferencing, has been quickly identify as a potentially inexpensive and broad-based medium for distance education-both as a supplement and a substitute to the more established video-teleconferencing technology. The purpose of this paper is to address technological, pedagogical, administrative issues regarding the use of video-conferencing technologies and the Internet for distance education. In particular, it reports some of the lessons learned in distance learning at the Naval Postgraduate School. Our case study suggests a fundamental shift in approaching education for a successful implementation of distance learning.


ELECTRONIC COMMERCE/ELECTRONIC DATA INTERCHANGE
Hung Q. Vu and Diem V. Nguyen
E-Mail: hung.q.vu@ccmail.irs.gov
E-Mail: nguyen@joy.gsfc.nasa.gov

Abstract
The global political and economic changes around the world today are demanding an increased orientation to global business opportunities. This global business environment is also made possible by advances in communication technologies -- from facsimile machines to electronic mail.


ISDN-BASED C INTERFACE ARCHITECTURE FOR PCS ACCESS SERVICES
Khiem Le, Ph.D.
Bell Communications Research Inc.
331 Newman Springs Road
Red Bank, NJ 07701 USA
Tel: (908) 758-5766

Abstract
The ISDN-based C interface architecture is a novel architecture for Personal Communications Systems PCS systems that enables a more efficient utilization of switching and signaling resources, and facilitates wireline and wireless service integration.

Traditional PCS systems consist of Radio Systems (RS) connected to a Mobile Switching Center/Visitor Location Register (MSC/VLR) at the end serving the mobile user, and MSC with Home Location Register (HLR) at the remote end. While RS functions are unique to the radio and wireless environment, many of the MSCís major functions, such as circuit switching, circuit conferencing, network signaling and trunking to/from the PSTN, are duplicate of those found in wireline switches.

In the ISDN-based C interface architecture for PCS systems, the MSC/VLR is replaced by an ISDN/AIN wireline switch, complemented by an AIN SCP-based Mobility Management Platform (MMP). Thus the ISDN/AIN switch provides the above mentioned functions, which are common to the wireline switch and MSC. The MMP houses the mobility management functions, which are those functions rendered necessary the PCS users mobility: location registration, authentication, etc. In particular, the MMP includes the Visitor Location Register (VLR).

The RS accesses the wireline network by means of the C interface, which consists of two components: Call Control and Mobility Management. Call Control terminates on the switch, and enables the RS to access switch- based services such as connection establishment/tearing down, and supplementary services (three-way calling, etc.). Mobility Management is the part that terminates on the MMP and offers mobility management functions to the RS.

The ISDN-based C interface architecture can support various radio technologies, including GSM, CDMA and PACS. All the protocols are based on existing, planned or defacto standards: ANSI T1 MMAP is the mobility management application protocol between the RS and the MMP, National ISDN DSS1 is the call control protocol between the RS and the switch and AIN is a defacto standard protocol between the switch and the MMP. In addition, seen from the MSC and HLR at the remote end, the ISDN/AIN switch and MMP behave like a regular MSC/VLR, and the MMP-based VLR communicates with the HLR by means of the standard Mobility Application Protocol (MAP).

By using the same ISDN and AIN platforms to provide services to wireline and wireless end users, the C interface architecture does not only utilizes resources more efficiently, but also facilitates wireline/wireless service integration. That is, the same services can potentially be offered to both wireline and wireless users, with the same look and feel.



MULTIMEDIA IN EDUCATION - AUTHORING TOOLS
Thuy-Linh Nguyen
University of Camberra & University College
UNSW (ADFA)
AUSTRALIA
E-Mail: t-nguyen@adfa.oz.au

Abstract
The "Cross-platform Multimedia Courseware Project" done at the University of Canberra, Australia, is an educational research which attempts to address various issues concerning the authoring process of multimedia educational software. This paper reports some findings relating to the two major authoring tools used, which are Visual Basic Standard v.3 and Macromedia Director v.4.0.4. It looks in particular at issues concerning performance, support for multimedia, support for computer-based training, and the authoring tools as a programming environment. In general we have found that Director can redraw bitmaps 1.3 - 2.1 times faster than Visual Basic, but much slower, possibly up to 7.2 times, in computation. It is generally better than Visual Basic in other areas, however it is simpler to learn, has a library of predefined objects ready to use, and is powerful in graphics drawing.


OUTAGE ANALYSIS OF FCC-REPORTABLE SERVICE OUTAGE DATA: METHODOLOGY AND RESULTS
Bichlien Hoang and Spilios E. Makris
Bichlien Hoang					Spilios E. Markis
Bellcore					Bellcore
NVC 2X-447					NVC 2Y-138
331 Newman Springs Road				331 Newman Springs Road
Red Bank, NJ 07701 USA				Red Bank, NJ 07701 USA
Tel: (908) 758-2475				Tel: (908) 758-5640
Fax: (908) 758-4389				Fax: (908) 758-4370
E-Mail: bhoang@notes.cc.bellcore.com
E-Mail: smakris@notes.cc.bellcore.com

Abstract
In February 1992 the Federal Communications Commission (FCC) challenged the telecommunications industry to develop an analytical method for quantifying service outages. This paper discusses: 1) the challenges in migrating from an outage frequency to a customer-impact based measure(outage index), 2) the outage index, which was developed originally at Bellcore and then became the basis for the new measure of network performance that was adopted by Committee T1, 3) the past and present network reliability performance in the U.S., as tracked by Bellcore and the Alliance for Telecommunication Industry Solutions (ATIS) Network Reliability Steering Committee (NRSC), and 4)future work for enhancing the outage index.


OVERVIEW OF WIRELESS DATA COMMUNICATIONS
Dr. Viet-Dung Hoang
E-Mail: vhoang@mitretek.org

Abstract
The advantages of wireless data communication technology center around the ability of users to access their enterprise wide information at any time in (virtually) any place. The elimination of fixed "telephone" outlets will result in proved user satisfaction, higher productivity, and greater operating efficiency.

By transmitting data over the airwaves is not as old hat as one would have thought, and if it was not for the need of product information by the marketers, wireless communications perhaps might never get off the ground. The reasons are quite simple: the total "bandwidth" is limited since only a certain amount of usable spectrum is available. While additional wire lines can always be installed if needed, new spectrum can not be created. The total amount of raw usable spectrum bandwidth available for wireless data communications is roughly equal to 2,500 to 3,000 millions of bit per second (Mbps).

The effects of limited available bandwidth, range and interference severely constrain the data rates. While typical wire data networks are designed with T1 as minimum unit capacity, wireless data networks are struggling to deliver 19.2 kbps links to mobile users. Furthermore, the practical throughput on wireless networks is usually about half of the "rated" capacity because of high overhead of signaling and error correction protocols.

The wireless data communication system can be classified into four type: paging, mobile, radio, cellular, and satellite. Paging is used for short notification messages applications; mobile radio for corporate database access, e-mail, credit authorization, and monitoring and surveillance applications; cellular for file transfer and FAX application; and satellite for transcontinental applications. This paper provides an overview of these four types, although it is heavily concentrated on the satellite based systems.