THE BEAUTY OF ATM
Thao Mong Le
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
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
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
The U.S. Naval Postgraduate School
Monterey, CA 93943 USA
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
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
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
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
University of Camberra & University College
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
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
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
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
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
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