Showing papers in "IEEE Network in 1994"

Abstract: The article describes an active map service (AMS) that supports context-aware computing by providing clients with information about located-objects and how those objects change over time. The authors focus on the communication issues of disseminating information from an active map server to its clients, and in particular, address how to deal with various overload situations that can occur. Simple unicast callbacks to interested clients work well enough if only a few located-objects are moving at any given time and only a few clients wish to know about any given move. However, if many people are moving about in the same region and many clients are interested in their motion, then the AMS may experience overload due to the quadratic nature of the communications involved. This overload affects both the server as well as any slow communications links being used. Mobile distributed computing enables users to interact with many different mobile and stationary computers over the course of the day. Navigating a mobile environment can be aided by active maps that describe the location and characteristics of objects within some region as they change over time. >

Abstract: Intrusion detection is a new, retrofit approach for providing a sense of security in existing computers and data networks, while allowing them to operate in their current "open" mode. The goal of intrusion detection is to identify unauthorized use, misuse, and abuse of computer systems by both system insiders and external penetrators. The intrusion detection problem is becoming a challenging task due to the proliferation of heterogeneous computer networks since the increased connectivity of computer systems gives greater access to outsiders and makes it easier for intruders to avoid identification. Intrusion detection systems (IDSs) are based on the beliefs that an intruder's behavior will be noticeably different from that of a legitimate user and that many unauthorized actions are detectable. Typically, IDSs employ statistical anomaly and rulebased misuse models in order to detect intrusions. A number of prototype IDSs have been developed at several institutions, and some of them have also been deployed on an experimental basis in operational systems. In the present paper, several host-based and network-based IDSs are surveyed, and the characteristics of the corresponding systems are identified. The host-based systems employ the host operating system's audit trails as the main source of input to detect intrusive activity, while most of the network-based IDSs build their detection mechanism on monitored network traffic, and some employ host audit trails as well. An outline of a statistical anomaly detection algorithm employed in a typical IDS is also included. >

Abstract: Distributed systems for locating people and equipment will be at the heart of tomorrow's active offices. Computer and communications systems continue to proliferate in the office and home. Systems are varied and complex, involving wireless networks and mobile computers. However, systems are underused because the choices of control mechanisms and application interfaces are too diverse. It is therefore pertinent to consider which mechanisms might allow the user to manipulate systems in simple and ubiquitous ways, and how computers can be made more aware of the facilities in their surroundings. Knowledge of the location of people and equipment within an organization is such a mechanism. Annotating a resource database with location information allows location-based heuristics for control and interaction to be constructed. This approach is particularly attractive because location techniques can be devised that are physically unobtrusive and do not rely on explicit user action. The article describes the technology of a system for locating people and equipment, and the design of a distributed system service supporting access to that information. The application interfaces made possible by or that benefit from this facility are presented. >

Abstract: To provide high-speed seamless services for mobile computing, an effective medium access control capable of dealing with mobility issues in multicell wireless local area networks is needed. The physical layers discussed include direct sequence spread spectrum (DS-SS), frequency hopped spread spectrum (FH-SS), and diffuse infrared. Both spread spectrum transmissions are in the 2.4 to 2.4835 GHz ISM band, according to FCC part 15.247. >

Abstract: The goal of the paper is to propose a general approach for the authentication of users in remote domains while maintaining strict separation of security domains. The article begins with a discussion of security issues specific to user mobility, with identification of authentication requirements. Authentication solutions in existing mobile-user environments are summarized, the authors' solution to authentication of mobile users is presented, then some variations on the theme are introduced. >

Abstract: A recently completed single-site study has yielded information about how Internet traffic will evolve, as new users discover the Internet and existing users find new ways to incorporate the Internet into their work patterns. The author reviews existing statistics and studies of network growth, which show that network traffic generally grows exponentially with time, at least until the network carrying capacity is reached. He then describes how he captured and reduced the data used in this study. The following points are also addressed: the overall growth in the site's wide-area traffic; the appearance of periodic traffic; the growth in network use by individual computers or users; and the changing geographic profile of the traffic. The implications and limitations of the results are also summarizes. >

Abstract: The authors have discussed several alternatives in wireless LAN design: media choice, operating frequency, operating mode, network topology, and access method. Although each technical choice presents both advantages and disadvantages, they argue that there is a design point that provides the best fit with present and future wireless LAN user needs. Considering all factors/spl mdash/including robustness, regulatory considerations, and interference avoidance/spl mdash/using a product based on the slow frequency-hopping spread spectrum, in the 2.4 GHz ISM band, relying on a base station remote station network topology and using a TDMA-based access method is the best way to meet the needs of radio-frequency wireless LAN users. The choices are many, but slow frequency-hopping at 2.4 GHz and TDMA-based medium access control provide the best mix of cost, range, interference, and performance. >

Abstract: The authors propose a communication and presentation model called XOCPN, which can specify temporal relationships for the presentation of pre-orchestrated multimedia data, and communication requirements for the timely delivery of these data through multiple virtual circuits (MVCs). In particular, XOCPN contains connection set-up for guaranteeing required QoS parameters for efficient delivery of multimedia data, and various grains of stream synchronization (e.g., intra-stream synchronization, inter-object synchronization, and interstream pacing). The source and the destination interact in harmony and carry out different functions embedded in the transmitter and the receiver XOCPNs to accomplish synchronous playout of multimedia data. A protocol architecture and a set of service primitives have been proposed for the realization of the proposed model in a practical environment. Subsequently, the authors present a communication architecture that can be implemented using an ATM-based network, due to its flexibility in handling various types of traffic. >

Abstract: ATM will provide flexibility in bandwidth allocation and will allow a network to carry heterogeneous services ranging from narrowband to wideband services. The challenge is to build fast packet switches able to match the high speeds of the input links and the high performance requirements imposed. The CCITT has standardized the asynchronous transfer mode (ATM) as the multiplexing and switching principle for the broadband integrated services digital network (B-ISDN). ATM is a packet and connection-oriented transfer mode based on statistical time division multiplexing techniques. The information flow is organized in fixed-size packets called cells, consisting of a user information field (48 octets) and a header (5 octets). The primary use of the header tag is to identify cells belonging to the same virtual channel and to make routing possible. Cell sequence on a virtual channel is preserved, a very low cell loss probability must be guaranteed ( >

Abstract: A UMTS (Universal Mobile Telecommunications System) user profile denotes in which domains and under which conditions a specific service is available to a user. As the research work on UMTS is still in progress, new requirements for the user profile and its management are likely to be set. This article discusses the UMTS user profile identification issues. The authors introduce first the concept of user profile and the UMTS entities related to it. Then, the user profile is described and its management requirements are discussed followed by the description of two scenarios proposed for the user profile identification. Finally, the authors give a comparison of the two scenarios and their concluding remarks. >

Abstract: Considers the security aspects of communication between two management processes operating in different management domains; identifies two major risks: the security of information exchanged during the management association, and control of access to the management information base (MIB); and enumerates the various threats that must be guarded against and possible methods of attack. Security techniques, including symmetric and public key cryptosystems, are employed in the design of a method of achieving a secure management association. A scheme of authorization control for MIB access is developed. The management of an open system's network resources takes place in the context of a management association. The resources themselves are controlled by an agent process which presents a view of these resources to the outside world as a number of managed objects, each of which contains a number of attributes. The collection of objects presented to the outside world by the agent is known as the MIB. A manager process regulates the operation of the managed resources by engaging in a management association with the agent and instructing it to carry out simple operations on elements of the MIB. Within a single management domain where all processing nodes and network links are under the control of the same administration, security is not such a critical issue. However, when the management association takes place across the boundary between two separate management domains, and make use of public data networks, security issues must be considered in greater detail. >

Abstract: As research has progressed, it has become clear that the main difficulties in ATM pertain to its operational details rather than the concept. And it seems likely that these control issues will be much more complicated and costly for ATM switches when compared with current telephone circuit switches. The asynchronous transfer mode (ATM) is the target switching technique for the future public broadband integrated services digital network (B-ISDN). The purpose of this article is to examine the management and control functions in ATM switching systems implied by current industry standards and agreements on OAM and traffic control. Until now, ATM research in the areas of switch design and traffic control have progressed essentially independently. First, we briefly review the B-ISDN Protocol Reference Model and its representation of the different information flows in ATM. Network management and traffic control principles in ATM, and in particular OAM, are overviewed. With this information as background, we attempt to infer their implications on the functional blocks of an ATM switching system. An example switch architecture model with distributed management and control functions is outlined, and some design issues are discussed. >

Abstract: The authors present an overview of the major principles and concepts of the INA architecture, describe the requirements imposed by telecommunications applications on a software architecture for such applications, and outline the major principles of the INA architecture and how these principles meet the requirements of telecommunications applications. They also describe the services provided by the distributed processing environment (DPE), which provides the infrastructure for distributed applications, the use of the architecture concepts in a specific application, and the status of the INA laboratory experiments and field trials currently under way. >

Abstract: Multimedia multi-user applications are becoming more and more important. Intensive research is underway on the design of protocols and protocol entities for future communication systems supporting multimedia multi-user applications. The development of a service description ensures that protocol designs actually produce the required functional behavior. The authors explain the approach to the description of a multimedia multi-user service. An example illustrates the use of the service description in the design of communication systems. Next, they present the basic requirements of multimedia and multi-user communications. A call model underlies and structures the service description. Finally, the authors describe the service in terms of service elements. >

Abstract: This article focuses on architectures for providing universal personal telecommunications (UPT) service to wireline users. Although UPT services could be provided to users of wireless phones, thereby giving those users personal communication services (PCS), the wireline environment introduces certain important complications. Unlike "smart" cellular phones, which can register themselves and the user automatically, wireline telephones are unable to automatically detect and register a UPT user. UPT therefore includes a manual registration procedure to associate a PTN with the phone where calls will be received or placed. Also, unlike personal communications terminals that are typically used by only one person, wireline phones are likely to be shared among other users. Therefore, the network must keep track of who is using the phone, so it can provide the appropriate telecommunications services. It would be difficult or impossible to implement UPT as a switch-based service. Fortunately, an intelligent network (IN) architecture that is well suited for implementing UPT is being deployed by many local exchange (LECs) and interexchange carriers (IXCs). >

Abstract: With the appropriate architecture, telecommunications services can work with computer applications components to support networked information services. ANSA is an architecture that enables telecommunications services and computer application components to work together despite diversity of programming languages, operating systems, computer hardware, networks, communications protocols and management, and security policies. The architecture is relevant to telecommunications, manufacturing, sales, cooperative working, banking, health service, research, and other applications. It provides a framework for the design and implementation of distributed computer systems supporting networked information services. The framework ensures that different design choices, made for particular applications, present the maximum opportunity for interworking. >

Abstract: The authors describe the performability manager, a distributed system component that contributes to a more effective and efficient use of system components and prevents quality of service (QoS) degradation. The performability manager dynamically reconfigures distributed systems whenever needed, to recover from failures and to permit the system to evolve over time and include new functionality. Large systems require dynamic reconfiguration to support dynamic change without shutting down the complete system. A distributed system monitor is needed to verify QoS. Monitoring a distributed system is difficult because of synchronization problems and minor differences in clock speeds. The authors describe the functionality and the operation of the performability manager (both informally and formally). Throughout the paper they illustrate the approach by an example distributed application: an ANSAware-based number translation service (NTS), from the intelligent networks (IN) area. >

Abstract: Describes nomadic computing services built with currently available hardware and used on a daily basis by a small community of users. This environment consists of applications accessing pagers, facsimile, answering machines, telephone lines, speech synthesis, and digital recording and playback. Its key contributions are the integration of multiple media into a cohesive nomadic information infrastructure and a graceful transition from desktop to nomadic locales. This integration is at the service and user interface levels; the point of the article is that one can successfully prototype a suite of multimedia nomadic services by cobbling together applications, shellscripts, and disparate hardware components. The nomadic services make strong use of speech to provide remote access over ordinary telephone lines to a suitable set of tasks that users normally perform at the desktop. The authors place particular emphasis on communication, spanning voice as well as text and facsimile messaging. In addition these services provide personal information management, remote database access, and short-term information caching. The link between nomadic and desktop computing also changes office applications-nomadic services utilize demanding new media and 24-hour access changes how subscribers use and rely on traditional desktop databases. >

Abstract: What is probably the most unique aspect of the North Carolina information highway is the spirit of cooperation that exists between the public and private sectors, as well as cooperation within each of those sectors. North Carolina initiated the first state-wide information highway to utilize asynchronous transfer mode (ATM) switching and synchronous optical network (SONET) transmission equipment. Several trials have been conducted using ATM technology, but this is the first operational network to be deployed on such a large scale. The initial sites include hospitals, universities, community colleges, public schools, correctional facilities, and various administrative government locations. North Carolina requested that telephone companies within the state work together to develop a proposal for a comprehensive network that would not only serve state government applications, but the applications of current and prospective businesses in the state. This allows the state to share risks associated with building the first network of this type, and also places the responsibility for operations and upgrades with the telephone companies, so that their expertise in these areas can be utilized. >

Abstract: To offer personal communication services (PCS) to large segments of the population, sophisticated digital radio access techniques and extensive use of "Advanced Intelligent Network" services of public wireline networks will be required. To accommodate wireless access on such a wide scale, a broad range of challenging new teletraffic problems will need to be solved. In this article the authors give a brief, high-level overview of some of the important teletraffic issues that they believe will need to be addressed to support widespread deployment of PCS. Much more work is needed in order to refine our understanding of these issues, to prioritize specific problems, and to solve them. The purpose of this article is not to provide an exhaustive list of all PCS teletraffic issues, but rather to stimulate discussion of these problems. >

Abstract: The telecommunications planners for the North Carolina State Government recognising the potential of asynchronous transfer mode and synchronous optical network, asked BellSouth, Carolina Telephone, and GTE to develop a proposal for a network based on ATM and SONET to enable a multitude of high-speed data and video applications throughout the state. This B-ISDN, now known as the North Carolina Information Highway (NCIH), has become widely recognized as a model for the National Information Infrastructure (NII). The services provided by the NCIH are designed to be able to support numerous emerging applications that are expected to provide significant benefits in the areas of education, health care, crime control, economic development, and government. >

Abstract: Medical applications employing an ATM network have been under development with the VISTAnet and Medical Information Communication Application (MICA) trials in North Carolina. The extraordinary switching and transport capabilities of ATM networks represent an enabling technology for many health care applications. VISTAnet and MICA have provided early experience with the networks to support such applications. The NCIH will provide a public ATM platform to expand such efforts throughout North Carolina, and will ultimately provide universal access to a myriad of public information services. VISTAnet has enabled studies in high-speed computation and networking, along with real-time multidimensional imaging. As a result, a new dynamic radiation therapy planning process has been developed that promises to advance the state of the art for radiation treatment. This articles describes the early medical prototype applications of VISTAnet and MICA, and discusses some of the emerging medical applications to be implemented in the NCIH, based on the information learned in the VISTAnet and MICA trials. >

Abstract: To support the North Carolina Information Highway network and its services, GTE has developed new capabilities for the integrated management of broadband networks. These include: functionally integrated network management, enabling GTE to monitor and control ATM, SONET, and other related networks in real time, these capabilities are provided by the TelOps Network Integrated Control System (TONICS); and automated service management, enabling GTE to provide service-level configuration and fault management for new broadband services, these capabilities are provided by the broadband service management system (BSMS). Together, TONICS and BSMS provide a complete and integrated solution for managing broadband networks such as the NCIH. >

Abstract: As the first information highway of its kind, the North Carolina Information Highway is likely to set an example for ATM broadband deployment not only in the BellSouth region but also in the rest of the country. The article outlines an evolutionary path for new network architectural features and additional video and data services that can be supported by the NCIH. These architectures will support the introduction of on-demand video services (e.g. the distance learning service), and other associated vertical services. As standard procedures are developed, users will be able to use data services like TCP/IP and frame relay over large-bandwidth ATM connections. In addition, they will have opportunities to use their existing applications in the legacy LANs, as well as with ATM endpoints. As ATM standards agreements are realized over the next few years, and the ATM technology cost curve continues to improve, the NCIH will prove to be a very cost-effective and high-performance alternative for all the high-speed communication needs of the North Carolina State Government. >

Abstract: The article first briefly reviews the relevant aspects of standard HIPPI channel operation, ad hoc serial HIPPI channel extension, and the rationale for HIPPI channel extension over WANs, and provides a description of standard STS-12c SONET (STM-4c). HIPPI over SONET encapsulation protocol, reliable flow control method and performance, and the actual implementation are then described, including maintenance needs such as SNMP monitoring, laser lifetime monitoring, and loopback functions. Concluding comments cover the status of the HIPPI-SONET development effort, other HIPPI-SONET developments, and the need and approach to providing HIPPI-ATM-SONET connectivity via adaptation of HIPPI-PH packets to standard ATM protocols. >

Abstract: Sexual discrimination as evidenced by various socioeconomic inequalities worldwide make women vulnerable to HIV/AIDS. HIV/AIDS is increasing faster among women than among men in many countries. 3000 women become infected with HIV each day. Success of long-term development efforts to improve womens status is needed to bring about changes in gender relations. The rapid spread of HIV/AIDS among women threatens socioeconomic development in many regions because women play a critical role in agriculture trade child rearing and family support. The primary mode of HIV transmission in most regions of the world is heterosexual intercourse. More women than men are HIV infected in Sub-Saharan Africa. In Zimbabwe between 1987 and 1993 there were 5 HIV-infected women 15-19 years old for every 1 HIV-infected young man. 70% of all HIV-infected women worldwide are 15-25 years old. The stereotype is that only homosexuals IV drug users and prostitutes spread HIV. In Sao Paulo Brazil AIDS is the major cause of death among 20-35 year old women. Since many cultures consider ignorance of sexual matters a sign of purity young women fear seeking reproductive health information and services. Most societies expect women to be monogamous but expect men to have extramarital affairs. Monogamy does not protect a woman from HIV infection if her husband has partners other than the wife. Women who ask their partner to use a condom or to avoid penetration are at risk of violence or abandonment. Women need to work together to shatter the myth that only women with many partners are at risk of HIV infection and to address their own attitudes. Men need to be more responsible in protecting themselves and their partners. Improved communication between partners is also needed. HIV prevention and counseling services through family planning programs help women protect themselves. HIV/AIDS is forcing us to face chronic problems including economic inequities violence and sexually transmitted diseases.

Abstract: This article describes the approach which has been used to implement a sector of the information highway throughout the state of North Carolina, with specific attention focused on the functionality of the equipment that comprises the North Carolina Information Highway (NCIH). This implementation of this information highway is based on ATM technology, used in both the switching systems of the network and the customer premises equipment (CPE). The large ATM switching systems provide the extensive number of connections that are predicted for the information highway. Multiple services can also be supported on the ATM switches. The information streams for these different services can all be converted into ATM format using the appropriate ATM adaptation layer for transport through the ATM network. By being able to support multiple services, and transport them across common ATM facilities, the ATM switches offer the NCIH great flexibility in the applications that can be provided to the customers. Use of the ATM technology allows the NCIH to provide the backbone for various services. To provide the distance learning service application and other applications on the NCIH, ATM capabilities are also being provided in CPE on a service multiplexer. >

Abstract: Recent reviews suggest that the addition of programs aimed at preventing and controlling sexually transmitted diseases (STDs) specifically human immunodeficiency virus (HIV) to existing family planning programs does not necessarily dilute overall program effectiveness. In Colombia Mexico and Jamaica where condom distribution and/or information to prevent HIV transmission was integrated into the activities of family planning field workers no negative effect on the image of condoms as a pregnancy prevention method was observed and there was a great demand on the part of family planning clients for information about acquired immunodeficiency syndrome (AIDS). In Brazil family planning staff are receiving training in HIV risk assessment and the counseling of women in partner negotiation skills. However steps must be taken to reach men since it is their high-risk behavior that puts most women at risk of HIV. Both separate STD clinics for men and condom social marketing projects have yielded promising results. Obstacles to the addition of STD services to family planning programs include the need to treat male partners as well as female clients a shortage of diagnostic tools and antibiotics for treatment and the fact that the majority of women with STDs are asymptomatic. Indicative of the increased attention being given this approach however is the recent release of guidelines by the US Agency for International Development Office of Population on how family planning programs should approach integration. Suggested activities include condom promotion behavior change counseling information contraceptive development and selected efforts at STD treatment.

Abstract: Women who have had unprotected intercourse can use emergency contraception to prevent pregnancy. Emergency contraception can be a backup contraceptive method under circumstances of incorrect method use or method failure. It can also be used in cases of sexual assault. Oral contraceptives (OCs) and IUDs can be used as safe and effective postcoital contraceptive methods. Since postcoital contraception is less effective and may cause bothersome side effects (e.g. nausea) it should not be used often. Women need to know about and have access to emergency contraception. Some family planning providers do not offer emergency contraception. Many providers do not have adequate knowledge of emergency contraception. Other barriers to emergency contraceptive use are that clinics are closed at night and during the weekend when the need is highest and the requirements for prescription. Emergency contraception protects against pregnancy by blocking ovulation fertilization transport of the fertilized ovum or implantation. Combined OCs (2 doses of 100 mcg ethinyl estradiol + 0.5 mg levonorgestrel taken 12 hours apart) are the most common emergency contraceptive method. Other hormonal methods of postcoital contraception are progestin-only OCs (2 doses of 0.75 mg levonorgestrel taken 12 hours apart) estrogen (5 mg ethinyl estradiol for 5 days) a synthetic androgen (2 doses of 400-600 mg danazol taken 12 hours apart) and an antiprogestin (600 mg mifepristone [RU-486]). The combined OC the androgen and the antiprogestin need to be taken within 72 hours of unprotected intercourse. The progestin-only OC and the estrogen must be taken within 8 hours and 48 hours of unprotected intercourse respectively. The IUD must be inserted within 5 days. It should be avoided in women at high risk of sexually transmitted diseases however. When a woman seeks emergency contraception providers should counsel her about effective regular contraception and ask her about her plans should she become pregnant.