Showing papers in "IEEE Communications Magazine in 1985"

The DARPA internet protocol suite

Abstract: THE MILITARY requirement for computer communications between heterogeneous computers on heterogeneous networks has driven the development of a standard suite of protocols to permit such communications to take place in a robust and flexible manner. These protocols support an architecture consisting of multiple packet switched networks interconnected by gateways. The DARPA experimental internet system consists of satellite, terrestrial, radio, and local networks, all interconnected through a system of gateways and a set of common protocols.

Message authentication

Abstract: In the last chapter, we discussed the data integrity threats and the use of hashing technique to detect if any modification attacks have taken place on the data. Another type of threat that exist for data is the lack of message authentication. In this threat, the user is not sure about the originator of the message. Message authentication can be provided using the cryptographic techniques that use secret keys as done in case of encryption. Message Authentication Code MAC MAC algorithm is a symmetric key cryptographic technique to provide message authentication. For establishing MAC process, the sender and receiver share a symmetric key K. Essentially, a MAC is an encrypted checksum generated on the underlying message that is sent along with a message to ensure message authentication. The process of using MAC for authentication is depicted in the following illustration −

Security in high-level network protocols

Abstract: here are several trends, which the widespread adoption of standard high-level network protocols will intensify, that emphasize the need to develop network security mechanisms. First, the increased use of networks to provide remote access to computer facilities makes attacking networks more attractive to an intruder. Second, the growing quantity and value of information made vulnerable by the breaching of network security makes networks tempting targets. Third, computer systems connected by networks are likely to cooperate in various ways to provide resource sharing for a user community. As a result of this sharing, the security of information on a given host may become dependent on the security measures employed by the network and by other hosts. Finally, the development of new network technologies facilitates certain kinds of attacks on communication systems; for example, it is easy for an intruder to monitor the transmissions of satellite and radio networks. Potential security violations can be divided into three distinct categories:

ISDN protocol architecture

Abstract: IT IS NOW widely recognized that the Integrated Services Digital Network (ISDN) concept is providing a useful framework for the development of future telecommunications networks and services. An ISDN can be regarded as a generalpurpose digital network capable of supporting (or integrating) a wide range of services (voice and non-voice) using a small set of standard multipurpose user-network interfaces. Relevant CCITT Recommendations (or standards) on ISDN interfaces were expected to be available in 1984, the final year of the current study period. This paper reviews CCITT progress on the architectural studies of protocols associated with ISDN's, in particular, the ISDN Protocol Reference Model being developed by Study Group XVIII. This Model, based on the concepts and principles of the ISO/CCITT Open Systems Interconnection (OSI) Reference Model, aims at providing a unified framework for modeling ISDN multiservice communications and capabilities. The new Model is applied to several possible ISDN communications configurations, enabling a number of technical issues to be easily identified.

What is network planning

Abstract: The National Communications System (NCS) in support of its primary mission is exploring revolutionary communication concepts for the 21 century. These concepts are in the specialized fields of smart materials and structures, advanced network architectures, and intelligent systems. The purpose of this report is to assess the state-ofthe-art and state-of-the-practice in these technologies and in intelligent software agents related to these concepts. Further, the ability of the telecommunications infrastructure to support agent-based monitoring, detection, planning, cooperation, and decision-making in support of National Security and Emergency Preparedness (NS/EP) situations was also investigated. Specificity, the report focuses on the evolving network infrastructure, wireless networks and Internet-based networks, to support both intelligent systems and smart structures. The finding of this report suggest that the NCS should work with its governmental and industrial partners to promote NS/EP requirements in there specifications, designs and implementations of these revolutionary concepts so they can be seamlessly incorporated into legacy and future communications systems. In support of these efforts, NCS should create an environment that fosters the development of proof-of-concept experiments exploring the integration of these technologies in the context of NS/EP situations and scenarios; wherein, integrated intelligent systems incorporating smart structures could combine wireless and Internet technologies to allow devices to communicate over the Internet and Public Switched Telephone Network (PSTN).

An informal overview of formal protocol specification

Abstract: A RAPIDLY GROWING area of research in computer communications is formal protocol specification. The importance of protocols arises from the fact that protocols form the nervous system of teleprocessing networks and, as such, are responsible for ensuring that the pieces of the system work as a harmonious whole. The complexity and size of today's systems and the fact that they are put together from subsystem components manufactured in different locations and even by different companies, virtually demand formal specification. And, there are many side benefits, as this tutorial points out.

Land mobile radio systems - A tutorial exposition

Abstract: ∗Southern Methodist University †Southern Illinois University Carbondale, viswa@engr.siu.edu ‡University of Puerto Rico Mayaguez Published in Gupta, S., Viswanathan, R., Muammar, R. (1985). Land mobile radio systems– A tutorial exposition. IEEE Communications Magazine, 23(6), 34-45. 1985 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author’s copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.

An interactive touch phone for office automation

Abstract: THIS PAPER describes the exploratory development of a microprocessor-controlled PABX telephone called the Touch Phone. Advanced hardware and software techniques have been utilized in the system design to implement new interface concepts for a user-friendly PABX telephone set. With its interactive capability, the user can easily gain access to the many features of a modern PABX system with minimal memorization. The user enters commands by touching "buttons" on a touch-sensitive screen that are drawn by the self-contained microprocessor. With the guidance of tree-like structured menus presented on an electroluminescent (EL) display panel, the user can interactively select the various features and options provided by the PABX system. The goals of the Touch Phone are to make the man-machine interaction simple and precise.

Mobile packet radio networks: State-of-the-art

Abstract: MUCH WORK HAS been done in the areas of packet switching, packet radio, and random communication channels. However, efforts combining these areas are not as plentiful. There are several reasons for this. One reason is, the packet communications area is relatively young. Much of the research into packet communications has been accomplished by computer scientists rather then communications engineers, with a resulting emphasis on architecture, protocols, software, and so on. Even the development of packet radio has not fostered extensive examination of link effects on system performances. The UHF line-of-sight links and SHF satellite links have been assumed to be perfect with packet collisions as the dominant error source, which is a good assumption under normal circumstances. However, abnormal circumstances including ionospheric scintillations and multipath fading are another source of error on degraded packet radio links, which characterize Mobile Packet Radio Networks (MPRNET). In this paper we define and discuss Mobile Packet Radio Networks and presend their channel characteristics. The performance avaluation of some channel access protocols for a Mobile Packet Radio Network link, which is a typical example of a degraded packet radio channel, is descirbed.