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Publications:

ARRL 6th Computer Networking Conference 1987

6th.jpeg

This proceeding is available on CD-ROM


Location:
Redondo Beach, California

Coordinators:
Harold Price, NK6K
Walter A. Linstruth, WA6JPR
Paul L. Rinaldo, W4RI

Hosted by:
TRW ARC
Southern California Digital Communications Council

Abstracts:
6th Computer Networking Conference
August 19, 1987

Estelle: A Formal Description Technique for Communication Protocols
by Michel Barbeau, VE2BPM
Introduction: Estelle is a FDT developed by ISO (International Standard Organization). It is based on an Extended Finite State Machine model (EFSM). A finite state machine is a simple abstract device which has states and transitions labelled by input and output symbols. A state transition table is one of the possible ways to represellt textually a FSM. FSM's are frequently used to model the control flow of systems. Communication software, such as data link protocols, have usually a compliment that can be represented by FSM's. As an example see the state transition tables of the AX.25 link-layer protocol in appendix D. Protocols have also data flow aspects involving interaction parameters, different kinds of variables and data operations. The data flow aspects are hard to represent using only FSM's. Estelle extend the idea of FSM in a sense that variables, actions and predicates, operating on those variables, are added to this basic model. The syntax of Estelle has been defined from the syntax of the programming language Pascal. New elements have been added in order to make easier the definition of aspects particular to comnlunication protocols. In Estelle can be expressed both the control flow aspect, using FSM's, and the data flou aspect, using Pascal's elements, of a comlllunication protocol. Protocol specifications written in the formal language Estelle are said formal with respect to informal specifications written in a natural language such as English.

Proceedings Paper



OSI: A Plan Comes Together
by J. Gordon Beattie, Jr., N2DSY, Thomas A. Moulton, W2VY
Abstract: This paper will provlde an overvlew of the current state of services avilable on the Amateur Packet Radio and then offer solutions to the problems and limitations found. This will include an outline of a communications architecture for distributed computer systems using the Open Systems Interconnection Reference Model (OSI-RM). We will also provlde a description of systems required to support the data transport and application needs of the Amateur Packet Network user. These OSI-based systems have been designed to inter-operate with each other and with other systems not part of the Amateur Packet Network. This architecturally consistent approach addresses the operatlonal Objectives of Services, Managibility, and Performance. It has the further advantage of world-wide acceptance.

Proceedings Paper



A High Performance Packet Switch
by Mike Brock, WB6HHV, Franklin Antonio, N6NKF, Tom Lafluer, KA6IQA
Abstract: This paper describes the PS-186TM, a high-speed multiport packet switch designed to support data rates up to 1 Mbit/second. It can also be used as a local packet node, mail system, or a gateway to other networks. It operates on 2.1 Watts of power. The PS-186 was designed by members of the San Diego Packet Radio Association (SANDPAC).

Proceedings Paper



The KISS TNC: A Simple Host-to-TNC Communications Protocol
by Mike Chepponis, K3MC, Phil Karn, KA9Q
Abstract: The KISS TNC provides direct computer to TNC communication using a simple protocol described here. Many TNCs now implement it, including the TAPR TNC-1 and TNC-2 (and their clones), the venerable VADCG TNC, the AEA PK-232/PK-87 and all TNCs in the Kantronics line. KISS has quickly become the protocol of choice for TCP/IP operation and multi-connect BBS software.

Proceedings Paper



Digital Signaling Processing and Amateur Radio
by Dr. Thomas A. Clark, W3IWI, Dr. Robert W. McGwier, N4HY
Introduction: Tom calls the necessary ingredient magic, and Paul Rinaldo, W4RI, calls the necessary ingredient an incubator[1][2]. Whatever you choose to call it, we have lacked the necessary ingredient in ham radio to broadly apply the collection of techniques known as digital signal processing (DSP). The magic in the amateur satellite service has been provided by AMSAT[3]. In the digital communications modes, the incubator was supplied by TAPR[4]. AMSAT and TAPR have joined to support an incubator project to achieve the broad use of DSP in amateur radio.

DSP is a field which has its roots in the mathematics of Newton, Gauss, and Fourier. These people lived hundreds of years ago. Why are we stessing these ancient techniques? Primarily because a much newer technological revolution has taken place which allows us to apply DSP techniques in increasingly complex combinations. Of course, we are talking about computers in general and microprocessors in particular. Until the very recent past, even microprocessor elements were primarily used in proprietary special purpose devices with specific tasks in mind. For example, there are DSP chip sets manufactured by several companies that are totally dedicated to being Bel-212 modems for phone line use. (...)

Proceedings Paper



A Duplex Packet Radio Repeater Approach to Layer One Efficiency
by Robert Finch, N6CXB, Scott Avent, N6BGW
Purpose: In January, 1984, South Coast Radio Relay, a Southern California Amateur Radio group specif ically chartered to experiment in state of the art message handling techniques, modified its two meter duplex voice repeater in Glendale, California, for full time digital communications. This operation has remained on the air since that time, under both the original callsign; N6TD/R and the since adopted call; N6GPP/R. This operation has undergone some specif ic changes in the past several years, but the basic user interface has essentially remained the same. This paper will examine the basic operational characteristics employed at the repeater site, specific to the repeater itself, and will aid the reader in duplicating the methods used to achieve the promise inherent in local area duplex packet operation.

Proceedings Paper



Packet Radio Developments over the Last Year
by Terry Fox, WB4JFI
Abstract: Over the last year AMRAD has been continuing it's work on the deveiopment of packet switc hardware and software. Our progress has been slower than we had hoped, due to our interests in other projects, such as spread spectrum. The hardware portion of our packet switch has made better progress than the software. Over the next vear we hope to make more progress in software development. What follows is a brief description of what I think have been some significant advances over the last year, along with some of my current thinking in packet network development.

Proceedings Paper



Thoughts on the Issues of Address Resolution and Routing in Amateur Packet Radio TCP/IP Networks
by Bdale Garbee, N3EUA
Abstract: The current KA9Q software includes a technique for automatic address resolution, but does not include automatic routing features. The difference between routing and address resolution is explained, and several concerns for on-air automatic routing algo- rithm implementations are mentioned.

Proceedings Paper



The Design of a Mail System for the KA9Q Internet Protocol
by Bdale Garbee, N3EUA, Gerard van der Grinten, PA0GRI
Abstract: The current implementation of the mail manipulation system that has been built by N3EUA and PA0GRl for the KA9Q Internet Protocol Package is described briefly. A proposal for the next generation of network mail handling for the KA9Q Internet environment is described. An important change in the way we can and should think about electronic mail in the amateur packet radio world is discussed.

Proceedings Paper



A Bit Error Rate Tester for Testing Digital Links
by Steve Goode, K9NG
Abstract: With the availability of several link-level protocols such as TEXNET and NETROM, many packet groups are installing inter-city digital links. As AEh and GLB begin shipping their digital radios and the 56 kbps radio demonstrated at the Dayton Hamfest becomes available, more Amateurs will require a method of testing the performance of these digital radios. This paper presents a test circuit which can be used during initial installation of a digital link to enable the installers to fine tune the radio on site. This circuit temporarily replaces the TNC or control computer and allows the installers to listen to the data link to determine how well it is performing. It can also be used for bench testing digital radios and modems.

Proceedings Paper



A 56 Kilobaud RF Modem
by Dale A. Heatherington, WA4DSY
Abstract: This paper describes a 56 kilobaud synchronous RF modem with a 70 kHz bandwidth. The modulation is bandwidth limited MSK generated by a digital state machine driving two digital-to-analog converters, and two double balanced modulators. The carrier phase is shifted plus or minus 90 degrees for each bit. Demodulation is accomplished with a standard quadrature detector chip but various coherent methods can be used for operation at lower signal to noise ratios. The design is relatively simple and easily reproduced.

Proceedings Paper



Reusable IP Addresses in a Dynamic Network
by Robert B. Hoffman, N3CVL
Abstract: The topology of amateur packet radio networks changes rapidly due to the frequent addition of new stations, shutting down of old stations, and changing location of others. This paper presents a method for managing IP address assignments within such a network.

Proceedings Paper



Software Design Issues for the PS-186 Advanced Packet Network Controller
by Brian Kantor, WB6CYT
Abstract: A fast network for amateur radio requires sophisticated node controllers to work well. Key to the performance of advanced node controller hardware is the design of the on-board software. Issues of highly-efficient device drivers, protocol encapsulation, and process management must be addressed to ensure acceptable pefformance with limited memory and affordable hardware. PS-186 hardware design issues are discussed in a companion paper by Michael Brock, Franklin Antonio, and Tom LaFleur.

Proceedings Paper



Another Look at Authentication
by Phil Karn, KA9Q
Abstract: A simple and effective technique for packet authentication in a datagram network is described that is based on the Data Encryption Standard (DES). In accordance with FCC rules, the actual data is not encrypted; rather DES is used to compute a special "cipher checksum" that is appended to the unencrypted user data before transmission. The recipient recomputes the cipher checksum and compares it against the incoming value, thereby detecting bogus or altered packets. This technique is potentially useful in a wide variety of amateur radio applications in addition to packet radio; for example, it could provide a secure control link for a remote repeater site.

Proceedings Paper



A High Performance, Collision-Free Packet Radio Network
by Phil Karn, KA9Q
Abstract: For the past several years, those discussing "level 3 networking" have made much of the performance gains to be had through hop-by-hop acknowledgements. In this paper I will show that, while sometimes helpful, hop-by-hop ACKing is not the panacea it is generally perceived to be. Only fundamental changes in the way we allocate and use frequencies will really fix the problem.

Proceedings Paper



The KA9Q Internet (TCP/IP) Package: A Progress Report
by Phil Karn, KA9Q
Abstract: For over two years, the author has led the development of C-language software implementing the ARPA Internet protocol suite (commonly called "TCP/IP"). Intended for amateur radio use, the software was originally written on and for the IBM PC and its clones running MS-DOS. However, the use of a de-facto industry standard protocol set has resulted in considerable interest in and contributions to the effort by non-amateurs as well. The software has been "ported" to several different computers and is enjoying increasing use in both conventional Local Area Network (LAN) environments as well as amateur packet radio. This paper describes the considerable progress this effort has made, and reflects on the choice of TCP/IP now that significant on-air experience has been gained.

Proceedings Paper



Approach for Digital Transmission of Pictures
by Thomas Kieselbach, DL2MDE
Abstract: "A picture 15 worth a 1000 words" is a saying confirmed daily. It should be remembered that transmission of picture signals began in the early days of radio. The individual techniques were adapted to the specific needs at the time, thereby resulting in diverse systems each being optimized in accordance with the requirements and the method of transmission used.

Proceedings Paper



RUDAK - The Packet Radio Experiment On-Board OSCAR P3C
by Hans peter Kuhlen, DKlYQ
Abstract: Nearly two years ago, AMSAT-DL initially published the outcome of its first RUDAK system design meeting at the 4th ARRL Conference in San Francisco [1]. At this time we wish to present the current status of the flight ready hardware and the completed and tested ground station equipment. This paper will briefly present the objectives of the RUDAK experiment and the performance achieved by the RUDAK transponder on-board OSCAR Phase 3 C. It will also include a description of a recommended user terminal which can be utilized for all satellite operating modes via OSCAR Phase 3 C, FUJI OSCAR 12, as well as for terrestrial packet radio.

Proceedings Paper



Improving Shared Channel Access Techniques for Amateur Packet Radio
by Brian Lloyd, WB6RQN
Abstract: Amateur Packet Radio has come of age. There are now many packet radio users in the Amateur community, well over 20,000 at this point. In the "olden days" when there were few users on a channel at any one time the need for effective channel access techniques was much less than it is now. The problems all result in the same symptoms: poor throughput and lost connections.

Proceedings Paper



The Noise Performance of Several Data Demodulators
by Hugo Lorente, LU4DXT
Abstract: This paper shows the noise performance of several data demodulators currently being used in pac~et radio. The bit error rate (BER) in presence of white Gaussian noise was measured on the followlng demodulators: 1) JAS-l PSg demodulator 2) Discriminator 3) AMD 7910 modem 4) Differential detector 5) G3RUH PSK demodulator 6) EXAR 2211 demodulator. The noise performance of this demodulators is graphically presented here and a brief description of the test gear used in these measurements is given in appendixes A and B.

Proceedings Paper



Overview of the TEXNET datagram protocol
by T.C. McDermott, N5EG
Abstract: This article is an overview of the TEXNET datagram network protocol. It is not intended as a specification. It deals i with the protocol within the network (intra-network). It does not deal with layer 3 protocol issues between the user and the network (inter-network).

Proceedings Paper



CSMA Multihop Networks: Throughput Analysis by Dr. Bob W. McGwier, N4HY
Abstract: Amateur Radio uses packet radio in a broadcast mode and typically uses omnidirectional antennas for transmission. If the two ends of the data transfer are not within communication range, we will use a digipeater. The protocol we use for medium access control is carrier sensed multiple access (CSMA) protocol. Under CSMA, a terminal will not transmit if it hears a transmission in its neighborhood. In a multihop environment (digipeater) such as ours, CSMA is subject to "hidden transmitter" interference. This is w hen two or more transmitters outside hearing range of each other key up at the same time and interfere with one or more recipients of the two or more packets being simultaneously transmitted. We call this a collision. We could almost completely eliminate this problem with busy tone multiple access (BTMA) protocol. The "almost completely" in the previous sentence is caused by the finite speed of light and the response time of the receiver bringing up the busy tone. BTMA has implicit in its nature seperate transmit and receive operation. Several papers have appeared analyzing throughput in CSMA packet radio networks. The best papers and the most useful (not always the same) are by Boorstyn and Kershenbaum and we include one of their papers as our only reference as it contains the most complete set of references and is the basis for the work described here. They have introduced a continuous time Markov Chain model which lends itself to numerical techniques for finding the steady state response of moderate sized (100-200 nodes) networks. This type of model allows for dependencies between non-adjacent nodes to be modeled and analyzed. The primary purpose of this paper is to introduce these ideas to the amateur radio literature, to supply some rigor to Clark's "But Wait There's More" treatise, and hopefully give one more nudge to do something about the problem.

Proceedings Paper



DSP Modems: It's Only Software
by Dr. Robert W. McGwier, N4HY
Abstract: Are you as tired of buying new modems as I am ? There is an alternative and I think a superior one in several regards. From the title, and the joint paper with Tom W3IWI, it should be obvious that we are talking about doing modems on DSP engines. Using a single chip processor as the basic building block, a low cost, high speed modem can be programmed to operate through unconditioned radios. If you want a different modem ten minutes later, you just change the software driving the chip. The primary advantages stated more explicitly are (1) a single piece of hardware can make and demodulate the phase or frequency modulated synchronous signal of your choice, and (2) the software can do very effective adaptive equalization to ameliorate the bad things the radio (filtering) is doing to your data signal.

Proceedings Paper



HF Packet: Where do we go from here?
by Barry D. McLarnon, VE3JF
Introduction: Packet radio on the HF bands is alive and well, and is steadily gaining in popularity. The HF links which have been established between widespread packet bulletin board systems have become a workhorse in moving error-free traffic beyond the limits of the VHF/UHF packet networks. These links will, of course, never be capable of handling huge volumes of traffic, like megabyte files: the bandwidth simply isn't sufficient. Satellites and expanded UHF/microwave links must be developed to meet these requirements; but it is probably safe to say that HF will always have a role to play in amateur data communications, both as a back-up to these higher-capacity (but more vulnerable to failure) systems, and for extending the network into remote areas where setting up a satellite station may not be feasible.

Proceedings Paper



FINDER--The Family Information Database for Emergency Responses
by W.E. Moerner, WN6I, Sharon Moerner, N6MWD, David Palmer, N6KL
Abstract: FINDER is a new packet radio database application utilizing multiple connect and a specific syntax to allow emergency response personnel to ascertain the status of their family members during a disaster. This paper describes the history, scope, operation, and design philosophy of the FINDER system.

Proceedings Paper



Dial "0"; for Operator: Message Routing in the Amateur Packet Network
by Thomas A. Moulton, W2VY
Abstract: Over the past several years a variety of message routing systems have been used. The tendency has been to not step back from the problems and address fundamental lssues. This pager will attempt to achieve that elusive goal and outline a routing system which will allow the Amateur community to operate with efficiency and ease.

Proceedings Paper



Packet Radio and IP for the Unix Operating System
by Clifford Neuman, NlDMM
Abstract: Many services are currently available on the ARPA Internet that would be of interest to amateur packet radio users. The ARPA Internet connects universities and other organizations around the world that speak TCP/IP. One advantage of running TCP/IP on packet radio is the ability to access these services, and to interconnect with other systems that are part of the internet This paper describes the implementation of AX.25 as a link layer protocol for the Unix operating system and the use of this system as an IP gateway between our local amateur packet radio network and our department's ethernet at the University of Washington, which in turn provides access to the entire Internet The potential role of such a system for amateur packet radio is discussed, and a mechanism to allow users that don't have the resources to run TCP/IP themselves to access such services is described.

Proceedings Paper



Pacgram Messaging Protocol for Packet Networks
by Jay Nugent, WB8TKL
Abstract: In the 5th Computer Networking Conference papers David Cheek, WA5MWD, included in his submission an attatchment containing the Pacgram Protocol Definition. In this paper you will find the latest revision of that Pacgram Protocol Definition with a synopsis of Pacgram's creation, where it is at now, and where I hope it will go in the amateur packet radio community.

Proceedings Paper



Performance Monitoring or I Wanna Fix it, Is it Broke?
by Skip Hansen, WB6YMH, Harold Price, NK6K
Abstract: Much of the performance information on Amateur Packet Radio is anecdotal and ephemeral; a subjective and non-detailed account usually limited to a gross statement of "goodness" or "badness", which is neither well documented nor long remembered. While there are several papers which describe the expected performance of CSMA-type systems, there is little actual data about the live amateur packet system. The authors discuss the need for accumulating performance data and describe work in progress to supply performance measurement software using a C program and a TNC with KISS software.

Proceedings Paper



ASC X12.A-1985: Draft Proposed American National Standard for Electronic Business Data Interchange Amateur Radio Message Transaction Set
by Jack Sanders, NC4E
Abstract: This standard contains the format and data content of the Amateur Radio Message Transaction Set for use within an Electronic Business Data Interchange (EBDI) environment. The ASC X12 family of Electronic Business Data Interchange standards are based on interdependency. Several of the ASC X12 standards define the data elements, data segments, control structures and acknowledgments that relate to transaction set standards. Availability of the following standards is required in order to interpret, understand, and use the ASC X12 family of standards.

Proceedings Paper



Design Abstractions for Protocol Software
by Paul Taylor, VK3BLY
Abstract: As amateur packet radio software becomes more complicated and software development environments improve, the use of high-level languages will become more favourable. A design approach for protocol software based on modules and Finite State Machines is described, which formalises the interface to IO devices, and extends the use of the protocol's State Machine model into the implementation stage. Its adoption should make implementations of Level 2 and 3 protocols quicker, easier, and more understandable.

Proceedings Paper



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