Performance Evaluation of Packet Radio Networks Yangwei Wang Iowa State University

Total Page:16

File Type:pdf, Size:1020Kb

Performance Evaluation of Packet Radio Networks Yangwei Wang Iowa State University Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1988 Performance evaluation of packet radio networks Yangwei Wang Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Electrical and Electronics Commons Recommended Citation Wang, Yangwei, "Performance evaluation of packet radio networks " (1988). Retrospective Theses and Dissertations. 8900. https://lib.dr.iastate.edu/rtd/8900 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS The most advanced technology has been used to photo­ graph and reproduce this manuscript from the microfilm master. UMI Alms the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely aifect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are re­ produced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. These are also available as one exposure on a standard 35mm slide or as a 17" x 23" black and white photographic print for an additional charge. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. University Microfilms International A Bell & Howell Information Company 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 313/761-4700 800/521-0600 Order Number 8909202 Performance evaluation of packet radio networks Wang, Yangwei, Ph.D. Iowa State University, 1988 Copyright ©1988 by Wang, Yangwei. All rights reserved. UMI SOON.ZeebRd. Ann Aibor, MI 48106 Performance evaluation of packet radio networks by Yangwei Wang A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Department: Electrical Engineering and Computer Engineering Major: Computer Engineering Signature was redacted for privacy. Signature was redacted for privacy. n Cha Major Work Signature was redacted for privacy. apartment Signature was redacted for privacy. For Graduate College Iowa State University Ames, Iowa 1988 Copyright © Yangwei Wang, 1988. All rights reserved. ii TABLE OF CONTENTS ACKNOWLEDGEMENTS vii ABSTRACT viii 1 INTRODUCTION 1 2 OPERATIONS OF PACKET RADIO NETWORKS 4 2.1 Network Devices 5 2.2 Hearing Characteristics 9 2.3 Network Organization and Routing 11 2.4 Capture Effect 19 2.5 Acknowledgement Mechanism 20 2.6 Random Access Methods 22 2.7 Channel Performance Measures 39 3 SINGLE-HOP PACKET RADIO NETWORKS 42 3.1 Introduction 42 3.2 The Single-hop Network Model 44 3.3 Mathematical Formulation 50 3.4 Applications 55 3.5 Summary 74 iii 4 MULTI-HOP PACKET RADIO NETWORKS 78 4.1 Introduction 78 4.2 Review of Previous Models 79 4.3 Multi-hop Network Model 83 4.4 Requirements for a Successful Transmission 87 4.5 Throughput and One-hop Progress 97 4.6 Summary 113 5 CONCLUSIONS AND FUTURE WORK 115 5.1 Conclusions 115 5.2 Future Work 117 6 BIBLIOGRAPHY 118 iv LIST OF TABLES Table 2.1: Maximum throughput for CDMA protocols 31 Table 2.2: Channel capacity of Random Access Protocols 41 V LIST OF FIGURES Figure 2.1: A basic packet radio unit 8 Figure 2.2: Operations of the ALOHA protocol 27 Figure 2.3: Operation of nonpersistent CSMA protocol 33 Figure 2.4: Operation of p-persistent CSMA protocol 34 Figure 2.5: Operations of the CSMA/CD protocol 38 Figure 3.1: Distance distribution functions 56 Figure 3.2: Mass distribution functions 58 Figure 3.3: Normalized power distribution functions 60 Figure 3.4: Throughput vs. distance in Example 1 63 Figure 3.5: Throughput vs. transmission probability in Example 1 . 65 Figure 3.6: Average throughput for M = 15 in Example 1 66 Figure 3.7: Average throughput for M = 50 in Example 1 67 Figure 3.8: Optimal throughput performance in Example 1 68 Figure 3.9: Throughput vs. distance in Example 2 72 Figure 3.10: Throughput vs. transmission probability in Example 2 . 73 Figure 3.11: Average throughput for M = 15 in Example 2 75 Figure 3.12: Optimal throughput performance in Example 2 76 vi Figure 4.1: Hearing area of a directional antenna 85 Figure 4.2: Total interference at a receiver 93 Figure 4.3: Normalized progress vs. normalized distance 102 Figure 4.4: Normalized progress vs. transmission probability 106 Figure 4.5: Normalized progress vs. antenna beam width 110 vii ACKNOWLEDGEMENTS I would like to take the opportunity to thank Prof. Terry A. Smay from the Department of Electrical and Computer Engineering, my major professor, for his patient guidance throughout my graduate study at Iowa State University, and Prof. Way Kuo from the Department of Industrial Engineering, my co-major professor, for providing me the opportunity to work on the Army C3INAT Project, the research experiences that I could never have in the classroom, and the financial supports. In addition, I would like to thank Dr. Chester S. Comstock, Dr. James A. Davis, Dr. Dale D. Grosvenor, and Dr. Arthur V. Pohm for serving on my Program of Study Committee and Dr. J. O. Kopplin, Chairman of the Department, for providing financial supports during early years of my study. Furthermore, I would like to thank my wife, Lingyuan, for cheering me up on numerous occasions and giving me a home always full of joys. Finally, I would like to thank my parents, General and Mrs. Yeh-Kai Wang, for their never-ending supports from the day I was born. Their love and encouragement make my pursuit of higher education possible. I therefore dedicate this dissertation to them. viii ABSTRACT The first ground wireless packet switching radio network, named the ALOHA network, was implemented in the early 1970s at University of Hawaii. The most distinct features of a packet radio network are: 1) the absence of physical connec­ tions between users, 2) the sharing of a common transmission medium, and 3) the broadcasting capability of each user. Today, the packet radio network technology is widely used in a variety of civilian as well as military applications. The throughput of a packet radio network is defined as the percentage of time the channel carries good packets. It is largely determined by the channel access method, the signal propagation characteristics, and the capture effect at a receiver. In this dissertation, we present two packet radio network models under the Slotted ALOHA channel access method and a capture model which is based on the relative strength of signal powers of the desired packet and the interfering packets. The first model is a single-hop network with a central station and finite number of users randomly distributed in a limited area. All the users communicate with each other through the central station, which is within one hop distance of all users. Given a density distribution function for the distance of a user, we show that there is an optimal transmission probabiUty which maximizes the throughput of the network. Also, under a light traffic load, the throughput of a remote user is ix relatively insensitive to its distance from the station. The second model is a multi-hop network where a user is equipped with a directional antenna and not every user can directly communicate with every other else. As a result, a user communicates with another user either directly in a single hop or through some intermediate users in multiple hops. The location of all users is modeled by a two-dimensional Poisson process with an average of A users per unit area. By balancing the transmission probability and the antenna beam width, we show that the maximum hop-by-hop progress of a packet can be achieved when the transmitter and the receiver are separated by an optimal distance. 1 1 INTRODUCTION The first wireless packet switching radio network in the data communication field was introduced in the early 1970s at the University of Hawaii [1,2]. The original system, named the ALOHANET, was designed to allow the shared access of a central computer located at the main campus of University of Hawaii by remote terminals scattered over near-by islands. As a result, the ALOHANET system was a single-hop system where all terminals are within radio line-of-sight and within transmission range of the central computer. Later on, the work done in Hawaii led to the development of a multi-hop packet radio network, called PRNET, to include repeaters to widen the geographical cov­ erage beyond the limited transmission range of a radio unit. PRNET was developed under the sponsorship of the U.S. Advanced Research Project Agency [3]. PRNET extended the capability of a packet radio network by permitting direct communi­ cations among mobile users over wide geographical areas, coexistence with existing users of the same frequency band, protection against roultipath effects, protection against jamming, ease of deployment and reconfigurability.
Recommended publications
  • Implementing MACA and Other Useful Improvements to Amateur Packet Radio for Throughput and Capacity
    Implementing MACA and Other Useful Improvements to Amateur Packet Radio for Throughput and Capacity John Bonnett – KK6JRA / NCS820 Steven Gunderson – CMoLR Project Manager TAPR DCC – 15 Sept 2018 1 Contents • Introduction – Communication Methodology of Last Resort (CMoLR) • Speed & Throughput Tests – CONNECT & UNPROTO • UX.25 – UNPROTO AX.25 • Multiple Access with Collision Avoidance (MACA) – Hidden Terminals • Directed Packet Networks • Brevity – Directory Services • Trunked Packet • Conclusion 2 Background • Mission County – Proverbial: – Coastline, Earthquake Faults, Mountains & Hills, and Missions – Frequent Natural Disasters • Wildfires, Earthquakes, Floods, Slides & Tsunamis – Extensive Packet Networks • EOCs – Fire & Police Stations – Hospitals • Legacy 1200 Baud Packet Networks • Outpost and Winlink 2000 Messaging Software 3 Background • Mission County – Proverbial: – Coastline, Earthquake Faults, Mountains & Hills, and Missions – Frequent Natural Disasters • Wildfires, Earthquakes, Floods, Slides & Tsunamis – Extensive Packet Networks • EOCs – Fire & Police Stations – Hospitals • Legacy 1200 Baud Packet Networks • Outpost and Winlink 2000 Messaging Software • Community Emergency Response Teams: – OK Drills – Neighborhood Surveys OK – Triage Information • CERT Form #1 – Transmit CERT Triage Data to Public Safety – Situational Awareness 4 Background & Objectives (cont) • Communication Methodology of Last Resort (CMoLR): – Mission County Project: 2012 – 2016 – Enable Emergency Data Comms from CERT to Public Safety 5 Background &
    [Show full text]
  • Reservation - Time Division Multiple Access Protocols for Wireless Personal Communications
    tv '2s.\--qq T! Reservation - Time Division Multiple Access Protocols for Wireless Personal Communications Theodore V. Buot B.S.Eng (Electro&Comm), M.Eng (Telecomm) Thesis submitted for the degree of Doctor of Philosophy 1n The University of Adelaide Faculty of Engineering Department of Electrical and Electronic Engineering August 1997 Contents Abstract IY Declaration Y Acknowledgments YI List of Publications Yrt List of Abbreviations Ylu Symbols and Notations xi Preface xtv L.Introduction 1 Background, Problems and Trends in Personal Communications and description of this work 2. Literature Review t2 2.1 ALOHA and Random Access Protocols I4 2.1.1 Improvements of the ALOHA Protocol 15 2.1.2 Other RMA Algorithms t6 2.1.3 Random Access Protocols with Channel Sensing 16 2.1.4 Spread Spectrum Multiple Access I7 2.2Fixed Assignment and DAMA Protocols 18 2.3 Protocols for Future Wireless Communications I9 2.3.1 Packet Voice Communications t9 2.3.2Reservation based Protocols for Packet Switching 20 2.3.3 Voice and Data Integration in TDMA Systems 23 3. Teletraffic Source Models for R-TDMA 25 3.1 Arrival Process 26 3.2 Message Length Distribution 29 3.3 Smoothing Effect of Buffered Users 30 3.4 Speech Packet Generation 32 3.4.1 Model for Fast SAD with Hangover 35 3.4.2Bffect of Hangover to the Speech Quality 38 3.5 Video Traffic Models 40 3.5.1 Infinite State Markovian Video Source Model 41 3.5.2 AutoRegressive Video Source Model 43 3.5.3 VBR Source with Channel Load Feedback 43 3.6 Summary 46 4.
    [Show full text]
  • A Survey on Aloha Protocol for Iot Based Applications
    ISSN: 2277-9655 [Badgotya * et al., 7(5): May, 2018] Impact Factor: 5.164 IC™ Value: 3.00 CODEN: IJESS7 IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY A SURVEY ON ALOHA PROTOCOL FOR IOT BASED APPLICATIONS Shikha Badgotya*1 & Prof.Deepti Rai2 *1M.Tech Scholar, Department of EC, Alpine Institute of Technology,, Ujjain (India) 2H.O.D, Department of EC, Alpine Institute of Technology, Ujjain (India) DOI: 10.5281/zenodo.1246995 ABSTRACT With the emergence of IoT based applications in industries and automation, protocols for effective data transfer was the foremost need. The natural choice was a random access protocol like ALOHA which could be incorporated in the ultra narrowband ISM band framework because of its simplicity and lack of overhead. Pure ALOHA faced the limitation of greater rate of collisions among the packets of data and also there was higher level of frame delays. Slotted ALOHA overcame these limitations to some extent in which the transfer of data takes place after channel polling. Though the drawbacks of PURE ALOHA are somewhat resolved in Slotted ALOHA, still some redundant transmissions and delay of frames exist. The present proposed work puts forth an efficient mechanism for Slotted ALOHA which implements polling of channel that is non persistent in nature to reduce the probability of collisions considerably. Further it presents a channel sensing methodology also for prevention of burst errors. Interleaving serves to be useful in case of burst errors and helps in preserving useful information. The survey should pave the path for IoT based applications working on an ultra narrowband architecture.
    [Show full text]
  • The Beginner's Handbook of Amateur Radio
    FM_Laster 9/25/01 12:46 PM Page i THE BEGINNER’S HANDBOOK OF AMATEUR RADIO This page intentionally left blank. FM_Laster 9/25/01 12:46 PM Page iii THE BEGINNER’S HANDBOOK OF AMATEUR RADIO Clay Laster, W5ZPV FOURTH EDITION McGraw-Hill New York San Francisco Washington, D.C. Auckland Bogotá Caracas Lisbon London Madrid Mexico City Milan Montreal New Delhi San Juan Singapore Sydney Tokyo Toronto McGraw-Hill abc Copyright © 2001 by The McGraw-Hill Companies. All rights reserved. Manufactured in the United States of America. Except as per- mitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher. 0-07-139550-4 The material in this eBook also appears in the print version of this title: 0-07-136187-1. All trademarks are trademarks of their respective owners. Rather than put a trademark symbol after every occurrence of a trade- marked name, we use names in an editorial fashion only, and to the benefit of the trademark owner, with no intention of infringe- ment of the trademark. Where such designations appear in this book, they have been printed with initial caps. McGraw-Hill eBooks are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training programs. For more information, please contact George Hoare, Special Sales, at [email protected] or (212) 904-4069. TERMS OF USE This is a copyrighted work and The McGraw-Hill Companies, Inc.
    [Show full text]
  • Medium Access Control Layer
    Telematics Chapter 5: Medium Access Control Sublayer User Server watching with video Beispielbildvideo clip clips Application Layer Application Layer Presentation Layer Presentation Layer Session Layer Session Layer Transport Layer Transport Layer Network Layer Network Layer Network Layer Univ.-Prof. Dr.-Ing. Jochen H. Schiller Data Link Layer Data Link Layer Data Link Layer Computer Systems and Telematics (CST) Physical Layer Physical Layer Physical Layer Institute of Computer Science Freie Universität Berlin http://cst.mi.fu-berlin.de Contents ● Design Issues ● Metropolitan Area Networks ● Network Topologies (MAN) ● The Channel Allocation Problem ● Wide Area Networks (WAN) ● Multiple Access Protocols ● Frame Relay (historical) ● Ethernet ● ATM ● IEEE 802.2 – Logical Link Control ● SDH ● Token Bus (historical) ● Network Infrastructure ● Token Ring (historical) ● Virtual LANs ● Fiber Distributed Data Interface ● Structured Cabling Univ.-Prof. Dr.-Ing. Jochen H. Schiller ▪ cst.mi.fu-berlin.de ▪ Telematics ▪ Chapter 5: Medium Access Control Sublayer 5.2 Design Issues Univ.-Prof. Dr.-Ing. Jochen H. Schiller ▪ cst.mi.fu-berlin.de ▪ Telematics ▪ Chapter 5: Medium Access Control Sublayer 5.3 Design Issues ● Two kinds of connections in networks ● Point-to-point connections OSI Reference Model ● Broadcast (Multi-access channel, Application Layer Random access channel) Presentation Layer ● In a network with broadcast Session Layer connections ● Who gets the channel? Transport Layer Network Layer ● Protocols used to determine who gets next access to the channel Data Link Layer ● Medium Access Control (MAC) sublayer Physical Layer Univ.-Prof. Dr.-Ing. Jochen H. Schiller ▪ cst.mi.fu-berlin.de ▪ Telematics ▪ Chapter 5: Medium Access Control Sublayer 5.4 Network Types for the Local Range ● LLC layer: uniform interface and same frame format to upper layers ● MAC layer: defines medium access ..
    [Show full text]
  • Kenwood TH-D74A/E Operating Tips
    1 Copyrights for this Manual JVCKENWOOD Corporation shall own all copyrights and intellectual properties for the product and the manuals, help texts and relevant documents attached to the product or the optional software. A user is required to obtain approval from JVCKENWOOD Corporation, in writing, prior to redistributing this document on a personal web page or via packet communication. A user is prohibited from assigning, renting, leasing or reselling the document. JVCKENWOOD Corporation does not warrant that quality and functions described in this manual comply with each user’s purpose of use and, unless specifically described in this manual, JVCKENWOOD Corporation shall be free from any responsibility for any defects and indemnities for any damages or losses. Software Copyrights The title to and ownership of copyrights for software, including but not limited to the firmware and optional software that may be distributed individually, are reserved for JVCKENWOOD Corporation. The firmware shall mean the software which can be embedded in KENWOOD product memories for proper operation. Any modifying, reverse engineering, copying, reproducing or disclosing on an Internet website of the software is strictly prohibited. A user is required to obtain approval from JVCKENWOOD Corporation, in writing, prior to redistributing this manual on a personal web page or via packet communication. Furthermore, any reselling, assigning or transferring of the software is also strictly prohibited without embedding the software in KENWOOD product memories. Copyrights for recorded Audio The software embedded in this transceiver consists of a multiple number of and individual software components. Title to and ownership of copyrights for each software component is reserved for JVCKENWOOD Corporation and the respective bona fide holder.
    [Show full text]
  • On-Demand Routing in Multi-Hop Wireless Mobile Ad Hoc Networks
    Available Online at www.ijcsmc.com International Journal of Computer Science and Mobile Computing A Monthly Journal of Computer Science and Information Technology ISSN 2320–088X IJCSMC, Vol. 2, Issue. 7, July 2013, pg.317 – 321 RESEARCH ARTICLE ON-DEMAND ROUTING IN MULTI-HOP WIRELESS MOBILE AD HOC NETWORKS P. Umamaheswari 1, K. Ranjith singh 2 1Periyar University, TamilNadu, India 2Professor of PGP College, TamilNadu, India 1 [email protected]; 2 [email protected] Abstract— An ad hoc network is a collection of wireless mobile nodes dynamically forming a temporary network without the use of any preexisting network infrastructure or centralized administration. Routing protocols used in ad hoc networks must automatically adjust to environments that can vary between the extremes of high mobility with low bandwidth, and low mobility with high bandwidth. This thesis argues that such protocols must operate in an on-demand fashion and that they must carefully limit the number of nodes required to react to a given topology change in the network. I have embodied these two principles in a routing protocol called Dynamic Source Routing (DSR). As a result of its unique design, the protocol adapts quickly to routing changes when node movement is frequent, yet requires little or no overhead during periods in which nodes move less frequently. By presenting a detailed analysis of DSR’s behavior in a variety of situations, this thesis generalizes the lessons learned from DSR so that they can be applied to the many other new routing protocols that have adopted the basic DSR framework. The thesis proves the practicality of the DSR protocol through performance results collected from a full-scale 8 node tested, and it demonstrates several methodologies for experimenting with protocols and applications in an ad hoc network environment, including the emulation of ad hoc networks.
    [Show full text]
  • ECE 158A: Lecture 13
    ECE 158A: Lecture 13 Fall 2015 Random Access and Ethernet! Random Access! Basic idea: Exploit statistical multiplexing Do not avoid collisions, just recover from them When a node has packet to send Transmit at full channel data rate No a priori coordination among nodes Two or more transmitting nodes ⇒ collision Random access MAC protocol specifies: How to detect collisions How to recover from collisions Key Ideas of Random Access Carrier sense Listen before speaking, and don’t interrupt Check if someone else is already sending data and wait till the other node is done Collision detection If someone else starts talking at the same time, stop Realize when two nodes are transmitting at once by detecting that the data on the wire is garbled Randomness Don’t start talking again right away Wait for a random time before trying again Aloha net (70’s) First random access network Setup by Norm Abramson at the University of Hawaii First data communication system for Hawaiian islands Hub at University of Hawaii, Oahu Alohanet had two radio channels: Random access: Sites sending data Broadcast: Hub rebroadcasting data Aloha Signaling Two channels: random access, broadcast Sites send packets to hub (random) If received, hub sends ACK (random) If not received (collision), site resends Hub sends packets to all sites (broadcast) Sites can receive even if they are also sending Questions: When do you resend? Resend with probability p How does this perform? Will analyze in class, stay tuned…. Slot-by-slot Aloha Example
    [Show full text]
  • Examining Ambiguities in the Automatic Packet Reporting System
    Examining Ambiguities in the Automatic Packet Reporting System A Thesis Presented to the Faculty of California Polytechnic State University San Luis Obispo In Partial Fulfillment of the Requirements for the Degree Master of Science in Electrical Engineering by Kenneth W. Finnegan December 2014 © 2014 Kenneth W. Finnegan ALL RIGHTS RESERVED ii COMMITTEE MEMBERSHIP TITLE: Examining Ambiguities in the Automatic Packet Reporting System AUTHOR: Kenneth W. Finnegan DATE SUBMITTED: December 2014 REVISION: 1.2 COMMITTEE CHAIR: Bridget Benson, Ph.D. Assistant Professor, Electrical Engineering COMMITTEE MEMBER: John Bellardo, Ph.D. Associate Professor, Computer Science COMMITTEE MEMBER: Dennis Derickson, Ph.D. Department Chair, Electrical Engineering iii ABSTRACT Examining Ambiguities in the Automatic Packet Reporting System Kenneth W. Finnegan The Automatic Packet Reporting System (APRS) is an amateur radio packet network that has evolved over the last several decades in tandem with, and then arguably beyond, the lifetime of other VHF/UHF amateur packet networks, to the point where it is one of very few packet networks left on the amateur VHF/UHF bands. This is proving to be problematic due to the loss of institutional knowledge as older amateur radio operators who designed and built APRS and other AX.25-based packet networks abandon the hobby or pass away. The purpose of this document is to collect and curate a sufficient body of knowledge to ensure the continued usefulness of the APRS network, and re-examining the engineering decisions made during the network's evolution to look for possible improvements and identify deficiencies in documentation of the existing network. iv TABLE OF CONTENTS List of Figures vii 1 Preface 1 2 Introduction 3 2.1 History of APRS .
    [Show full text]
  • 6.02 Notes, Chapter 15: Sharing a Channel: Media Access (MAC
    MIT 6.02 DRAFT Lecture Notes Last update: November 3, 2012 CHAPTER 15 Sharing a Channel: Media Access (MAC) Protocols There are many communication channels, including radio and acoustic channels, and certain kinds of wired links (coaxial cables), where multiple nodes can all be connected and hear each other’s transmissions (either perfectly or with some non-zero probability). This chapter addresses the fundamental question of how such a common communication channel—also called a shared medium—can be shared between the different nodes. There are two fundamental ways of sharing such channels (or media): time sharing and frequency sharing.1 The idea in time sharing is to have the nodes coordinate with each other to divide up the access to the medium one at a time, in some fashion. The idea in frequency sharing is to divide up the frequency range available between the different transmitting nodes in a way that there is little or no interference between concurrently transmitting nodes. The methods used here are the same as in frequency division multiplexing, which we described in the previous chapter. This chapter focuses on time sharing. We will investigate two common ways: time division multiple access,orTDMA , and contention protocols. Both approaches are used in networks today. These schemes for time and frequency sharing are usually implemented as communica­ tion protocols. The term protocol refers to the rules that govern what each node is allowed to do and how it should operate. Protocols capture the “rules of engagement” that nodes must follow, so that they can collectively obtain good performance.
    [Show full text]
  • Sistemas Informáticos Curso 2005-06 Sistema De Autoconfiguración Para
    Sistemas Informáticos Curso 2005-06 Sistema de Autoconfiguración para Redes Ad Hoc Miguel Ángel Tolosa Diosdado Adam Ameziane Dirigido por: Profª. Marta López Fernández Dpto. Sistemas Informáticos y Programación Grupo de Análisis, Seguridad y Sistemas (GASS) Facultad de Informática Universidad Complutense de Madrid AGRADECIMIENTOS: Queremos agradecer la dedicación de la profesora Marta López Fernández, Directora del presente Proyecto de Sistemas Informáticos, y del resto de integrantes del Grupo de Análisis, Seguridad y Sistemas (GASS) del Departamento de Sistemas Informáticos y Programación de la Universidad Complutense de Madrid, y de forma muy especial a Fabio Mesquita Buiati y a Javier García Villalba, Miembro y Director del citado Grupo, respectivamente, por el asesoramiento y las facilidades proporcionadas para el buen término de este Proyecto. 2 Índice RESUMEN ....................................................................................................................... 5 ABSTRACT ..................................................................................................................... 6 PALABRAS CLAVE....................................................................................................... 7 1-INTRODUCCIÓN....................................................................................................... 8 1.1- MOTIVACIÓN ......................................................................................................... 8 1.2 – OBJETIVO .............................................................................................................
    [Show full text]
  • Ethernet: an Engineering Paradigm
    Ethernet: An Engineering Paradigm Mark Huang Eden Miller Peter Sun Charles Oji 6.933J/STS.420J Structure, Practice, and Innovation in EE/CS Fall 1998 1.0 Acknowledgements 1 2.0 A Model for Engineering 1 2.1 The Engineering Paradigm 3 2.1.1 Concept 5 2.1.2 Standard 6 2.1.3 Implementation 6 3.0 Phase I: Conceptualization and Early Implementation 7 3.1 Historical Framework: Definition of the Old Paradigm 7 3.1.1 Time-sharing 8 3.1.2 WANs: ARPAnet and ALOHAnet 8 3.2 Anomalies: Definition of the Crisis 10 3.2.1 From Mainframes to Minicomputers: A Parallel Paradigm Shift 10 3.2.2 From WAN to LAN 11 3.2.3 Xerox: From Xerography to Office Automation 11 3.2.4 Metcalfe and Boggs: Professional Crisis 12 3.3 Ethernet: The New Paradigm 13 3.3.1 Invention Background 14 3.3.2 Basic Technical Description 15 3.3.3 How Ethernet Addresses the Crisis 15 4.0 Phase II: Standardization 17 4.1 Crisis II: Building Vendor Support (1978-1983) 17 4.1.1 Forming the DIX Consortium 18 4.1.2 Within DEC 19 4.1.3 Within Intel 22 4.1.4 The Marketplace 23 4.2 Crisis III: Establishing Widespread Compatibility (1979-1984) 25 4.3 The Committee 26 5.0 Implementation and the Crisis of Domination 28 5.1 The Game of Growth 28 5.2 The Grindley Effect in Action 28 5.3 The Rise of 3Com, a Networking Giant 29 6.0 Conclusion 30 A.0 References A-1 i of ii ii of ii December 11, 1998 Ethernet: An Engineering Paradigm Mark Huang Eden Miller Charles Oji Peter Sun 6.933J/STS.420J Structure, Practice, and Innovation in EE/CS Fall 1998 1.0 Acknowledgements The authors would like to thank the following individuals for contributing to this project.
    [Show full text]