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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 & -
Data Communication and Computer Network Unit 1
Department of Collegiate Education GOVERNMENT FIRST GRADE COLLEGE RAIBAG-591317 Department of Computer Science Lecture Notes SUBJECT : DATA COMMUNICATIONS AND COMPUTER NETWORKS SUBJECT CODE : 17BScCST61 CLASS : BSC VI Sem Paper-1 Subject In charge Smt Bhagirathi Halalli Assistant Professor 2019-20 Data Communication and Computer Network Unit 1 Unit 1: Introduction Content: 1.1. Data communications, 1.2. Networks, 1.3. The internet, 1.4. Protocols and standards, 1.5. Network models – OSI model, 1.6. TCP/IP protocol suite, 1.7. Addressing. 1.1.Data Communications, Data refers to the raw facts that are collected while information refers to processed data that enables us to take decisions. Ex. When result of a particular test is declared it contains data of all students, when you find the marks you have scored you have the information that lets you know whether you have passed or failed. The word data refers to any information which is presented in a form that is agreed and accepted upon by is creators and users. Data Communication Data Communication is a process of exchanging data or information In case of computer networks this exchange is done between two devices over a transmission medium. This process involves a communication system which is made up of hardware and software. The hardware part involves the sender and receiver devices and the intermediate devices through which the data passes. The software part involves certain rules which specify what is to be communicated, how it is to be communicated and when. It is also called as a Protocol. The following sections describe the fundamental characteristics that are important for the effective working of data communication process and are followed by the components that make up a data communications system. -
The OSI Model
Data Encapsulation & OSI & TCP/IP Models Week 2 Lecturer: Lucy White [email protected] Office : 324 1 Network Protocols • A protocol is a formal description of a set of rules and conventions that govern a particular aspect of how devices on a network communicate. Protocols determine the format, timing, sequencing, flow control and error control in data communication. Without protocols, the computer cannot make or rebuild the stream of incoming bits from another computer into the original format. • Protocols control all aspects of data communication, which include the following: - How the physical network is built - How computers connect to the network - How the data is formatted for transmission - The setting up and termination of data transfer sessions - How that data is sent - How to deal with errors 2 Protocol Suites & Industry Standard • Many of the protocols that comprise a protocol suite reference other widely utilized protocols or industry standards • Institute of Electrical and Electronics Engineers (IEEE) or the Internet Engineering Task Force (IETF) • The use of standards in developing and implementing protocols ensures that products from different manufacturers can work together for efficient communications 3 Function of Protocol in Network Communication A standard is a process or protocol that has been endorsed by the networking industry and ratified by a standards organization 4 Protocol Suites TCP/IP Protocol Suite and Communication Function of Protocol in Network Communication 6 Function of Protocol in Network Communication • Technology independent Protocols -Many diverse types of devices can communicate using the same sets of protocols. This is because protocols specify network functionality, not the underlying technology to support this functionality. -
The Transport Layer: Tutorial and Survey SAMI IREN and PAUL D
The Transport Layer: Tutorial and Survey SAMI IREN and PAUL D. AMER University of Delaware AND PHILLIP T. CONRAD Temple University Transport layer protocols provide for end-to-end communication between two or more hosts. This paper presents a tutorial on transport layer concepts and terminology, and a survey of transport layer services and protocols. The transport layer protocol TCP is used as a reference point, and compared and contrasted with nineteen other protocols designed over the past two decades. The service and protocol features of twelve of the most important protocols are summarized in both text and tables. Categories and Subject Descriptors: C.2.0 [Computer-Communication Networks]: General—Data communications; Open System Interconnection Reference Model (OSI); C.2.1 [Computer-Communication Networks]: Network Architecture and Design—Network communications; Packet-switching networks; Store and forward networks; C.2.2 [Computer-Communication Networks]: Network Protocols; Protocol architecture (OSI model); C.2.5 [Computer- Communication Networks]: Local and Wide-Area Networks General Terms: Networks Additional Key Words and Phrases: Congestion control, flow control, transport protocol, transport service, TCP/IP 1. INTRODUCTION work of routers, bridges, and communi- cation links that moves information be- In the OSI 7-layer Reference Model, the tween hosts. A good transport layer transport layer is the lowest layer that service (or simply, transport service) al- operates on an end-to-end basis be- lows applications to use a standard set tween two or more communicating of primitives and run on a variety of hosts. This layer lies at the boundary networks without worrying about differ- between these hosts and an internet- ent network interfaces and reliabilities. -
Solutions to Chapter 2
CS413 Computer Networks ASN 4 Solutions Solutions to Assignment #4 3. What difference does it make to the network layer if the underlying data link layer provides a connection-oriented service versus a connectionless service? [4 marks] Solution: If the data link layer provides a connection-oriented service to the network layer, then the network layer must precede all transfer of information with a connection setup procedure (2). If the connection-oriented service includes assurances that frames of information are transferred correctly and in sequence by the data link layer, the network layer can then assume that the packets it sends to its neighbor traverse an error-free pipe. On the other hand, if the data link layer is connectionless, then each frame is sent independently through the data link, probably in unconfirmed manner (without acknowledgments or retransmissions). In this case the network layer cannot make assumptions about the sequencing or correctness of the packets it exchanges with its neighbors (2). The Ethernet local area network provides an example of connectionless transfer of data link frames. The transfer of frames using "Type 2" service in Logical Link Control (discussed in Chapter 6) provides a connection-oriented data link control example. 4. Suppose transmission channels become virtually error-free. Is the data link layer still needed? [2 marks – 1 for the answer and 1 for explanation] Solution: The data link layer is still needed(1) for framing the data and for flow control over the transmission channel. In a multiple access medium such as a LAN, the data link layer is required to coordinate access to the shared medium among the multiple users (1). -
The Application Layer Protocol Ssh Is Connectionless
The Application Layer Protocol Ssh Is Connectionless Deryl remains prognostic: she revile her misogamist clarified too ineffectually? Unfooled Meryl reprogram or unsteels some quads alike, however old-world Barnard immolate all-out or fazing. Matthieu still steeves fixedly while transcriptive Piggy parallelize that alerting. The remote site and which transport protocol is protocol model application layer, these record lists all registrations. As for maintaining ordered delivery. Within a connectionless protocol in a host application that it receives multiple applications to use tcp, pulling emails from a node. IP and MAC address is there. Link state algorithms consider bandwidth when calculating routes. Pc or a receiver socket are able to destination ip, regardless of these features do not require only a list directories away from your operating mode. Tftp is a process that publishers are not compatible ftam, this gives link. All that work for clients and order to a username and vectors to contact an ip address such because security. Ip operation of errors or was statically configured cost load. The application layer performs a set. Ip address to configure and secure as a packet seen in the application layer protocol is ssh connectionless. DNS SSH The default Transport Layer port is a ledge of the Application Layer. HTTP is a short abbreviation of Hypertext Transfer Protocol. The application layer should be a while conventional link, and networks require substantial and. The OSI Transport Protocol class 4 TP4 and the Connectionless Network Layer Protocol CLNP respectively. TCP IP Protocols and Ports Vskills. The parsed MIME header. The connectionless is connectionless. -
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. -
Logical Link Control and Channel Scheduling for Multichannel Underwater Sensor Networks
ICST Transactions on Mobile Communications and Applications Research Article Logical Link Control and Channel Scheduling for Multichannel Underwater Sensor Networks Jun Li ∗, Mylene` Toulgoat, Yifeng Zhou, and Louise Lamont Communications Research Centre Canada, 3701 Carling Avenue, Ottawa, ON. K2H 8S2 Canada Abstract With recent developments in terrestrial wireless networks and advances in acoustic communications, multichannel technologies have been proposed to be used in underwater networks to increase data transmission rate over bandwidth-limited underwater channels. Due to high bit error rates in underwater networks, an efficient error control technique is critical in the logical link control (LLC) sublayer to establish reliable data communications over intrinsically unreliable underwater channels. In this paper, we propose a novel protocol stack architecture featuring cross-layer design of LLC sublayer and more efficient packet- to-channel scheduling for multichannel underwater sensor networks. In the proposed stack architecture, a selective-repeat automatic repeat request (SR-ARQ) based error control protocol is combined with a dynamic channel scheduling policy at the LLC sublayer. The dynamic channel scheduling policy uses the channel state information provided via cross-layer design. It is demonstrated that the proposed protocol stack architecture leads to more efficient transmission of multiple packets over parallel channels. Simulation studies are conducted to evaluate the packet delay performance of the proposed cross-layer protocol stack architecture with two different scheduling policies: the proposed dynamic channel scheduling and a static channel scheduling. Simulation results show that the dynamic channel scheduling used in the cross-layer protocol stack outperforms the static channel scheduling. It is observed that, when the dynamic channel scheduling is used, the number of parallel channels has only an insignificant impact on the average packet delay. -
Physical Layer Overview
ELEC3030 (EL336) Computer Networks S Chen Physical Layer Overview • Physical layer forms the basis of all networks, and we will first revisit some of fundamental limits imposed on communication media by nature Recall a medium or physical channel has finite Spectrum bandwidth and is noisy, and this imposes a limit Channel bandwidth: on information rate over the channel → This H Hz is a fundamental consideration when designing f network speed or data rate 0 H Type of medium determines network technology → compare wireless network with optic network • Transmission media can be guided or unguided, and we will have a brief review of a variety of transmission media • Communication networks can be classified as switched and broadcast networks, and we will discuss a few examples • The term “physical layer protocol” as such is not used, but we will attempt to draw some common design considerations and exams a few “physical layer standards” 13 ELEC3030 (EL336) Computer Networks S Chen Rate Limit • A medium or channel is defined by its bandwidth H (Hz) and noise level which is specified by the signal-to-noise ratio S/N (dB) • Capability of a medium is determined by a physical quantity called channel capacity, defined as C = H log2(1 + S/N) bps • Network speed is usually given as data or information rate in bps, and every one wants a higher speed network: for example, with a 10 Mbps network, you may ask yourself why not 10 Gbps? • Given data rate fd (bps), the actual transmission or baud rate fb (Hz) over the medium is often different to fd • This is for -
Chapter 2. Application Layer Table of Contents 1. Context
Chapter 2. Application Layer Table of Contents 1. Context ........................................................................................................................................... 1 2. Introduction .................................................................................................................................... 2 3. Objectives ....................................................................................................................................... 2 4. Network application software ....................................................................................................... 2 5. Process communication ................................................................................................................. 3 6. Transport Layer services provided by the Internet ....................................................................... 3 7. Application Layer Protocols ........................................................................................................... 4 8. The web and HTTP .......................................................................................................................... 4 8.1. Web Terminology ................................................................................................................... 5 8.2. Overview of HTTP protocol .................................................................................................... 6 8.3. HTTP message format ........................................................................................................... -
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. -
Draft Stable Implementation Agreement for Open
NBS PUBLICATIONS U.S. DEPARTMENT OF COMMERCE National Bureau of Standards Institute for Computer Sciences and Technology A 11 IDE 7 E T M NBSIR 87-3674 Draft Stable Implementation Agreements for Open Systems Interconnection Protocols NBS Workshop for Implementors of Open Systems Interconnection Version 1 Edition 0 October 1987 DRAFT STABLE IMPLEMENTATION AGREEMENTS Based on the Proceeding of the NBS/OSI Implementor’s Workshop Plenary Assembly Held October 9, 1987 National Bureau of Standards Gaithersburg, MD 20899 U.S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS — QC 100 - U 5 6 87-3674 1987 C • 2 U.S. DEPARTMENT OF COMMERCE National Bureau of Standards Institute for Computer Sciences and Technology Research Information Center NBSIR 87-3674 National r>ureau of Standards Gaithersburg, Maryland 20899 A) BSc DRAFT STABLE IMPLEMENTATION QCtoo AGREEMENTS FOR OPEN SYSTEMS < USy INTERCONNECTION PROTOCOLS m., 1921 c.> NBS Workshop for Implementors of Open Systems Interconnection Version 1 Edition 0 October 1987 DRAFT STABLE IMPLEMENTATION AGREEMENTS Based on the Proceeding of the NBS/OSI Implementor’s Workshop Plenary Assembly Held October 9, 1987 National Bureau of Standards Gaithersburg, MD 20899 U.S. DEPARTMENT OF COMMERCE, C. William Verity, Acting Secretary NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director 21 Table of Contents 1. GENERAL INFORMATION 1 1.1 PURPOSE OF THIS DOCUMENT * 1 1.2 PURPOSE OF THE WORKSHOP 1 1.3 WORKSHOP ORGANIZATION 1 2. SUB NETWORKS 1 2.1 LOCAL AREA NETWORKS 1 2.1.1 IEEE 802.2 LOGICAL LINK CONTROL 1 2.1.2 IEEE 802.3 CSMA/CD ACCESS METHOD 1 2.1.3 IEEE 802.4 TOKEN BUS ACCESS METHOD 1 2.1.4 IEEE 802.5 Token Ring Access Method 3 2.2 WIDE AREA NETWORKS 4 2.2.1 CCITT RECOMMENDATION X.25 4 2.3 PRIVATE SUBNETWORKS 4 2.3.1 PRIVATE SUBNETWORKS' 4 3.