Showing papers on "Fast packet switching published in 1982"
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TL;DR: An approximation method for estimating the average number of data packets in a SENET-concept integrated voice and data system is presented and its estimates are found to be in good agreement with simulation results.
Abstract: This paper presents an approximation method for estimating the average number of data packets in a SENET-concept integrated voice and data system. The method is simple to use and its estimates are found to be in good agreement with simulation results. In general, the method applies to any system that integrates packet traffic with a more slowly varying traffic class that can preempt a portion of the packet transmission capacity.
71 citations
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25 Jun 1982TL;DR: In this paper, the authors describe a packet switching system in which packets comprising logical addresses and voice/data information are communicated through the system by packet switching networks which are interconnected by high-speed digital trunks with each of the latter being directly terminated on both ends by trunk controllers.
Abstract: A communication method and packet switching system in which packets comprising logical addresses and voice/data information are communicated through the system by packet switching networks which are interconnected by high-speed digital trunks with each of the latter being directly terminated on both ends by trunk controllers. During initial call setup of a particular call, central processors associated with each network in the desired route store the necessary logical to physical address information in the controllers which perform all logical to physical address translations on packets of the call. Each network comprises stages of switching nodes which are responsive to the physical address associated with a packet by a controller to communicate this packet to a designated subsequent node. The nodes provide for variable packet buffering, packet address rotation techniques, and intranode and internode signaling protocols. Each packet has a field which is automatically updated by the controllers for accumulating the total time delay incurred by the packet in progressing through the networks. Each processor has the capability of doing fault detection and isolation on the associated network, trunks, and controllers by the transmission of a single test packet. The testing is done solely in response to the test packet and no preconditioning of controllers or networks is necessary.
70 citations
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28 Jul 1982TL;DR: In this article, a packet including data for detecting a data error is formed for a data unit made up of a series of data packets sent to a packet mode terminal, and send to the packetmode terminal.
Abstract: It is efficient to detect a data error, which is produced in a packet switching network, in a range between final users of data. A packet including data for detecting a data error is formed for a data unit made up of a series of data packets sent to a packet mode terminal, and send to the packet mode terminal. A data error is detected by the data for detecting a data error each time the above-mentioned series of data packets are received.
47 citations
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TL;DR: This paper shows that an assignment which achieves both objectives exists and develops a branch-and-bound algorithm to find it, and suggests several heuristics which require much less computational effort and give very close to optimal results.
Abstract: In this paper, we examine the problem of time-slot assignment in an SS/TDMA system operating in a packet-switched environment. We seek to assign time slots in order to minimize average packet waiting time and in order to maximize transponder utilization. We show that an assignment which achieves both objectives exists and develop a branch-and-bound algorithm to find it. In addition, we suggest several heuristics which require much less computational effort and give very close to optimal results. We derive theoretical bounds on the performance of these heuristics and perform simulation trials to show that, on average, the heuristics are very much better than their bounds suggest, and are, in fact, extremely close to optimal.
46 citations
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TL;DR: The movable boundary scheme suggested for commercial implementation of integrated multi-plexers is shown to offer optimal or near-optimal performance.
Abstract: Recently, emphasis has been placed on integrated communication facilities capable of handling both line-switching and packet-switch-ing digital traffic. The problem of dynamically allocating the bandwidth of a trunk to both types of traffic is formulated as a Markovian decision process. Line switching is modeled as a time division multiplexing loss scheme over a varying portion of a fixed time frame. Packet-switching traffic is served through the remaining portion of the frame and requires queueing at the multiplexer-concentrator. Two different cost criteria are examined involving probability of blocking for line switching and average queueing delay for packets. The corresponding optimization problems are presented under reasonable simplifying assumptions. The movable boundary scheme suggested for commercial implementation of integrated multi-plexers is shown to offer optimal or near-optimal performance.
46 citations
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TL;DR: It is seen that several of the hybrid approaches perform very Well in comparison with circuit and packet switching techniques, in terms of their ability to service different traffic mixtures both efficiently and effectively.
Abstract: This paper describes and evaluates variations of a generic hybrid switching concept for integrated voice and data communications. Concepts examined include the Slotted ENvelope NETwork approach, the enhanced hybrid (SENET with time assignment speech interpolation/time assignment data interpolation), the flexible hybrid, and the variable length frame/packet approach. Primary criteria used to evaluate the concepts are transmission throughput efficiency and delay versus information throughput. Other criteria, such as voice continuity and routing/flow control, were also applied. It is seen that several of the hybrid approaches perform very Well in comparison with circuit and packet switching techniques, in terms of their ability to service different traffic mixtures both efficiently and effectively.
23 citations
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01 Dec 1982
21 citations
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15 Jan 1982
TL;DR: In this paper, the flag/packet transition in a packet mode channel is detected in a connection module and is transmitted as a particular word in a predetermined time interval of the outgoing multiplex of this module, at the same time as the address of the channel, thereby precluding the use of purpose-built links.
Abstract: The switching network included in the system is connected to circuit mode and/or packet mode mono- or multi-channel digital lines via connection modules. These modules enable the system connections to be standardized and accept thus any number of multiplexed channels in the lines and any transmission mode, namely duplex or half-duplex. The flag/packet transition in a packet mode channel is detected in a connection module and is transmitted as a particular word in a predetermined time interval of the outgoing multiplex of this module, at the same time as the address of the channel, thereby precluding the use of purpose-built links.
18 citations
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30 Aug 1982
TL;DR: This book discusses Packet Switching in a Telephone World, Getting Started with Network Basics, and Quantitative Tradeoffs-Packet, Circuit, and Message Switching.
Abstract: One What is a Packet?.- 1. To Switch or Not to Switch.- What Is Packet Switching?.- Why Use a Switched Network?.- Summary.- Suggested Readings.- 2. Packet Switching in a Telephone World.- Switching through the Telephone.- Transparent and Transactional Switching.- Approaches to Switching Compared.- Data Communications versus Voice Communications.- Data Call Statistics.- The Why and Where of Packet Switching.- Summary.- Suggested Readings.- 3. Circuit Switching/Message Switching/Packet Switching-A Quick Comparison.- Circuit Switching.- Message Switching.- Packet Switching.- Circuit Switching of Data-Advantages and Disadvantages.- Message Switching of Data-Advantages and Disadvantages.- Packet Switching of Data-Advantages and Disadvantages.- Summary 38 Suggested Readings.- 4. Getting Started with Network Basics.- The Network Environment.- The Example of the Public Telephone Network.- The Network User and the Network Supplier-Two Sides of the Coin.- Design Considerations.- Summary.- Suggested Readings.- 5. What Is an Erlang? An Introduction to Telecommunications Traffic Engineering.- Statistical Behavior of Network Users.- Traffic and User Satisfaction.- Blocking, Lines, and Erlangs.- Networks with Storage and Delay Instead of Blocking.- Capacity of Networks-Some Examples.- Summary.- Suggested Readings.- 6. Quantitative Tradeoffs-Packet, Circuit, and Message Switching.- Packet Switching-Operational Detail and Possible Faults.- Packet Switching-Overhead Structure Fundamentals.- Delay Comparison-Ideal Case.- Data Traffic Impact on Processor Loading.- Overhead in Circuit Switching and Packet Switching.- A Nationwide Data Network.- Summary.- Suggested Readings.- Two Operational Protocols-Packet Switching In Networks.- 7. Protocol Structures in Packet Switched Networks.- Types of Network Protocols.- The International Standards Organization (ISO) Protocol Hierarchy.- The ARPANET Approach to Protocols.- Virtual Circuit.- Datagrams.- Two Classes of Terminals.- Summary.- Suggested Readings.- 8. The User-Network Interface-The X.25 Standard.- The Packet-Switched Network User's Perspective.- The X.25 Protocol-Level 3 Features and Facilities.- User Actions under the X.25 Protocol.- Summary.- Suggested Readings.- 9. Control and Monitoring in a Network-Some Considerations.- The Role of Control.- Network Control Centers for Packet Networks.- Summary.- Suggested Readings.- Three Packet Networks in the Real World-Topology, Routing, Robustness, and Some Lucky Guesses.- 10. Topological Principles-Some Tricks to Make Packet Switching Work Better.- Alternative Topological Structures.- The General Topological Design Problem.- Desirable Topological Features for Packet Switching.- Summary.- Suggested Readings.- 11. Network Design Case Example-Even a Bad Guess Is Better Than None.- The Network Design Requirements.- The Impact of Topology and Data Rate on Network Resources.- Detailed Requirements and Bad Guesses.- Summary.- Suggested Readings.- 12. Routing in Packet Networks.- Alternative Routing Methods.- Advantages and Disadvantages of Routing Methods.- Approaches to Adaptive Directory Routing.- Summary.- Suggested Readings.- Four Packet Switching Without Packet Switches.- 13. Resource Sharing and Multiple Access Techniques.- The General Problem of Communications Resource Sharing.- The Satellite-Based ALOHA Technique.- The Network Aspect of the Packet Broadcast Channel.- Capacity and Delay of the ALOHA Channel.- ALOHA Channel Delay Characteristics.- Summary.- Suggested Readings.- 14. Improvements on the Basic ALOHA Channel-Slots and Reservations.- Increasing the Capacity of the Packet Broadcast Channel.- The Slotted ALOHA Channel.- Slotted ALOHA Channel with Capture.- Packet Broadcast Channels with Capacity Reservation.- Highlight Comparison of Multiple Access Techniques.- Summary.- Suggested Readings.- 15. Terrestrial Packet Radio Systems.- Terrestrial Repeaters and Local Networks.- Carrier Sense Multiple Access-Listen Before You Send.- Summary.- Suggested Readings.- 16. Combination of Satellite and Terrestrial Connectivity-The General Optimization Problem.- Serving Users without Dedicated Earth Stations-The General Problem.- Deriving the Optimum Value of the Number of Earth Stations.- Applications and Examples of the Random Network Analysis.- Summary.- Suggested Readings.- Five Data Networks, Packet Switching, and the Common Carriers.- 17. The Carrier Marketplace.- Common Carrier Services and Facilities.- Common Carriers in the United States.- Summary.- Suggested Readings.- 18. Value-Added Networks (VANs) and Packet Switching.- Public Networks and the Role of VANs.- The Telenet Packet Switched Network.- The Tymnet Nationwide Data Network.- Worldwide Packet Switching Services.- Summary.- Suggested Readings.- 19. A Tariff for Every Occasion.- A Sample of Common Carrier Communications Tariffs.- A Current and Future Tariff Cost Model.- Summary.- Suggested Readings.- 20. Some New Common Carrier Prospects.- Some Proposed New Telecommunications Services.- AT&T's Advanced Communications Service (ACS).- The Nationwide Network of Satellite Business Systems (SBS).- The Xerox Telecommunications Network (XTEN).- ACS, SBS, and STEN Compared.- Summary.- Suggested Readings.- Six Integrated Networks and the Future of Packet Switching.- 21. Hybrid Techniques: Combining Circuit and Packet Switching.- Classification of Information and Switching Techniques.- Approaches to Integrating Circuit and Packet Switching.- The Master Frame Approach to Integrated Switching.- Summary.- Suggested Readings.- 22. Integrated Services Networks.- Voice Digitization.- General Structure of Integrated Services Packet Switched Networks.- Cost/Performance Analysis.- Summary.- Suggested Readings.- 23. The Outlook for Packet Switching-And What to Do about It.
8 citations
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TL;DR: The architecture of a hybrid switching network employing both circuit switching and packet switching, and the concept of metapacket which can be employed in some relatively small-scale networks to average the load of packets and to reduce data transmission time is described.
Abstract: This paper describes the architecture of a hybrid switching network employing both circuit switching and packet switching. The network usually operates in a packet switching mode, but, depending on the traffic conditions, it can use special control packets to temporarily change certain lines to a circuit switching mode. The change between the two switching modes is performed dynamically depending on the traffic load of the network. Also described in this paper is the concept of metapacket which can be employed in some relatively small-scale networks to average the load of packets and to reduce data transmission time.
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15 Apr 1982TL;DR: In this article, a trans-multiplexer arrangement for interconnection of a time division multiplex line and a packet multiplexer was proposed, in which the trans-operator converts data for each of a plurality of terminals on the time division MULE in the unit of a packet, for allocation on the packet MULE line, and a section which identifies the time position of each data unit on the TDM line, prepares a specific packet containing the position information and allocates the specific packet before the data packet on the PULSE line.
Abstract: A digital data transmission system with a transmultiplexer arrangement for interconnection of a time division multiplex line and a packet multiplex line. The transmultiplexer has a section which converts data for each of a plurality of terminals on the time division multiplex line in the unit of a packet, for allocation on the packet multiplex line, and a section which identifies the time position of each data unit on the time division multiplex line, prepares a specific packet containing the position information and allocates the specific packet before the data packet on the packet multiplex line. The transmultiplexer also has a section which periodically allocates data on the packet multiplex line allotted with a specific packet containing position information of a terminal before a data packet corresponding to the terminal on the time division multiplex line in accordance with the position information of the terminal.
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TL;DR: The problems involved in Speech Transmission in packets are addressed, and a few specific cases of Packet Voice Transmission are examined, where silence periods are eliminated.
Abstract: The growth of computer networks has led to the development of the Packet Switching and Packet Broadcast Techniques. Especially useful for bursty traffic, they are of use for speech which is inherently so, with about 50% of the time occupied by silence periods. In Packet Transmission of speech, we digitize the speech and transmit packets of fixed or variable size and reassemble the bits at the destination.Unlike transmission of data, where the bit error rate is most important, in speech the prime consideration is delay. Depending upon the digitizing method, we have different error tolerance limits.In this paper, we first address the problems involved in Speech Transmission in packets, and then examine a few specific cases of Packet Voice Transmission. The concepts of TASI are also inherent in Packet Voice Transmission, where silence periods are eliminated. This involves the use of efficient speech activity detectors. Since there is a certain amount of error tolerance present in digitized speech (albeit in ...
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01 Jan 1982
TL;DR: The concept of "penalty functions" are introduced and incorporate these in the packet switching node model in order to give priority to packets that have reached their destination node and thus should be lost.
Abstract: The objective of this research is in general to develop analytic tools for the performance study of computer networks, and is in particular motivated by a need to understand how restricted buffer sharing policies can be used for congestion control in the nodes of a packet switching computer communication network. Models of a single packet switching node with finite storage and restricted buffer sharing policies are developed. Effexts of acknowledgement signals as well as retransmission are considered. We introduce the concept of "penalty functions" and incorporate these in the packet switching node model in order to give priority to packets that have reached their destination node and thus should be lost. The single packet switching node models are used to form a model of a complete packet switching network. We present for the different models comprehensive results as thoughput, delays, blocking probabilities and buffe allocation schemes. We derive a number of analytic tools, inroduce some new concepts and clarify some techniques, used in our models, to compute the main performance characteristics. (Less)
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TL;DR: The Northern Telecom SL-10 Packet Switching System is steadily enhanced to provide better access services for users, and a whole new Subsystem has evolved to handle strategies for loading processors in parallel and to load intelligent peripherals.
Abstract: The Northern Telecom SL-10 Packet Switching System is steadily enhanced to provide better access services for users. Equally important to them, but less visible, are enhancements to improve availability and increase throughput. To this end, intelligent peripheral devices, such as storage controllers and line servers, have been added to the Switch and new strategies, especially for software loading, have been devised. Such additions have had an impact on the software architecture. The Resource Subsystem now has to cope with a wider variety of devices, including intelligent peripheral devices. The File Subsystem has been generalized to accommodate files on different types of volumes, e.g., disks and tape cartridges. A whole new Subsystem has evolved to handle strategies for loading processors in parallel and to load intelligent peripherals. The SL-10 Packet Switch software architecture, with its process environment structured in Subsystems, has proven well suited to these requirements.