Showing papers on "Transmission delay published in 1972"

The Control of Congestion in Packet-Switching Networks

Abstract: Any communication network has a finite traffic capacity and if it is offered traffic beyond the limit it must reject some of it. The data-communication network studied here is one employing packet switching, like the Advanced Research Project Agency (ARPA) network. It handles blocks of data, called packets, and longer messages are subdivided, rather in the same way that store in a computer is allocated in pages. A method of controlling congestion is proposed in which there is a finite number of packet carriers in the whole network. When a packet of data is delivered to its destination node the "empty" packet is available for reuse. The empties move randomly round the network and new data must capture an empty packet carrier before being launched into the network. Various elaborations are described that avoid delay in normal conditions. This so-called "isarithmic" method of congestion control supplements and does not replace end-to-end flow control.

Proposed organisation for packet-switched data-communication network

Abstract: A processor-controlled packet-store-and-forward data-communication system is described and performance figures are presented The philosophy of the system is characterised by the use of a route-search packet to establish the availability of both a route through the network and the destination terminal before the message data is accepted by the network Subsequent message-data packets are constrained to follow the path established by the route search and are maintained in correct sequence by a comprehensive acknowledgment-and-signalling procedure This also provides the facility of error correction by retransmission, and is the basis of a convenient method for the control of buffer storage within the network The exchange implementation comprises a control computer operating in conjunction with link terminal units that are dedicated to the control of the input and output links of the exchange and to packet assembly and checking functions Each of these units consists of a small autonomous microcomputer module controlled by a changeable microprogram They can thus be readily adapted to accommodate the characteristics of the particular links and error-control facilities employed

Features of a Proposed Synchronous Data Network

Abstract: Marketing surveys on data communication have indicated the possible need for a new data service. Technical studies have resulted in a number of detailed proposals for providing a service which, although functionally distinct, is physically integrated with other telecommunications services. The proposed network utilizes synchronous digital transmission with a processor-controlled TDM switching structure. A range of speeds is available. Users' data bytes are structured in "envelopes" to provide an inband control signaling facility. The use of a processor for switch control gives greater flexibility, allows the implementation of sophisticated diagnostics, and, with high-speed interswitch signaling, reduces overall call set-up times. The proposed network is hybrid in that it can operate in a conventional circuit switched mode, or operate in a "packet" switched mode. Extensive multiplexing is used to increase transmission utilization and reduce local area transmission costs.

Bi-filar delay line

Abstract: This invention involves a bi-filar wound distributed constant variable delay line, exhibiting increased delay and bandwidth performance for a given volume, as compared to presently known designs and methods. A wiper arm is used to adjust the delay. The greatly enhanced figure of merit of electrical parameters of this bi-filar device is noted at all settings of the delay line, i.e., whether the wiper arm is set for one-fourth, one-half or full delay, etc.

Delay equalizer network including negative delay circuits

Abstract: An equalizer circuit for equalizing delay in the passband of signals in a transmission line employs both positive and negative delay equalizer sections. By use of negative delay which subtracts from the delay in the line, uniform delay of lower time magnitude is obtainable than by use of positive delay circuits alone. Also, by using one or more negative delay sections a given equalization envelope is obtainable employing fewer equalizer sections. Lattice or bridge-T circuits are employed in the delay equalizer. The negative delay lattice sections include resistance elements selected in accordance with criteria herein set forth to provide the negative delay.

Wave packet scattering and time delay

Abstract: The t = 0 wave function is derived, following the treatment of Rosenfeld, but using the Green's function for the radial wave equation to simplify the calculation of the Laplace transform. The treatment is extended to include the case of a packet initially within the potential, and the wave function for a decaying wave packet is derived. This agrees in form with the wave function obtained by Jeukenne in another approach.