Showing papers on "Fast packet switching published in 1977"

The Throughput of Packet Broadcasting Channels

Abstract: Packet broadcasting is a form of data communications architecture which can combine the features of packet switching with those of broadcast channels for data communication networks. Much of the basic theory of packet broadcasting has been presented as a byproduct in a sequence of papers with a distinctly practical emphasis. In this paper we provide a unified presentation of packet broadcasting theory. In Section II we introduce the theory of packet broadcasting data networks. In Section III we provide some theoretical results dealing with the performance of a packet broadcasting network when the users of the network have a variety of data rates. In Section IV we deal with packet broadcasting networks distributed in space, and in Section V we derive some properties of power-limited packet broadcasting channels, showing that the throughput of such channels can approach that of equivalent point-to-point channels.

A Multiaccess Model for Packet Switching with a Satellite Having Some Processing Capability

Abstract: A multiaccess model for packet switching with a satellite having the capability of interrogating the uplink header and creating the downlink header is proposed. The satellite broadcasts slot assignments, based on the users' reported queue status, to the users for transmission in the next frame. With the protocols being done at both the earth stations and at the satellite, the proposed multiaccess model avoids collisions that are prevalent in schemes of the ALOHA type. The actual model is too complex to handle analytically. We derive analytical equations for a two-group model. Calculated and simulated buffer overflow probabilities as a function of traffic intensity and buffer size are compared. We also evaluate the performance of the actual model in terms of average system delay as a function of traffic intensity by means of computer simulation.

A Reliable Control Protocol for High-Speed Packet Transmission

Abstract: This paper describes a control protocol for high-speed transfers between transceivers in a data communication system. One particularly suitable application of current topical interest would be to control lines linking nodes in a local area packet-switching system. The protocol applies for fixed-length data packets which must ultimately be received at their destination in sequence. With these specifications, a set of rules which is easy to implement in practice is established. The result is a packet interlock method of numbering packet transmissions and jumping back to retransmit a series of packets under error conditions. Problems associated with multiple errors, dummy packets, initial synchronization and resynchronization are investigated and found to be readily overcome by the proposed protocol.

Switching arrangement for pulse code modulation time division switching systems

Abstract: A switching arrangement for pulse code modulation (PCM) time division multiplex telecommunication switching system is described. The frame storages for incoming and outgoing directions of transmission as well as their address memories, and the crosspoint address memory form a memory unit. The frame storages are read-in in cyclic sequence and read out selectively and it is possible to transfer information from anyone of the frame storages to either the same PCM trunk or to the space division switching network. Thus, there is a possibility both for return switching to the same PCM trunk and for switching through other switching units in a time-space-space-time format.

The new possibilities of telephone switching

Abstract: Switching system architectures have evolved to be responsive to the needs of the user. Their design has been constrained by the existing environment which treats terminals, transmission channels, and switching entities as separate "black boxes." Telephone switching circuits have used relatively expensive discrete components, and hence, system designers used common control techniques to minimize the system cost. This was done by providing the circuits in common whenever this was possible. Such common circuits were associated with a switched path for the period of time for which the functions of the circuit were required. This was followed by "one at a time" operation and by the use of stored program controls. The advent of low-cost electronic circuit components has resulted in the application of digital techniques to switching systems. For the first time, the combination of switching and transmission is possible. This is the near-term objective. The long-term objective, made possible by forecasts of low-cost memory and electronic gate circuits, is the combination of switching, transmission, and the terminals. This will result in much more complex terminals.

Introduction to Packet Switching

Abstract: The first network developments were an extension of the input-output system of the computer. They acted simply as a distribution network for a central computer. Figure 1 illustrates the forms that they took, in particular the multidrop line and then the concentrator which, by applying some intelligence remotely, can reduce the overhead traffic on the main lines to the centre. In the more elaborate versions the concentrators themselves form a multidrop configuration.