Showing papers on "Routing table published in 1969"

Adaptive Routing Techniques for Distributed Communications Systems

Abstract: The concept of a netted or distributed communications system is significant because it offers a major advantage over conventional communications systems, i.e., a better chance of providing surviving lines of communication after an attack on the system. During and after an attack, however, an effective adaptive routing technique is necessary to adjust the routing tables of the message-switching control system to the changing situation. Previously investigated adaptive routing techniques are shown to be insufficient for the task, and a number of promising alternatives are formulated and investigated such as some stochastic techniques, which use information on messages passing through the network to adjust the tables, and some deterministic techniques, which use dynamic programming or graph-theoretic algorithms to recalculate changes in the tables from observed changes in the network. Each alternative has operational advantages, which make it good for certain types of communications systems, and certain disadvantages if applied to others. Regions of applicability and inapplicability, with respect to the above system parameters, are given for the various techniques. Recommended techniques are specified for two currently proposed applications of distributed communications systems. A number of research areas are pointed out in which further efforts in the analysis and simulation of adaptive routing techniques will have useful payoffs in the design of future distributed communications systems.

Traffic control for modifying the routing plan in a network of switching centers

Abstract: A communications network is disclosed wherein the code translation and routing apparatus at each switching center includes a memory having a number of code words and a number of routing words. Each code word stores a code which usually comprises three or six digits used in an associative search by comparison with the corresponding dialed digits. Each code word or group of code words is followed by one or three routing words, each of which designates one or more trunk groups, which may comprise a primary route and a number of alternate routes. Some of the code words include an automatic traffic control digit which directs which one of three routing words is to be used. The value of the traffic digit for each code or group of codes may be modified by a traffic controller by a call from a special station, to thereby designate which one of three predetermined routing plans stored in the respective routing words is to be used. Thus under abnormal traffic conditions caused, for example, by overloads in emergencies, or destruction of facilities, the traffic routing plan may be modified.

Routing doctrines and their implementation in message-switching networks

Abstract: Three practical constraints on the choice of a deterministic routing doctrine for a connected network are defined, leading to a class of doctrines for which a weighted graph of the network exists so that the specified routes are given uniquely by minimum-cost routes through the graph. A technique for finding such a weighted graph is given. An adaptive routing doctrine is defined, which considers the current delays along links of the network. The implementation of such a doctrine is discussed, and a ‘distributed’ solution described which is efficient, decentralised, and resilient under fault conditions. More general adaptive routing doctrines are defined, considering two parameters associated with each link, where the routing of a message may depend on its history as well as its present position and destination. A device called a dynamic route selector is described, which takes routing decisions according to the most general doctrine discussed. It is faster than a digital computer. Finally a method for first introducing deterministic, and then adaptive, routing on a computer-based network is outlined.

Routing device with stationary routing tool

Abstract: Routing devices that can conveniently and quickly cause door panels, or the like, to be slotted on a mass production basis for purposes of associating hinges therewith that require slots formed in the panels. The routing tools thereof are held stationary and the panels are fed toward the routing tools.

Routing techniques for distributed communica

Abstract: The concept of a netted or distributed communications system is significant because it offers a major advantage over conventional communications systems, i.e., a better chance of pro- viding surviving lines of communication after an attack on the sys- tem. During and after an attack, however, an effective adaptive routing technique is necessary to adjust the routing tables of the message-switching controi system to the changing situation. Pre- vious:y investigated adaptive routing techniques are shown to be insufficient for the task, and a number of promising alternatives are formulated and investigated such as some stochastic techniques, which use information on messages passing through the network to adjust the tables, and some deterministic techniques, which use dynamic programming or graph-theoretic algorithms to recalculate changes in the tables from observed changes in the network. Each alternative has operational advantages, which make it good for certain types of communications systems, and certain disadvantages if applied to others. Regions of applicability and inapplicability, with respect to the above system parameters, are given for the various techniques. Recommended techniques are specified for two currently proposed applications of distributed communications sys- tems. A number of research areas are pointed out in which further efforts in the analysis and simulation of adaptive routing techniques will have useful payoffs in the design of future distributed com- munications systems.