International Business Machines Corporation

Eli Upfal

Jehoshua Bruck

Howard Thomas Olnowich

James William Feeney

Marc Snir

Disclosed is is a switch-based network interconnection which uses intelligent switching apparatus devices for improving the performance and connection establishing capability of multi-stage switching networks. The invention method is particularly effective In asynchronous circuit-switched networks. The most important feature of the invention methodology is the an increasing probability for the success of making a connection through all the stages of a multi-satge network. As a connection progresses through a multi-stage network, it must win successive stages of the network, one at a time, until it has made its way from on side of the network to the other and established the commanded source-to-destination connection. The uniqueness in the present invention is that as the connection at each stage of the network is established, looking forward to the next stage, the probability will be greater of establishing the next connection without encountering blocking than it was for the present stage. This presents an ever increasing probability for establishing a successful connection as a path works its way through the network. This is opposite of most traditional networks, whose probabiltiy for success diminishes with every stage in the connection sequence.

Increasing probability multi-stage network

A multi-stage circuit switched network for improving connection establishment using intelligent switching devices. As a transmission makes its way through the network stages, the probability of connecting to a destination increases, i.e., the chance of encountering a blocked device output is decreased. This is opposite of most traditional networks, whose probability for success diminishes with every stage in the connection sequence.

Disclosed is a method and apparatus for improving the performance and connection establishing capability of multi-stage switching networks by providing additional intelligent features in the individual switching apparatus devices at each stage of the network. The invention method is particularly effective in asynchronous circuit-switched networks. The most important feature to be added is adaptivity of the switching apparatus; where adaptivity means the ability of each switching element to determine for itself which of several optional alternate paths to try at each stage of the network based on availability. This is a better approach because it brings the decision directly to the switching apparatus involved, which has the data required to make an intelligent path selection decision to circumvent blocking in the multi-stage network.

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Palo Alto, CA, United States of America

Eli Upfal