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Path Finding in Telephone Switching Network

IP.com Disclosure Number: IPCOM000073501D
Original Publication Date: 1970-Dec-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 3 page(s) / 34K

Publishing Venue

IBM

Related People

Leblanc, R: AUTHOR

Abstract

In a telephone switching network, when the blocking rate is high, i.e. at the peak traffic hours, it is profitable to determine as soon as possible that there is no path available between the two terminals involved. The purpose of the present system is to solve that problem.

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Path Finding in Telephone Switching Network

In a telephone switching network, when the blocking rate is high, i.e. at the peak traffic hours, it is profitable to determine as soon as possible that there is no path available between the two terminals involved. The purpose of the present system is to solve that problem.

The figure is a schematic view of a connection path between two extensions E and E', through a 4-stage matrix switching network and a junctor J.

Assuming that the addresses of E and E' are s r q p and s' r' q' p', respectively, and that the address of J is a b c d, the addresses of the elements involved in the connecting path are: extension s r q p, matrix s r q, link s r q Oa, matrix s r Oa, link s r Oa b, matrix s Oa b, link s Oa b c, matrix Oa b c, link Oa b c d, junctor a b c d, link 1a b c d, matrix 1a b c, link s' 1a b c, link s' p' 1a b, matrix s' r' 1a, link s' r' q' 1a, matrix s' r' q', and extensions s' r' q' p', wherein the bit 0 or 1 has been introduced to distinguish one side of junctor J from the other.

Considering two four-stage conjugated matrices, i.e. having equal a, b and c values, there are only m possible ways to connect them together through a junctor, if m is the total number of the different values assumed by parameter d. Therefore, if at a given moment all corresponding m junctors are busy, it is useful to be aware of such a blocking situation before initiating a search for a free junctor.

This can be achieved by means of a dynamic table indicating at any moment whether there is at least one free junctor capable of connecting two given four- stage conjugated matrices together.

If n is the total number of possible values of parameter c, the table will be comprised of n words: each word will correspond...