US 5,229,990 A · N+K sparing in a telecommunications switching environment

Abstract

An N+1 sparing strategy for both line circuits and switching nodes of a self-routing 3-stage Benes packet telecommunications network. Line circuits selectively serve either their own telecommunications line or the line normally served by the corresponding line circuit of the preceding row of the switching matrix. A row of spare line circuits and switching nodes is provided. Upon failure of a matrix internal node, line circuits modify packet addresses to reroute packets normally served by the failed node, or nodes below it within the same switching stage, to the next-lower row. Upon failure of a matrix edge node, line circuits of the failed node's row are disabled and line circuits of each row below it commence to serve the lines normally served by the preceding row. Active line circuits also modify packet addresses to reroute packets normally served by the last-stage node of the failed node's row, or rows below it, to the next-lower row. Upon failure of a line circuit, it is disabled and corresponding line circuits of each row below it commence to serve the lines normally served by the corresponding line circuit of the preceding row. Active line circuits also modify packet addresses to reroute packets normally switched to the failed line circuit or to the corresponding line circuits of the rows below it, to the corresponding line circuit of the next-lower row.

Claims36

Dependent claims

A telecommunications system comprising:

a plurality of switching nodes interconnected to form switching stages and rows including a normally spare row of a switching matrix, the nodes for routing received telecommunications through the matrix;
and
first means in cooperative arrangement with the switching nodes and responsive to a signal identifying an individual node of an individual row other than the spare row, for re-routing telecommunications normally received by the individual node to a node both (a) of the same stage as the individual node and (b) not of the spare row, and for re-routing telecommunications, received without the re-routing by any node to which telecommunications are being re-routed, to a node of the same stage as the individual node, the re-routing including re-routing telecommunications, received without the re-routing by one of the nodes to which telecommunications are being re-routed, to a node of both the same stage as the individual node and of the spare row.

A telecommunications switching system employing an "N+K"-type of sparing strategy wherein N is an integer greater than one and K is an integer at least equal to one, comprising:

a plurality of switching nodes interconnected to form switching stages and a sequence of rows including a sequentially-last row of a switching matrix, the sequentially-last row being a spare row in an absence of failure of one of the switching nodes, the nodes for routing received telecommunications through the matrix;
and
means in cooperative arrangement with the switching nodes and responsive to failure of one of the switching nodes of a row other than the spare row, for causing telecommunications that are received in an absence of the failure (a) by the failed node and (b) by nodes that are both in a same stage as the failed node and in rows sequentially-subsequent to the row that includes the failed node, each to be instead received by a node that is both in the same stage as the failed node and in a row sequentially-subsequent to the row that includes the node that receives the telecommunication in the absence of the failure.

In a self-routing packet telecommunications switching system having a plurality of first switching nodes interconnected to form a sequence of first rows and internal and edge stages of a switching matrix for routing received packets through the matrix by using addresses included with the received packets and the nodes of each different stage using a different portion of the addresses, and a plurality of first line circuits connected to first nodes of the edge switching stages and included in the rows of the first nodes to which they are connected each for normally interfacing a first telecommunication line to the first nodes, the improvement comprising:

second switching nodes interconnected with each other to form a second row of the matrix and further interconnected with the first nodes and included in the switching stages, the second switching nodes being spare switching nodes for the first switching nodes;
and
the first line circuits each including
first means for receiving and storing a first address identifying one of a first node and a first line circuit around which received packets are to be routed,
second means connected to the first means, for comparing the first address with a routing address included with a packet received by the line circuit, and
third means connected to the second means, for incrementing a portion of the routing address included with the received packet when the second means determine that the first address is equal to or smaller than the routing address included with the received packet, to cause the first and the second nodes to reroute the received packet around the one of the first node and the first line circuit identified by the first address.

3 more elements

Dependencies are inferred from the claim text.

N+K sparing in a telecommunications switching environment

Life of this patent

N+K sparing in a telecommunications switching environment

Life of this patent

Abstract

Claims36