Patent EP0484943A2 successfully refreshed from Google Patents.
EP0484943A2
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EP
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Method for restructuring communications network based on asynchronous transfer mode in case of failure
Assignee: Fujitsu Ltd
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Filing: 1991-11-07
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Granted: —
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Expires: 2011-11-07
Abstract
Abstract A method for structuring a communications network based on an asynchronous transfer mode in which communications are held with the use of cells transferred between a node (C) on the upstream side and a node (D) on the downstream side. The method for structuring the network includes a step for preparing a plurality of VPI conversion tables for converting VPIs of the cell input under normal communicating conditions and that of the cell input in the event of a failure and outputting the cell with the VPI converted. The prepared VPI conversion tables are reorganized for each node and the reorganized VPI conversion tables are distributed to all nodes. Then, an alternate route monitoring and switching virtual path (15, 16) is set up in each alternate route and a monitoring cell is periodically transmitted along the alternate route. When a failure occurs, the VPI conversion table is switched over according to the pattern of the failure and the input VPI is converted in accordance with the switched VPI conversion table, and thereby, an alternate virtual path is set up in the relevant alternate route.
Inventors
- 👤 Takafumi c/o Fujitsu Limited Chujo
- 👤 Hiroaki c/o Fujitsu Limited Komine
- 👤 Keiji c/o Fujitsu Limited Miyazaki
- 👤 Takao c/o Fujitsu Limited Ogura
- 👤 Tetsuo c/o Fujitsu Limited Soejima
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 20:14
CPC Classifications
H; H04; H04L; H04L45/00; H04L45/02; H04L45/10; H04L45/28; H04L69/00; H04L69/40
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
228 words
A method for structuring a communications network based on an asynchronous transfer mode holding communications with cells transferred between a first node on the upstream side and a second node on the downstream side, said first node and second node being connected by a working route and by a plurality of alternate routes each including a plurality of intermediate nodes, said working route including at least one link accommodating working virtual paths and connecting said first and second nodes, each of said alternate routes including a plurality of links connecting adjoining nodes, and each of said links being capable of accommodating a plurality of virtual paths, said method for structuring a communications network comprising the steps of: preparing a first VPI conversion table according to which the virtual path identifier (VPI) of the input cell is converted to be output under normal communicating conditions; preparing a plurality of second VPI conversion tables according to which the VPI of the input cell is converted into the VPI for an alternate virtual path corresponding to every failure pattern; reorganizing said first and second VPI conversion tables for each node; distributing the reorganized first and second VPI conversion tables to all of said nodes; setting up an alternate route monitoring and switching virtual path in each of said alternate routes; and transmitting a monitoring cell along each of said alternate routes.
Claim 2
Dependent Claim
41 words
A method for structuring a communications network according to claim 1, wherein said first VPI conversion table includes a VPI conversion table for the alternate route monitoring and switching virtual path and a VPI conversion table for the alternate virtual path.
Claim 3
Dependent Claim
141 words
A method for structuring a communications network according to claim 1, wherein said second node, when a failure occurs in said working route, detects the failure; said second node transmits an alarm for station to the first node; said first node, upon receipt of the alarm for station, transmits a switching command cell to switch said first VPI conversion table to said second VPI conversion table along each of said alternate route monitoring and switching virtual paths; said first node and said intermediate nodes switch said first VPI conversion table to said second VPI conversion table prepared in advance corresponding to every failure pattern; and convert the VPI of the input cell in accordance with the switched second VPI conversion table and transmit the cell along said alternate route, whereby an alternate virtual path is set up in said alternate route.
Claim 4
Dependent Claim
86 words
A method for structuring a communications network according to claim 3, wherein one of said nodes, when it detects said switching command cells from a plurality of alternate route monitoring and switching virtual paths incorporated in the links constituting said alternate route, gives a notice of coincident failures to all of the nodes on the downstream side and an operation system; and the operation system, upon receipt of the notice of coincident failures, arbitrates the contention of coincident failures and sets up the alternate route anew.
Claim 5
Dependent Claim
86 words
A method for structuring a communications network according to claim 3, wherein said first node, when the failure of said working route is repaired, receives a command for recovering the normal-state VPI conversion table transmitted from said operation system; said first node transmits a switching command cell based on said command for recovery along said alternate route monitoring and switching virtual path; and said intermediate node, upon receipt of said switching command cell, switches the second VPI conversion table back to the first VPI conversion table.
Claim 6
Dependent Claim
57 words
A method for structuring a communications network according to claim 1, wherein one of said intermediate nodes, upon detecting a malfunction of the alternate route in which said intermediate node is included during the course of normal communication, gives a notice of the malfunction to all of the nodes on the downstream side and the operation system.
Claim 7
Dependent Claim
35 words
A method for structuring a communications network according to claim 3, wherein said alternate route monitoring cell is transmitted periodically and, when a failure occurs, said VPI conversion table switching command cell is transmitted periodically.
Claim 8
Dependent Claim
38 words
A method for structuring a communications network according to claim 7, wherein the period of transmission of said VPI conversion table switching command cell and the period of transmission of said monitoring cell are adapted to be variable.
Claim 9
Dependent Claim
35 words
A method for structuring a communications network according to claim 8, wherein the period of transmission of said VPI conversion table switching command cell is shorter than the period of transmission of said monitoring cell.
References Cited (Backward Citations)
No citation records indexed.
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