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Optical transmission system and transmission line switching control method

  • US 5,978,354 A
  • Filed: 03/18/1996
  • Issued: 11/02/1999
  • Est. Priority Date: 07/21/1995
  • Status: Expired due to Term
First Claim
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1. A 1:

  • N transmission-line switching control method in an optical transmission system, which has N-number of working optical transmission lines and one protection optical transmission line, for sending and receiving data, in accordance with a frame format having overhead, between stations via said transmission lines, and, when a failure has developed in a transmission line, inserting a K1 byte or a K2 byte, which are for transmission-line switching, into the overhead, sending and receiving the K1, K2 bytes between stations via the protection transmission line and switching the failed transmission line to the protection transmission line, said method comprising the steps of;

    providing repeater stations in the working transmission lines and providing protection transmission line connecting units, at positions in the protection transmission line corresponding to positions at which said repeater stations are disposed, for switching a failed transmission line to the protection transmission line in every section demarcated by said repeater stations;

    providing an overhead processor in each working and protection terminal station, each repeater station, and each protection transmission line connecting unit; and

    causing the overhead processor of a working terminal station or repeater station that has detected occurrence of failure in an optical transmission line to send the K1 byte to and receive the K2 byte from the overhead processor of an opposing working terminal station or repeater station via the overhead processor of a protection terminal station or protection transmission line connecting unit and switch the failed transmission line section to the protection transmission line,wherein each of said protection transmission line connecting units;

    retains numbers of transmission lines which it itself must manage at occurrence of failure of a transmission line;

    when the K1 byte (transmission-line switching request) having a switching request level andan overhead byte is employed, together with a transmission-line designating bit of the K1 byte, to designate the number of a transmission line.

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