Optical network

A time-division multiplex transmission optical network, comprising at least:

• a plurality of pieces of transmission equipment having switching information;
• and
• a plurality of optical paths which connect said plurality of pieces of transmission equipment to one another;
• wherein said optical paths are used as working optical paths or protection optical paths,
• and said plurality of optical paths are assigned predetermined time division multiplex signals and at least a transmission frame having overhead information is used to perform digital transmission, and
• said plurality of optical paths include optical paths which connect said plurality of pieces of transmission equipment in a straight chain form;
• wherein the switching information includes at least numbers of working optical paths highest in importance, numbers of transmission equipment which transmitted the switching information, and switched states of the transmission equipment.

A wavelength division multiplexing optical network, comprising at least:

• a plurality of pieces of transmission equipment having switching information;
• and
• optical paths which connect said plurality of pieces of transmission equipment to one another;
• wherein said optical paths are assigned wavelengths of predetermined transmission light and at least a transmission frame having overhead information is used to perform digital transmission,
• said overhead information has switching control information about a failure, and
• said each transmission equipment has memory means constituting a wavelength address map for storing therein at least information of wavelength addresses on said respective optical paths and failure information on said respective optical paths, and is constructed such that when a failure occurs in a working optical path, optical-path switching is done based on the switching control information about the failure, the wavelength address information and the failure information on the optical paths;
• wherein the switching information includes at least numbers of working optical paths highest in importance, numbers of transmission equipment which transmitted the switching information, and switched states of the transmission equipment.

A wavelength division multiplexing optical network, comprising at least:

• a plurality of pieces of transmission equipment having switching information;
• and
• optical paths which connect said plurality of pieces of transmission equipment to one another;
• wherein said optical paths are used as working optical paths or protection optical paths and are assigned wavelengths of predetermined transmission light, and at least a transmission frame having overhead information is used to perform digital transmission,
• said overhead information has switching control information about a failure, and
• said each transmission equipment has memory means constituting a wavelength address map for storing therein at least information of wavelength addresses on said respective optical paths and failure information on said respective optical paths, and is constructed such that when a failure occurs in a working optical path, the working optical path is switched to a protection optical path, based on the switching control information about the failure, the wavelength address information and the failure information on the optical paths;
• wherein the switching information includes at least numbers of working optical paths highest in importance, numbers of transmission equipment which transmitted the switching information, and switched states of the transmission equipment.

An optical network, comprising at least:

• a plurality of pieces of transmission equipment having switching information;
• and
• a plurality of optical paths which connect said plurality of pieces of transmission equipment to one another;
• wherein at least two of said optical paths are placed in one optical transmission line and at least a transmission frame having overhead information is used to perform digital transmission, thereby allowing signal multiplexing transmission, and
• said plurality of optical paths include a plurality of optical paths connecting said plurality of pieces of transmission equipment in a straight chain form;
• wherein the switching information includes at least numbers of working optical paths highest in importance, numbers of transmission equipment which transmitted the switching information, and switched states of the transmission equipment.

A wavelength division multiplexing survival network, comprising at least:

• several pieces of transmission equipment having switching information;
• working optical paths which connect said transmission equipment to one another and are assigned optical wavelengths;
• and
• protection optical paths which connect said transmission equipment and are assigned optical wavelengths;
• wherein said each transmission equipment has memory means constituting a wavelength address map for storing therein at least information of wavelength addresses and failure information on said respective optical paths, and performs digital transmission by using at least a transmission frame having overhead information;
• wherein the switching information includes at least numbers of working optical paths highest in importance numbers of transmission equipment which transmitted the switching information, and switched states of the transmission equipment;
• and
• wherein said network is constructed so as to be capable of performing the following switching determining steps:
• (1) a step 1 for determining whether an automatic protection switching byte of said overhead information shows a failure pattern,
• (2) a step 2 for determining whether the automatic protection switching byte of said overhead information is destined for the transmission equipment which received the same,
• (3) a step 3 for starting a switching operation when the automatic protection switching byte is destined for the transmission equipment which received the same, and
• (4) a step 4 for transferring the automatic protection switching byte when the automatic protection switching byte is undestined for the transmission equipment which received the same.