Abstract: The present invention relates to a packet transfer unit, which comprises a search key memory that stores a search key for a transfer destination of a packet and verification information generated from the search key, in association with a storage location of transfer information memorized in a transfer information memory, wherein a transfer information acquisition unit searches the search key memory by using the search key generated based on the header information and the verification information generated from the search key, acquires storage location information of the transfer information from the search key memory when a match with the search key and the verification information memorized in the search key memory is found, and acquires the transfer information stored in the transfer information memory based on the acquired storage location information, and wherein a transfer unit transfers the packet based on the acquired transfer information.

Abstract: The present invention relates to a packet transfer unit, which comprises a search key memory that stores a search key for a transfer destination of a packet and verification information generated from the search key, in association with a storage location of transfer information memorized in a transfer information memory, wherein a transfer information acquisition unit searches the search key memory by using the search key generated based on the header information and the verification information generated from the search key, acquires storage location information of the transfer information from the search key memory when a match with the search key and the verification information memorized in the search key memory is found, and acquires the transfer information stored in the transfer information memory based on the acquired storage location information, and wherein a transfer unit transfers the packet based on the acquired transfer information.

Abstract: The present invention relates to a packet transfer unit, which comprises a search key memory that stores a search key for a transfer destination of a packet and verification information generated from the search key, in association with a storage location of transfer information memorized in a transfer information memory, wherein a transfer information acquisition unit searches the search key memory by using the search key generated based on the header information and the verification information generated from the search key, acquires storage location information of the transfer information from the search key memory when a match with the search key and the verification information memorized in the search key memory is found, and acquires the transfer information stored in the transfer information memory based on the acquired storage location information, and wherein a transfer unit transfers the packet based on the acquired transfer information.

Abstract: Each routing unit of the network routing apparatus includes: one or a plurality of transfer means each for extracting a packet header of a packet received from a line, and one or a plurality of search means each for extracting output destination information using the packet header received from each transfer means; wherein, in each routing unit, one search means is connected to one transfer means, or a plurality of transfer means are connected to one search means, or a plurality of search means are connected to one transfer means, or a plurality of search means and a plurality of transfer means are connected to one another.

Abstract: An optical crossconnect apparatus which includes one terminal connected to a transmission path from one optical transmission terminal station and another terminal connected to a transmission path from another optical transmission terminal station, a first optical signal switch having “M1” ports and “N1” ports, through which the optical signal can pass, a second optical signal switch having “M2” ports and “N2” ports, through which the optical signal can pass, and “L” optical signal repeaters, one end connected to the “N1” ports of the first optical signal switch, and the other end connected to the “N2” ports of the second optical switch. The “N1” and the “N2” ports are equal to “L” optical signal repeaters. The “M1” ports of the first optical signal switch connected to the one terminal, and the “M2” ports of the second optical signal switch connected to the other terminal are larger than, or equal to 2.

Abstract: A method for managing virtual links within a multiple protocol label switched network is provided. A virtual link which includes a set of links between two devices is regarded as a single entity by a control component of a label switching router. Each packet to be transported on the virtual link is labeled based on its assigned forwarding equivalence class. A specific label is bound to a corresponding forwarding equivalence class. Such packets can be forwarded onto any one of the links within the virtual link. To load balance the various links within the virtual link, different selected hash functions are used at selected times to apportion the packets. depending on the load conditions.

Abstract: The present invention relates to a packet transfer unit, which comprises a search key memory that stores a search key for a transfer destination of a packet and verification information generated from the search key, in association with a storage location of transfer information memorized in a transfer information memory, wherein a transfer information acquisition unit searches the search key memory by using the search key generated based on the header information and the verification information generated from the search key, acquires storage location information of the transfer information from the search key memory when a match with the search key and the verification information memorized in the search key memory is found, and acquires the transfer information stored in the transfer information memory based on the acquired storage location information, and wherein a transfer unit transfers the packet based on the acquired transfer information.

Abstract: An optical crossconnect apparatus which includes one terminal connected to a transmission path from one optical transmission terminal station and another terminal connected to a transmission path from another optical transmission terminal station, a first optical signal switch having “M1” ports and “N1” ports, through which the optical signal can pass, a second optical signal switch having “M2” ports and “N2” ports, through which the optical signal can pass, and “L” optical signal repeaters, one end connected to the “N1” ports of the first optical signal switch, and the other end connected to the “N2” ports of the second optical switch. The “N1” and the “N2” ports are equal to “L” optical signal repeaters. The “M1” ports of the first optical signal switch connected to the one terminal, and the “M2” ports of the second optical signal switch connected to the other terminal are larger than, or equal to 2.

Abstract: Each routing unit of the network routing apparatus includes: one or a plurality of transfer means each for extracting a packet header of a packet received from a line, and one or a plurality of search means each for extracting output destination information using the packet header received from each transfer means; wherein, in each routing unit, one search means is connected to one transfer means, or a plurality of transfer means are connected to one search means, or a plurality of search means are connected to one transfer means, or a plurality of search means and a plurality of transfer means are connected to one another.

Abstract: An optical crossconnect apparatus which includes one terminal connected to a transmission path from one optical transmission terminal station and another terminal connected to a transmission path from another optical transmission terminal station, a first optical signal switch having “M1” ports and “N1” ports, through which the optical signal can pass, a second optical signal switch having “M2” ports and “N2” ports, through which the optical signal can pass, and “L” optical signal repeaters, one end connected to the “N1” ports of the first optical signal switch, and the other end connected to the “N2” ports of the second optical switch. The “N1” and the “N2” ports are equal to “L” optical signal repeaters.

Abstract: A first object of the invention of the present application is to provide an optical network capable of flexibly performing a choice of protection optical paths upon the occurrence of a failure without depending on an installation form of an optical transmission line, e.g., an optical fiber. A second object of the invention of the present application is to allow an improvement in the efficiency of use of an optical transmission line, e.g., an optical fiber employed in an optical network. The invention of the present application provides a wavelength division multiplexing transmission optical network having at least a plurality of pieces of transmission equipment and a plurality of optical paths connecting the transmission equipment and wherein wavelengths of predetermined transmission light are assigned to the optical paths and a transmission frame having overhead information is at least used to perform digital transmission.

Abstract: A method for managing virtual links within a multiple protocol label switched network is provided. According to one aspect of the method, a virtual link which is made up of a set of links between two devices within the multiple protocol label switched network is regarded as a single entity by a control component of a label switching router. Each packet to be transported on the virtual link is labeled based on its assigned forwarding equivalence class. A specific label is bound to a corresponding forwarding equivalence class. The specific label are used on packets belonging to the same forwarding equivalence class and such packets can then be forwarded onto any one of the links within the virtual link. Furthermore, according to another exemplary aspect of the method, each forwarding equivalence class can be mapped to one of the links within an outgoing virtual link without changing the output label. This mapping is performed using a selected hash function.

Abstract: An optical crossconnect apparatus which includes one terminal connected to a transmission path from one optical transmission terminal station and another terminal connected to a transmission path from another optical transmission terminal station, a first optical signal switch having “M1” ports and “N1” ports, through which the optical signal can pass, a second optical signal switch having “M2” ports and “N2” ports, through which the optical signal can pass, and “L” optical signal repeaters, one end connected to the “N1” ports of the first optical signal switch, and the other end connected to the “N2” ports of the second optical switch. The “N1” and the “N2” ports are equal to “L” optical signal repeaters.

Abstract: An optical crossconnect apparatus which includes one terminal connected to a transmission path from one optical transmission terminal station and another terminal connected to a transmission path from another optical transmission terminal station, a first optical signal switch having “M1” ports and “N1” ports, through which the optical signal can pass, a second optical signal switch having “M2” ports and “N2” ports, through which the optical signal can pass, and “L” optical signal repeaters, one end connected to the “N1” ports of the first optical signal switch, and the other end connected to the “N2” ports of the second optical switch. The “N1” and the “N2” ports are equal to “L” optical signal repeaters.

Abstract: Input/output fibers for the optical cross-connect system are classified into working fibers and protecting fibers. In a normal time (a state in which there occurs no failure), there turns out to be a one-to-one correspondence between a line terminal and a working fiber. Namely, connection property required for the switch matrix in the optical cross-connect system is not necessarily strictly non-blocking connections among all of the fibers. The connection property is a one-to-one connection relationship with the working fibers, and is a predetermined connection relationship with the protecting fibers at the time of a failure occurrence. Utilization thereof makes it possible to extremely downsize scale of the switch.

Abstract: Input/output fibers for the optical cross-connect system are classified into working fibers and protecting fibers. In a normal time (a state in which there occurs no failure), there turns out to be a one-to-one correspondence between a line terminal and a working fiber. Namely, connection property required for the switch matrix in the optical cross-connect system is not necessarily strictly non-blocking connections among all of the fibers. The connection property is a one-to-one connection relationship with the working fibers, and is a predetermined connection relationship with the protecting fibers at the time of a failure occurrence. Utilization thereof makes it possible to extremely downsize scale of the switch.

Abstract: A method for restoration from a fault in a communication network formed by interconnecting a plurality of nodes including at least one set of node equipment each including a line terminal equipment and an optical cross-connect equipment, via a plurality of transmission lines using optical fibers. According to this method for restoration from a fault, if a line terminal equipment of at least one set of node equipment has detected a fault in an optical fiber under communication, it gives a command functioning as trigger for optical fiber change-over to an optical cross-connect equipment included in the node equipment. Upon receiving this command functioning as the trigger, the optical cross-connect equipment exchanges change-over control information indicating optical switch setting situation between it and an optical cross-connect equipment included in another node equipment, and forms a restoration route.

Abstract: To obtain an optical functional device such that the reflectivity of a facet and the loss of coupling with a fiber are reduced, a mode conversion region for changing the beam spot size is formed on the input facet and/or the output facet in an optical function region and the facet of the side to be connected with a fiber in the mode conversion region is formed obliquely to the direction of propagation of light.

Abstract: An optical modulating element has a core layer and first and second cladding layers sandwiching the core layer. The core layer is made of one or semiconductors belonging to a point group 43m or 42m, and has TM.sub.00 and TE.sub.00 propagation modes. The direction of light of said TM.sub.00 and TE.sub.00 propagation modes is parallel to the [110] or [-110] direction of crystal orientation. The change amount of an index of refraction of the core layer caused by the application of an electric field to the core layer in the direction parallel to the [001] direction is different for the two propagation modes.

Abstract: A method for producing a polarizer patterned with a plural number of portions having a polarizing ability or direction of polarization comprising the first step of producing a surface oriented in a pre-determined direction on a substrate, the second step of producing a polymerizable molecular layer which comprises polymerizable molecules on the above surface, the third step of polymerizing the molecules in said polymerizable molecular layer into a desired pattern and the fourth step of removing the unpolymerized portion of said polymerizable molecular layer.