Abstract: A method for preventing a temporary traffic interruption between two client ports and the consequent state transition of the receiving port in a communication network providing for the transmission of a data stream between two clients along at least one path when a fault condition is detected in the path. The method includes the steps of monitoring the data stream directed to the receiver and, upon detecting in the data stream an error sequence capable of starting the state transition, replacing the data stream with a filling data stream to prevent the receiver from detecting an error condition, and resuming the forwarding of the received data stream after a predetermined time interval. An apparatus able to mask to the receiver for the predetermined time interval, a storage area network and a computer program product are also disclosed.

Abstract: A system for updating a data set through a geographical communication network. The data set is stored in a recovery storage unit located in a recovery data center and has to be updated with data blocks generated by a processing system located in a primary data center.

Abstract: A method for preventing a temporary traffic interruption between two client ports and the consequent state transition of the receiving port in a communication network providing for the transmission of a data stream between two clients along at least one path when a fault condition is detected in the path. The method includes the steps of monitoring the data stream directed to the receiver and, upon detecting in the data stream an error sequence capable of starting the state transition, replacing the data stream with a filling data stream to prevent the receiver from detecting an error condition, and resuming the forwarding of the received data stream after a predetermined time interval. An apparatus able to mask to the receiver for the predetermined time interval, a storage area network and a computer program product are also disclosed.

Abstract: A system for updating a data set through a geographical communication network. The data set is stored in a recovery storage unit located in a recovery data centre and has to be updated with data blocks generated by a processing system located in a primary data centre.

Abstract: This invention concerns a method of and a device for optical demultiplexing that are based on the four wave mixing between the signals to be demultiplexed and pump signals. The two signals are fed into a polarization maintaining fiber (14), which divides them into two components with orthogonal polarization, separated in time; and the four wave mixing is performed separately on the two components, thereby originating two separate signals that are polarization-rotated and re-combined. (FIG. 1).

Abstract: The circuit includes an electro-optical mixer, such as an electro-optical Mach-Zehnder modulator, with non-linear behavior. The modulator receives as input an optical signal (Pin) at the frequency to be divided, in addition to an electric signal (e3) at a given frequency, usually corresponding to the frequency deriving from such division. The output optical signal (Pout) from modulator exhibits a modulation spectrum containing the frequency difference between the frequency to be divided and at least one harmonic of the frequency of the above electric signal. After having been converted into an electric signal (e1), the output signal of the mixer is subjected to a filtering action to extract the above frequency difference component. This latter one is then used both as electrical signal (e3) for the mixing, and as output signal from the divider (e2). The preferred application is to OTDM systems, to extract a synchronism signal as tributary signal frequency.

Abstract: The circuit includes an electro-optical mixer, such as an electro-optical Mach-Zehnder modulator, with non-linear behavior. The modulator receives as input an optical signal (Pin) at the frequency to be divided, in addition to an electric signal (e3) at a given frequency, usually corresponding to the frequency deriving from such division. The output optical signal (Pout) from modulator exhibits a modulation spectrum containing the frequency difference between the frequency to be divided and at least one harmonic of the frequency of the above electric signal. After having been converted into an electric signal (e1), the output signal of the mixer is subjected to a filtering action to extract the above frequency difference component. This latter one is then used both as electrical signal (e3) for the mixing, and as output signal from the divider (e2). The preferred application is to OTDM systems, to extract a synchronism signal as tributary signal frequency.

Abstract: The circuit includes an electro-optical mixer, such as an electro-optical Mach-Zehnder modulator (2), with non-linear behaviour. The modulator (2) receives as input an optical signal (Pin) at the frequency to be divided, in addition to an electric signal (e3) at a given frequency, usually corresponding to the frequency deriving from such division. The output optical signal (Pout) from modulator (2) exhibits a modulation spectrum containing the frequency difference between the frequency to be divided and at least one harmonic of the frequency of the above electric signal. After having been converted into an electric signal (e1), the output signal of the mixer is subjected to a filtering action (8) to extract the above frequency difference component. This latter one is then used both as electrical signal (e3) for the mixing, and as output signal from the divider (e2). The preferred application is to OTDM systems, to extract a synchronism signal at tributary signal frequency.