Abstract: In an approach to secure firmware updating, a system comprises: one or more user devices, each of the one or more user devices having one or more firmware modules; one or more computing devices; a digital signature repository; and a z-engine circuitry. The z-engine circuitry is configured to: receive firmware for a particular user device of the one or more user devices; receive a non-repeating input data; retrieve a hardware digital profile of the particular user device from the digital signature repository; process the non-repeating input data with the hardware digital profile to generate a unique result; perform a hash operation on the unique result to generate an encryption key; encrypt the firmware for the particular user device with the encryption key; and send the encrypted firmware to the particular user device.

Abstract: A method of encrypting an optical communications signal involves determining an encryption function, filtering an electrical input signal using the encryption function to generate an encrypted electrical signal, and modulating an optical source using the encrypted electrical signal to generate a corresponding encrypted optical signal. This is then transmitted through an optical communications system. The encryption is selected such as to substantially remove symbol definition from the optical signal. This method provides digital signal processing of an electrical input signal in order to derive a signal for controlling an optical modulator in such a way that the optical signal transmitted over the link is a continuous analogue signal rather than a series of discrete symbols which alternate between well-defined signal values. This makes it difficult for a third party to derive the binary bit sequence encoded by the optical signal.

Abstract: An optical communications system has a transmitter which uses modulation using multiple level phase and/or amplitude modulation, and is adaptable to provide modulation for different signals using different selections of the multiple levels. A receiver is able to perform demodulation from the multiple level phase and/or amplitude modulation, and is adaptable to provide demodulation of signals modulated using the different selections of the multiple levels. This provides an adaptive modulation system, so that different bit rates can be employed for different links.

Abstract: A system for monitoring a communications network generates a total value figure, using a store of value information. The system can identify which of the monitored flows of traffic rely on a given one or more of the components of the network, and generate a total value of all the identified flows. This type of value information can be easier for network operators to interpret because the information is more direct, and more explicit. Also, many specific rules/warnings about reconfigurations need not be provided. Values can be sent to remote field workers, or used for network configuration, network planning, and financial reporting.

Abstract: A system for monitoring a communications network generates a total value figure, using a store of value information. The system can identify which of the monitored flows of traffic rely on a given one or more of the components of the network, and generate a total value of all the identified flows. This type of value information can be easier for network operators to interpret because the information is more direct, and more explicit. Also, many specific rules/warnings about reconfigurations need not be provided. Values can be sent to remote field workers, or used for network configuration, network planning, and financial reporting.

Abstract: An optical switch comprising two segments at least partially separated by a surface that is partially reflective and partially transmissive to the optical signals being switched, each segment having at least one optical input and at least one optical output, the segments being arranged such that an optical signal can be switched from said input to said output by reflection from said surface, with the optical signal that is generated by transmission through said surface being directed to an output of the other segment.

Abstract: A method and apparatus suitable for testing the operation of a photonic switch are described. The photonic switch includes switching means arranged to redirect (and hence switch) an incident optical signal. Operation of the switching means can be verified by providing a test optical signal arranged to be incident upon the switching means, the test optical signal path being distinct from the switched optical signal path.

Abstract: A wavelength demultiplexer for demultiplexing optical signals carrying data, is also used to route a separate monitoring signal on to any of the demultiplexed output paths, by changing the wavelength of the monitoring signal. This enables optical paths through a switching arrangement to be verified or tested. A multiplexer at the output of the switching arrangement may be used to detect which of the output paths of the switching element has the monitoring signal. This saves the need for individual couplers to couple a monitoring signal on to each of the inputs, and off each of the outputs of the switching element. The saving in terms of component count, cost, and reduced size increases as the number of channels increases.

Abstract: An optical switch comprising two segments at least partially separated by a surface that is partially reflective and partially transmissive to the optical signals being switched, each segment having at least one optical input and at least one optical output, the segments being arranged such that an optical signal can be switched from said input to said output by reflection from said surface, with the optical signal that is generated by transmission through said surface being directed to an output of the other segment.

Abstract: A method of transmitting packet traffic between first and second network nodes in a shared protection optical transmission network, the method comprising defining first and second traffic paths between said nodes, at least one of said paths being a shared protection path, and allocating traffic along said paths utilising link aggregation.