Abstract: In order to restore a network after a failure, it is important to have sufficient spare capacity available. To ensure restorability, a Hamiltonian mesh, being a closed sequence of links traversing each network node exactly once, is determined and half of its capacity is reserved for restoration purpose. In the case of a line failure of a link other than the links of the Hamiltonian mesh, affected traffic is split in two portions and rerouted over the two directions of the Hamiltonian mesh. In the case the network has no Hamiltonian mesh, a mesh coverage is determined and sufficient spare capacity reserved for restoration purpose.

Abstract: A method of transmitting a concatenated signal consisting of at least two component signals over an optical network comprising at least three network elements (1, 2, 3, 7, 8, 9, 10) is disclosed in which at least two component signals are transmitted on at least two different wavelengths, and in which the component signals are assigned to the wavelengths for each section between two network elements (1, 2, 3, 7, 8, 9, 10) in such a way as to minimize differential delays between the component signals for a predetermined receiving location. Concatenated transmission capacity can be allocated even if it is no longer available on one wavelength as a coherent whole.

Abstract: An optical connection and a connection unit between individual installation units (2) is proposed for the exchange of data between devices, in which the devices (1) communicate with one another by means of optical signals, and the optical signals overcome at least the distance between two adjacent installation units.

Abstract: Restoration of a link in fixed wireless transmission network, in the case of failure, is achieved by redirecting a directional antenna of a first network element from a second failed network element to a third network element, whereby a new microwave link in the network is established. A network element suited to allow fast and effective restoration in a fixed wireless transmission network has a directional antenna and corresponding control circuitry which are controlled by a control device to redirect transmission direction in the case of a failure. Preferably, the directional antenna is a phased array antenna. The control device can either be a central network management system or a local control system of the network node.

Abstract: A Network restoration device for restoring static paths in a transmission network upon occurrence of a failure, the restoration device comprising means for retrieving an initial configuration of said transmission network from a central network managing device, means for tracking the current network status by tapping messages on a communication path between said network managing device and network elements, duplicating said messages, and evaluating them, means for detecting a failure to be restored by evaluating alarm messages, means for taking over control over the network from said network managing device upon detection of a failure, means for evaluating a restoration configuration of said transmission network and for restoring failed paths by deploying said restoration configuration, and means for informing said network managing device of the restoration configuration.

Abstract: In order to restore a network after a failure, it is important to have sufficient spare capacity available. To ensure restorability, a Hamiltonian mesh, being a closed sequence of links traversing each network node exactly once, is determined and half of its capacity is reserved for restoration purpose. In the case of a line failure of a link other than the links of the Hamiltonian mesh, affected traffic is split in two portions and rerouted over the two directions of the Hamiltonian mesh. In the case the network has no Hamiltonian mesh, a mesh coverage is determined and sufficient spare capacity reserved for restoration purpose.

Abstract: An optical cross-connect (OCX) contains an optical switching array (A, S) based on MEM technology, which is used for switching optical connections. The switching array (A) consists of a plurality of movable miniature mirrors (M), with a reflective coating (RL), respectively arranged in the light path of the individual optical connections. In order to generate a monitoring signal for each of the optical communication signals to be switched, a light component (THRU) passing through the reflective coating (RL) is detected at least at some of the miniature mirrors (M). To that end, the miniature mirror (M) has a photosensitive layer (PL) which is arranged under a light-reflecting layer (RL) and which responds to the light components (THRU) passing through the light-reflecting layer, in order to generate the monitoring signal.

Abstract: A method for transmitting a signal for the transfer of information from a signal source (1) to a signal sink (7) spatially remote therefrom wherein, at least over a part of the path between the signal source and the signal sink, the signal is transmitted as an optical signal via at least one free optical link between an optical transmitter (3) and an optical receiver (5), is characterised in that the signal is multiplied or split into two or more identical signals, that each of these mutually identical signals is transmitted from an optical transmitter to an optical receiver in each case as an optical signal via its own optical path comprising at least one free optical link, and that the received signals are combined via a signal combiner (6) and fed as one single signal to the signal sink. In this way a reliable transmission of optical signals through free space can be ensured using very simple means.

Abstract: A method for transmitting a signal for the transfer of information from a signal source (1) to a signal sink (7) spatially remote therefrom wherein, at least over a part of the path between the signal source and the signal sink, the signal is transmitted as an optical signal over at least one free optical link between an optical transmitter (3) and an optical receiver (5), is characterised in that prior to its transmission the signal to be transmitted is split into signal packets (SP), that each signal packet is assigned a signal sequence (OH) characteristic of the signal packet and is transmitted together with the relevant signal packet at a higher bit rate than the original signal, and that the characteristic signal sequences are used to detect, and optionally correct, errors in the transmitted signal and/or to synchronise the transmission path. In this way a reliable transmission of optical signals through free space can be ensured using very simple means.

Abstract: An optical connection and a connection unit between individual installation units (2) is proposed for the exchange of data between devices, in which the devices (1) communicate with one another by means of optical signals, and the optical signals overcome at least the distance between two adjacent installation units.

Abstract: A network node (10) for switching digital information of different protocol types is described. The network node (10) comprises a plurality of modules (11). An arrangement of the modules (11) on the basis of a Banyan matrix type is provided. Control means are assigned to each module (11).

Abstract: A frame-structured bus system, particularly for a local operation network for automotive applications, is disclosed in which a plurality of bus stations share a data bus, and in which one of the bus stations generates a sequence of data frames of constant bit length. Each data frame includes an isochronous frame module and an asynchronous frame module, and the division of each data frame into the isochronous and asynchronous frame modules is dynamically variable. The message transmitted by a station is passed through a central star coupler to all stations.