Abstract: The present invention relates to the introduction of an outstation into an optical network. The optical network has a central station, and a plurality of previously introduced outstations which are optically connected to the central station. The network is operable in: a normal operating state in which data traffic is received from previously introduced outstations at a normal data rate; and, a set-up state in which the transmission of data traffic from the previously introduced outstations is restricted relative to the normal state, the method including the step of: when the network is in the set-up state, performing a set-up operation for introducing the outstation into the optical network, the set-up operation involving the transmission of set-up data from the outstation being introduced, wherein the set-up data is transmitted at a reduced rate relative to the normal operating rate.

Abstract: The present invention relates to the introduction of an outstation into an optical network. The optical network has a central station, and a plurality of previously introduced outstations which are optically connected to the central station. The network is operable in: a normal operating state in which data traffic is received from previously introduced outstations at a normal data rate; and, a set-up state in which the transmission of data traffic from the previously introduced outstations is restricted relative to the normal state, the method including the step of: when the network is in the set-up state, performing a set-up operation for introducing the outstation into the optical network, the set-up operation involving the transmission of set-up data from the outstation being introduced, wherein the set-up data is transmitted at a reduced rate relative to the normal operating rate.

Abstract: A channel assignment process for a multi-stage switch arrangement having a plurality of inputs arranged in a plurality of logical associations and a plurality of outputs, wherein time-slotted traffic is received by each logical association of inputs is operated on by one or more switching stages arranged to operate only on traffic provided by the respective logical association of inputs, the channel assignment process comprising: for each logical association, aggregating the time-slots carrying traffic from the inputs forming said logical association to form a channel comprising a plurality of logically associated time-slots; determining a path through a spatial switching stage of the switch arrangement arranged to receive a said channel from each of said logical associations of inputs of the switch arrangement; determining a path for each time-slot within each logical association such that a plurality of end-to-end time-space channels are provided for one or more inputs of the switch arrangement to their req

Abstract: A matching method for a multi-stage switch arrangement having a plurality of logically associated inputs and a plurality of outputs, wherein the matching method comprises the steps of: for each logical association of inputs, aggregating service requests from every one of the inputs which form said logical association; resolving contention for said aggregated service requests between all of the logical associations to the outputs of the switch arrangement; and repeating the above steps in the matching method within each logical association for a subset of the inputs forming each said logical association until contention is resolved between the individual inputs of the switch arrangement and the outputs of the switch arrangement.

Abstract: Switch requests within a packet switch are allocated by processing switch request data for each input port to generate request data for each input port-output port pairing; and generating an allocation plan by sorting the request data relating to each of the input/output pairs in terms of their queue length, and for each such pair, considered in the sorted order, allocating as many of the requests in the queue as can be accommodated in the remaining time slots.

Abstract: In a packet switch, a switch request allocation plan is generated by reducing the number of queue requests VOQ relating to each of one or both sets of ports I1 .IN, O1 .ON, by a value such that the number of requests relating to each member of the set or sets of ports is no greater than the number of requests (frame value F) that can be handled by the switch (10). This reduction may be individually done for each queue. Alternatively all queues relating to a given port, or to any port, may have their length reduced by a single value determined by the size of the longest queue. A further stage may then apply other allocation rules to allocate requests remaining unallocated by the previous stage.