Abstract: A communications switching system includes a switching network and a number of access units. The switching network includes a number of multiplexing arrangements and a number of switching arrangements. In order to provide redundancy in the system, a number of multiplexing and switching arrangements are built together to form a number of combined multiplexing and switching arrangements, and a common protection switching arrangement is arranged to provide protection switching both between access units and multiplexing switching arrangements and between access units and accessing networks.

Abstract: A time frame switching method and system of data units that utilize a common time reference, which is divided into a plurality of contiguous periodic time frames. The system is designed to operate with time frames, which have a plurality of predefined time durations. The plurality of data units that are contained in each of the time frames are forwarded in a pipelined manner through the network switches. The system operates with high-speed wavelength division multiplexing (WDM) links, i.e., with multiple lambdas, having a plurality of transmission capacities. The outcome of this method is called fractional lambda switching with a plurality of time frame durations.

Abstract: An expandable network constructed from a plurality of identical network fabric cards which uses a plurality of selected row address bits to route connection paths between adjacent columns of interconnecting switches and a software algorithm for implementing a network of any whole number power of 2 rows or ports by assigning numbers of the network switches and attached nodes are described.

Abstract: A self-healing ring switch transmission system uses space division switches disposed upstream and downstream of an add drop switch in order to determine a correspondence with a plurality of ring-switch modes by merely changing the software. This is accomplished by having one output highway of the add drop switch and one output highway of a space division switch connected with an input stage of a selector for selecting one time slot of the two output highways.

Abstract: In order that the various ring-switching modes of 2-Fiber BLSR, 4-Fiber BLSR and UPSR may be switched merely by changing a software, space division switches are disposed across an add drop switch, and one output drop switch and one output of the second space division switch are connected with the input stage of a selector which can be selected at the unit of a time slot. As a result, the various ring-switching modes can be switched merely by changing the software while suppressing the scale of the switch. Moreover, the change from the ring switch to the linear switch and vice versa can be effected.