Communications network with switching distributed among a central switching node and optical input and output sub-networks

摘要

A communications network in which a central switching node (70) has at least two sets of both input ports (52) and output ports (56) coupled to respective sets of transmitters (T.sub.ij) and receivers (R. sub.ij) by passive optical networks (54) and (58) and demultiplexers (52) and multiplexers (59). The transmitters (T.sub.ij) are tunable so that each can be selectively the input ports (52). The receivers (R.sub.ij) are also tunable so the output ports (56) can be selectively coupled to the one or more of the receivers (R.sub.ij). Alternatively, the demultiplexers (55) and multiplexers (59) can be tunable. This devolves some of the switching function outside the central switching node (50) thereby reducing the component count.