Abstract: Protection techniques within optical communication networks are extremely important. An alternative to a line protection scheme, as most current optical communication networks use, is to utilize a path protection technique in which working and protection paths that are desired are assigned during network setup. During normal operations, only the working path is configured within the network elements' switch fabric with protection paths being left unconfigured. If a failure indication is detected in the working path by a network element, a protection entry within a routing table of the network element is looked up to determine protection switching data that is required to switch the data traffic to the pre-assigned protection path. This protection switching data is inserted within the path overhead for the data traffic so that it can be communicated to all of the network elements that require their switch fabrics reconfigured to establish the protection path of communications.

Abstract: Protection techniques within optical communication networks are extremely important. An alternative to a line protection scheme, as most current optical communication networks use, is to utilize a path protection technique in which working and protection paths that are desired are assigned during network setup. During normal operations, only the working path is configured within the network elements' switch fabric with protection paths being left unconfigured. If a failure indication is detected in the working path by a network element, a protection entry within a routing table of the network element is looked up to determine protection switching data that is required to switch the data traffic to the pre-assigned protection path. This protection switching data is inserted within the path overhead for the data traffic so that it can be communicated to all of the network elements that require their switch fabrics reconfigured to establish the protection path of communications.

Abstract: The present invention relates to a local node for use in a synchronous optical network ring. The local node includes a group of working transmission lines and a protection line, for connecting to a remote node. The local node further includes a control unit for monitoring the working transmission lines and, upon detection of a data transmission impairment over a particular working transmission line, invoking a protection switch event causing re-routing of optical signals from the particular working transmission line to the protection line. Should the control unit detect simultaneous data transmission impairments over two or more working transmission lines, the control unit will choose to protect a particular working transmission line on the basis of a user-defined priority scheme.