Abstract: A method and apparatus for restoring communications in a network. The network includes a plurality of nodes, with each pair of nodes connected by a link, and with each link having information channels and restoration channels. An idle signal is sent on each restoration channel for each link. The failure of a link is detected, with the failed link connecting an originating node with a terminating node. In addition, the failed link includes at least one information channel carrying information signals. An alternate path through the network is determined for the information signals using restoration and idle signals sent over the restoration channels. The information signals are then routed from the originating node to the terminating node in accordance with the alternate path.

Abstract: A method for lightpath restoration in a reconfigurable optical network comprises the steps of naming each network addressable element in said reconfigurable optical network, determining current topology in said reconfigurable optical network, determining current resources in said reconfigurable optical network, requesting establishment of a lightpath, requesting reservation of restoration capacity, allocating the lightpath, and reserving the restoration capacity. Also disclosed is a method for lightpath restoration that comprises the steps of reserving restoration capacity, detecting transmission failures in the reconfigurable optical network, handling exceptions as a result of transmission failures, and allocating transmission capacity.

Abstract: A method for lightpath provisioning in a reconfigurable optical network that comprises the steps of naming each network addressable element in the reconfigurable optical network, determining current resources therein, determining current topology therein, requesting establishment of a lightpath, and allocating the lightpath. A system for lightpath provisioning in a reconfigurable optical network is also provided, comprising means for naming each network addressable element in the reconfigurable optical network, means for determining current topology in the reconfigurable optical network, means for determining current resources in the reconfigurable optical network, means for requesting establishment of a lightpath, means for allocating the lightpath and means for removing the lightpath upon completion.

Abstract: A transparent optical switch includes network management and performance monitoring using bit level information obtained by extracting selected information on a polling basis and analyzing the extracted information in the electrical domain. In one embodiment, a signal is injected into the switch fabric of the switch via a demultiplexing device. The injected signal is extracted at the output of the switching fabric via an N:1 switch and analyzed by a signal analyzer to verify input to output connections. In another embodiment, an optical switch includes first and second switch fabrics for 1:2 broadcast capability. In a further embodiment, an optical communication system includes a plurality of optical networks and a plurality of optical switches that cooperate to generate unequipped signals and to obtain autonomously switch-to-switch port connectivity information required for auto-topology discovery.

Abstract: Data are rerouted over a network having a uniform-capacity Tandem Connection by detecting a failure in a link in a path, maintaining the path through a Tandem Connection that does not include the failed link, and rerouting the data through the Tandem Connection based on information embedded in a tandem layer in the data, and independent of the constituent payload capacities within the tandem connection.

Abstract: The present invention provides improved methods and systems to build an integrated IP network in which high-quality services such as voice and best-effort data services can be provided with higher reliability and lower cost. A new type of router, called a PACS router, is disclosed in which the user terminals, computer servers, access routers and other service terminals are connected to the integrated router. A PACS router includes a packet-switching fabric and a circuit-switching fabric interconnected by channelized high-speed links. The PACS router creates and uses two types of channels within channelized high-speed links, which in turn are transported from one router to another via SONET network links. The channels are labeled as either packet-channel or circuit-channel according to the usage of these channels. High-quality services are mapped into a circuit-channel at the service originating router and routed through the circuit-switching fabrics in the routers.

Abstract: A transparent optical switch includes network management and performance monitoring using bit level information obtained by extracting selected information on a polling basis and analyzing the extracted information in the electrical domain. In one embodiment, a signal is injected into the switch fabric of the switch via a demultiplexing device. The injected signal is extracted at the output of the switching fabric via an N:1 switch and analyzed by a signal analyzer to verify input to output connections. In another embodiment, an optical switch includes first and second switch fabrics for 1:2 broadcast capability. In a further embodiment, an optical communication system includes a plurality of optical networks and a plurality of optical switches that cooperate to generate unequipped signals and to obtain autonomously switch-to-switch port connectivity information required for auto-topology discovery.

Abstract: Data are rerouted over a network having a uniform-capacity Tandem Connection by detecting a failure in a link in a path, maintaining the path through a Tandem Connection that does not include the failed link, and rerouting the data through the Tandem Connection based on information embedded in a tandem layer, and independent of the constituent payload capacities within the tandem connection.

Abstract: A method and apparatus for restoring communications in a network. The network includes a plurality of nodes, with each pair of nodes connected by a link, and with each link having information channels and restoration channels. An idle signal is sent on each restoration channel for each link. The failure of a link is detected, with the failed link connecting an originating node with a terminating node. In addition, the failed link includes at least one information channel carrying information signals. An alternate path through the network is determined for the information signals using restoration and idle signals sent over the restoration channels. The information signals are then routed from the originating node to the terminating node in accordance with the alternate path.

Abstract: Flexibility is achieved in provisioning communication rings with an integrated DCS that allows any port that is connected to a line interface unit within the integrated DCS to be coupled within the integrated DCS—pursuant to software controlled provisioning—to any other port that is connected to a line interface unit within the integrated DCS. This is accomplished by merging the cross connect fabrics of the ADM portions of the integrated DCS with the cross connect fabric of the DCS portion of the integrated DCS, by incorporating at least some of the switching controls of the ADMs in the ADM portion of the integrated DCS in the controller of the DCS, and by insuring that the SONET K-bytes can be passed by the controller of the flexible integrated DCS from any line interface unit to any other line interface unit.

Abstract: A method and system provide capacity-efficient restoration within an optical fiber communication system. The system includes a plurality of nodes each interconnected by optical fibers. Each optical fiber connection between nodes includes at least three channel groups with different priority levels for restoration switching in response to a connection failure. The system maintains and restores full-capacity communication services by switching at least a portion of the channel groups from a first optical fiber connection to a second optical fiber connection system based on the priority levels assigned to the channel groups. Service reliability is effectively maintained without incurring additional costs for dedicated spare optical fiber equipment by improving idle capacity utilization.

Abstract: A method and apparatus for restoring communications in a network. The network includes a plurality of nodes, with each pair of nodes connected by a link, and with each link having information channels and restoration channels. An idle signal is sent on each restoration channel for each link. The failure of a link is detected, with the failed link connecting an originating node with a terminating node. In addition, the failed link includes at least one information channel carrying information signals. An alternate path through the network is determined for the information signals using restoration and idle signals sent over the restoration channels. The information signals are then routed from the originating node to the terminating node in accordance with the alternate path.

Abstract: A method and system provide capacity-efficient restoration within an optical fiber communication system. The system includes a plurality of nodes each interconnected by optical fibers. Each optical fiber connection between nodes includes at least three channel groups with different priority levels for restoration switching in response to a connection failure. The system maintains and restores full-capacity communication services by switching at least a portion of the channel groups from a first optical fiber connection to a second optical fiber connection system based on the priority levels assigned to the channel groups. Service reliability is effectively maintained without incurring additional costs for dedicated spare optical fiber equipment by improving idle capacity utilization.

Abstract: An in-band fault detection and isolation system and method for networks such as Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) networks. Fault detection may be quickly and efficiently performed by a network without requiring modification to any add/drop multiplexers (ADMs) and/or without the involvement of an external network management system (NMS). To accomplish this without violating SONET/SDH standards, a new signal, called a fault isolation signal in the path (FIS-P), is proposed. The FIS-P may be used in lieu of an AIS-P to support special applications on certain digital cross connect (DCS)-to-DCS path segments. Moreover, the present invention may be implemented such that the behavior, of path terminating equipment (PTE) is unaffected.

Abstract: A method for lightpath restoration in a reconfigurable optical network comprises the steps of naming each network addressable element in said reconfigurable optical network, determining current topology in said reconfigurable optical network, determining current resources in said reconfigurable optical network, requesting establishment of a lightpath, requesting reservation of restoration capacity, allocating the lightpath, and reserving the restoration capacity. Also disclosed is a method for lightpath restoration that comprises the steps of reserving restoration capacity, detecting transmission failures in the reconfigurable optical network, handling exceptions as a result of transmission failures, and allocating transmission capacity.

Abstract: A method for lightpath provisioning in a reconfigurable optical network that comprises the steps of naming each network addressable element in the reconfigurable optical network, determining current resources therein, determining current topology therein, requesting establishment of a lightpath, and allocating the lightpath. A system for lightpath provisioning in a reconfigurable optical network is also provided, comprising means for naming each network addressable element in the reconfigurable optical network, means for determining current topology in the reconfigurable optical network, means for determining current resources in the reconfigurable optical network, means for requesting establishment of a lightpath, means for allocating the lightpath and means for removing the lightpath upon completion.

Abstract: Restoration of service in a mesh network (10) upon the failure of a working channel (16) on a link (14I) connecting a pair of nodes (12A and 12D) is accomplished by first attempting to route traffic on an restoration channel (18) in the same link when such a channel is available. If such “localized” restoration can not be accomplished, then the end-point (traffic originating and/or terminating) nodes that are connected by a path that includes the link having the failed working channel then implements a precomputed path. Each pre-computed path identifies a collection of channels in a series of links that connect the end-point nodes (and any intermediate nodes) so as to bypass traffic around the link having the failed working channel. The pre-computed path information is typically pre-stored in the end-point nodes to enable the end-point nodes to effect rapid restoration in the event localized restoration in not achievable.

Abstract: A method and apparatus for restoring communications in a network. The network includes a plurality of nodes, with each pair of nodes connected by a link, and with each link having information channels and restoration channels. An idle signal is sent on each restoration channel for each link. The failure of a link is detected, with the failed link connecting an originating node with a terminating node. In addition, the failed link includes at least one information channel carrying information signals. An alternate path through the network is determined for the information signals using restoration and idle signals sent over the restoration channels. The information signals are then routed from the originating node to the terminating node in accordance with the alternate path.

Abstract: A method of performing errorless switching in a ring network having one or more rings and a plurality of transmitting routes. The transmission delays or lengths of at least predetermined sections of the routes are compared, and the comparison is used to determine the value of a first delay added to one of the routes. Another delay is added to enable phase alignment of signals so that errorless switching can be achieved. The delays are then adjusted to reduce cumulative delays which could degrade the quality of data transmission.

Abstract: An errorless line protection apparatus involves receipt of data from an active line and a standby line. A determination is made as to whether the data from the active line leads or lags the data on the standby line. A switching system directs the leading data to a lead channel containing a controllable amount of time delay up to the maximum amount that the leading data is expected to led the lagging data. Lagging data is directed to a lag channel. A selected one of the data from the lead channel or the lag channel is delivered to an output line.