Abstract: A system for communicating optical traffic between ring networks includes a first optical ring network and a second optical ring network. Each optical ring network is operable to communicate optical traffic comprising a plurality of wavelengths. The system includes a first ring interconnect (RIC) node and a second RIC node, and each RIC node is coupled to the first and second optical ring networks. The first RIC node is operable to communicate optical traffic between the first and second optical ring networks, and the second RIC node is operable to communicate optical traffic between the first and second optical ring networks when the first RIC node is unable to communicate optical traffic between the first and second optical ring networks. The second RIC node may be operable to determine when the first RIC node is unable to communicate optical traffic between the first and second optical ring networks.

Abstract: An add/drop node (OADN) comprises a network optical fiber carrying a signal on an optical network. A network drop splitter is coupled to the network optical fiber and to stages of drop splitters, the stages of drop splitters being operable to passively split an optical signal from the network drop splitter into multiple copies of the signal. The OADN further comprises at least one filter operable to receive at least a copy of the signal from at least one drop splitter to create a filtered copy, and further comprises at least one broadband receiver operable to receive the filtered copy from the filter.

Abstract: An optical network includes an optical ring and at least three subnets. Each subnet includes a plurality of add/drop nodes coupled to the optical ring. The add/drop nodes are operable to passively add a first traffic stream in a first direction on the optical ring and a second traffic stream in a second direction on the optical ring. The first traffic stream comprises different content than the second traffic stream, and the first traffic stream and the second traffic stream are transmitted on the same wavelength. The network also includes a plurality of gateway nodes. The gateway nodes are each coupled to the optical ring at a boundary between neighboring subnets and are operable to selectively pass and terminate wavelengths between subnets to allow wavelength reuse in the subnets.

Abstract: An optical network includes an optical ring and a plurality of add/drop nodes coupled to the optical ring. Each of the add/drop nodes is operable to passively add and drop one or more traffic streams to and from the optical ring, and each traffic stream comprises a channel. A hub node also coupled to the optical ring is operable to selectively pass and terminate individual traffic streams.

Abstract: A method and system for control signaling in an open ring optical network includes transmitting traffic in an optical ring. At each of a plurality of nodes along the ring, local traffic is passively added to and passively dropped from the connected ring. At each node, an ingress optical supervisory channel (OSC) signal is dropped from the ring to a managing element. An egress OSC signal is added to the ring from the managing element. The OSC signals may be in-band signal or out-of-band signals.

Abstract: A flexible open ring optical network includes a plurality of nodes connected by twin or other suitable optical rings. Each node is operable to passively add and passively drop traffic from the rings. The nodes may include a transport element for each ring. The transport elements include an optical splitter element and an optical combiner element. The optical splitter element is operable to passively combine an add signal including local add traffic and a first transport signal including ingress traffic from a coupled optical ring to generate a second transport signal including egress traffic for transmission on the coupled optical ring. The optical combiner element is coupled to the optical splitter element and is operable to passively split a third transport signal including the ingress traffic to generate a drop signal including local drop traffic and a fourth transport signal including the ingress traffic.

Abstract: An optical network includes a plurality of subnets. The subnets each include a plurality of add/drop nodes coupled to the optical ring and operable to passively add and drop traffic to and from the optical ring. The network further includes a plurality of gateway nodes. The gateway nodes are each coupled to the optical ring at a boundary between neighboring subnets and operable to selectively pass and terminate wavelengths between subnets to allow wavelength reuse in the subnets and to provide protection switching.

Abstract: A system and method for assigning a traffic channel to a wavelength in a multi-ring optical network having bifurcated work and protect wavelengths includes determining a transport direction for the traffic channel in a ring of the multi-ring optical network. An inter/intra ring type of the traffic channel is determined. The traffic channel is assigned to a wavelength in the ring based on the transport direction and the inter/intra ring type of the traffic channel. In a particular embodiment, the traffic channel may be assigned to one of an odd and even wavelength based on the transport direction and one of a high and low wavelength based on the inter/intra ring type.

Abstract: The method and system for testing during operation of an open ring network includes opening a ring of the network at the node. Traffic circulating on the ring is dropped in the node to a monitoring element prior to or at the opening of the ring in the node. At the monitoring element, a signal received from the ring is tested. During tested and while the ring is open, traffic continues to be communicated between each node on at least one of the ring or a second ring each connecting the nodes of the network.

Abstract: This invention relates to an SDH transmission technique, wherein one SDH transmission equipment is provided with a first switching control part which performs a line switching control between a work line and a protection line in accordance with setting information on a line switching control and a setting information transfer part which transfers the setting information to other SDH transmission equipment as setting information at other SDH transmission equipment, while other SDH transmission equipment is provided with a setting information detection part which detects the setting information transferred from the one SDH transmission equipment and a second line switching control part which performs a line switching control at own side in accordance with the setting information detected by the setting information detection part.

Abstract: A node for an optical network includes a first transport element operable to be coupled to an optical ring and to transport traffic in a first direction and a second transport element operable to be coupled to the optical ring and to transport traffic in a second, disparate direction. The first and second transport elements each include an optical splitter element operable to split an ingress signal into an intermediate signal and a drop signal. A filter in each node is operable to reject a first sub-band of the network from the intermediate signal to generate a passthrough signal including a plurality of disparate sub-bands of the network. Each node further includes an add element operable to add local traffic in the first sub-band to the passthrough signal for transport in the network.

Abstract: An add/drop node (OADN) comprises a network optical fiber carrying a signal on an optical network. A network drop splitter is coupled to the network optical fiber and to stages of drop splitters, the stages of drop splitters being operable to passively split an optical signal from the network drop splitter into multiple copies of the signal. The OADN further comprises at least one filter operable to receive at least a copy of the signal from at least one drop splitter to create a filtered copy, and further comprises at least one broadband receiver operable to receive the filtered copy from the filter.

Abstract: A network synchronization controller and method for effectively preventing a timing loop from happening in a synchronous network. A clock status message controller, disposed in each network element on the network, produces and sends clock status messages which are each composed of clock quality data and synchronization control data. The clock quality data indicates the quality level of a clock signal that each network element supplies to its neighboring network elements. The synchronization control data contains information to be used to make the network synchronized with a single reference timing source. A clock selector chooses one of the clock signals received from other network elements, based on the clock status messages received along with the clock signals.

Abstract: Proposed is an optical clock distribution system in the WDM network, which particularly relates to a system to control clock synchronization between optical transmission devices constituting an optical communication network. The optical clock distribution system includes an optical clock generator converting a clock signal of PRC (Primary Reference Clock) level into an optical clock signal having a wavelength &lgr;0; a wavelength multiplexer wavelength-multiplexing the optical clock signal having wavelength &lgr;0 together with other optical wavelength data; and a wavelength-demultiplexer provided in a unit of the network, wavelength-demultiplexing the optical clock signal having wavelength &lgr;0, wherein the other optical wavelength data are processed in the unit of the network using the wavelength-demultiplexed optical clock signal having wavelength &lgr;0 as a reference clock.

Abstract: This invention relates to an SDH transmission technique, wherein one SDH transmission equipment is provided with a first switching control part which performs a line switching control between a work line and a protection line in accordance with setting information on a line switching control and a setting information transfer part which transfers the setting information to other SDH transmission equipment as setting information at other SDH transmission equipment, while other SDH transmission equipment is provided with a setting information detection part which detects the setting information transferred from the one SDH transmission equipment and a second line switching control part which performs a line switching control at own side in accordance with the setting information detected by the setting information detection part.

Abstract: In order to increase the efficiency of large-capacity transmission, the continuity of divided signals generated by dividing a multiplexed signal is maintained and the original large-capacity multiplexed signal is restored. A signal dividing section divides a multiplexed signal to generate a plurality of divided signals in the STS or STM transmission interface format. A guarantee information adding section adds guarantee information for guaranteeing the continuity of the divided signals to each of the divided signals to generate transmission signals. A signal sending section sends the transmission signals via a transmission line in the transmission interface format. A signal receiving section receives the transmission signals. A signal restoring section restores the multiplexed signal by constructing the divided signals on the basis of the guarantee information.

Abstract: In a mesh-type network, a managing section manages QoS (Quality of Service) information, which is accumulated QoS information (inter-neighboring-node QoS information q) between neighboring node apparatuses, about QoS for candidate signal transmission routes in the network at the individual node apparatuses. And a control section controls a signal transmission route selection operation at the self node apparatus based on the network QoS information Q being managed by the managing section. With this construction, it is possible to set/manage a line route satisfying a desired QoS independently at the individual node apparatuses with maximum ease and flexibleness.