Abstract: An optical network system, including multiple nodes, an optical switch, and a switch controller, is configured to achieve communication in the optical domain. Each node is configured to receive both high frequency and low frequency inputs, generally utilized for handling data and addressing information, respectively. The two types of information are combined to create an amplitude modulated optical signal. Subsequently, the two types of information are separated by examining the optical power average of the signal being transmitted. Using one portion of the signal for addressing information, the switch controller can perform necessary routing and arbitration functions. Appropriate communications can then be sent back to the nodes and the optical switch to achieve the necessary configuration. The protocol utilized allows for subsequent arbitration and data transmission cycles, allowing the system and switch controller to configure transmission paths and arbitrate any communication issues.

Abstract: A method embodiment includes determining whether a communication received from a first processor connected to a network interface unit is intended for a second processor connected to the network interface unit. The method embodiment also includes selecting a first communication path between a route through a switch and a route directly to the second processor through which to route the communication from the network interface unit to the second processor. The method embodiment further includes routing the communication from the network interface unit to the second processor through the first communication path.

Abstract: Optical fiber interconnection devices, which can take the form of a module, are disclosed that include an array of optical fibers and multi-fiber optical-fiber connectors, for example, two twelve-port connectors or multiples thereof, and three eight-port connectors or multiples thereof. The array of optical fibers is color-coded and is configured to optically interconnect the ports of the two twelve-port connectors to the three eight-port connectors in a manner that preserves transmit and receive polarization. In one embodiment, the interconnection devices provide optical interconnections between twelve-fiber optical connector configurations to eight-fiber optical connector configurations, such as from twelve-fiber line cards to eight-fiber line cards, without having to make structural changes to cabling infrastructure. In one aspect, the optical fiber interconnection devices provide a migration path from duplex optics to parallel optics.

Abstract: A source based scheme to establish communication paths in an optical network. According to one embodiment of the invention, a number of wavelength division multiplexing access nodes of an optical network employ a source based scheme to establish communication paths. Each of these access nodes stores a set of one or more network topology databases based on a set of one or more connectivity constraints.

Abstract: An optical connection path surveillance device for a transparent optical network includes analysis means (80, 81) adapted to detect node signatures carried by an optical signal in transit at a point of said network, each node signature including information uniquely associated with a switching node of the network. The analysis means include calculation means (81) adapted to determine a number of hops from said detected node signatures and error detection means (81) adapted to compare said number of hops to a predetermined threshold in order to detect a routing error in relation to said optical signal if said threshold is exceeded. In one embodiment, a surveillance device detects looped paths on the basis of the detected node signatures.

Abstract: A fiber channel switch element and method for routing fiber channel frames is provided. The switch element includes a receive segment that can add a virtual storage area network (“VSAN”) tagging header to frames that are received by the receive segment; and strip the VSAN tagging header before frames are sent to ports that do not support virtual fabric capability. The receive segment includes a table used for matching fabric extension parameters. An incoming frame's VSAN identity value is compared to a control word entry to generate a value used for routing the incoming frame. The table is used to determine if a frame is part of a virtual fabric. The routing table for each port is used to route frames and the routing table includes entries for supported virtual fabrics.

Abstract: A network planning tool and method for configuring a connection-oriented packet network over a WDM optical network without an optical control layer, such as a SONET/SDH layer. The optical network includes a plurality of optical fibers interconnected through nodes and the connection-oriented packet network, such an Ethernet network, MPLS network, or pseudowire network, includes two or more terminal devices. The method and tool function by building an association between the components of the physical layer, such as the optical fiber, and their geographic location or path. The connection-oriented packet network is configured by building multi-link trunks (MLTs) between terminal devices, where the MLTs are built by aggregating lightpaths that traverse distinctive geographic paths. The MLTs are planned and configured through aggregating lightpaths that traverse incongruent sets of photonic elements.

Abstract: In a wavelength allocation method in a wavelength division multiplexing network, a 3R wavelength converter having a limited wavelength conversion range is disposed according to a wavelength conversion band of each node, at least one path set between transmitting/receiving nodes is selected, routing paths corresponding to the number of the selected at least one path set between the transmitting/receiving nodes having a request for a new optical path generation are extracted, it is determined whether there is a wavelength consecutive segment set that satisfies a maximum transmission distance for guaranteeing transmission quality of an optical signal and that includes one consecutive wavelength among the extracted routing paths, and a path using a first-fit wavelength is selected from paths of each wavelength consecutive segment and the wavelength is allocated when determining that there is a wavelength consecutive segment set.

Abstract: The present invention relates to a communication path calculation method and module. More particularly, the present invention provides a communication path calculation method and module that are implemented or incorporated in a transmission apparatus including a ROADM or the like which performs WDM communication, advertises information on a wavelength which can be added or dropped, as information on a link, and uses the information to autonomously calculate a communication path. Optical transmission equipment that is accommodated in a WDM network over which a wavelength-division multiplexed signal is transferred includes a reconfigurable OADM module. For calculation of a communication path, the OADM module creates a link table listing clients of the own equipment and connected WDMs, and advertises the link table to the other pieces of equipment accommodated by the network as pieces of information on restrictions to be imposed on routing from the own equipment.

Abstract: A path routing computation method enables reduction of the memory capacity for path routing computation. The method is characterized in that a wavelength convertible subnetwork in which paths are connected in a mesh form; a first and second wavelength inconvertible subnetworks have a starting point node and an end point node, respectively, and include a plurality of nodes and connected via the wavelength convertible subnetwork, and out of the nodes constituting the first and second wavelength inconvertible subnetworks, a node has a port connected to the wavelength convertible subnetwork is defined as a border node, and the method includes the steps of: obtaining, for the first wavelength inconvertible subnetwork, a path from the starting point node to a border node in the first subnetwork; and obtaining, for the second wavelength inconvertible subnetwork, a path from the end point node to a border node in the second wavelength inconvertible subnetwork.

Abstract: A network design that reduces the number of wavelengths needed to support communications in a Wavelength Division Multiplexing (WDM) network is disclosed. Wavelengths are reused in isolated sub-networks that do not share common network paths, allowing for the reduction in cost of the WDM equipment supporting the communications in the network.

Abstract: Various embodiments of the present invention are directed to a method for creating and optimizing a DWDM optical fiber network that is configured to service a set of demands associated with a region of interest.

Abstract: Disclosed is a method of reorganizing a wavelength division multiplexing network using dynamic watermarks and a computer readable recoding medium for storing a program for executing the same method. The reorganization method of organizing a wavelength division multiplexing (WDM) network using a dynamic watermark of the invention includes the steps a) collecting load information for optical paths of the WDM network from nodes on the optical paths; b) detecting optical paths having maximum load and minimum load from the collected load information and computing a maximum value and a minimum value based on the collected load information; and c) resetting an upper watermark and a lower watermark based on the maximum value and the minimum value.

Abstract: An agile transparent network with a trail routing and switching (also called “engineering”) mechanism is provided that enables efficient use of regenerators and wavelengths available in the network, while maintaining a very efficient time-to-service. The trail engineering mechanism allows fast, automatic establishment of new connections based on the current network architecture, connectivity and loading and also on conditions in the connection request. Selection of regenerator sites and of the wavelengths used on each regenerator segment is performed with optimal use of current network resources, while ensuring that the quality of the selected trail is adequate for the respective call. The mechanism provides for both distance and performance balancing, and it optimizes the network response time.

Abstract: An optical access network method, an optical access network and an optical switch for an optical access network, capable of solving all the three problems in the conventional GE-PON: transmission distance problem, security problem and communication interference problem. The optical access network comprises an OLT, a plurality of ONUs and one or more stages of optical switches, which are connected one another. In the direction from the OLT to the ONU, each frame (packet) transmitted from the OLT to one of the ONUs is checked so that only the destination ONU specified in the frame (packet) is connected to the OLT. In the direction from the ONU to the OLT, a control message transmitted from the OLT to one of the ONUs is checked so that only one ONU which has been given a transmission allowance from the OLT is connected to the OLT with respect to each frame (packet).

Abstract: A communication recovering system for a wavelength division multiplexed passive optical network (WDM PON). The communication recovering system can recover fault of optical fibers between the central office and the remote nodes without additional optical fibers by grouping two remote nodes and employing AWGs having periodic transmission characteristics, and can also simply and rapidly recover such a fault with minimal optical loss using 1×N structure of the AWGs and On-Off optical switches, although protection optical fibers are additionally installed therein. The communication recovering system has advantages in that it can simplify network structure, be cost-effectively implemented, reduce optical loss, and rapidly perform protection of optical fiber fault.

Abstract: Disclosed is an optical packet communication system using a wavelength-offset polarization-division multiplexing labeling. An optical signal transmitter which is provided at an ingress node positioned at a sending end in an optical packet switching network, generates and combines packet data and a label, and transmits the combined packet data and label to a core node, wherein the packet data and label have polarization directions perpendicular to each other and maintain a predetermined wavelength interval. A label swapping device detects the label from the combined packet data and label received from the optical signal transmitter, detects next moving position information of the packet data, for generating a new label, substitutes the detected label by the new label, combines the new label with the packet data, and transmits the combined packet data and new label to a next moving position.

Abstract: A method for monitoring lightpaths in an optical network comprising nodes interconnected by wavelength-multiplexed links is disclosed. Each lightpath is identified by a respective optical signature. A node stores identifiers of optical signatures of lightpaths designated to traverse the node and identifiers of adjacent nodes. Each node also maintains a record of all optical signatures it detects. A command-line interface associated with a selected node tracks a selected lightpath, designated to traverse the selected node, by propagating messages in an upstream direction, a downstream direction, or both, requesting other nodes to provide information pertinent to the selected lightpath. The selected node may also send messages to all its neighboring nodes requesting each to indicated detection, or otherwise, of the selected lightpath.

Abstract: A method and apparatus for providing a load balanced circuit path between a source node and a destination node within a SONET ring comprising a plurality of nodes and connected by links by iteratively selecting facilities within a link that have bandwidth utilization levels that are below a threshold level. In an alternative embodiment, an alternate path is selected in case facilities meeting the threshold level can not be found. The threshold level is changed incrementally if facilities and links within the first path and/or alternate path do not meet the threshold levels.

Abstract: A method and apparatus for fault notification in an optical network are described herein. In one embodiment, an exemplary process includes detecting at a node that at least a portion of a first unidirectional path of an optical circuit is down, where the first unidirectional path is originated from a first terminating node. In response to the detection, the node signals the first terminating node by removing at least a portion of light of a second unidirectional path in an opposite direction of the first unidirectional path of the optical circuit, to indicate a path between the node and the first terminating node is down. Other methods and apparatuses are also described.

Abstract: A diversification route (Connection-B) is generated after establishing a first path (Connection-A) through the network (10) between an ingress client node (12) and an egress client node (14) through a first ingress network element (16) within the optical network. Information identifying the first network element is passed by the ingress client node (12) to a second network element (18) in the network. Information identifying the first path and desired diversity type is passed from the second network element (18) to the first network element (16). In response to receiving the information identifying the first path, an entity list associated with the first path is passed from the first network element (16) to the second network element (18). The second path (Connection-B) is established responsive to the information associated with the first path (Connection-A).

Abstract: A method and apparatus for scheduling data burst transmission in a wavelength-division-multiplexing photonic burst-switched network is disclosed. In one embodiment, a scheduler determines a set of weighting factors at each wavelength for each of the lightpath segments among all the network nodes. These weighting factors may be used to calculate a set of coarse-grained bandwidth allocation factors, one for each potential lightpath formed from the available lightpath segments between an ingress node and an egress node. The scheduler may schedule the transmission of the data burst on one of the lightpaths that has a coarse-grained bandwidth allocation factor which indicates that it can support the requested bandwidth. The scheduler may periodically update the set of weighting factors at each wavelength for each of the lightpath segments.

Abstract: A method of and system for determining a path through which to route a connection in a photonic network in which optically viable photonic paths of one or more physical links are determined and considered as “virtual” links in a “virtual” topology. Routing is then performed using the “virtual” topology rather than the physical topology to compute “virtual” paths of one or more “virtual” links.

Abstract: A method includes subdividing a mesh having a plurality of interconnected nodes into a plurality of regions. Each region has an associated primary node. A pre-determined path segment is defined between at least two primary nodes. A primary path between at least two primary nodes is selected utilizing only primary nodes and the pre-determined path segments.

Abstract: Reroutable protection schemes of an optical network are described herein. In one embodiment, an access node detects that at least a portion of a first path of an optical circuit fails based on a loss of a light of the at least a portion of the first path. In response to the detection, the access node provisions a second path leading to a destination node of the first path without waiting for an update of a routing database regarding the failure of the first path, where the second path satisfies a set of disjointness requirements with respect to the first path. Other methods and apparatuses are also described.

Abstract: An all-optical, optical cross-connect includes first and second pluralities of multiport optical devices. Each of the first plurality of multiport optical devices have at least one input port for receiving a WDM optical signal and a plurality of output ports for selectively receiving one of more wavelength components of the optical signal. Each of the second plurality of multiport optical devices have a plurality of input ports for selectively receiving one of more wavelength components of the optical signal and at least one output port for selectively receiving one of more wavelength components of the optical signal. At least one of the first or second plurality of multiport optical devices are all-optical switches that can route every wavelength component independently of every other wavelength component.

Abstract: An optical network is operable to carry optical traffic in a plurality of wavelengths between a plurality of nodes. The optical network includes a light-trail, a convener node, one or more intervening nodes, and an end node. The light-trail is established in the optical network between the convener node and the end node and couples the convener node, the intervening nodes, and the end node. Furthermore, the light-trail is associated with one of a plurality of wavelengths. The convener node and the intervening nodes are each operable to determine whether another node having a higher priority is transmitting optical traffic on the light-trail and, in response to determining that no node having a higher priority is transmitting on the light-trail, transmit optical traffic to one of the nodes in the light-trail. The convener node and the intervening nodes are each further operable to indicate to one or more nodes on the light-trail that optical traffic is being transmitted on the light-trail.

Abstract: Method and apparatus for dynamic provisioning of reliable connections in the presence of multiple failures in optical networks are described. One embodiment is a method for allocation of protection paths after a failure in an optical network. The method comprises, responsive to a failure in an active lightpath, switching traffic on the active lightpath to a protection path; subsequent to the switching, identifying all active lightpaths in the network that no longer have an available protection path; and attempting to allocate a protection path to each of the identified active lightpaths.

Abstract: An optical cross-connect for selecting a path between an access-line connected to a router and a trunk-line connected to another optical cross-connect the optical cross-connect has a hash-table H for randomly specifying a trunk-line number k as elements h(i,j)=k in the order of selection j for every access-line number i; and a path selection means for selecting a path of trunk-line number k with a busy flag that has been reset, in the order of selection j by using the hash-table H when a path addition to an access-line number i is requested, the path selection means setting the busy flags of all elements h that specify the selected trunk-line number k in the hash-table H.

Abstract: A method of determining a transmission route for optical signals in an optical signal transmission system comprising a transmitter for optical signals, a receiver for the optical signals, and repeaters for repeating the optical signals transmitted from the transmitter to the receiver, and having transmission routes between the transmitter and the receiver, wherein the numbers of the wavelength components of the optical signals that has been in-use in each section defined to each of the transmission routes, the acquired numbers of wavelength components are compared among the transmission routes, and one of the transmission routes having the minimum number of wavelength components is determined as the transmission route used to set the line.

Abstract: A method and system for allocating bandwidth in a communication network is disclosed. Processing a request for bandwidth includes evaluating potential paths. Configuration rules and propagation rules may be applied to eliminate non-viable paths. A path quality indicator for remaining paths is derived based on calculations and signal characteristic measurements. A path having a suitable path quality indicator is selected and may be validated using existing representative or new signals.

Abstract: An optical channel monitor assembly for simultaneously measuring the optical power levels of multiple series of dense wavelength division multiplexed channels or the like traveling on separate optical fibers in an optical communications system includes an arrayed waveguide grating router having a first side and a second side, the first side including a first plurality of ports and the second side including a second plurality of ports, the first plurality of ports in optical communication with the second plurality of ports, wherein the first side includes a first input port for collectively receiving a first series of optical channels, wherein the second side includes a first plurality of output ports for individually delivering the first series of optical channels, wherein the second side includes a second input port for collectively receiving a second series of optical channels, and wherein the first side includes a second plurality of output ports for individually delivering the second series of optical cha

Abstract: A wavelength access server (WAS) architecture provides aggregation of traffic streams of diverse data communication protocols as well as provision of wavelength resources in an optical transport network. The WAS provides functions such as service traffic adaptation, traffic aggregation and segmentation, traffic classification, optical inter-working and system management. In particular, system management includes aspects such as signaling, connection management, resource co-ordination, protection prioritization and access policy management.

Abstract: An embodiment of the invention provides a method and apparatus for restoring a connection in a network. The connection is typically a sub network connection (SNC). In an embodiment, a failed line in a link connecting a first node and a second node is detected, where the failed line is associated with a sub network connection (SNC). The sub network connection (SNC) is then mapped to an alternate line in the link. The first node will change cross connections in a switch fabric in the first node, while the second node will change cross connections in a switch fabric in the second node, so that both nodes can transmit data on the selected alternate line, in order to restore the SNC.

Abstract: A network of spine switches and leaf switches is disclosed wherein the spine switches and leaf switches are coupled using a simplified interconnect made up of multiple signal carrying media (SCM's). In the simplified interconnect, “virtual” links are used rather than physical links to couple the leaf switches to the spine switches. The virtual links are implemented using wavelength division multiplexing. By implementing virtual links, the network achieves the same connectivity as that provided by a Clos network without the complex interconnect that is typically required in a Clos network.

Abstract: Systems and methods for providing fractional bandwidth communication channels in classes of service that do not normally support these types of channels. In one embodiment, a method comprises receiving one or more frames, wherein each frame contains non-QoS header information, classifying the one or more frames based on the corresponding non-QoS header information and scheduling delivery of the one or more frames based upon corresponding frame classifications, wherein frames in classifications corresponding to QoS circuits are scheduled in a manner that meets QoS requirements associated with the QoS circuits. When the frames are classified, they are forwarded to dynamically allocated queues corresponding to the respective classifications. Frames are scheduled for delivery from the queues according to a modified bin-filling algorithm that is designed to meet the QoS requirements of the respective circuits. This method may be implemented, for example, in a Fibre Channel Class 2 or Class 3 fabric.

Abstract: A first route is associated with a first channel of two or more channels in a first dense wavelength division multiplex (DWDM) link. A second route is associated with a second channel of the two or more channels in the first dense wavelength division multiplex (DWDM) link. A third route is associated with a third channel of two or more channels in a second dense wavelength division multiplex (DWDM) link. The first route, the second route and the third route provide similar connections. The first DWDM link is different from the second DWDM link. The third route is preselected as an alternate diverse route for a connection through the first route.

Abstract: Methods and apparatus for managing an optical network using pilot tones are provided. One method includes selecting an optical path having a plurality of nodes from a database defining an expected optical network. A detected list of pilot tones associated with each node of the selected optical path is generated. An expected list of pilot tones associated with each node of the selected optical path is generated. The detected and expected lists are compared to identify any mismatched nodes.

Abstract: In order to determine a spectral route between a departure node (N1) and an arrival node (N6) in a WDM optical telecommunications network, the method comprises a step of determining a spatial route connecting the departure node to the arrival node, said spatial route comprising a sequence of route segments (Li), each route segment directly interconnecting two network nodes and being capable of conveying at least one wavelength. The method further comprises the following steps: identifying wavelengths that are usable along each of the route segments; and constructing a graph in which the vertices (i,fk,?l) are the wavelengths usable in the route segments and the arcs joining each of two consecutive vertices are the transitions between the wavelengths represented respectively by said consecutive vertices.

Abstract: To optimize the resources of an optical transmission network using wavelength division multiplexing, assigning carrier frequencies to signals to be transmitted consists in associating N sets of optical frequencies of the comb with N respective ranges of consecutive error rate values, each of the sets comprising frequencies generating a mean error rate in the associated range, defining a measured signal transmission constraint level that is a function of the transmission constraint parameter(s) and may take N distinct values referred to as constraint values, associating the N constraint values in increasing order respectively with the N sets of frequencies in decreasing order of the error rate values of the associated N ranges, assigning any signal to be transmitted a constraint value obtained by applying the measurement, and assigning the signal to be transmitted a carrier frequency belonging to one of the sets of frequencies that is associated with a constraint value at least equal to the constraint value as

Abstract: Systems and techniques to optically boost a router. In general, in one implementation, the technique includes: receiving an optical signal defining a packet of data, initiating electronic routing of the optical packet, and initiating optical routing of the optical packet. The optical routing involves determining forwarding information based on a routing field in the optical packet, and if optical forwarding is available, terminating the electronic routing of the packet before completion of the electronic routing, and forwarding the optical signal, which defines the packet, based on the determined forwarding information.

Abstract: The optically-switched optical network comprises information signal channels allocated for optically transmitting one or more information signals; routing signal channels allocated for optically transmitting routing signals in parallel with the information signals; and switching nodes each operable in responsive to at least one of the routing signals to switch a multi-wavelength optical signal comprising the one or more information signals and the routing signals to another of the switching nodes.

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 architecture and method for performing dynamic route discovery and time slot reservation provisioning within optical-switched networks. The method employs extensions to the RSVP-TE signaling protocol, which uses various messages to reserve resources. Under a peer routing embodiment, routing trees and resource availability data are maintained by the edge nodes. A lightpath route is dynamically selected based on selection criteria applied to the routing tree data and the availability of resources along the lightpath. Link state information, including resource reservation data, is broadcast by the switching nodes to update the edge nodes of their resource availability. A resource reservation message is passed between nodes defined by an explicit route contained in the message, and resource availability is confirmed for the entire lightpath prior to confirming the resource reservations.

Abstract: An optoelectronic device that has a network address (e.g., IF address) and participates in in-band traffic for purposes of performing functions (e.g., network diagnostics, network control, network provisioning, fault isolation, etc.) that are traditionally performed by host equipment. An embodiment of the invention may have a protocol engine and a status monitoring module. The protocol engine identifies data packets that are addressed to the optoelectronic device, and allows the optoelectronic device to insert packets of information generated by the device into in-band data. Logic of the optoelectronic device may modify the operating parameters of the device according to the control information included in the data packets. The status monitoring module detects the device's physical conditions and the conditions of its links.

Abstract: According to one embodiment, providing optical signal regeneration information for an optical path includes sending a path message through the optical path. The optical path comprises a sequence of nodes of a communication network, where the sequence of nodes comprises an initiating node, a set of intermediate nodes, and a terminating node. The path message communicates optical signal regeneration information specifying optical signal regeneration for one or more regenerating nodes of the sequence of nodes. A regenerating node receives the path message. The regenerating node is configured according to the optical signal regeneration information. The configured regenerating node is operable to perform optical signal regeneration.

Abstract: A network planning tool and method for configuring a connection-oriented packet network over a WDM optical network without an optical control layer, such as a SONET/SDH layer. The optical network includes a plurality of optical fibers interconnected through nodes and the connection-oriented packet network, such an Ethernet network, MPLS network, or pseudowire network, includes two or more terminal devices. The method and tool function by building an association between the components of the physical layer, such as the optical fiber, and their geographic location or path. The connection-oriented packet network is configured by building multi-link trunks (MLTs) between terminal devices, where the MLTs are built by aggregating lightpaths that traverse distinctive geographic paths. The MLTs are planned and configured through aggregating lightpaths that traverse incongruent sets of photonic elements.

Abstract: An architecture and method for performing dynamic route discovery and variable time slot reservation provisioning within optical-switched networks. The method employs extensions to the RSVP-TE signaling protocol, which uses various messages to reserve network resources. Under an overlay routing embodiment, network resources are reserved via a resource reservation message that is sent hop-by-hop between switching nodes, wherein the next hops are dynamically selected based on routing tree tables in the switching nodes. The concatenation of hops forms the route for the reserved lightpath. The resource reservation request is passed between nodes defined by a dynamically routed path, and resource availability is confirmed for the entire lightpath prior to confirming the resource reservations.

Abstract: A switching apparatus for switching an optical channel overhead in an optical supervisory channel is disclosed. The switching apparatus can suppress a terminated optical channel defect occurred by a defect of upper layers of the optical channel or a defect of the optical channel transmitter and also can maintain the corresponding optical channel at the wavelength converted optical transport network system. Furthermore, an apparatus for forwarding an optical channel maintenance signal is disclosed too. The apparatus includes the switching apparatus and transmits only an add and drop optical channel maintenance signal information to the CPU and generate the LOS suppression signal with respect to the optical channel according to the occurrence of malfunction, thus directly transmitting the suppression signal to the corresponding optical channel unit.

Abstract: A multi-layer photonic network and nodes used therein are provided. The multi-layer photonic network comprises a packet network which performs switching and transfer in packet units, and a photonic network comprising optical transmission lines and photonic switches, and which accommodates the packet network. The multi-layer photonic network also has a two layer structure of optical wavelength links (O-LSPs) and packet links (E-LSPs). The O-LSPs are constituted by the optical transmission lines and comprise optical wavelength switching capability (LSC) which is capable of switching in optical wavelength units and packet switching capability (PSC) which is capable of switching in packet units at both their ends. The E-LSPs include the O-LSPs and PSCs at both their ends. Each node includes a section for automatically establishing an O-LSP according to an establishment request for an E-LSP while taking account of path information including path cost, resource consumption, and traffic quantity.