Abstract: An example embodiment involves a method for adjusting an operating parameter of a node in an optical network which comprises a plurality of nodes, the method comprising the steps of: measuring at the node a value of at least one characteristic associated with the operating parameter of the node; distributing the value of the characteristic to all of the other nodes in the network; receiving at the node the value of the characteristic for all of the other nodes in the network; deriving at the node optical impairment data for each link of the network based on the received values of the characteristic for all of the nodes; calculating at the node the preferred value of the operating parameter for each node based on the derived optical impairment data; and adjusting the operating parameter of the node based on the calculated preferred value for the node.

Abstract: A distributed packet switch to control data packet flows in a network is described. The distributed packet switch includes a means for operating over an asynchronous burst optical closed fiber medium. The distributed packet switch also includes at least one control system provided at a node to control data packet flow characteristics, such that the switch is configured to operate dependent on at least one efficiency parameter.

Abstract: In a mesh network, a network element for providing protection switching in a 1:N shared mesh protection scheme having a first protection path associated with a pair of working paths selected from the N working paths is disclosed.

Abstract: A distributed packet switch to control data packet flows in a network is described. The distributed packet switch includes a means for operating over an asynchronous burst optical closed fiber medium. The distributed packet switch also includes at least one control system provided at a node to control data packet flow characteristics, such that the switch is configured to operate dependent on at least one efficiency parameter.

Abstract: In a mesh network, a network element for providing protection switching in a 1:N shared mesh protection scheme having a first protection path associated with a pair of working paths selected from the N working paths is disclosed.

Abstract: In a mesh communications network, in which working and protection paths may be established, channels used to carry protection traffic between nodes are shared across multiple protection paths. Channels need only be shared if sharing does not adversely impact network usage. If working and protection paths become susceptible to single points of failure, channels need not be shared.

Abstract: A node within a mesh network includes an Optical Connection Controller (OCC) and a network element. When a connection path within the mesh network is required, an OCC determines if a particular connection path requires a network element to operate as a virtual gateway to separate the mesh network into separate protection domains for that particular connection path. A connection path might require separate protection domains in cases in which the number of network elements and/or repeater/amplifier components for a particular connection path is greater than a threshold, the total length of links for the connection path is above a threshold and/or another factor that could cause the recovery time for the connection path to increase beyond an acceptable threshold level. If the OCC determines that one or more virtual gateways are required for a particular connection path, the OCC selects an appropriate network element within the network to operate as a virtual gateway for that particular connection path.

Abstract: Synchronization and desynchronization of a data signal transported in a synchronous frame across a synchronous communications network, such as SONET/SDH, reduces waiting-time jitter. A timing estimate (F) indicative of a relationship between a data rate (f1) of the data signal and a reference frequency (f2) of the synchronous communications network is calculated and communicated through the synchronous communications network, for example in the Synchronous Payload Envelope of a SONET frame. The data signal is recovered using a desynchronizer Phase-Locked Loop steered by the timing estimate (F). The timing estimate (F) can be any one or more of: a ratio between the data rate (f1) and the reference frequency (f2); a difference between the data rate (f1) and the reference frequency (f2); and a phase difference between a recovered data clock signal associated with the data rate (f1) and a reference clock signal associated with the reference frequency (f2).

Abstract: A traffic recovery mechanism for communication networks uses a layer-1 adaptive rate protection scheme that compliments layer-3 restoration mechanisms. The protection scheme allocates less bandwidth to the traffic during a protection switch than during the normal operating conditions. This scheme allows the network to roll off more gracefully from the perspective of the applications routed through it. Rate adaptation is effected by a new interface between the data equipment and the transport network, which switches information transfer rate between two or more predetermined levels.

Abstract: A shared mesh protection scheme defines an associated protection path when a working connection is established. During the protection path definition, the corresponding protection path information is sent down to a switch card of network elements making up the protection path. Upon detection of the failure, the network elements using an overhead byte message will inform the routing source network element of the connection of the failure in the working path. The overhead bytes used are interrupt driven bytes located in the line and path overhead of network traffic. The routing source node of the connection will then send the corresponding overhead byte messages down the protection path to provide for protection path establishment according to the preloaded data located at the switch card. It should be noted that each connection can have a source and termination element which relates to the source from where the corresponding connection was set-up rather than the direction of the payload transmission.

Abstract: A shared mesh protection scheme defines an associated protection path when a working connection is established. During the protection path definition, the corresponding protection path information is sent down to a switch card of network elements making up the protection path. Upon detection of the failure, the network elements using an overhead byte message will inform the routing source network element of the connection of the failure in the working path. The overhead bytes used are interrupt driven bytes located in the line and path overhead of network traffic. The routing source node of the connection will then send the corresponding overhead byte messages down the protection path to provide for protection path establishment according to the preloaded data located at the switch card. It should be noted that each connection can have a source and termination element which relates to the source from where the corresponding connection was set-up rather than the direction of the payload transmission.

Abstract: A shared mesh protection scheme defines an associated protection path when a working connection is established. Both global and local protection schemes are used to provide advantages similar to ring and span protection switching in ring networks. During the global protection path definition, the corresponding protection path information is sent down to a switch card of network elements making up the protection path. Upon detection of the failure, the network elements using an overhead byte message will inform the routing source network element of the connection of the failure in the working path The overhead bytes used are interrupt driven bytes located in the line and path overhead of network traffic The routing source node of the connection will then send the corresponding overhead byte messages down the protection path to provide for protection path establishment according to the preloaded data located at the switch card.

Abstract: A method for computing a backup path for protecting a first working path in a data transport network that includes a plurality of working paths. The method includes determining a route of the backup path by selecting individual backup path segments from a set of possible segments in the data transport network. In the case of a segment that is shared between the first working path and one or more other working paths, the selection process takes into account the existence of a potential point of failure common to the working paths sharing the segment.

Abstract: In a mesh communications network, in which working and protection paths may be established, channels used to carry protection traffic between nodes are shared across multiple protection paths. Channels need only be shared if sharing does not adversely impact network usage. If working and protection paths become susceptible to single points of failure, channels need not be shared.

Abstract: A node within a mesh network includes an Optical Connection Controller (OCC) and a network element. When a connection path within the mesh network is required, an OCC determines if a particular connection path requires a network element to operate as a virtual gateway to separate the mesh network into separate protection domains for that particular connection path. A connection path might require separate protection domains in cases in which the number of network elements and/or repeater/amplifier components for a particular connection path is greater than a threshold, the total length of links for the connection path is above a threshold and/or another factor that could cause the recovery time for the connection path to increase beyond an acceptable threshold level. If the OCC determines that one or more virtual gateways are required for a particular connection path, the OCC selects an appropriate network element within the network to operate as a virtual gateway for that particular connection path.

Abstract: Optical clock recovery is performed on an optical signal containing both data and clock information by applying it to a photodetector and adding part of the resulting electrical signal to the bias of a self-pulsating laser diode so as to force its pulsation frequency to the frequency and phase of the clock component of the optical signal.

Abstract: This device consists primarily of a mounting plate in which are removably received spaced apart letters, having base means for enabling them to be secured within the mounting plate by suitable fasteners, the bases of the letters abutting with each other, and the device includes a hinged and spring loaded portion which will enable the letters to be reflected rearwardly if struck by a pedestrian.