摘要:
A network architecture is provided for enabling end-to-end paths to be computed across a plurality of network domains. The network architecture comprises a plurality of child path computation elements associated with a plurality of respective network domains, each child path computation element adapted to compute a path segment within its respective network domain. A parent path computation element adapted to compute an end-to-end path across a plurality of network domains in conjunction with the plurality of respective child path computation elements.
摘要:
Dynamic restoration involves routing and bandwidth assignment of an unplanned restoration path in a wavelength switched optical network (20), having regeneration nodes (60), nodes each having a ROADM (62) having drop paths and add paths. An electrical switch (68) provides configurable regeneration capacity by coupling selected drop paths to selected add paths. Some of the configurable regeneration capacity is kept for unplanned restoration paths. A PCE determines (120) routing and bandwidth assignments for an unplanned restoration path for the traffic flow to avoid a fault, and sends (130) configuration messages to the nodes to set up the unplanned restoration path dynamically and to configure the electrical switch to provide regeneration on the path. Keeping some reconfigurable regeneration capacity enables much longer unplanned paths to be found to avoid faults, and enables wavelength conversion if needed. Thus the reliability of finding at least one path avoiding the fault can be increased.
摘要:
Recovery from failure of a working path for communications traffic in a connection-oriented network, where the working path has a preplanned recovery path, involves initiating recovery by requesting computation of a new recovery path for the communications traffic to avoid the failure. If the recovery is not successful within a time limit, recovery is carried out using the preplanned recovery path. Determining if the recovery is not successful and initiating the recovery using the preplanned recovery path can be controlled by an ingress node of the working path. By trying to compute a new recovery path first, network resources can be used more efficiently, as the new recovery path is likely to reuse most of the working path, since it is computed knowing the location of the fault.
摘要:
Dynamic restoration involves routing and bandwidth assignment of an unplanned restoration path in a wavelength switched optical network (20), having regeneration nodes (60), nodes each having a ROADM (62) having drop paths and add paths. An electrical switch (68) provides configurable regeneration capacity by coupling selected drop paths to selected add paths. Some of the configurable regeneration capacity is kept for unplanned restoration paths. A PCE determines (120) routing and bandwidth assignments for an unplanned restoration path for the traffic flow to avoid a fault, and sends (130) configuration messages to the nodes to set up the unplanned restoration path dynamically and to configure the electrical switch to provide regeneration on the path. Keeping some reconfigurable regeneration capacity enables much longer unplanned paths to be found to avoid faults, and enables wavelength conversion if needed. Thus the reliability of finding at least one path avoiding the fault can be increased.
摘要:
A connection-oriented optical network (2) comprises nodes (10) and optical links (5) between nodes. Each node (10) has a power control unit (60) for controlling an optical amplifier (43) at the node. A node, in response to a requirement to set up a new connection in the network, signals to a power control unit (60) at each of a plurality of downstream nodes along a path of the new connection to cause the power control unit at the node to adjust the optical amplifier at the node to support a new optical channel to carry the new connection. The node (10) can signal to tear down an existing connection in a similar way. A downstream node determines a number of optical channels for which the optical amplifier can be adjusted concurrently, based on an existing number of active optical channels.
摘要:
A method of configuring a path between an ingress node and an egress node in an optical communications network, the path comprising a first hop and a subsequent hop. The method includes: a) selecting a candidate hop for the first hop of the path; b) obtaining a value of a signal feasibility parameter for the candidate hop; c) determining whether said value lies within an acceptable value range and if one is, accepting said candidate hop for the first hop of the path, and if one is not, repeating steps a. to c.; d) selecting a candidate hop for the subsequent hop of path; e) obtaining a value of a signal feasibility parameter for a combined path comprising the first hop and the candidate hop for the subsequent hop of the path; f) determining whether said value lies within an acceptable value range, if one is, acceptable value range accepting said candidate hop for the subsequent hop of the path, and if one is not, repeating steps d. and e.; and g) generating and transmitting a control signal for configuring the path. Each step of obtaining a value of a signal feasibility parameter comprises checking whether a measured value of the signal feasibility parameter is available, and if one is, retrieving said measured value and if one is not, calculating an estimated value of the signal feasibility parameter.
摘要:
A method of configuring a path between an ingress node and an egress node in an optical communications network, the path comprising a first hop and a subsequent hop. The method includes: a) selecting a candidate hop for the first hop of the path; b) obtaining a value of a signal feasibility parameter for the candidate hop; c) determining whether said value lies within an acceptable value range and if one is, accepting said candidate hop for the first hop of the path, and if one is not, repeating steps a. to c.; d) selecting a candidate hop for the subsequent hop of path; e) obtaining a value of a signal feasibility parameter for a combined path comprising the first hop and the candidate hop for the subsequent hop of the path; f) determining whether said value lies within an acceptable value range, if one is, acceptable value range accepting said candidate hop for the subsequent hop of the path, and if one is not, repeating steps d. and e.; and g) generating and transmitting a control signal for configuring the path. Each step of obtaining a value of a signal feasibility parameter comprises checking whether a measured value of the signal feasibility parameter is available, and if one is, retrieving said measured value and if one is not, calculating an estimated value of the signal feasibility parameter.
摘要:
The invention relates to a method in a border node of an optical network and in an external optical channel originating apparatus and to a border node of an optical network and a router. The invention is particularly applicable to optical path validation in an optical network for an externally originating optical channel. The invention may be used during an optical path fault recovery operation.In the method in a border node of an optical network optical channel traffic parameter associated with an optical channel are received from an optical channel originator external to the optical network. The received optical channel traffic parameters are used to determine the suitability of at least one optical path within the optical network for an externally originating optical channel. If a suitable optical path is determined an optical channel availability message indicating the availability at the border node of an optical path within the optical network for the optical channel is sent to the optical channel originator.In the method in an optical channel originator external to an optical network the optical channel traffic parameters associated with an optical channel originating at the optical channel originator are sent to a border node of the optical network. An optical channel availability message indicating the availability at the optical network border node of an optical path within the optical network for the optical channel with which the optical channel traffic parameters are associated is received from the border node. An available optical channel status of the optical channel is determined from the received optical channel availability message for the optical channel.
摘要:
A network architecture is provided for enabling end-to-end paths to be computed across a plurality of network domains. The network architecture comprises a plurality of child path computation elements associated with a plurality of respective network domains, each child path computation element adapted to compute a path segment within its respective network domain. A parent path computation element adapted to compute an end-to-end path across a plurality of network domains in conjunction with the plurality of respective child path computation elements.
摘要:
Recovery from failure of a working path for communications traffic in a connection-oriented network, where the working path has a preplanned recovery path, involves initiating recovery by requesting computation of a new recovery path for the communications traffic to avoid the failure. If the recovery is not successful within a time limit, recovery is carried out using the preplanned recovery path. Determining if the recovery is not successful and initiating the recovery using the preplanned recovery path can be controlled by an ingress node of the working path. By trying to compute a new recovery path first, network resources can be used more efficiently, as the new recovery path is likely to reuse most of the working path, since it is computed knowing the location of the fault.