Worldcom, Inc.

Alcatel

Ciena Corporation

Mci Communications Corporation

Mci Worldcom, Inc.

Sridhar Alagar

Bryan J McGlade

Lee Dennis Bengston

Mark W Sees

Sig Harold Badt, Jr

Jasvantrai C Shah

Hal Badt

Ashley W Brimmage

Paul T Baniewicz

Frederick R Ellefson

S Hal Badt, Sr

Holden Jessup

Rohit Sharma

Will L Russ

John David Allen

Brian Pheiffer

Clint Allen Wagner

Rainer Iraschko

Fred Ellefson

Tim T Chao

Stephane St Laurent

A system for use in a bi-directional path switched ring network for detecting a failed optical path and establishing a protection path so as to allow signals from the failed optical path to be re-routed via the protection path is provided. According to one aspect of the system, upon detecting a failure relating to an optical path, the destination node generates a connection request message for transmission to the source node. The connection request message is passed to the source node via one or more intermediate nodes, if any. Each intermediate node examines the connection request message accordingly reserves the requisite wavelength from the protection capacity so as to allow signals from the failed optical path to be re-routed. Upon receiving the connection request message, the source node readies its switching equipment to re-route signals from the failed optical path and generates an acknowledgment message and propagates it back to the destination node via the intermediate nodes. The intermediate nodes and the destination node, upon receipt of the acknowledgement message, also ready their respective switching equipment to carry the re-routed signals via the previously reserved wavelength from the protection capacity. According to another aspect of the system, a contention resolution mechanism is provided to resolve contending connection request messages received at a node requesting the same wavelength to be reserved from the protection capacity for different failed optical paths. A message format is used for the connection request which allows the connection request message to include information relating to the type of failure experienced by a failed optical path and other priority data. Such information is then used by a node to determine priority between two contending connection request messages.

Method and system for bi-directional path switched network

A network wherein a plurality of links connects a plurality of nodes such as cross-connects in a communication circuit network with paths interconnecting the nodes, and with there being spare capacity between a sufficient number of nodes to accommodate at least some rerouting of traffic immediately upon detection of a break in a traffic span in the network so as to restore circuit continuity within a predetermined maximum time using an improved failure detection, isolation, and recovery

Telecommunications network distributed restoration method and system

A network wherein a plurality of links connects a plurality of nodes such as cross-connects in a communication circuit network with paths interconnecting the nodes, and with there being spare capacity between a sufficient number of nodes to accommodate at least some rerouting of traffic immediately upon detection of a break in a traffic span in the network so as to restore circuit continuity within a predetermined maximum time using an improved failure detection, isolation, and recovery scheme.

In a path-based distributed restoration algorithm provisioned telecommunications network, the origin and destination nodes of a failed path are apprised of the portions of the path that remain intact by &ldquo;reuse&rdquo; messages that are sent from the custodial nodes that are adjacent to the failure. As each reuse message reaches an intermediate node, the node ID of the intermediate node is appended to a field of the message so that, as the reuse messages are propagated along the intact portions of the failed path, a cumulative list of nodes that are encountered by the messages passing from the custodial nodes to the origin and destination nodes is set forth. Thus, the origin/destination node, when in receipt of a reuse message, can read from the field that has the cumulative list of nodes a description of the intact portions remaining from the original path. These intact portions are preferably used only for restoring of the same path that included the portions prior to failure and are not available for restoring any other paths that happened to fail simultaneously.

System and method for restricted reuse of intact portions of failed paths

In a telecommunications network provisioned with different types of restoration processes, to ensure that the operation of one restoration process does not infringe upon other nodes that are actively executing a different restoration process, a request is sent by one of the restoration processes, under the guise of the operation system that oversees that process, to the operation system that oversees the other restoration process. The controller of the nodes that are performing the other restoration process, in receipt of the request, sends a disable restoration process message to those nodes under its control. Each of those nodes, upon receipt of the disable restoration process message, would disable the restoration process it is provisioned with so long as it is not actively engaging in that restoration process. If it is, it will continue to execute that restoration process until a safe stop point is reached, at which time it ceases that restoration process. Upon cessation of the particular restoration process, the node sends an acknowledge message to its controller, which, when in receipt of such acknowledge message from all of the nodes under its control, sends a disable acknowledged message to the controller of the first restoration process informing the latter that the nodes under its control can now be operated using the first restoration process. The above method is applicable to a telecommunications network provisioned with multiple layers of restoration processes including for example DRA, RTR and centralized restoration.

Method of coordinating the respective operations of different restoration processes

In a telecommunications network provisioned with a distributed restoration scheme, to determine the reactions and responses of the network while the network is &ldquo;live&rdquo; or operational, an exercise information message is provided to the network for presenting a simulated failure or failures thereto. This exercise information message is broadcast to all of the nodes of the network so that every node is aware of the simulated failure scenario. Modified DRA messages that indicate that they are exercise only messages are used by the nodes for executing the exercise restoration process. Such exercise restoration process will proceed as if an actual failure has occurred with the notable exception that no actual cross-connections will be made. Certain functionalities are provisioned to the nodes to allow the exercise restoration process to be aborted if a real failure is detected or upon the expiration of a timer. The exercise restoration process can also be terminated by a command from the network management.

Method of exercising a distributed restoration process in an operational telecommunications network

A system and method for restoring communication between at least one pair of nodes in a network. Distributed intelligence is provided by messaging between adjacent nodes in the network. The messages in combination with user-configurable timers and rules provide fault isolation, forward flooding, reverse linking and connection.

Implementation protocol for SHN-based algorithm restoration platform

Growing community of inventors

Richardson, TX, United States of America

Sridhar Alagar