Nortel Networks Corporation

Yang Sup Lee

Dan R Oprea

Wang-Hsin Peng

Methods and apparatus are provided for bandwidth management within Automatically Switched Optical Networks. An Optical Connection Controller (OCC) provides threshold based load balancing using an upper and a lower threshold for each port of a network element, and once port usage exceeds the upper threshold no more connections are allowed through the port until the port usage falls below the lower threshold. The OCC also minimizes fragmentation of a port so as to reduce the probability of call rejection as a result of fragmentation. The OCC also maintains a database of shortest paths between a network element and each destination, so that connections can be re-established quickly through alternate paths in the event of failure of a link or node. The OCC also provides the entire network with notification of a fault, thereby enhancing CR-LDP fault notification messaging.

Control plane architecture for automatically switched optical network

A fairness scheme is disclosed for managing data flow between nodes in a bi-directional ring network. A method in accordance with the invention controls the output bandwidth of nodes in a bi-directional ring network by: identifying a congested span comprising a head node having a congested downstream link, and a plurality of chain nodes contributing to the congestion in the downstream link: adjusting the output bandwidth of the head node as a function of the congestion in the downstream link; and adjusting the output bandwidth of the chain nodes as a function of the congestion in the downstream link.

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Gloucester, Canada

Yang Sup Lee