AT&T Intellectual Property I, LP

At+t Corp.

John Lester Strand

Angela L Chiu

Robert Duncan Doverspike

Rakesh Sinha

Martin Birk

Sheryl Leigh Woodward

Mark David Feuer

Robert William Tkach

Weiyi Zhang

Balagangadhar Bathula

Guangzhi Li

Bruce Gilbert Cortez

Fang Yu

Gokhan Sahin

Gagan Choudhury

Thomas S Afferton

A method, computer-readable storage device and apparatus for routing traffic in a reconfigurable optical add-drop multiplexer layer of a dense wavelength division multiplexing network are disclosed. For example, the method determines the reconfigurable optical add-drop multiplexer layer has asymmetric traffic, and routes the asymmetric traffic in the reconfigurable optical add-drop multiplexer layer over a plurality of asymmetrical optical connections, wherein the plurality of asymmetrical optical connections is provided with only uni-directional equipment in the reconfigurable optical add-drop multiplexer layer.

Method and apparatus for routing traffic using asymmetrical optical connections

A method and system for providing joint IP/Optical Layer restoration mechanisms for the IP over Optical Layer architecture, particularly for protecting against router failure within such architecture, includes any one of plural node elements participating in the detection and restoration of the joint IP/Optical Layer architecture upon the failure of a router in one of the nodes. The plural node elements may include, but are not limited to, one of plural routers and an optical cross-connect.

Joint IP/optical layer restoration after a router failure

Systems and methods are described that provide a distributed restoration signaling protocol for shared mesh restoration with standbys for transparent optical networks.

Standby restoration signaling for optical networks

Systems and methods are described for restoring wavelength services in mesh networks using pre-configured, standby lightpaths. The standby lightpaths are pre-cross-connected lightpaths that provide connectivity between switching nodes having a fiber link of degree-2 or higher. The restoration method overcomes the problem of optical impairments for long haul connections, avoids wavelength power balancing delays, provides wavelength conversion for capacity efficiency, and allows sharing of links across nonsimultaneous failures.

Shared mesh restoration with pre-configured standby lightpaths

A connection in an optical communication system is routed over a sequence of cross-connects and aggregated links comprising multiple links. A different link selection algorithm is used for service provisioning than is used for restoration, i.e., after a cable cut or other failure or incident has made one or paths in the network suddenly unavailable. In particular, a special link selection algorithm called the Interleave algorithm is used for restoration different from the well known Best-Fit algorithm used for provisioning. The Interleave algorithm substantially reduces the probability of glare while maintaining near-optimum capacity utilization.

Link selection schemes for avoiding channel contention

A method includes receiving a restoration indicator associated with a path that includes an optical cross-connect (OXC). The OXC is reconfigured from a standby configuration to a restoration configuration in response to the restoration indicator. An optical signal received in a first direction at a first wavelength is optically regenerated to produce an optical signal in the first direction at a second wavelength. An optical signal received in a second direction at the second wavelength is optically regenerated to produce an optical signal in the second direction at the first wavelength.

Methods of restoration in an ultra-long haul optical network

An arrangement provides low cost path protection in an optical communications network. The arrangement has a portionthat provides (broadcasts) an outbound optical signal, and at least first and second transmitting portionstransmit the outbound optical signal simultaneously onto at least first and second respective mutually distinct optical pathways. Meanwhile, a selection arrangementselects among plural incoming optical signals (via) according to a SELECT control signalto provide a selected signal, and an analyzeranalyzes characteristics of the selected signal to provide the SELECT control signal

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Holmdel, NJ, United States of America

John Lester Strand