Nortel Networks Corporation

Northern Telecom Limited

Paul Arthur Bullock

Siraj Nour Elahmadi

Kesavamurthy Nagaraj

Nigel Baker

Thomas P Flanagan

A symmetrical capacity network may be adapted to accommodate asymmetrical network traffic patterns by deploying Protected Dedicated Wavelengths (PDWs) between one or more head-end nodes and the access nodes on a ring-based topology network. The PDWs include pairs of wavelengths extending in opposite directions around the fibers forming the original ring and terminating at the intended access node. The pairs of wavelengths form unidirectional working and protection paths from the head-end node to the intended access nodes. By deploying the symmetric capacity and asymmetric capacity on the same platform within the head-end node, it is possible to apply policy across the network resources to allow traffic flows to be selectively placed on the most appropriate network resource.

Method and apparatus for providing integrated symmetric and asymmetric network capacity on an optical network

A system and method for transmitting and restoring an optical signal in an optical ring is presented. The optical ring comprises a plurality of nodes, each node containing an optical cross connect switching fabric coupled to a data switch. The optical cross connect switching fabric and the data switch are coupled to a short reach side of a wavelength translation device. A long reach side of the wavelength translation device is coupled to a dense wave division multiplex (DWDM) coupler. The optical cross connect switching fabric and the data switch include a protect channel and a working channel for transporting the optical signal. The wavelength translation device receives the optical signal at a high speed rate, where the optical signal is a short reach optical signal and originates from a high speed interface on the data switch. The wavelength translation device then maps the short reach optical signal into a long reach DWDM optical signal at the high speed rate and forwards, via the DWDM coupler, the long reach optical signal to an adjacent DWDM coupler located at an adjacent node. If a link failure occurs and has not recovered, and the protect channel is not available, optical cross connect switching fabrics at adjacent nodes on each side of the failed link switch the optical signal to an alternate diverse protect port. An optical pass through of the switched optical signal between any transit nodes in the optical ring is then configured resulting in a restoration path for the working channel.

System and method for transmitting and restoring an optical signal

A system and method for connecting traffic along a communications network is accomplished by rerouting traffic upon the detection of a fault condition along a primary connection path. Signals are divided into different wavelength regions labeled red and blue, respectively. The wavelength bands between transmit and receive channels are alternated between red and blue band regions and then combined, multiplexed or &ldquo;bundled&rdquo; together by a wideband wavelength division multiplexer in a single non wavelength specific transmission medium for connection to a single uni-directional Optical Cross Connect System (OCCS) port. Additionally, the receiving end of a single medium is connected to a wavelength division multiplexer which unbundles the combined red and blue band signals upon reception.

Apparatus and method for restoring fiber optic communications network connections

An optical communications network configured in a shared protect capacity architecture. The network includes a plurality of shared and unshared nodes; a plurality of working lines connecting the plurality of nodes to form a ring that shares two or more nodes with another ring; a shared protect fiber optic line connecting the two shared nodes; and a plurality of protect lines connecting the plurality of unshared nodes which are connected by the plurality of working lines. By optically coupling a first Add-Drop Multiplexer of a first shared node to a first port of an optical cross connect using a first connecting path; optically coupling a second Add-Drop Multiplexer of the first shared node to a second port of the optical cross connect using a second connecting path; and optically coupling a third port of the Optical Cross Connect to a second shared node through a shared protect path, both rings may use the shared protect path to re-route traffic therethrough in the event that one of the rings has a break which severs the working and protect lines which couple two of the nodes thereof. The reduction in the quantity of protect lines, hence the fiber, and the equipment resulting in the associated cost savings are transparent to bit or baud rate, type of optical fiber, and signal format.

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Plano, TX, United States of America

Paul Arthur Bullock