Kesavamurthy Nagaraj

US Patent:

6483803, Nov 19, 2002

Filed:

Jul 11, 1997

Appl. No.:

08/893433

Inventors:

Siraj Nour Elahmadi - Dallas TX
Paul Arthur Bullock - Plano TX
Kesavamurthy Nagaraj - Plano TX

Assignee:

Nortel Networks Limited - St. Laurent

International Classification:

G01R 3108

US Classification:

370216, 370225, 370535

Abstract:

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 âbundledâ 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.

US Patent:

6735392, May 11, 2004

Filed:

Oct 18, 1999

Appl. No.:

09/420329

Inventors:

Siraj Elahmadi - Dallas TX
Paul A. Bullock - Plano TX
Nigel Baker - Harlow, GB
Kesavamurthy Nagaraj - Plano TX

Assignee:

Nortel Networks Limited - St. Laurent

International Classification:

G02F 100

US Classification:

398 7, 398 1, 398 4, 398 20, 398 34

Abstract:

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.

US Patent:

6870813, Mar 22, 2005

Filed:

Sep 7, 2000

Appl. No.:

09/658530

Inventors:

Humair Raza - Richardson TX, US
Ra'ed Awdeh - Richardson TX, US
Kesavamurthy Nagaraj - Plano TX, US

Assignee:

Nortel Networks Limited - St. Laurent

International Classification:

H04L012/28
H04L012/66
H04J003/02

US Classification:

370238, 370352, 370404, 370539

Abstract:

The present invention discloses novel network architectures for evolving traditional service provider networks. The network architecture of the invention has a transport layer including an optical network. At least one node of the network architecture includes a large packet switch that is coupled to the transport layer and to an access layer. The large packet switch aggregates a plurality of services from the access layer. The large packet switch also performs packet level grooming of the information from the services prior to transport of the information via the transport layer. The optical network performs restoration for the network architecture. In one embodiment, the optical network is an optical ring network including at least one optical switch and restoration is performed at the layer-(optical layer). In another embodiment, the optical network is a bi-directional line-switched ring (BLSR) utilizing a Synchronous Optical Network (SONET) standard and restoration is performed by the layer-(SONET layer). The network architectures of the invention by utilizing a large packet switch to perform service aggregation and packet level grooming, and by performing restoration either at the layer-(optical layer) or layer-(SONET layer), creates a single converged network that achieves the superior restoration performance needed for carrier grade availability but at much lower costs than traditional service providers which operate multiple overlay networks.

US Patent:

7649847, Jan 19, 2010

Filed:

Jan 7, 2005

Appl. No.:

11/031715

Inventors:

Humair Raza - Richardson TX, US
Ra'ed Awdeh - Richardson TX, US
Kesavamurthy Nagaraj - Plano TX, US

Assignee:

Nortel Networks Limited - St. Laurent, Quebec

International Classification:

H04L 12/28
H04L 12/66
H04J 3/02

US Classification:

370238, 370352, 370404, 370539

Abstract:

The present invention discloses novel network architectures for evolving traditional service provider networks. The network architecture of the invention has a transport layer including an optical network. At least one node of the network architecture includes a large packet switch that is coupled to the transport layer and to an access layer. The large packet switch aggregates a plurality of services from the access layer. The large packet switch also performs packet level grooming of the information from the services prior to transport of the information via the transport layer. The optical network performs restoration for the network architecture. In one embodiment, the optical network is an optical ring network including at least one optical switch and restoration is performed at the layer-0 (optical layer). In another embodiment, the optical network is a bi-directional line-switched ring (BLSR) utilizing a Synchronous Optical Network (SONET) standard and restoration is performed by the layer-1 (SONET layer). The network architectures of the invention by utilizing a large packet switch to perform service aggregation and packet level grooming, and by performing restoration either at the layer-0 (optical layer) or layer-1 (SONET layer), creates a single converged network that achieves the superior restoration performance needed for carrier grade availability but at much lower costs than traditional service providers which operate multiple overlay networks.

US Patent:

61542962, Nov 28, 2000

Filed:

Nov 5, 1997

Appl. No.:

8/964823

Inventors:

Siraj Nour Elahmadi - Dallas TX
Paul A. Bullock - Plano TX
Kesavamurthy Nagaraj - Plano TX
Thomas Flanagan - Plano TX

Assignee:

Northern Telecom Limited - Montreal

International Classification:

H04B 1008

US Classification:

359119

Abstract:

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.

US Patent:

61047198, Aug 15, 2000

Filed:

Dec 19, 1997

Appl. No.:

8/994740

Inventors:

Wei Henry Chang - Plano TX
Basudeb Dash - Plano TX
Kesavamurthy Nagaraj - Plano TX

Assignee:

Nortel Networks Corporation - Montreal

International Classification:

H04L 1254

US Classification:

370428

Abstract:

A system and method for supporting concurrent message streams. The state machine is used for modeling a digital system having several states. The states represent messages in the digital system. Added to the state machine is a regressive state. The regressive state is connected to each of the states and all transitions between the states go through the regressive state. Also, queues are provided with the state machine to facilitate the concurrent message streams. A queue may be provided with each state so that if multiple message streams are at a single state, they may be stored in the queue provided with the state. Alternatively, a queue may be provided with each message stream so that each queue can keep track of the state at which the corresponding message stream is located.