Gang C Liu

US Patent:

6762997, Jul 13, 2004

Filed:

Mar 29, 2000

Appl. No.:

09/537791

Inventors:

Gang Liu - North Plainfield NJ

Assignee:

Lucent Technologies Inc. - Murray Hill NJ

International Classification:

H04L 1256

US Classification:

370238, 370400

Abstract:

A method is disclosed for determining the shortest paths between a source node and a destination node in a network wherein the paths satisfy imposed system constraints. In accordance with the method of the invention, candidate paths are evaluated by accumulating system parameter information from a source node and projecting the system parameter information ahead to the destination node. When the accumulated and projected system parameter information for the candidate path satisfies the imposed system constraints, the candidate path is saved for further evaluation. The candidate paths are sorted in the order such that those paths most-likely to have the shortest lengths and satisfy the imposed system constraint are evaluated first. In one embodiment of the invention, candidate paths that fail to satisfy the imposed system constraints are removed from further processing. Thus, only candidate paths that have at least one complete path that satisfies the imposed system constraints are evaluated further.

US Patent:

6782198, Aug 24, 2004

Filed:

Nov 10, 2000

Appl. No.:

09/710269

Inventors:

Gang Liu - North Plainfield NJ

Assignee:

Lucent Technologies Inc. - Murray Hill NJ

International Classification:

H04B 1008

US Classification:

398 3, 398 4, 398 5

Abstract:

Recovery from link failure in a WDM ring network is implemented by forming an active ring and a protection ring through the same nodes. Failure in any wavelength channel of a link causes a node adjacent to the link to reroute any subsequent incoming signal from the source node and on the active ring to the protection ring and in an opposite direction. The oppositely directed signal is rerouted again at the other adjacent node back to the active ring to arrive at the destination node. The physical ring serving as the active ring to odd wavelength channels serves as the protection ring to even wavelength channels, and vice versa.

US Patent:

7058296, Jun 6, 2006

Filed:

Mar 12, 2001

Appl. No.:

09/805021

Inventors:

Iraj Saniee - New Providence NJ, US
Eric Bouillet - Eatontown NJ, US
Gang Liu - Denver CO, US

Assignee:

Lucent Technologies Inc. - Murray Hill NJ

International Classification:

H04J 14/00

US Classification:

398 3

Abstract:

A procedure for designing WDM optical networks provides both working circuits and protection circuits for carrying traffic demands between node pairs. The protection circuits are activated for the purpose of network recovery in case of a fault on a working circuit. Each protection circuit is link-disjoint, and preferably node-disjoint, from its corresponding working circuit. The network is subdivided into logically defined rings, such that each working and protection circuit lies on one or more of the rings. In particular embodiments of the invention, the joint routing of circuits is carried out so as to minimize the total length of the working and protection circuits according to a length that includes a weight for each link. The weight is selected to promote the efficient packing of optical fibers with wavelength channels.

US Patent:

7466913, Dec 16, 2008

Filed:

Oct 7, 2005

Appl. No.:

11/245597

Inventors:

Iraj Saniee - New Providence NJ, US
Eric Bouillet - Eatontown NJ, US
Gang Liu - Denver CO, US

Assignee:

Alcatel-Lucent USA Inc. - Murray Hill NJ

International Classification:

H04J 14/00

US Classification:

398 3

Abstract:

A procedure for designing WDM optical networks provides both working circuits and protection circuits for carrying traffic demands between node pairs. The protection circuits are activated for the purpose of network recovery in case of a fault on a working circuit. Each protection circuit is link-disjoint, and preferably node-disjoint, from its corresponding working circuit. The network is subdivided into logically defined rings, such that each working and protection circuit lies on one or more of the rings. In particular embodiments of the invention, the joint routing of circuits is carried out so as to minimize the total length of the working and protection circuits according to a length that includes a weight for each link. The weight is selected to promote the efficient packing of optical fibers with wavelength channels.

US Patent:

20090129771, May 21, 2009

Filed:

Dec 15, 2008

Appl. No.:

12/335437

Inventors:

Iraj Saniee - New Providence NJ, US
Eric Bouillet - Eatontown NJ, US
Gang Liu - Denver CO, US

International Classification:

H04B 10/00

US Classification:

398 3

Abstract:

A procedure for designing WDM optical networks provides both working circuits and protection circuits for carrying traffic demands between node pairs. The protection circuits are activated for the purpose of network recovery in case of a fault on a working circuit. Each protection circuit is link-disjoint, and preferably node-disjoint, from its corresponding working circuit. The network is subdivided into logically defined rings, such that each working and protection circuit lies on one or more of the rings. In particular embodiments of the invention, the joint routing of circuits is carried out so as to minimize the total length of the working and protection circuits according to a length that includes a weight for each link. The weight is selected to promote the efficient packing of optical fibers with wavelength channels.