Patents by Inventor Guangzhi Li

Guangzhi Li has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20120213520
    Abstract: A method of providing routes through heterogeneous subsystems in an optical network is disclosed, which includes generating, using a processing device, a reachability matrix based on subnetwork information; and generating, using the processing device, a topology associated with the optical network using the reachability matrix. The method also includes determining, using the processing device, a shortest path through the optical network using the reachability matrix and a cost model graph; and displaying, using a graphical user interface, subsystems associated with the shortest path, regeneration locations associated with the shortest path, wavelengths associated with the shortest path, the topology, and the shortest path. Corresponding apparatus and computer-readable storage media are also disclosed.
    Type: Application
    Filed: February 18, 2011
    Publication date: August 23, 2012
    Applicant: AT&T INTELLECTUAL PROPERTY I LP
    Inventors: Robert Doverspike, Guangzhi Li, Angela Lan Chiu, Monica Gerhardstein, Yici Guo, Dongmei Wang, Dahai Xu
  • Patent number: 8208371
    Abstract: Certain exemplary embodiments provide a method comprising: in a network at a node located on a label switched path: selecting a backup path to respond to a failure; and for each link along the backup path, reserving a backup bandwidth, wherein the backup bandwidth is sufficient to reroute traffic around the failure.
    Type: Grant
    Filed: June 18, 2008
    Date of Patent: June 26, 2012
    Assignee: AT&T Intellectual Property II, LP
    Inventors: Guangzhi Li, Dongmei Wang
  • Publication number: 20120087665
    Abstract: A method and apparatus for providing a route recommendation are disclosed. For example, the method obtains network topology information, wherein the network topology information comprises a plurality of underlying subnetwork types for a network. The method creates a cost model for the network, and receives a request from a user for a connection to be supported by the network. The method provides the route recommendation for supporting the connection by applying the cost model.
    Type: Application
    Filed: October 11, 2010
    Publication date: April 12, 2012
    Inventors: GUANGZHI LI, Angela Lan Chiu, Chris Dailey, Robert Duncan Doverspike, Monica Naukam Gerhardstein, Dah-Min David Hwang, Dongmei Wang, Dahai Xu
  • Patent number: 8150257
    Abstract: 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.
    Type: Grant
    Filed: June 20, 2008
    Date of Patent: April 3, 2012
    Assignee: AT&T Intellectual Property II, LP
    Inventors: Gagan L. Choudhury, Angela Lan Chiu, Robert Duncan Doverspike, Guangzhi Li, John L. Strand
  • Patent number: 7974183
    Abstract: The present invention is directed to methods for signaling that enable bandwidth reservation, path restoration, path normalization, and path removal in a mesh network that supports shared mesh restoration.
    Type: Grant
    Filed: December 10, 2009
    Date of Patent: July 5, 2011
    Assignee: AT&T Intellectual Property II, LP
    Inventors: Guangzhi Li, Jennifer Yates, Dongmei Wang, Charles Robert Kalmanek, Jr.
  • Patent number: 7904571
    Abstract: A method and apparatus for generating at least one aggregate (e.g., a set of aggregates) for a given area of a network such that the number of aggregates is minimized subject to a maximum acceptable path selection error are disclosed. One operational benefit of the present method is that network administrators can select aggregates for an area based solely on the topology of the area without worrying about remaining areas of the OSPF network. Another benefit is that the present method enables trade-offs between the number of aggregates and the bound on the path selection error.
    Type: Grant
    Filed: May 31, 2006
    Date of Patent: March 8, 2011
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Charles R. Kalmanek, Jr., Guangzhi Li, Aman M. Shaikh, Jennifer M. Yates, Dongmei Wang
  • Publication number: 20110038251
    Abstract: Disclosed herein are systems, methods, and computer readable media for modifying IP backbone link weights such that multicast traffic and unicast traffic will not travel on a same path between nodes. The method comprises assigning link weights to nodes within an IP backbone such that multicast forwarding paths and unicast forwarding paths are failure disjoint, and delivering undelivered multicast packets using IP unicast encapsulation to the loopback address of next hop router on a multicast tree upon link/interface failure.
    Type: Application
    Filed: October 22, 2010
    Publication date: February 17, 2011
    Applicant: AT&T Labs
    Inventors: Guangzhi Li, Dongmei Wang
  • Patent number: 7859993
    Abstract: Systems and methods are described for restoring IP traffic flows routed in an IP network in less than 100 ms after the IP network sustains a network failure. The systems and methods are a two-phase fast reroute that uses distributed optimized traffic engineering during backup tunnel restoration and end-to-end tunnel restoration that maximizes sharing among all independent failure scenarios and minimizes the total capacity, total cost, or a linear combination of the two. For defined failure condition scenarios, restoration traffic is routed using pre-computed backup tunnels using a constrained shortest path first method where link weights along the path are chosen dynamically and depend on available and total capacity of the link, latency, and other cost measures such as IP port costs. During the capacity allocation phase, the method reuses capacity already allocated for other independent failure scenarios as much as possible but also adds capacity, if necessary.
    Type: Grant
    Filed: June 18, 2008
    Date of Patent: December 28, 2010
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Gagan L. Choudhury, Angela Lan Chiu, Robert Duncan Doverspike, Guangzhi Li
  • Patent number: 7830785
    Abstract: Disclosed herein are systems, methods, and computer readable media for modifying IP backbone link weights such that multicast traffic and unicast traffic will not travel on a same path between nodes. The method comprises assigning link weights to nodes within an IP backbone such that multicast forwarding paths and unicast forwarding paths are failure disjoint, and delivering undelivered multicast packets using IP unicast encapsulation to the loopback address of next hop router on a multicast tree upon link/interface failure.
    Type: Grant
    Filed: January 25, 2008
    Date of Patent: November 9, 2010
    Assignee: AT&T Labs, Inc.
    Inventors: Guangzhi Li, Dongmei Wang
  • Patent number: 7782772
    Abstract: Label contention in a label switched network is resolved by applying a contention resolution scheme that reconciles policies for handling unidirectional and bidirectional label switched path setup.
    Type: Grant
    Filed: October 25, 2007
    Date of Patent: August 24, 2010
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Robert Duncan Doverspike, Charles Robert Kalmanek, Jr., Guangzhi Li, Jennifer Yates
  • Patent number: 7769296
    Abstract: Multiplex-demultiplex (mux/demux) “groups” multiplex and demultiplex a predetermined maximum number of optical wavelengths. A method for assigning wavelengths of fiber links and mux/demux groups to given traffic (or traffic segments) in an optical communications network, minimizes over all terminals a total number of mux/demux groups required. The method (FIG. 5) involves (510) sorting the terminals in order of size of load. Further, for each traffic segment between pairs of first and second terminals, the method involves (516) assigning a smallest wavelength that is available between the first and second terminals and that is available on the segment path between the terminals; and in the terminals, (518) deploying mux/demux groups supporting the assigned wavelengths. A modified method (FIGS. 6A, 6B), as well as a method for dynamically assigning and deploying newly arriving traffic segments (FIG. 7), are also provided.
    Type: Grant
    Filed: February 17, 2005
    Date of Patent: August 3, 2010
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Angela Lan Chiu, Dah-Min D. Hwang, Guangzhi Li
  • Publication number: 20100091647
    Abstract: The present invention is directed to methods for signaling that enable bandwidth reservation, path restoration, path normalization, and path removal in a mesh network that supports shared mesh restoration.
    Type: Application
    Filed: December 10, 2009
    Publication date: April 15, 2010
    Inventors: Guangzhi Li, Jennifer Yates, Dongmei Wang, Charles Robert Kalmanek, JR.
  • Patent number: 7688720
    Abstract: A method of selecting a restoration path in a mesh telecommunication network is disclosed that advantageously is practical and flexible and may be pre-computed along with a service connection path during the setup of the connection. The information used to select the restoration path can be advantageously distributed among nodes in the network.
    Type: Grant
    Filed: June 16, 2005
    Date of Patent: March 30, 2010
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Robert Duncan Doverspike, Charles Robert Kalmanek, Jr., Guangzhi Li
  • Publication number: 20100067899
    Abstract: Systems and methods are described that provide a distributed restoration signaling protocol for shared mesh restoration with standbys for transparent optical networks.
    Type: Application
    Filed: September 4, 2009
    Publication date: March 18, 2010
    Inventors: Guangzhi Li, Angela Lan Chiu, Robert Duncan Doverspike, John L. Strand
  • Patent number: 7652983
    Abstract: The present invention is directed to methods for signaling that enable bandwidth reservation, path restoration, path normalization, and path removal in a mesh network that supports shared mesh restoration.
    Type: Grant
    Filed: June 25, 2002
    Date of Patent: January 26, 2010
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Guangzhi Li, Jennifer Yates, Dongmei Wang, Charles Robert Kalman
  • Patent number: 7613135
    Abstract: A system and method for routing packet traffic is disclosed. A system that incorporates teachings of the present disclosure may include, for example, a router having a routing element that routes packet traffic according to Internal Gateway Protocol (IGP) weights that prevent multicast packet traffic and unicast packet traffic from occupying a common unidirectional link. Other embodiments are disclosed.
    Type: Grant
    Filed: October 13, 2006
    Date of Patent: November 3, 2009
    Assignee: AT&T Intellectual Property I, L.P.
    Inventors: Guangzhi Li, Robert Duncan Doverspike, Dongmei Wang
  • Publication number: 20090252033
    Abstract: Systems and methods to distribute media content are provided. A particular method includes receiving first link weighting factors and second link weighting factors at a router of a node of a multicast network and determining a primary path to a next hop node based on the first link weighting factors. Additionally, the method includes determining a backup path from a router of the primary path to the next hop node based on the second link weighting factors. The backup path does not overlap any primary path between two nodes of the network. Further, the method includes receiving a data packet from a parent node and routing a copy of the data packet from the router to the next hop node via the backup path, when a network link related to the router has failed. The method also includes routing data packets via a re-configured multicast tree that excludes the failed link.
    Type: Application
    Filed: April 8, 2008
    Publication date: October 8, 2009
    Applicant: AT&T Knowledge Ventures, L.P.
    Inventors: Kadangode Ramakrishnan, Robert Duncan Doverspike, Guangzhi Li, Dongmei Wang, Kostas Oikonomou
  • Publication number: 20090190478
    Abstract: Disclosed herein are systems, methods, and computer readable media for modifying IP backbone link weights such that multicast traffic and unicast traffic will not travel on a same path between nodes. The method comprises assigning link weights to nodes within an IP backbone such that multicast forwarding paths and unicast forwarding paths are failure disjoint, and delivering undelivered multicast packets using IP unicast encapsulation to the loopback address of next hop router on a multicast tree upon link/interface failure.
    Type: Application
    Filed: January 25, 2008
    Publication date: July 30, 2009
    Applicant: AT&T Labs
    Inventors: Guangzhi LI, Dongmei Wang
  • Patent number: 7450496
    Abstract: A method of selecting a restoration path in a mesh telecommunication network is disclosed that advantageously is practical and flexible and may be pre-computed along with a service connection path during the setup of the connection. The information used to select the restoration path can be advantageously distributed among nodes in the network.
    Type: Grant
    Filed: January 4, 2007
    Date of Patent: November 11, 2008
    Inventors: Robert Duncan Doverspike, Charles Robert Kalmanek, Jr., Guangzhi Li
  • Publication number: 20080253281
    Abstract: Certain exemplary embodiments provide a method comprising: in a network at a node located on a label switched path: selecting a backup path to respond to a failure; and for each link along the backup path, reserving a backup bandwidth, wherein the backup bandwidth is sufficient to reroute traffic around the failure.
    Type: Application
    Filed: June 18, 2008
    Publication date: October 16, 2008
    Applicant: AT&T CORPORATION
    Inventors: Guangzhi Li, Dongmei Wang