Patents by Inventor Nicholas G. Duffield

Nicholas G. Duffield 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).

  • Patent number: 8730807
    Abstract: Certain exemplary embodiments comprise a method comprising: for selected traffic that enters a backbone network via a predetermined ingress point and is addressed to a predetermined destination, via a dynamic tunnel, automatically diverting the selected traffic from the predetermined ingress point to a processing complex; and automatically forwarding the selected traffic from the processing complex toward the predetermined destination.
    Type: Grant
    Filed: July 19, 2012
    Date of Patent: May 20, 2014
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Christopher J. Chase, Nicholas G. Duffield, Albert G. Greenberg, Oliver Spatscheck, Jacobus E. Van der Merwe, Neal Shackleton
  • Publication number: 20120281586
    Abstract: Certain exemplary embodiments comprise a method comprising: for selected traffic that enters a backbone network via a predetermined ingress point and is addressed to a predetermined destination, via a dynamic tunnel, automatically diverting the selected traffic from the predetermined ingress point to a processing complex; and automatically forwarding the selected traffic from the processing complex toward the predetermined destination.
    Type: Application
    Filed: July 19, 2012
    Publication date: November 8, 2012
    Applicant: AT&T INTELLECTUAL PROPERTY II, LP
    Inventors: Christopher J. Chase, Nicholas G. Duffield, Albert G. Greenberg, Oliver Spatscheck, Jacobus E. Van der Merwe, Neal Shackleton
  • Patent number: 8228818
    Abstract: Certain exemplary embodiments comprise a method comprising: for selected traffic that enters a backbone network via a predetermined ingress point and is addressed to a predetermined destination, via a dynamic tunnel, automatically diverting the selected traffic from the predetermined ingress point to a processing complex; and automatically forwarding the selected traffic from the processing complex toward the predetermined destination.
    Type: Grant
    Filed: September 28, 2005
    Date of Patent: July 24, 2012
    Assignee: AT&T Intellectual Property II, LP
    Inventors: Christopher J. Chase, Nicholas G. Duffield, Albert G. Greenberg, Oliver Spatscheck, Jacobus E. Van der Merwe, Neal Shackleton
  • Patent number: 8031599
    Abstract: A signature-based traffic classification method maps traffic into preselected classes of service (CoS). By analyzing a known corpus of data that clearly belongs to identified ones of the preselected classes of service, in a training session the method develops statistics about a chosen set of traffic features. In an analysis session, relative to traffic of the network where QoS treatments are desired (target network), the method obtains statistical information relative to the same chosen set of features for values of one or more predetermined traffic attributes that are associated with connections that are analyzed in the analysis session, yielding a statistical features signature of each of the values of the one or more attributes. A classification process then establishes a mapping between values of the one or more predetermined traffic attributes and the preselected classes of service, leading to the establishment of QoS treatment rules.
    Type: Grant
    Filed: December 10, 2009
    Date of Patent: October 4, 2011
    Inventors: Nicholas G. Duffield, Matthew Roughan, Subhabrata Sen, Oliver Spatscheck
  • Patent number: 8028055
    Abstract: Two regularized estimators that avoid the pathologies associated with variance estimation are disclosed. The regularized variance estimator adds a contribution to estimated variance representing the likely error, and hence ameliorates the pathologies of estimating small variances while at the same time allowing more reliable estimates to be balanced in the convex combination estimator. The bounded variance estimator employs an upper bound to the variance which avoids estimation pathologies when sampling probabilities are very small.
    Type: Grant
    Filed: November 17, 2008
    Date of Patent: September 27, 2011
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Nicholas G. Duffield, Carsten Lund, Mikkel Thorup
  • Patent number: 7953020
    Abstract: A method is disclosed for implementing and reporting network measurements between a source of probe packets and an element, such as a router. The invention exploits commonly implemented features on commercial elements. By exploiting these features, the expense of deploying special purpose measurement devices can be avoided. In one aspect of the invention, a plurality of probe packets is transmitted in a packet network with each of the probe packets having the same key and the same aggregation characteristic. A report is then received from an instructionless element regarding the plurality of probe packets, thereby enabling measurement of a parameter of the packet network.
    Type: Grant
    Filed: June 30, 2006
    Date of Patent: May 31, 2011
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Lee Breslau, Nicholas G. Duffield, Subhabrata Sen
  • Publication number: 20100085889
    Abstract: A signature-based traffic classification method maps traffic into preselected classes of service (CoS). By analyzing a known corpus of data that clearly belongs to identified ones of the preselected classes of service, in a training session the method develops statistics about a chosen set of traffic features. In an analysis session, relative to traffic of the network where QoS treatments are desired (target network), the method obtains statistical information relative to the same chosen set of features for values of one or more predetermined traffic attributes that are associated with connections that are analyzed in the analysis session, yielding a statistical features signature of each of the values of the one ore more attributes. A classification process then establishes a mapping between values of the one or more predetermined traffic attributes and the preselected classes of service, leading to the establishment of QoS treatment rules.
    Type: Application
    Filed: December 10, 2009
    Publication date: April 8, 2010
    Inventors: Nicholas G. Duffield, Matthew Roughan, Subhabrata Sen, Oliver Spatscheck
  • Patent number: 7660248
    Abstract: A signature-based traffic classification method maps traffic into preselected classes of service (CoS). By analyzing a known corpus of data that clearly belongs to identified ones of the preselected classes of service, in a training session the method develops statistics about a chosen set of traffic features. In an analysis session, relative to traffic of the network where QoS treatments are desired (target network), the method obtains statistical information relative to the same chosen set of features for values of one or more predetermined traffic attributes that are associated with connections that are analyzed in the analysis session, yielding a statistical features signature of each of the values of the one or more attributes. A classification process then establishes a mapping between values of the one or more predetermined traffic attributes and the preselected classes of service, leading to the establishment of QoS treatment rules.
    Type: Grant
    Filed: January 23, 2004
    Date of Patent: February 9, 2010
    Inventors: Nicholas G. Duffield, Matthew Roughan, Subhabrata Sen, Oliver Spatscheck
  • Patent number: 7574506
    Abstract: A method and apparatus for the estimation of traffic matrices in a network are disclosed.
    Type: Grant
    Filed: September 26, 2007
    Date of Patent: August 11, 2009
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Nicholas G. Duffield, Albert Gordon Greenberg, John G. Klincewicz, Matthew Roughan, Yin Zhang
  • Publication number: 20090161570
    Abstract: Two regularized estimators that avoid the pathologies associated with variance estimation are disclosed. The regularized variance estimator adds a contribution to estimated variance representing the likely error, and hence ameliorates the pathologies of estimating small variances while at the same time allowing more reliable estimates to be balanced in the convex combination estimator. The bounded variance estimator employs an upper bound to the variance which avoids estimation pathologies when sampling probabilities are very small.
    Type: Application
    Filed: November 17, 2008
    Publication date: June 25, 2009
    Inventors: Nicholas G. Duffield, Carsten Lund, Mikkel Thorup
  • Patent number: 7536455
    Abstract: Two regularized estimators that avoid the pathologies associated with variance estimation are disclosed. The regularized variance estimator adds a contribution to estimated variance representing the likely error, and hence ameliorates the pathologies of estimating small variances while at the same time allowing more reliable estimates to be balanced in the convex combination estimator. The bounded variance estimator employs an upper bound to the variance which avoids estimation pathologies when sampling probabilities are very small.
    Type: Grant
    Filed: July 18, 2006
    Date of Patent: May 19, 2009
    Assignee: AT&T Corp.
    Inventors: Nicholas G. Duffield, Carsten Lund, Mikkel Thorup
  • Patent number: 7508769
    Abstract: Traffic measurement should make it possible to obtain the spatial flow of traffic through the domain, i.e., the paths or trajectories followed by packets between any ingress and egress point of the domain. A method of sampling packet trajectories in a packet switching network allows the direct inference of traffic flows through a measurement domain by observing the trajectories of a subset of all packets traversing the network. A method which assumes that the measurement domain does not change comprises the steps of selecting packets for sampling in accordance with a sampling function of the packet content and generating a practically unique label for each sampled packet. The method does not rely on routing state, its implementation cost is small, and the measurement reporting traffic is modest and can be controlled precisely. Using the same hash function will yield the same sample set of packets in the entire domain, and enables us to reconstruct packet trajectories.
    Type: Grant
    Filed: May 6, 2004
    Date of Patent: March 24, 2009
    Assignee: AT&T Intellectual Property, II, L.P.
    Inventors: Nicholas G. Duffield, Matthias Grossglauser
  • Publication number: 20070268882
    Abstract: A method is disclosed for implementing and reporting network measurements between a source of probe packets and an element, such as a router. The invention exploits commonly implemented features on commercial elements. By exploiting these features, the expense of deploying special purpose measurement devices can be avoided. In one aspect of the invention, a plurality of probe packets is transmitted in a packet network with each of the probe packets having the same key and the same aggregation characteristic. A report is then received from an instructionless element regarding the plurality of probe packets, thereby enabling measurement of a parameter of the packet network.
    Type: Application
    Filed: June 30, 2006
    Publication date: November 22, 2007
    Inventors: Lee Breslau, Nicholas G. Duffield, Subhabrata Sen
  • Patent number: 7299283
    Abstract: The present invention provides apparatus for sampling data flows in a data network in order to estimate a total data volume in the network. Sampling the data flows in the data network reduces the network resources that must be expended by the network to support the associated activity. The present invention enables the service provider of the data network to control sampled volumes in relation to the desired accuracy. The control can be either static or can be dynamic for cases in which the data volumes are changing as a function of time.
    Type: Grant
    Filed: June 27, 2006
    Date of Patent: November 20, 2007
    Assignee: AT&T Corp.
    Inventors: Nicholas G. Duffield, Carsten Lund, Mikkel Thorup
  • Patent number: 7293086
    Abstract: A method and apparatus for the estimation of traffic matrices in a network are disclosed. Mechanisms are disclosed for measuring traffic volume from a plurality of ingress points to a plurality of egress points in a large scanl network, such as an IP backbone network. The traffic matrix is advantageously inferred from widely available link load measurements such as SNMP data.
    Type: Grant
    Filed: July 25, 2003
    Date of Patent: November 6, 2007
    Assignee: AT&T Corp.
    Inventors: Nicholas G. Duffield, Albert Gordon Greenberg, John G. Klincewicz, Matthew Roughan, Yin Zhang
  • Patent number: 7197048
    Abstract: The invention provides apparatus and methods for a Virtual Private Network (VPN) in a network that offers a simple user interface for efficient utilization of network resources. The VPN is defined for a specified set of endpoints each of which is associated with a single “hose.” A hose provides access to the VPN through an access point which may be a node of the network, for example. The hose is a single interface to the VPN for communication to all other endpoints of the VPN. The VPN achieves network resource allocation efficiency by exploiting resource sharing possibilities via multiplexing routing paths between endpoints and dynamic resource allocation techniques that permit real time resource allocation resizing. When a VPN is established with a VPN service provider, the routing paths between the endpoints of the VPN is optimized for multiplexing opportunities so that resource allocations between nodes along routing paths within the IP network is reduced to a minimum.
    Type: Grant
    Filed: June 23, 2004
    Date of Patent: March 27, 2007
    Assignee: AT&T Corp
    Inventors: Nicholas G. Duffield, Albert G. Greenberg, Pawan Goyal, Partho P. Mishra, Kadangode K. Ramakrishnan, Jacobus Frasmus van der Merwe
  • Patent number: 7080136
    Abstract: The present invention provides a method and apparatus for sampling data flows in a data network in order to estimate a total data volume in the network. Sampling the data flows In the data network reduces the network resources that must be expended by the network to support the associated activity. The present Invention enables the service provider of the data network to control sampled volumes in relation to the desired accuracy. The control can be either static or can be dynamic for cases in which the data volumes are changing as a function of time.
    Type: Grant
    Filed: January 24, 2002
    Date of Patent: July 18, 2006
    Assignee: AT & T Corp.
    Inventors: Nicholas G. Duffield, Carsten Lund, Mikkel Thorup
  • Patent number: 6912232
    Abstract: The invention provides apparatus and methods for a Virtual Private Network (VPN) in a network that offers a simple user interface for efficient utilization of network resources. The VPN is defined for a specified set of endpoints each of which is associated with a single “hose.” A hose provides access to the VPN through an access point which may be a node of the network, for example. The hose is a single interface to the VPN for communication to all other endpoints of the VPN. The VPN achieves network resource allocation efficiency by exploiting resource sharing possibilities via multiplexing routing paths between endpoints and dynamic resource allocation techniques that permit real time resource allocation resizing. When a VPN is established with a VPN service provider, the routing paths between the endpoints of the VPN is optimized for multiplexing opportunities so that resource allocations between nodes along routing paths within the IP network is reduced to a minimum.
    Type: Grant
    Filed: October 19, 1999
    Date of Patent: June 28, 2005
    Assignee: AT&T Corp.
    Inventors: Nicholas G. Duffield, Albert G. Greenberg, Pawan Goyal, Partho P. Mishra, Kadangode K. Ramakrishnan, Jacobus Erasmus van der Merwe
  • Patent number: 6873600
    Abstract: Traffic measurement should make it possible to obtain the spatial flow of traffic through the domain, i.e., the paths or trajectories followed by packets between any ingress and egress point of the domain. A method of sampling packet trajectories in a packet switching network allows the direct inference of traffic flows through a measurement domain by observing the trajectories of a subset of all packets traversing the network. A method which assumes that the measurement domain does not change comprises the steps of selecting packets for sampling in accordance with a sampling function of the packet content and generating a practically unique label for each sampled packet. The method does not rely on routing state, its implementation cost is small, and the measurement reporting traffic is modest and can be controlled precisely. Using the same hash function will yield the same sample set of packets in the entire domain, and enables us to reconstruct packet trajectories.
    Type: Grant
    Filed: October 16, 2000
    Date of Patent: March 29, 2005
    Assignee: AT&T Corp.
    Inventors: Nicholas G. Duffield, Matthias Grossglauser
  • Publication number: 20020188710
    Abstract: The present invention provides a method for sampling data flows in a data network in order to estimate a total data volume in the network. Sampling the data flows in the data network reduces the network resources that must be expended by the network to support the associated activity. The present invention enables the service provider of the data network to control sampled volumes in relation to the desired accuracy. The control can be either static or can be dynamic for cases in which the data volumes are changing as a function of time.
    Type: Application
    Filed: January 24, 2002
    Publication date: December 12, 2002
    Applicant: AT&T Corp.
    Inventors: Nicholas G. Duffield, Carsten Lund, Mikkel Thorup