Patents by Inventor Carsten Lund

Carsten Lund 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: 7796619
    Abstract: The present invention is directed to a method and system for deriving traffic demands for a packet-switched network. A novel model of defining traffic demands as a volume of load originating from an ingress link and destined to a set of egress links enables support for traffic engineering and performance debugging of large operational packet-switched networks.
    Type: Grant
    Filed: September 26, 2005
    Date of Patent: September 14, 2010
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Anja Feldmann, Albert Gordon Greenberg, Carsten Lund, Nicholas Reingold, Jennifer Lynn Rexford, Frederick D. True
  • Patent number: 7796607
    Abstract: Example scalable multi-protocol label switching (MPLS) based virtual private networks (VPNs) and methods to implement the same are disclosed. A disclosed example spoke provider edge (PE) router for an MPLS-based VPN includes a truncated virtual routing and forwarding (VRF) table containing a first value referencing a hub PE router and a second value referencing a first customer edge (CE) router coupled to the VPN via the PE router, and a forwarding module to forward a packet received from the first CE router to the hub PE router when the packet contains an address referencing a second CE router coupled to the VPN via a second spoke PE router.
    Type: Grant
    Filed: May 30, 2008
    Date of Patent: September 14, 2010
    Assignees: AT&T Intellectual Property I, L.P., Trustees of Princeton University
    Inventors: Alexandre Gerber, Subhabrata Sen, Carsten Lund, Dan Pei, MohammadTaghi Hajiaghayi, Changhoon Kim
  • Patent number: 7764625
    Abstract: The invention relates to streaming algorithms useful for obtaining summaries over unaggregated packet streams and for providing unbiased estimators for characteristics, such as, the amount of traffic that belongs to a specified subpopulation of flows. Packets are sampled from a packet stream and aggregated into flows and counted by implementation of: (a) Adaptive Sampled NetFlow (ANF), and adjusted weight (AANF) of a flow (f) is calculated as follows: AANF(f)=i(f)/p?; i(f) being the number of packets counted for a flow f, and p? being the sampling rate at end of a measurement period; or (b) Adaptive Sample-and-Hold (ASH), and adjusted weight (AASH) of a flow (f) is calculated as follows: AASH(f)=i(f)+(1?p?)/p?; i(f) being the number of packets counted for a flow f, and p? being the sampling rate at end of a measurement period.
    Type: Grant
    Filed: June 10, 2008
    Date of Patent: July 27, 2010
    Assignee: AT&T Intellectual Property I, L.P.
    Inventors: Nicholas Duffield, Edith Cohen, Haim Kaplan, Carsten Lund, Mikkel Thorup
  • Patent number: 7746808
    Abstract: The invention relates to streaming algorithms useful for obtaining summaries over unaggregated packet streams and for providing unbiased estimators for characteristics, such as, the amount of traffic that belongs to a specified subpopulation of flows. Packets are sampled from a packet stream and aggregated into flows and counted by implementation of Adaptive Sample-and-Hold (ASH) or Adaptive NetFlow (ANF), adjusting the sampling rate based on a quantity of flows to obtain a sketch having a predetermined size, the sampling rate being adjusted in steps; and transferring the count of aggregated packets from SRAM to DRAM and initializing the count in SRAM following adjustment of the sampling rate.
    Type: Grant
    Filed: June 10, 2008
    Date of Patent: June 29, 2010
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Nicholas Duffield, Edith Cohen, Haim Kaplan, Carsten Lund, Mikkel Thorup
  • Publication number: 20100157809
    Abstract: Disclosed herein are systems, computer-implemented methods, and computer-readable media for sampling network traffic. The method includes receiving a desired quantity of flow record to sample, receiving a plurality of network flow record each summarizing a network flow of packets, calculating a hash for each flow record of based on one or more invariant part of a respective flow, generating a quasi-random number from the calculated hash for each respective flow record, generating a priority from the calculated hash for each respective flow record, and sampling exactly the desired quantity of flow records, selecting flow records having a highest priority first. In one aspect, the method further partitions the plurality of flow records into groups based on flow origin and destination, generates an individual priority for each partitioned group, and separately samples exactly the desired quantity of flow records from each partitioned group, selecting flows having a highest individual priority first.
    Type: Application
    Filed: December 23, 2008
    Publication date: June 24, 2010
    Applicant: AT&T Intellectual Property I, L.P.
    Inventors: Nicholas Duffield, Lee M. Breslau, Cheng Ee, Alexandre Gerber, Carsten Lund, Subhabrata Sen
  • Publication number: 20100161791
    Abstract: Disclosed herein are systems, computer-implemented methods, and computer-readable media for sampling network traffic. The method includes receiving a plurality of flow records, calculating a hash for each flow record based on one or more invariant part of a respective flow, generating a quasi-random number from the calculated hash for each respective flow record, and sampling flow records having a quasi-random number below a probability P. Invariant parts of flow records include destination IP address, source IP address, TCP/UDP port numbers, TCP flags, and network protocol. A plurality of routers can uniformly calculate hashes for flow records. Each router in a plurality of routers can generate a same quasi-random number for each respective flow record and uses different values for probability P. The probability P can depend on a flow size. The method can divide the quasi-random number by a maximum possible hash value.
    Type: Application
    Filed: December 23, 2008
    Publication date: June 24, 2010
    Applicant: AT&T Intellectual Property I.L.P.
    Inventors: Nicholas Duffield, Lee M. Breslau, Cheng Ee, Alexandre Gerber, Carsten Lund, Subhabrata Sen
  • Publication number: 20100150005
    Abstract: A system and method to use network flow records to generate information about changes in network routing and to understand the impact of these changes on network traffic. The inferences made can be determinative, if sufficient information is available. If sufficient information is not available to make determinative inferences, inferences may be made that narrow the range of possible changes that may have occurred to network traffic and the underlying network.
    Type: Application
    Filed: December 16, 2008
    Publication date: June 17, 2010
    Applicant: AT&T MOBILITY II LLC
    Inventors: Alexandre Gerber, Lee Breslau, Subhabrata Sen, Nicholas Duffield, Carsten Lund, Cheng Ee, Amogh Dhamdhere
  • Publication number: 20100150004
    Abstract: Methods and apparatus to bound network traffic estimation error for multistage measurement sampling and aggregation are disclosed.
    Type: Application
    Filed: December 15, 2008
    Publication date: June 17, 2010
    Inventors: Nicholas Duffield, Carsten Lund, Mikkel Thorup, Edith Cohen
  • Publication number: 20100146100
    Abstract: A system includes an information storage module and an inspection module. The information storage module is configured to store a plurality of tags. Each tag is associated with a known set of traffic types of a plurality of known sets of traffic types. The inspection module is configured to compare a traffic flow to a set of traffic types to determine a matching set of traffic types, request a tag from the information storage module, and mark the traffic flow with the tag. The tag corresponds to the matching set of traffic types.
    Type: Application
    Filed: December 5, 2008
    Publication date: June 10, 2010
    Applicant: AT&T CORP.
    Inventors: Alexandre Gerber, Oliver Spatscheck, Carsten Lund, Frederick True, Ajay Todimala, Jeffrey Erman
  • Publication number: 20100138529
    Abstract: The present invention relates to a method of obtaining a generic sample of an input stream. The method is designated as VAROPTk. The method comprises receiving an input stream of items arriving one at a time, and maintaining a sample S of items i. The sample S has a capacity for at most k items i. The sample S is filled with k items i. An nth item i is received. It is determined whether the nth item i should be included in sample S. If the nth item i is included in sample S, then a previously included item i is dropped from sample S. The determination is made based on weights of items without distinguishing between previously included items i and the nth item i. The determination is implemented thereby updating weights of items i in sample S. The method is repeated until no more items are received.
    Type: Application
    Filed: December 1, 2008
    Publication date: June 3, 2010
    Applicant: AT&T INTELLECTUAL PROPERTY I, LP
    Inventors: Nicholas Duffield, Carsten Lund, Mikkel Thorup, Edith Cohen, Haim Kaplan
  • Publication number: 20100115604
    Abstract: Methods and apparatus to dynamically control access from VPNs to shared resources are disclosed. A disclosed example route reflector comprises a memory to implement a database, a user interface module to receive a request to permit access for a VPN to a shared resource, a BGP engine to process BGP advertisements, a network interface to receive a first BGP advertisement from a PE router associated with the VPN that includes a first RT associated with the VPN, and a shared resource access controller to update the database based on the request, to query the database to determine whether the VPN has access to the shared resource in response to the first BGP advertisement, and to direct the BGP engine to form a second BGP advertisement based on the first BGP advertisement that includes a second RT associated with the shared resource when the VPN has access to the shared resource.
    Type: Application
    Filed: October 31, 2008
    Publication date: May 6, 2010
    Inventors: Alexandre Gerber, Carsten Lund, Jacobus Van der Merwe, Michael Satterlee
  • Publication number: 20090316590
    Abstract: The preferred embodiments of the present invention can include sampling packets transmitted over a network based on the content of the packets. If a packet is sampled, the sampling unit can add one or more fields to the sampled packet that can include a field for a number of bytes contained in the packet, a packet count, a flow count, a sampling type, and the like. The sampled packets can be analyzed to discern desired information from the packets. The additional fields that are added to the sampled packets can be used during the analysis.
    Type: Application
    Filed: May 13, 2008
    Publication date: December 24, 2009
    Applicant: AT&T LABORATORIES, INC.
    Inventors: Carsten Lund, Edith Cohen, Nicholas Duffield, Alexandre Gerber, Adam Hersh, Oliver Spatscheck, Mikkel Thorup, Frederick True
  • Publication number: 20090303879
    Abstract: The invention relates to streaming algorithms useful for obtaining summaries over unaggregated packet streams and for providing unbiased estimators for characteristics, such as, the amount of traffic that belongs to a specified subpopulation of flows. Packets are sampled from a packet stream and aggregated into flows and counted by implementation of: (a) Adaptive Sampled NetFlow (ANF), and adjusted weight (AANF) of a flow (f) is calculated as follows: AANF(f)=i(f)/p?; i(f) being the number of packets counted for a flow f, and p? being the sampling rate at end of a measurement period; or (b) Adaptive Sample-and-Hold (ASH), and adjusted weight (AASH) of a flow (f) is calculated as follows: AASH(f)=i(f)+(1?p?)/p?; i(f) being the number of packets counted for a flow f, and p? being the sampling rate at end of a measurement period.
    Type: Application
    Filed: June 10, 2008
    Publication date: December 10, 2009
    Inventors: Nicholas Duffield, Edith Cohen, Haim Kaplan, Carsten Lund, Mikkel Thorup
  • Publication number: 20090303901
    Abstract: The invention relates to streaming algorithms useful for obtaining summaries over unaggregated packet streams and for providing unbiased estimators for characteristics, such as, the amount of traffic that belongs to a specified subpopulation of flows. Packets are sampled from a packet stream and aggregated into flows and counted by implementation of Adaptive Sample-and-Hold (ASH) or Adaptive NetFlow (ANF), adjusting the sampling rate based on a quantity of flows to obtain a sketch having a predetermined size, the sampling rate being adjusted in steps; and transferring the count of aggregated packets from SRAM to DRAM and initializing the count in SRAM following adjustment of the sampling rate.
    Type: Application
    Filed: June 10, 2008
    Publication date: December 10, 2009
    Inventors: Nicholas Duffield, Edith Cohen, Haim Kaplan, Carsten Lund, Mikkel Thorup
  • Publication number: 20090299288
    Abstract: The present invention relates to methods and devices for providing a reduced risk of free flow from medical devices such as an infusion pump. A medicament containing reservoir is provided with a piston having a sealing portion formed by a material of a first stiffness. The piston further comprises a frictional enhancing member having one or more reservoir wall engaging portions and being at least partly made of a material having a stiffness greater than the first stiffness. By arranging the frictional enhancing member to exert a radially outwards directed force component against the cylindrical wall an increased friction is provided between the piston and the reservoir wall.
    Type: Application
    Filed: April 19, 2007
    Publication date: December 3, 2009
    Applicant: Novo Nordisk AG
    Inventors: Gunnar Monrad Sie, Carsten Lund
  • Publication number: 20090296714
    Abstract: Example scalable multi-protocol label switching (MPLS) based virtual private networks (VPNs) and methods to implement the same are disclosed. A disclosed example spoke provider edge (PE) router for an MPLS-based VPN includes a truncated virtual routing and forwarding (VRF) table containing a first value referencing a hub PE router and a second value referencing a first customer edge (CE) router coupled to the VPN via the PE router, and a forwarding module to forward a packet received from the first CE router to the hub PE router when the packet contains an address referencing a second CE router coupled to the VPN via a second spoke PE router.
    Type: Application
    Filed: May 30, 2008
    Publication date: December 3, 2009
    Inventors: Alexandre Gerber, Subhabrata Sen, Carsten Lund, Dan Pei, MohammadTaghi Hajiaghayi, Changhoon Kim
  • Publication number: 20090254638
    Abstract: A method of assigning a server to a client system includes determining an ingress point of the client system and identifying possible egress points for the client system. The method further includes selecting the server from a plurality of servers to reduce network cost and delivery time.
    Type: Application
    Filed: December 23, 2008
    Publication date: October 8, 2009
    Applicant: AT&T INTELLECTUAL PROPERTY I, L.P.
    Inventors: Oliver Spatscheck, David L. Applegate, Alexandre Gerber, Carsten Lund
  • Publication number: 20090177159
    Abstract: The present application relates to methods and devices for providing a reduced risk of free flow from medical devices such as an infusion pump. A medicament containing reservoir (100) is provided with a piston having a sealing portion (121) formed by a material of a first stiffness. The piston further comprises a core member (110) of a material having a stiffness larger than said first stiffness, the core member comprising one or more connective members (111) being adapted to cooperate with said one or more protrusions of the linear actuation member. The one or more connective members being adapted to be substantially rigid in the axial direction while being resilient in a radial direction, thereby forming a releasable snap or friction fit connection with the linear actuation member.
    Type: Application
    Filed: April 19, 2007
    Publication date: July 9, 2009
    Inventors: Helene Juhldal Knopper, Carsten Lund
  • 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