Patents by Inventor Kadangode K. Ramakrishnan

Kadangode K. Ramakrishnan 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: 8107479
    Abstract: A system and method for providing telephony and high-speed data access over a broadband access network, comprising a network interface unit (NIU) coupled to a backup local exchange carrier (LEC) line, the broadband access network coupled to the NIU, an intermediate point-of-presence (IPOP) coupled to the broadband access network, and at least one external access network coupled to the IPOP. The system also provides for a fail-safe mode in which the NIU supports the LEC line for lifeline services.
    Type: Grant
    Filed: November 10, 2003
    Date of Patent: January 31, 2012
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Steven Michael Bellovin, Joseph Henry Condon, Richard Vandervoort Cox, Alexander Gibson Fraser, Charles Robert Kalmanek, Jr., Alan Edward Kaplan, Thomas Joseph Killian, William Todd Marshall, Peter Z. Onufryk, Kadangode K. Ramakrishnan, Norman Loren Schryer
  • Patent number: 8108544
    Abstract: A method of obtaining content includes receiving a playfile. The playfile includes a chunk ID corresponding to a chunk of the content, a packet ID corresponding to a packet of the chunk, and a hash of the packet. The method further includes obtaining the chunk from a peer, determining a calculated hash for the packet, and discarding the chunk when the calculated hash does not match the hash in the playfile.
    Type: Grant
    Filed: December 10, 2008
    Date of Patent: January 31, 2012
    Assignee: AT&T Intellectual Property I, LP
    Inventors: Kadangode K. Ramakrishnan, Vijay Gopalakrishnan, Fang Yu
  • Publication number: 20110286342
    Abstract: Methods and apparatus to route packets in a network are disclosed. A disclosed example method includes receiving a packet in a packet aggregator, accessing a forwarding table to determine a router within a router array to which the packet is to be forwarded, transmitting the packet to the determined router via a first interface of the packet aggregator, identifying a second interface within the router to which the packet is to be forwarded, forwarding the packet from the router via the second interface to a virtual interface within the packet aggregator, and statically forwarding the packet from the packet aggregator to a destination based on the virtual interface that received the packet.
    Type: Application
    Filed: May 24, 2010
    Publication date: November 24, 2011
    Inventors: Cheng Tien Ee, Lee M. Breslau, Kadangode K. Ramakrishnan
  • Publication number: 20110286457
    Abstract: Methods and apparatus to route control packets based on address partitioning. A disclosed example method includes receiving a packet in a server, determining the packet is a control packet, forwarding the packet to a processor, identifying via the processor an address prefix of the packet, accessing a forwarding table and determining via the processor at least one of a router or an outgoing interface that corresponds to the identified address prefix, transmitting the packet from the processor to the server via the outgoing interface, and statically forwarding the packet from the server to the router based on an interface that received the packet from the processor.
    Type: Application
    Filed: May 24, 2010
    Publication date: November 24, 2011
    Inventors: Cheng Tien Ee, Lee M. Breslau, Kadangode K. Ramakrishnan
  • Patent number: 8064446
    Abstract: A method and system are described to multicast with an adaptive dual state. The system receives multicast traffic over a membership tree including a first plurality of nodes connected in a first topology destined for a plurality of multicast members of a first multicast group. Next, the system determines a rate of multicast traffic that exceeds a predetermined threshold based on the receiving the multicast traffic. Next, the system generates a dissemination tree including a second plurality of nodes connected in a second topology to reduce a number of hops to communicate the multicast traffic to the plurality of multicast members of the first multicast group. Finally, the system forwards the multicast traffic to the plurality of multicast members of the first multicast group over the dissemination tree.
    Type: Grant
    Filed: April 1, 2008
    Date of Patent: November 22, 2011
    Assignee: AT&T Intellectual Property I, L.P.
    Inventors: Kadangode K. Ramakrishnan, Divesh Srivastava, Tae W. Cho, Yin Zhang, Michael Rabinovich
  • Patent number: 8031627
    Abstract: Example methods and apparatus to deploy and monitor network layer functionalities are disclosed. A disclosed example method includes receiving an Internet Protocol (IP) packet at an input of a server, the IP packet being received from a communicatively coupled router, identifying the IP packet as a production IP packet or a non-production IP packets, when the IP packet is the non-production IP packet, manipulating data within the IP packet to monitor network layer functionality, forwarding the manipulated non-production IP packet to the router, and when the IP packet is the production IP packet, forwarding the production IP packet to the router without manipulating data within the IP packet.
    Type: Grant
    Filed: December 24, 2008
    Date of Patent: October 4, 2011
    Assignee: AT&T Intellectual Property I, L.P.
    Inventors: Cheng Tien Ee, Lee M. Breslau, Kadangode K. Ramakrishnan
  • Publication number: 20110231661
    Abstract: A method for transferring content includes requesting the content from a serving peer and sending the content to a requesting peer. Requesting the content includes sending a request to a tracker, receiving a request token, a path identifier, and a first peer identifier from the tracker, and sending a request message to a second peer. The first peer identifier includes an identity of a first peer, and the request message includes the request token, the path identifier, and the first peer identifier. Sending the content includes receiving the request token and the path identifier from a third peer, sending a return message to a fourth peer, and transferring the content from the serving peer to the requesting peer through a transfer path. The return message includes the path identifier and a second peer identifier. The second peer identifier includes an identity of a fifth peer. The transfer path includes at least the second, fourth, and fifth peers.
    Type: Application
    Filed: March 22, 2010
    Publication date: September 22, 2011
    Applicant: AT&T INTELLECTUAL PROPERTY I, L.P.
    Inventors: Kadangode K. Ramakrishnan, Vijay Gopalakrishnan, Fang Yu, David Lee
  • Patent number: 7957404
    Abstract: Signaling messages are exchanged for a call between a calling party to a called party. A setup message for the call is exchanged through at least one gate controller. Network resources are reserved for the call based on the exchanged setup messages. An end-to-end message for the call is exchanged without the end-to-end message being routed through the at least one gate controller.
    Type: Grant
    Filed: October 25, 2007
    Date of Patent: June 7, 2011
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Pawan Goyal, Albert Gordon Greenberg, Partho Pratim Mishra, Kadangode K. Ramakrishnan
  • Publication number: 20110122764
    Abstract: A second link in a network is reconfigured after failure of a first link, so that multiple-link failures may be survived. After receipt of an OSPF link state advertisement (LSA) indicating use of a backup path bl after the failure of link l, new backup paths are determined for each impacted link (x,y) that has a backup path sharing one or more links with the backup path bl. The new backup paths are computed while ignoring the failed link l, the impacted link (x,y), and links common to the backup paths b(x,y) and bl. The LSA protocol is modified to accommodate information used in determining whether a link is an impacted link.
    Type: Application
    Filed: November 24, 2009
    Publication date: May 26, 2011
    Inventors: Kadangode K. Ramakrishnan, Rakesh Kumar Sinha, Ajay Kumar Todimala
  • Patent number: 7944844
    Abstract: Example methods and apparatus to monitor network layer functionalities are disclosed. A disclosed example method includes receiving a first probe packet at an input of a first server, the first probe packet being received from a router, the first probe packet being generated and transmitted from a second server that is one-hop away from the first server in a network, determining if the first server is a final destination of the first probe packet, and if the first server is not the final destination of the first probe packet, generating a second probe packet and transmitting the second probe packet to the router for transmission toward the final destination.
    Type: Grant
    Filed: December 24, 2008
    Date of Patent: May 17, 2011
    Assignee: AT&T Intellectual Property I, L.P.
    Inventors: Cheng Tien Ee, Lee M. Breslau, Kadangode K. Ramakrishnan
  • Publication number: 20110106961
    Abstract: A content delivery system includes a unicast content delivery module, a multicast content delivery module, and a content monitor module. The unicast content delivery module is configured to provide content using a unicast protocol, and the multicast content delivery module is configured to provide the content using a multicast protocol. The content monitor module is configured to receive requests from a plurality of clients for the content, count the requests to determine if the number of requests exceeds a threshold, and instruct the plurality of clients to receive the content from the multicast content delivery module when the number of requests exceeds the threshold.
    Type: Application
    Filed: October 29, 2009
    Publication date: May 5, 2011
    Applicant: AT&T INTELLECTUAL PROPERTY I, L.P.
    Inventors: Alan L. Glasser, Andrew G. Gauld, Vijay Gopalakrishnan, John F. Lucas, Kadangode K. Ramakrishnan
  • Publication number: 20110099437
    Abstract: A particular device includes a transmitter. The transmitter is adapted to estimate a packet erasure rate for packets of a data window to be transmitted to a receiver. The transmitter is adapted to determine a number of proactive forward error control (FEC) packets for the data window based on the estimated packet erasure rate. The transmitter is adapted to determine a packet size for the packets in the data window based on a window size of the data window and the determined number of proactive FEC packets. The transmitter is also adapted to transmit the data window to the receiver. The packets in the transmitted data window have a size corresponding to the determined packet size and include the determined number of proactive FEC packets.
    Type: Application
    Filed: January 4, 2011
    Publication date: April 28, 2011
    Applicants: AT&T INTELLECTUAL PROPERTY II, L.P. (fka AT&T Corp.), RENSSELAER POLYTECHNIC INSTITUTE
    Inventors: Kadangode K. Ramakrishnan, Shivkumar Kalyanaraman, Vijaynarayanan Subramanian, Omesh Tickoo
  • Patent number: 7929527
    Abstract: A transport protocol that achieves improved performance in an environment where paths are lossy and a plurality of paths are employed to transfer data, essentially in parallel, from a source to a destination. The protocol is implemented with the aid of an aggregate flow manager (AFM) at the source that considers and controls the data flow through the plurality of paths. With some preselected regularity the AFM determines a number of packets to be included in a Forward Error Correction (FEC) block of packets, creates the block, and transmits the segments of the block over the plurality of paths. As necessary, the destination sends information to the source of what additional information needs to be sent. This additional information might be reactive error correcting (RFEC) packets, or a retransmission of the missed packets.
    Type: Grant
    Filed: April 18, 2008
    Date of Patent: April 19, 2011
    Inventors: Kadangode K. Ramakrishnan, Shivkumar Kalyanaraman, Koushik Kar, Vicky Sharma, Vijaynarayanan Subramanian
  • Patent number: 7907522
    Abstract: Method and apparatus for effectively supporting resource allocation and admission control of a Virtual Private Network in a service provider network.
    Type: Grant
    Filed: May 16, 2008
    Date of Patent: March 15, 2011
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Satish Raghunath, Kadangode K. Ramakrishnan
  • Patent number: 7903564
    Abstract: A method and apparatus for increasing the capability of a network topology model having a plurality of nodes connected by existing links to maintain service continuity in the presence of faults. The steps of the method include adding new links to the network topology model to protect against single node failures, and adjusting link weights for the network topology model to reduce at least one of a cost of network operation and an imbalance in link utilizations. Preferably, the link weights are adjusted to reduce the imbalance in link utilizations without deteriorating the cost of network operation. The link weights are preferably adjusted to reduce the cost of network operation without increasing the imbalance in link utilizations. Preferably, the link weights are adjusted to reduce the cost of network operation without increasing the imbalance in link utilizations while keeping the utilization for each link below a specific threshold.
    Type: Grant
    Filed: December 21, 2009
    Date of Patent: March 8, 2011
    Assignee: AT&T Property II, L.P.
    Inventors: Kadangode K. Ramakrishnan, Mukul Goyal
  • Patent number: 7889654
    Abstract: Provided are apparatuses and methods for transmitting or receiving data packets in a data block in a communication network with a transport protocol. In one example, a loss tolerant TCP protocol is used in which a maximum segment size (MSS) may be adapted to a minimum granularity of a congestion window. Also, proactive forward error correction (FEC) packets may be added to a window of the data block. The number of proactive FEC packets may be determined, for example, based on an estimate erasure rate. In addition, reactive FEC packets may be added to the data block. Also, a receiver may receive data packets in a data block and process a selective acknowledgment (SACK) responsive to the data packets received.
    Type: Grant
    Filed: December 1, 2005
    Date of Patent: February 15, 2011
    Assignees: AT&T Intellectual Property II, L.P., Rensselaer Polytechnic Institute
    Inventors: Kadangode K. Ramakrishnan, Shivkumar Kalyanaraman, Vijaynarayanan Subramanian, Omesh Tickoo
  • Publication number: 20100316046
    Abstract: Network resources for a call between a calling party and a called party are allocated. The network resources for the call are reserved based on a reservation request. The network resources are reserved before any one network resource from the reserved network resources is committed. The reserved network resources for the call are committed when a called party indicates acceptance for the call.
    Type: Application
    Filed: August 13, 2010
    Publication date: December 16, 2010
    Inventors: Charles Robert Kalmanek, JR., William Todd Marshall, Partho Pratim Mishra, Douglas M. Nortz, Kadangode K. Ramakrishnan
  • Publication number: 20100313251
    Abstract: A method of configuring a network access device connected to an access network connected to a plurality of service networks, the network device having a first network address allocated to a subscriber of services of a first service provider provided by a first service network, with a new network address allocated to a second subscriber of services of either the first service provider, or a second service provider provided by a second service network. The method comprises the steps of: sending a request from the network access device to the access network with user credentials for the second subscriber requesting access to the first service provider or a change to the second service provider; receiving a response from the access network; and initiating a network address change request using a configuration protocol.
    Type: Application
    Filed: August 16, 2010
    Publication date: December 9, 2010
    Applicant: AT&T Intellectual Property II, L.P.
    Inventors: Sean E. Carolan, John W. Garrett, Charles Robert Kalmanek, JR., Han Q. Nguyen, Kadangode K. Ramakrishnan
  • Patent number: 7808968
    Abstract: The present invention discloses an efficient architecture for routing in a very large autonomous system where many of the layer 3 routers are attached to a common connection-oriented layer 2 subnetwork, such as an ATM network. In a preferred embodiment of the invention, a permanent topology of routers coupled to the subnetwork is connected by permanent virtual circuits. The routers can further take advantage of both intra-area and inter-area shortcuts through the layer 2 network to improve network performance. The routers pre-calculate shortcuts using information from link state packets broadcast by other routers and store the shortcuts to a given destination in a forwarding table, along with corresponding entries for a next hop along the permanent topology. The present invention allows the network to continue to operate correctly if layer 2 resource limitations preclude the setup of additional shortcuts.
    Type: Grant
    Filed: January 29, 2004
    Date of Patent: October 5, 2010
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Charles Robert Kalmanek, Jr., Anthony G Lauck, Kadangode K. Ramakrishnan
  • Patent number: 7801056
    Abstract: A method of configuring a network access device connected to an access network connected to a plurality of service networks, the network device having a first network address allocated to a subscriber of services of a first service provider provided by a first service network, with a new network address allocated to a second subscriber of services of either the first service provider, or a second service provider provided by a second service network. The method comprises the steps of: sending a request from the network access device to the access network with user credentials for the second subscriber requesting access to the first service provider or a change to the second service provider; receiving a response from the access network; and initiating a network address change request using a configuration protocol.
    Type: Grant
    Filed: December 29, 2005
    Date of Patent: September 21, 2010
    Assignee: AT&T Intellectual Property II, L.P.
    Inventors: Sean E. Carolan, John W. Garrett, Charles Robert Kalmanek, Jr., Han Q. Nguyen, Kadangode K. Ramakrishnan