Patents Assigned to Cisco Systems, Inc.
  • Patent number: 7216175
    Abstract: A system for determining subscriber information includes an access server coupled to a number of subscribers using a communication network, a memory coupled to the access server, and a processor coupled to the memory. The access server receives a communication from a particular subscriber using a particular one of a number of virtual circuits associated with the communication network. The memory stores subscriber information for the subscribers, wherein the subscriber information is indexed by path information that identifies a virtual circuit assigned to the particular subscriber. The processor determines subscriber information for communication to the particular subscriber based upon the path information and the particular virtual circuit used to receive communication from the particular subscriber.
    Type: Grant
    Filed: January 20, 2000
    Date of Patent: May 8, 2007
    Assignee: Cisco Systems, Inc.
    Inventors: Aravind Sitaraman, Dennis J. Cox, John A. Joyce, Shujin Zhang
  • Patent number: 7206922
    Abstract: The present invention provides a processor with an instruction memory hierarchy and a method for distributing instructions to an array of multithreaded processing units organized in processor clusters. The instruction memory hierarchy comprises a processor cluster, an instruction request bus, an instruction request arbiter, and an instruction memory. The instruction request arbiter controls submissions of instruction requests from multithreaded processing units within the processor clusters to the instruction memory. The processor clusters send instruction requests responsive to a cache miss by a processor, or processor thread, within the processor cluster. The instruction request arbiter resolves conflicts between instruction requests attempting to access to a common cache set within the instruction memory. The instruction memory broadcasts instruction data to the processor clusters responsive to non-conflicting instruction requests forwarded from the instruction request arbiter.
    Type: Grant
    Filed: December 30, 2003
    Date of Patent: April 17, 2007
    Assignee: Cisco Systems, Inc.
    Inventor: Donald Steiss
  • Patent number: 7119577
    Abstract: A method and apparatus for efficient implementation and evaluation of state machines and programmable finite state automata is described. In one embodiment, a state machine architecture comprises a plurality of node elements, wherein each of the plurality of node elements represents a node of a control flow graph. The state machine architecture also comprises a plurality of interconnections to connect node elements, a plurality of state transition connectivity control logic to enable and disable connections within the plurality of interconnections to form the control flow graph with the plurality of node elements, and a plurality of state transition evaluation logic coupled to the interconnections and operable to evaluate input data against criteria, the plurality of state transition evaluation logic to control one or more state transitions between node elements in the control flow graph.
    Type: Grant
    Filed: August 27, 2003
    Date of Patent: October 10, 2006
    Assignee: Cisco Systems, Inc.
    Inventor: Harshvardhan Sharangpani
  • Patent number: 7085918
    Abstract: Embodiments of the invention provide a programmable FSA building block, having a number of programmable registers and associated logic implemented therein, that provide the capability of contextually evaluating complex REs of arbitrary size against multiple data streams. Embodiments of the invention provide fully programmable hardware in which all of the states of an RE are instantiated and all of the states are fully connected. For one embodiment, the building blocks have a fixed number of states to facilitate implementation on a chip. For such an embodiment, an RE having an excessive number of states is implemented on two or more FSA building blocks and the FSA building blocks are then stitched together to effect evaluation of the RE. For one embodiment, two or more REs having a number of states less than the fixed number of states of a building block may be implemented with a single building block.
    Type: Grant
    Filed: January 8, 2004
    Date of Patent: August 1, 2006
    Assignee: Cisco Systems, Inc.
    Inventors: Harshvardan Sharangpani, Manoj Khare, Kent Fielden, Rajesh Patil, Judge Kennedy Arora
  • Patent number: 7039716
    Abstract: Devices, software and methods are provided for encoding voice data to conceal packet loss. In addition to regular encoding, an abbreviated portion of the frame is encoded, and transmitted redundantly afterwards. Optionally the redundant encoding is in relation to an attribute of the sound represented by the data. The attribute of the sound can be pitch information, peak information, or bandwidth information.
    Type: Grant
    Filed: October 30, 2000
    Date of Patent: May 2, 2006
    Assignee: Cisco Systems, Inc.
    Inventor: Ramanathan Jagadeesan
  • Patent number: 7035262
    Abstract: A system and method are disclosed for using standard issue synchronous optical network (SONET) framers to comply with current automatic protection system (APS) standards. Each standard framer includes its own section, line, and path layer termination. The working set of lines and protection set of lines of the APS system are switched after the path layer rather than before. A firmware solution allows for a proper use of various error indication signals.
    Type: Grant
    Filed: December 19, 2001
    Date of Patent: April 25, 2006
    Assignee: Cisco Systems, Inc.
    Inventor: Aniruddha Joshi
  • Patent number: 7012901
    Abstract: Devices, software and methods are provided for generating aggregate comfort noise for teleconferencing over IP networks. A transcoding component includes a decoder for decoding streams of packets. A summing component has a summer with summing inputs to receive the decoded streams of packets. The summing component has at least one silence flag input, and an additional signaling path is used by the transcoding component to signal to the silence flag input if any of the decoded streams of packets includes a silence identification packet. In another embodiment, the summing component may or may not include the silence flag input, but the device includes an aggregate comfort noise generation component. The aggregate comfort noise may be programmed to be a balanced representation of all background noises.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: March 14, 2006
    Assignee: Cisco Systems, Inc.
    Inventors: Ramanathan Jagadeesan, Luke K. Surazski
  • Patent number: 6957358
    Abstract: A system and method are disclosed for dividing a network into clock partitions to limit the overhead created by transmitting clock sources. A clock partition can be implemented through several methods. A first method turns off the clock topology exchange on ports connected to the nodes outside the partition. A second method appends a four-byte partition identifier to network clock distribution protocol (NCDP) messages. A third method uses private network-network interface (PNNI) peer group identification to determine the clock partition group.
    Type: Grant
    Filed: January 28, 2002
    Date of Patent: October 18, 2005
    Assignee: Cisco Systems, Inc.
    Inventors: Krishna Sundaresan, Chandrasekar Krishnamurthy, Mahesh Chellappa
  • Patent number: 6950213
    Abstract: In accordance with an embodiment of the present invention, a fax decoding/re-encoding system for transferring fax images between a sending fax machine and a receiving fax machine includes a decoder responsive to an encoded fax image defined by rows of scan lines. The decoder decodes the scan lines of the encoded fax image and generates run-length representation of the encoded fax image. A scanline manipulation device is responsive to the run-length representation for manipulating the same and generating a manipulated fax image without generating a bitmap of the encoded fax image. The fax decoding/re-encoding system further including a re-encoder responsive to said manipulated fax image and adaptive to generate a re-encoded fax image that is substantially the same as the encoded fax image, wherein the fax decoding/re-encoding system avoids the need for a bitmap for generating a re-encoded fax image thereby substantially reducing re-encoding time.
    Type: Grant
    Filed: December 20, 2000
    Date of Patent: September 27, 2005
    Assignee: Cisco Systems, Inc.
    Inventor: Vladimir Alexandrovich Gurevich
  • Patent number: 6948044
    Abstract: Methods and apparatus are provided improving data access efficiency in a storage area network. Mechanisms are provided to allow a virtual disk address to be efficiently mapped to a particular physical partition in a virtual disk while recognizing the mirroring, striping, and concatenation characteristics associated with the virtual disk. A variety of indices are used to allow direct access of a physical partition upon identification of a virtual disk address.
    Type: Grant
    Filed: July 30, 2002
    Date of Patent: September 20, 2005
    Assignee: Cisco Systems, Inc.
    Inventor: Varagur V. Chandrasekaran
  • Patent number: 6931101
    Abstract: Provided is a method and apparatus for inband testing of an echo canceller. The apparatus includes a signal generator for generating an excitation signal including a preamble portion and a test portion. The echo canceller receives the excitation signal at a decoder. The decoder differentiates the preamble from the test portion and obtains control information by decoding the preamble portion. A controller configures the echo canceller during testing according to the control information obtained from the preamble portion. A strength of the present invention is that the preamble portion allows precise control of the echo canceller during testing by synchronizing the test control to the location of the preamble. This allows exacting control of the echo canceller during testing to within a single sample time of the excitation signal, e.g., 125 microseconds.
    Type: Grant
    Filed: May 26, 2000
    Date of Patent: August 16, 2005
    Assignee: Cisco Systems, Inc.
    Inventor: Herbert M. Wildfeuer
  • Patent number: 6888801
    Abstract: Devices, software and methods are provided for determining a quality of service for a Voice over Internet Protocol (VoIP) connection. A round trip time of packets is measured between the devices that are exchanging voice data. In addition, at least one performance parameter is determined, such as packet delay or packet loss. A quality of service is then determined from the round trip time and the performance parameter.
    Type: Grant
    Filed: October 27, 2000
    Date of Patent: May 3, 2005
    Assignee: Cisco Systems, Inc.
    Inventor: Thomas J. Hock
  • Patent number: 6832279
    Abstract: An apparatus and technique off-loads responsibility for maintaining order among requests directed to a same address on a split transaction bus from a processor to a split transaction bus controller, thereby increasing the performance of the processor. The present invention comprises an ordering circuit that enables the controller to defer issuing a subsequent (write) request directed to an address on the bus until a previous (read) request directed to the same address completes. By off-loading responsibility for maintaining order among requests from the processor to the controller, the invention enhances performance of the processor since the processor may proceed with program execution without having to stall to ensure such ordering. The ordering circuit maintains ordering in an efficient manner that is transparent to the processor.
    Type: Grant
    Filed: May 17, 2001
    Date of Patent: December 14, 2004
    Assignee: Cisco Systems, Inc.
    Inventors: Kenneth H. Potter, Trevor Garner
  • Patent number: 6831898
    Abstract: The invention replicates a packet requiring high availability and transmits it from two or more ports of a switch, for example a wiring closet Layer 2 switch. The parent packet carries a unique sequence number. The copies of the packet each carry the parent packet's unique sequence number. Each copy of the packet then travels on separate pathways through routers (Layer 3 network devices). The pathways are maintained separate by assigning high costs in a LSP routing sense to links connecting the two paths, and by assigning low costs to links along the desired paths. The two identical packets converge on the destination station. The destination station accepts the first packet with a particular sequence number, and discards any later packets with the same sequence number. In the event that a link in one path has a catastrophic failure, then the packet travelling along the other path reaches the destination station and service remains operative without interruption.
    Type: Grant
    Filed: August 16, 2000
    Date of Patent: December 14, 2004
    Assignee: Cisco Systems, Inc.
    Inventors: Thomas J. Edsall, Silvano Gai, Soei-Shin Hang
  • Patent number: 6792457
    Abstract: A method and apparatus for providing computer network access points the capability for multiple-level accounting. A gateway device located at the access point is capable of generating Internet protocol accounting start and stop requests based on various events that need to be accounted for when a user accesses a network. These events include the user account logon, the service establishments and the Point to Point protocol (PPP) connections between the gateway device and public and private domains within the network. The counter is capable of tracking the duration of sessions and connections and the byte-count associated with the specified session or connection. The gateway device communicates with an accounting server which stores the accounting requests and matches start requests with subsequent stop requests.
    Type: Grant
    Filed: June 7, 2000
    Date of Patent: September 14, 2004
    Assignee: Cisco Systems, Inc.
    Inventors: Shujin Zhang, Shuxian Lou, Roman Peter Kochan, Aravind Sitaraman
  • Patent number: 6729929
    Abstract: A communications system extending over a cellular region and formed of a plurality of wireless cells. The communications system extends over a cellular region formed of a plurality of wireless cells. Each cell covers an area which includes a portion of the cellular region. Each particular cell includes a base station having a transmitter for transmitting a particular cell signal having parameters including a transmitting frequency and a transmitting power. The particular cell signal is transmitted to cover a portion of the cell region. Each of the base stations includes a parameter detector for detecting the other parameters of the other cell signals from the other cells in the cellular region. A parameter controller controls the particular parameters for the particular cell. The parameters for the particular cell are based upon the other parameters for the other cell signals so that the particular cell signal does not interfere with the other cell signals in the cellular region.
    Type: Grant
    Filed: March 17, 1999
    Date of Patent: May 4, 2004
    Assignee: Cisco Systems, Inc.
    Inventors: Ian Leslie Sayers, Paul Jan Long, Peter Kendall Cripps
  • Patent number: 6704883
    Abstract: A distributed computer network testing system includes a test controller and at least one test agent. One or more test agents are configured with interpreters configured to execute instructions contained in a test script. When the test begins, the test controller publishes the test script to an event engine that broadcasts the script on the network. Test agents subscribing to the test script receive the script. Script receipt is the event that triggers test script execution by each interpreter on each subscribing test agent. Each test agent sends test results to the test controller that, in turn, sends all results to a test analysis agent. The analysis agent analyzes the test results and produces a test report that is output to the user.
    Type: Grant
    Filed: December 22, 1999
    Date of Patent: March 9, 2004
    Assignee: Cisco Systems, Inc.
    Inventors: Chen Zhang, Donald T. Wooton
  • Publication number: 20040039820
    Abstract: A content-aware flow switch intercepts a client content request in an IP network, and transparently directs the content request to a best-fit server. The best-fit server is chosen based on the type of content requested, the quality of service requirements implied by the content request, the degree of load on available servers, network congestion information, and the proximity of the client to available servers. The flow switch detects client-server flows based on the arrival of TCP SYNs and/or HTTP GETs from the client. The flow switch implicitly deduces the quality of service requirements of a flow based on the content of the flow. The flow switch also provides the functionality of multiple physical web servers on a single web server in a way that is transparent to the client, through the use of virtual web hosts and flow pipes.
    Type: Application
    Filed: July 17, 2002
    Publication date: February 26, 2004
    Applicant: Cisco Systems, Inc.
    Inventors: Steven Colby, John J. Krawczyk, Raj Krishnan Nair, Katherine Royce, Kenneth P. Siegel, Richard C. Stevens, Scott Wasson
  • Patent number: 6611624
    Abstract: A system for performing frame accurate bitstream splicing includes a first pre-buffer, a second pre-buffer, a seamless splicer, and a post-buffer. The system also includes a time stamp extractor, a time stamp adjuster, and a time stamp replacer for timing correction. The first and second pre-buffers are input buffers to the seamless splicer, and the post-buffer is coupled to the output of the seamless splicer. The seamless splicer receives the two streams via the first and second pre-buffers and produces a single spliced bitstream at its output in response to the cue tone signal. The seamless splicer provides the first bitstream, then re-encodes portions of the first and second bit streams proximate the splicing points (both the exit point and the entry point), and then switches to providing a second bitstream. The seamless splicer also performs rate conversion on the second stream as necessary to ensure decoder buffer compliance for the spliced bitstream.
    Type: Grant
    Filed: October 15, 1998
    Date of Patent: August 26, 2003
    Assignee: Cisco Systems, Inc.
    Inventors: Ji Zhang, Yi Tong Tse
  • Patent number: 6606681
    Abstract: A method and apparatus for realizing a content addressable memory. The content addressable memory including an associative memory portion including N entries, each entry including a key and an M-bit type indicator. The content addressable memory further including a random access memory portion. The random access memory portion includes K*N entries where a single key stored as an entry in the associative memory portion is mapped to K entries in the random access memory portion, where K is greater than 1.
    Type: Grant
    Filed: February 23, 2001
    Date of Patent: August 12, 2003
    Assignee: Cisco Systems, Inc.
    Inventor: Necdet Uzun