Patents by Inventor Varadarajan Srinivasan

Varadarajan Srinivasan 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: 10693894
    Abstract: Upon receiving malware detection rules that are to be identified with respect to an input traffic stream, a sequence of state definitions are generated for each of the rules. The state definitions for each rule correspond to respective segments of the rule and specify conditions under which a state machine is to transition between search states corresponding to those segments, at least one of the segments corresponding to multiple characters within the input traffic stream. A state machine transitions between search states corresponding to one or more of the rules in accordance with contents of the input traffic stream and the conditions specified by the sequence of state definitions.
    Type: Grant
    Filed: January 15, 2019
    Date of Patent: June 23, 2020
    Assignee: Redberry Systems, Inc.
    Inventors: Sandeep Khanna, Varadarajan Srinivasan, Madhavan Bakthavatchalam
  • Patent number: 10218721
    Abstract: Upon receiving malware detection rules that are to be identified with respect to an input traffic stream, a sequence of state definitions are generated for each of the rules. The state definitions for each rule correspond to respective segments of the rule and specify conditions under which a state machine is to transition between search states corresponding to those segments, at least one of the segments corresponding to multiple characters within the input traffic stream. A state machine transitions between search states corresponding to one or more of the rules in accordance with contents of the input traffic stream and the conditions specified by the sequence of state definitions.
    Type: Grant
    Filed: April 3, 2018
    Date of Patent: February 26, 2019
    Assignee: Redberry Systems, Inc.
    Inventors: Sandeep Khanna, Varadarajan Srinivasan, Madhavan Bakthavatchalam
  • Patent number: 10033750
    Abstract: In a malware detection device, first characters in a network traffic flow are compared with a plurality of entries within a ternary content addressable memory (TCAM), the plurality of entries including a first entry that constitutes a first segment of a malware signature. In response to an output from the first TCAM indicating that the first characters match the first entry, a variable-character expression engine determines whether second characters in the network traffic flow match a first variable-length regular expression, the variable-length regular expression corresponding to a second segment of the malware signature. A comparand value is generated that includes third characters in the network traffic flow and an expression-match value that indicates whether the second characters match the first variable-length regular expression. The TCAM compares the first comparand value with the plurality of entries therein as part of a determination whether the network traffic flow contains the malware signature.
    Type: Grant
    Filed: December 5, 2017
    Date of Patent: July 24, 2018
    Assignee: Redberry Systems, Inc.
    Inventors: Madhavan Bakthavatchalam, Varadarajan Srinivasan, Sandeep Khanna
  • Patent number: 9967272
    Abstract: Upon receiving malware detection rules that are to be identified with respect to an input traffic stream, a sequence of state definitions are generated for each of the rules. The state definitions for each rule correspond to respective segments of the rule and specify conditions under which a state machine is to transition between search states corresponding to those segments, at least one of the segments corresponding to multiple characters within the input traffic stream. A state machine transitions between search states corresponding to one or more of the rules in accordance with contents of the input traffic stream and the conditions specified by the sequence of state definitions.
    Type: Grant
    Filed: December 5, 2017
    Date of Patent: May 8, 2018
    Assignee: Redberry Systems, Inc.
    Inventors: Sandeep Khanna, Varadarajan Srinivasan, Madhavan Bakthavatchalam
  • Publication number: 20180114023
    Abstract: Upon receiving malware detection rules that are to be identified with respect to an input traffic stream, a rule database that requires less storage capacity than the malware detection rules is generated by substituting tokens for selected symbol strings within the malware detection rules. A compressed traffic stream is generated by substituting the tokens for instances of the selected symbol strings within the input traffic stream, and then compared with the rule database to determine whether the input traffic stream contains one or more symbol sequences that correspond to any of the malware detection rules.
    Type: Application
    Filed: October 24, 2017
    Publication date: April 26, 2018
    Inventors: Madhavan Bakthavatchalam, Sandeep Khanna, Varadarajan Srinivasan
  • Patent number: 9349738
    Abstract: A content addressable memory (CAM) device can include a plurality of CAM cells each formed within a cell area of a substrate. Each cell area can have a cell length dimension in a first direction parallel to a substrate surface. The CAM device can also include at least one common line comprising a contiguous region of the substrate doped to a first conductivity type and formed in a base semiconductor region doped to a second conductivity type. The common line can extend in the first direction for more than one cell length and can be commonly coupled to non-power supply connections to the plurality of CAM cells.
    Type: Grant
    Filed: February 4, 2008
    Date of Patent: May 24, 2016
    Assignee: Broadcom Corporation
    Inventors: Bindiganavale S. Nataraj, Varadarajan Srinivasan
  • Patent number: 9063840
    Abstract: A CAM device including a CAM array, multiple match resolution (MMR) circuitry, and a priority encoder allows the addresses of multiple matching locations resulting from a first search operation to be generated without losing the match results generated in second search operation initiated prior to detection of the multiple match condition for the first search operation. When the multiple match condition is detected, the MMR circuitry asserts a stall signal that stalls search operations in the CAM array. The asserted stall signal also causes the match results of the first and second search operations to be stored in separate memory elements so that the addresses of all matching locations for the first search operation can be generated without disturbing the match results of the second search operation.
    Type: Grant
    Filed: March 1, 2010
    Date of Patent: June 23, 2015
    Assignee: Broadcom Corporation
    Inventors: Chetan Deshpande, Sandeep Khanna, Varadarajan Srinivasan
  • Patent number: 8982596
    Abstract: A CAM device includes a CAM array that can implement column redundancy in which a defective column segment in a selected block can be functionally replaced by a selected column segment of the same block, and/or by a spare column segment of the same block.
    Type: Grant
    Filed: November 21, 2011
    Date of Patent: March 17, 2015
    Assignee: Netlogic Microsystems, Inc.
    Inventors: Varadarajan Srinivasan, Bindiganavale S. Nataraj, Sandeep Khanna
  • Patent number: 8913412
    Abstract: A content addressable memory (CAM) device having any number of rows, each of the rows including a match line connected to a plurality of CAM cells, a match line detector circuit, and an incremental match line charge circuit. The detector circuit generates a feedback signal based on a detected match line voltage. The charge circuit partially pre-charges the match line to an intermediate voltage during a pre-charge phase of a compare operation, and then selectively charges the match line higher towards a supply voltage in response to the feedback signal.
    Type: Grant
    Filed: November 29, 2011
    Date of Patent: December 16, 2014
    Assignee: Netlogic Microsystems, Inc.
    Inventors: Sandeep Khanna, Bindiganavale S. Nataraj, Varadarajan Srinivasan
  • Patent number: 8767488
    Abstract: A method and apparatus for performing half-column redundancy in a CAM device is disclosed, capable of replacing a defective half-column in the CAM array with only one half of another column. For example, present embodiments can provide twice the redundancy by replacing only one half of a defective CAM cell with one half of a spare cell or of a selected cell. The half-column redundancy disclosed herein provides finer granularity and higher effectiveness to the redundancy scheme as compared to conventional redundancy schemes employed on a CAM array. Thus, the CAM array can be designed and fabricated with a higher yield without having to accommodate for more spare columns than employed by conventional redundancy schemes, allowing for more efficient use of silicon area and a more robust CAM array design.
    Type: Grant
    Filed: November 21, 2011
    Date of Patent: July 1, 2014
    Assignee: NetLogic Microsystems, Inc.
    Inventors: Varadarajan Srinivasan, Sandeep Khanna, Bindiganavale S. Nataraj
  • Patent number: 8369121
    Abstract: The power consumption of a search engine such as a CAM device is dynamically adjusted to prevent performance degradation and/or damage resulting from overheating. For some embodiments, the CAM device is continuously sampled to generate sampling signals indicating the number of active states and number of compare operations performed during each sampling period. The sampling signals are accumulated to generate an estimated device power profile, which is compared with reference values corresponding to predetermined power levels to generate a dynamic power control signal indicating predicted increases in the device's operating temperature resulting from its power consumption. The dynamic power control signal is then used to selectively reduce the input data rate of the CAM device, thereby reducing power consumption and allowing the device to cool.
    Type: Grant
    Filed: January 17, 2012
    Date of Patent: February 5, 2013
    Assignee: NetLogic Microsystems, Inc.
    Inventors: Carl Gyllenhammer, Greg Watson, Venkat Gaddam, Varadarajan Srinivasan, Sandeep Khanna, Chetan Deshpande
  • Publication number: 20120113703
    Abstract: The power consumption of a search engine such as a CAM device is dynamically adjusted to prevent performance degradation and/or damage resulting from overheating. For some embodiments, the CAM device is continuously sampled to generate sampling signals indicating the number of active states and number of compare operations performed during each sampling period. The sampling signals are accumulated to generate an estimated device power profile, which is compared with reference values corresponding to predetermined power levels to generate a dynamic power control signal indicating predicted increases in the device's operating temperature resulting from its power consumption. The dynamic power control signal is then used to selectively reduce the input data rate of the CAM device, thereby reducing power consumption and allowing the device to cool.
    Type: Application
    Filed: January 17, 2012
    Publication date: May 10, 2012
    Inventors: Carl Gyllenhammer, Greg Watson, Venkat Gaddam, Varadarajan Srinivasan, Sandeep Khanna, Chetan Deshpande
  • Patent number: 8111533
    Abstract: The power consumption of a search engine such as a CAM device is dynamically adjusted to prevent performance degradation and/or damage resulting from overheating. For some embodiments, the CAM device is continuously sampled to generate sampling signals indicating the number of active states and number of compare operations performed during each sampling period. The sampling signals are accumulated to generate an estimated device power profile, which is compared with reference values corresponding to predetermined power levels to generate a dynamic power control signal indicating predicted increases in the device's operating temperature resulting from its power consumption. The dynamic power control signal is then used to selectively reduce the input data rate of the CAM device, thereby reducing power consumption and allowing the device to cool.
    Type: Grant
    Filed: July 25, 2011
    Date of Patent: February 7, 2012
    Assignee: NetLogic Microsystems, Inc.
    Inventors: Carl Gyllenhammer, Greg Watson, Venkat Gaddam, Varadarajan Srinivasan, Sandeep Khanna, Chetan Deshpande
  • Publication number: 20110317462
    Abstract: The power consumption of a search engine such as a CAM device is dynamically adjusted to prevent performance degradation and/or damage resulting from overheating. For some embodiments, the CAM device is continuously sampled to generate sampling signals indicating the number of active states and number of compare operations performed during each sampling period. The sampling signals are accumulated to generate an estimated device power profile, which is compared with reference values corresponding to predetermined power levels to generate a dynamic power control signal indicating predicted increases in the device's operating temperature resulting from its power consumption. The dynamic power control signal is then used to selectively reduce the input data rate of the CAM device, thereby reducing power consumption and allowing the device to cool.
    Type: Application
    Filed: July 25, 2011
    Publication date: December 29, 2011
    Inventors: Carl Gyllenhammer, Greg Watson, Venkat Gaddam, Varadarajan Srinivasan, Sandeep Khanna, Chetan Deshpande
  • Patent number: 8031503
    Abstract: The power consumption of a search engine such as a CAM device is dynamically adjusted to prevent performance degradation and/or damage resulting from overheating. For some embodiments, the CAM device is continuously sampled to generate sampling signals indicating the number of active states and number of compare operations performed during each sampling period. The sampling signals are accumulated to generate an estimated device power profile, which is compared with reference values corresponding to predetermined power levels to generate a dynamic power control signal indicating predicted increases in the device's operating temperature resulting from its power consumption. The dynamic power control signal is then used to selectively reduce the input data rate of the CAM device, thereby reducing power consumption and allowing the device to cool.
    Type: Grant
    Filed: June 23, 2010
    Date of Patent: October 4, 2011
    Assignee: NetLogic Microsystems, Inc.
    Inventors: Carl Gyllenhammer, Greg Watson, Venkat Gaddam, Varadarajan Srinivasan, Sandeep Khanna, Chetan Deshpande
  • Patent number: 8023301
    Abstract: Present embodiments allow a search engine to quickly save and restore state information to and from an external state memory when switching between multiple data flows by transferring the state information between the search engine and the external state memory in a parallel manner. More specifically, for CAM-based search engines configured according to present embodiments, the CAM array includes state information gating circuits that selectively allow state information stored in the CAM array's match latches to be transposed onto the array's bit lines and then read from the array using the array's sense amplifiers.
    Type: Grant
    Filed: October 6, 2010
    Date of Patent: September 20, 2011
    Assignee: NetLogic Microsystems, Inc.
    Inventors: Varadarajan Srinivasan, Maheshwaran Srinivasan, Chetan Deshpande, Sandeep Khanna, Venkat Rajendher Reddy Gaddam
  • Patent number: 8023300
    Abstract: Present embodiments allow a search engine to quickly save and restore state information to and from an external state memory when switching between multiple data flows by transferring the state information between the search engine and the external state memory in a parallel manner. More specifically, for CAM-based search engines configured according to present embodiments, the CAM array includes state information gating circuits that selectively allow state information stored in the CAM array's match latches to be transposed onto the array's bit lines and then read from the array using the array's sense amplifiers.
    Type: Grant
    Filed: June 18, 2010
    Date of Patent: September 20, 2011
    Assignee: NetLogic Microsystems, Inc.
    Inventors: Varadarajan Srinivasan, Chetan Deshpande, Maheshwaran Srinivasan, Sandeep Khanna, Venkat Rajendher Reddy Gaddam
  • Patent number: 7924590
    Abstract: A content search system includes CAM device, a compiler, and an image loader. The CAM device, which includes a plurality of rows of CAM cells and a number of counter circuits selectively interconnected by a programmable interconnect structure (PRS), performs regular expression search operations. The compiler selectively converts the regular expression into a number of various bit groups, and the image loader loads corresponding bit groups into the CAM cells, into a number of memory elements that control configuration of the PRS, and into the counter circuits.
    Type: Grant
    Filed: July 27, 2010
    Date of Patent: April 12, 2011
    Assignee: NetLogic Microsystems, Inc.
    Inventors: Alexei Starovoitov, Maheshwaran Srinivasan, Varadarajan Srinivasan, Sandeep Khanna, Sachin Joshi, Mark Birman
  • Patent number: 7924589
    Abstract: A content addressable memory (CAM) device includes an array having a number N of CAM rows, each row including a plurality of CAM cells coupled to a match line, a spare CAM row including a plurality of CAM cells coupled to a spare match line, and row replacement circuitry configured to functionally replace a defective CAM row and each subsequent CAM row in the array with corresponding next adjacent CAM rows, wherein a last CAM row in the array is functionally replaced by the spare CAM row.
    Type: Grant
    Filed: January 12, 2009
    Date of Patent: April 12, 2011
    Assignee: NetLogic Microsystems, Inc.
    Inventors: Varadarajan Srinivasan, Sandeep Khanna
  • Patent number: 7920397
    Abstract: A memory device operates in a calibration mode during which the effects of bit line leakage current are measured and to operate in a normal mode during which the bit line current is adjusted to compensate for leakage according to the results of the calibration mode. In the calibration mode, a leakage-free sense operation is performed to determine the differential voltage generated on the bit lines in response to a data value. Then, a leakage-susceptible test read operation is performed to determine the differential voltage generated on the bit lines in response to the data value. A detection circuit measures the difference between the differential voltages generated in the leakage-free and leakage-susceptible test read operations to generate a compensation signal, which subsequently adjusts the bit line compensation current during the normal mode.
    Type: Grant
    Filed: April 30, 2010
    Date of Patent: April 5, 2011
    Assignee: NetLogic Microsystems, Inc.
    Inventors: Bindiganavale S. Nataraj, Sandeep Khanna, Varadarajan Srinivasan