Communication apparatus, communication state detecting method, and communication state detecting program
| Title: | Communication apparatus, communication state detecting method, and communication state detecting program |
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| Patent Number: | 9,461,772 |
| Publication Date: | October 04, 2016 |
| Appl. No: | 14/342223 |
| Application Filed: | July 24, 2012 |
| Abstract: | A packet interval (a time difference between sequentially received packets) in a certain previous time is calculated and a cumulative distribution function of the calculated packet interval is obtained. Meanwhile, a function value-corresponding to-flow end that is a boundary value of the cumulative distribution function to be considered as a flow end (timeout) in the range of a cumulative distribution function value is stored. From the cumulative distribution function obtained as described above, a value of a packet interval mapped to a cumulative distribution function value that matches the function value-corresponding to-flow end is set as a threshold. That is, the threshold is dynamically set based on a previous packet interval. Therefore, a packet stop period from a last packet reception time to a current time is measured, and it is detected as a flow timeout at a timing when the measured value is equal to or greater than the threshold. |
| Inventors: | Iizuka, Hiroyuki (Tokyo, JP); Tanaka, Toshiyasu (Tokyo, JP); Yoshimura, Koichi (Tokyo, JP); Iwai, Masahito (Tokyo, JP); Ito, Tetsuya (Tokyo, JP) |
| Assignees: | NEC Communication Systems, Ltd. (Tokyo, JP) |
| Claim: | 1. A communication apparatus, comprising: a threshold setting unit configured to dynamically set a threshold based on a packet interval that is a difference between reception times of a plurality of previously consecutively received packets; and a timeout detecting unit configured to detect a flow end by comparing a packet stop period, counted from a packet reception time to a current time, with the threshold, wherein the threshold setting unit further includes a packet interval calculating unit configured to calculate the packet interval of a plurality of packets corresponding to each previously received flow; a cumulative distribution function computing unit configured to obtain a cumulative distribution function of the packet interval; and a packet interval-to-threshold acquisition unit configured to acquire, from the cumulative distribution function, a packet interval mapped to a cumulative distribution function value that matches a function value which is previously set to indicate a boundary value of the cumulative distribution function assumed as the flow end, thus setting the acquired packet interval to the threshold. |
| Claim: | 2. The communication apparatus according to claim 1 , wherein the packet interval calculating unit further includes a flow database management unit configured to calculate the packet interval using an entry which includes a reception time and flow information indicating a flow for each previously received packet stored in the flow database, wherein the flow database management unit creates the entry corresponding to the received packet, registers the entry in the flow database, and removes the entry of a packet corresponding to a flow that is detected as a timeout using the timeout detecting unit from the flow database. |
| Claim: | 3. The communication apparatus according to claim 1 , further comprising a flow detecting unit configured to detect the flow ends based on a flag indicating the flow end stored in the received packet. |
| Claim: | 4. The communication apparatus according to claim 1 , further comprising a sleep control unit configured to set a sleep state in a period during which the flow stops upon detecting the flow end. |
| Patent References Cited: | 7385924 June 2008 Riddle 7426181 September 2008 Feroz 7457870 November 2008 Lownsbrough 7843843 November 2010 Papp, III 8793361 July 2014 Riddle 2003/0219014 November 2003 Kotabe 2010/0080246 April 2010 Iwakura et al. 2010/0284300 November 2010 Deshpande 2011/0075583 March 2011 Imai et al. 2002-262333 September 2002 2008-197910 August 2008 2008-197910 August 2008 2010-041644 February 2010 2010-081343 April 2010 2011-077954 April 2011 |
| Other References: | Notice of Allowance issued by the Japan Patent Office for Japanese Patent Application No. 2013-532494 mailed Jan. 6, 2015 (4 pgs.). cited by applicant Kang, I. and Kim, H., “Determining Embryonic Connection Timeout in Stateful Inspection,” ICC '03, IEEE International Conference on Communications, vol. 1, pp. 458-462 (Mar. 2003). cited by applicant International Search Report corresponding to PCT/JP2012/068730, dated Sep. 12, 2012; 2 pages. cited by applicant International Search Report corresponding to PCT/JP2012/068730, dated Sep. 25, 2012; 4 pages. cited by applicant |
| Primary Examiner: | Hoang, Thai |
| Attorney, Agent or Firm: | Wilmer Cutler Pickering Hale and Dorr LLP |
| Accession Number: | edspgr.09461772 |
| Database: | USPTO Patent Grants |
| Language: | English |
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