# US 9,438,523 B2 · Method and apparatus for deriving a packet select probability value > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,438,523 B2 - Document ID: US9438523B2 - Status: Granted - Kind: B2 - Application number: 14/261,548 - Filed: 2014-04-25 - Published: 2015-08-27 - Granted: 2016-09-06 - Earliest claimed: 2014-02-24 - Assignees: Freescale Semiconductor, Inc. - Applicants: Florinel Iordache; George Stefan - Inventors: Florinel Iordache; George Stefan - Web page: https://patentgrep.com/patent/US9438523B2 ## CPC - H04L 47/2441: relying on flow classification, e.g. using integrated services [IntServ] - H04L 47/29: {using a combination of thresholds} - H04L 47/30: in combination with information about buffer occupancy at either end or at transit nodes - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method and apparatus for deriving a packet select probability value for a data packet. The method comprises determining a queue length value for a target buffer of the data packet, calculating a queue congestion value based at least partly on the queue length value and a packet select queue length range, and calculating the packet select probability value for the data packet based at least partly on an exponential function e−x, where x is computed based at least partly on the queue congestion value. ## Claims ### Claim 1 A data packet routing device comprising a signal processing component, the signal processing component configured to: receive an indication of a data packet received at the data packet routing device; determine a queue length value for a target buffer of the data packet; calculate a queue congestion value based at least partly on the queue length value and a packet select queue length range; calculate a packet select probability value for the data packet based at least partly on an exponential function e−x, where x is computed based at least partly on the queue congestion value; and select the data packet based on the packet select probability value, wherein the data packet routing device drops or queues the data packet based on the selection of the data packet by the signal processing component. ### Claim 2 (depends on 1) The data packet routing device of claim 1, wherein the queue congestion value Qcon is calculated based on: Q con = max ⁢ ⁢ TH - Av max ⁢ ⁢ TH - min ⁢ ⁢ TH where Av represents the determined queue length value, maxTH represents a maximum queue length threshold and minTH represents a minimum queue length threshold; maxTH-minTH defining the packet select queue length range. ### Claim 3 (depends on 1) The data packet routing device of claim 1, wherein x is further computed based on an aggressiveness factor K, such that x=K*Qcon. ### Claim 4 (depends on 3) The data packet routing device of claim 3, wherein the aggressiveness factor K comprises a user configurable aggressiveness factor. ### Claim 5 (depends on 3) The data packet routing device of claim 3, wherein the aggressiveness factor K comprises an adaptively configurable aggressiveness factor. ### Claim 6 (depends on 1) The data packet routing device of claim 1, wherein the queue length value comprises an average queue length for the target buffer of the data packet. ### Claim 7 (depends on 6) The data packet routing device of claim 6, wherein the queue length value Av is calculated based on: Av=Ao*(1−2−n)+Qc*(2−n) where n represents a user configurable weighting factor, Ao represents a previously determined average queue length value and Qc represents a current queue length. ### Claim 8 (depends on 1) The data packet routing device of claim 1, wherein the signal processing component is further configured to: determine a class of traffic to which the data packet belongs, obtain a set of active queue management parameters for the determined class of traffic, and derive a packet select probability value for the data packet based at least partly on the obtained set of active queue management parameters. ### Claim 9 (depends on 8) The data packet routing device of claim 8, wherein the set of active queue management parameters comprises at least one from a group comprising at least one of: a maximum queue length threshold maxTH; a minimum queue length threshold minTH; and an aggressiveness factor K. ### Claim 10 (depends on 1) The data packet routing device of claim 1, wherein the signal processing component implements a random early detection active queue management process using the packet select probability value. ### Claim 11 A non-transitory computer program product comprising executable program code stored therein for deriving a packet select probability value for a data packet and selecting the data packet based on the packet select probability value, the program code executable to: receive an indication of receipt of the data packet; determine a queue length value for a target buffer of the data packet; calculate a queue congestion value based at least partly on the queue length value and a packet select queue length range; calculate the packet select probability value for the data packet based at least partly on an exponential function e−x, where x is computed based at least partly on the queue congestion value; select the data packet based on the packet select probability value; and drop or queue the data packet based on the selection of the data packet. ### Claim 12 (depends on 11) The non-transitory computer program product of claim 11, wherein the non-transitory computer program product comprises at least one from a group including: a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a Read Only Memory, ROM, a Programmable Read Only Memory, PROM, an Erasable Programmable Read Only Memory, EPROM, an Electrically Erasable Programmable Read Only Memory, EEPROM, and a Flash memory. ### Claim 13 (depends on 11) The non-transitory computer program product of claim 11, wherein the queue congestion value Qcon is calculated based on: Q con = max ⁢ ⁢ TH - Av max ⁢ ⁢ TH - min ⁢ ⁢ TH where Av represents the determined queue length value, maxTH represents a maximum queue length threshold and minTH represents a minimum queue length threshold; maxTH-minTH defining the packet select queue length range. ### Claim 14 (depends on 11) The non-transitory computer program product of claim 11, wherein x is further computed based on an aggressiveness factor K, such that x=K*Qcon. ### Claim 15 (depends on 14) The non-transitory computer program product of claim 14, wherein the aggressiveness factor K comprises a user configurable aggressiveness factor. ### Claim 16 (depends on 14) The non-transitory computer program product of claim 14, wherein the aggressiveness factor K comprises an adaptively configurable aggressiveness factor. ### Claim 17 (depends on 11) The non-transitory computer program product of claim 11, wherein the queue length value comprises an average queue length for the target buffer of the data packet. ### Claim 18 (depends on 17) The non-transitory computer program product of claim 17, wherein the queue length value Av is calculated based on: Av=Ao*(1−2−n)+Qc*(2−n) where n represents a user configurable weighting factor, Ao represents a previously determined average queue length value and Qc represents a current queue length.