Method and device for determining a time-parameter
First Claim
1. A method of determining a parameter associated with a retransmission time-out feature in a data unit transmitter implementing a protocol that provides an acknowledgment feature of sending acknowledgment messages for the correct receipt of data units from the receiver to the sender of a communication, and provides said retransmission time-out feature of retransmitting data units if an acknowledgment does not arrive at the sender within a time-out period, comprising the steps of:
- measuring a round trip time value, the round trip time being indicative of the time that passes between the sending of a given data unit and the receipt of the acknowledgment corresponding to said given data unit, calculating a new smoothed round trip time value at least on the basis of a stored smoothed round trip time value and said measured round trip time value, calculating a new mean deviation value indicative of the mean deviation of said round trip time values over time, at least on the basis of a stored mean deviation value, said measured round trip time value and said stored smoothed round trip time value, and calculating said parameter at least on the basis of said new smoothed round trip time value and said new mean deviation value, where a contribution of said measured round trip time value to said new mean deviation value is different if said measured round trip time value is smaller than a predetermined threshold that is determined on the basis of said stored smoothed round trip time value, than if said measured round trip time value is greater than said predetermined threshold.
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Abstract
A method and device for determining a parameter (RTO) associated with a retransmission time-out feature in a data unit transmitter implementing a protocol (TCP) that provides an acknowledgment feature and a retransmission time-out feature, where according to one aspect decreasing values of the round trip time (RTT) are treated differently with respect to their influence on a mean deviation parameter (RTTVAR) than increasing values of the round trip time, where according to another aspect weight values (g, h, w) used in the determination of the parameter (RTO) are chosen such that at least one of them is time variable, and where according to a further aspect the parameter (RTO) is also calculated on the basis of a value (SR) indicative of the number of spurious time-outs in the communication.
77 Citations
45 Claims
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1. A method of determining a parameter associated with a retransmission time-out feature in a data unit transmitter implementing a protocol that provides an acknowledgment feature of sending acknowledgment messages for the correct receipt of data units from the receiver to the sender of a communication, and provides said retransmission time-out feature of retransmitting data units if an acknowledgment does not arrive at the sender within a time-out period, comprising the steps of:
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measuring a round trip time value, the round trip time being indicative of the time that passes between the sending of a given data unit and the receipt of the acknowledgment corresponding to said given data unit, calculating a new smoothed round trip time value at least on the basis of a stored smoothed round trip time value and said measured round trip time value, calculating a new mean deviation value indicative of the mean deviation of said round trip time values over time, at least on the basis of a stored mean deviation value, said measured round trip time value and said stored smoothed round trip time value, and calculating said parameter at least on the basis of said new smoothed round trip time value and said new mean deviation value, where a contribution of said measured round trip time value to said new mean deviation value is different if said measured round trip time value is smaller than a predetermined threshold that is determined on the basis of said stored smoothed round trip time value, than if said measured round trip time value is greater than said predetermined threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 28, 29, 34, 35, 40)
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11. A method of determining a parameter associated with a retransmission time-out feature in a data unit transmitter implementing a protocol that provides an acknowledgment feature of sending acknowledgment messages for the correct receipt of data units from the receiver to the sender of a communication, and provides said retransmission time-out feature of retransmitting data units if an acknowledgment does not arrive at the sender within a time-out period, comprising the steps of:
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measuring a round trip time value, the round trip time being indicative of the time that passes between the sending of a given data unit and the receipt of the acknowledgment corresponding to said given data unit, calculating a new smoothed round trip time value at least on the basis of a stored smoothed round trip time value, said measured round trip time value, and a first weight factor, calculating a new mean deviation value indicative of the mean deviation of said round trip time values over time, at least on the basis of a stored mean deviation value, said measured round trip time value, said stored smoothed round trip time value, and a second weight factor (h), and calculating said parameter at least on the basis of said new smoothed round trip time value, said new mean deviation value, and a third weight factor, where at least one of said first, second and third weight factors is variable over time. - View Dependent Claims (12, 13, 14, 15, 16, 30, 31, 36, 37, 41)
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17. A method of determining a parameter associated with a retransmission time-out feature in a data unit transmitter implementing a protocol that provides an acknowledgment feature of sending acknowledgment messages for the correct receipt of data units from the receiver to the sender of a communication, and provides said retransmission time-out feature of retransmitting data units if an acknowledgment does not arrive at the sender within a time-out period, comprising the steps of:
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measuring a round trip time value, the round trip time being indicative of the time that passes between the sending of a given data unit and the receipt of the acknowledgment corresponding to said given data unit, calculating a new smoothed round trip time value at least on the basis of a stored smoothed round trip time value and said measured round trip time value, calculating a new mean deviation value indicative of the mean deviation of said round trip time values over time, at least on the basis of a stored mean deviation value, said measured round trip time value and said stored smoothed round trip time value, and calculating said parameter at least on the basis of said new smoothed round trip time value and said new mean deviation value, where said parameter is also calculated on the basis of a value indicative of the number of spurious time-outs that occurred in said communication between said sender and said receiver. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 32, 33, 38, 39, 42)
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43. A data unit transmitter arranged for implementing a protocol that provides an acknowledgment feature of sending acknowledgment messages for the correct receipt of data units from the receiver to the sender of a communication, and provides a retransmission time-out feature of retransmitting data units if an acknowledgment does not arrive at the sender within a time-out period, and arranged for determining a parameter associated with said retransmission time-out feature, comprising:
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a round trip time measurer arranged for measuring a round trip time value, the round trip time being indicative of the time that passes between the sending of a given data unit and the receipt of the acknowledgment corresponding to said given data unit, and a calculator arranged for calculating a new smoothed round trip time value at least on the basis of a stored smoothed round trip time value and said measured round trip time value, calculating a new mean deviation value indicative of the mean deviation of said round trip time values over time, at least on the basis of a stored mean deviation value, said measured round trip time value and said stored smoothed round trip time value, and calculating said parameter at least on the basis of said new smoothed round trip time value and said new mean deviation value, where said calculator is furthermore arranged such that a contribution of said measured round trip time value to said new mean deviation value is different if said measured round trip time value is smaller than a predetermined threshold that is determined on the basis of said stored smoothed round trip time value, than if said measured round trip time value is larger than said predetermined threshold.
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44. A data unit transmitter arranged for implementing a protocol that provides an acknowledgment feature of sending acknowledgment messages for the correct receipt of data units from the receiver to the sender of a communication, and provides a retransmission time-out feature of retransmitting data units if an acknowledgment does not arrive at the sender within a time-out period, and arranged for determining a parameter associated with said retransmission time-out feature, comprising:
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a round trip time measurer arranged for measuring a round trip time value, the round trip time being indicative of the time that passes between the sending of a given data unit and the receipt of the acknowledgment corresponding to said given data unit, and a calculator arranged for calculating a new smoothed round trip time value at least on the basis of a stored smoothed round trip time value, said measured round trip time value, and a first weight factor, calculating a new mean deviation value indicative of the mean deviation of said round trip time values over time, at least on the basis of a stored mean deviation value, said measured round trip time value, said stored smoothed round trip time value, and a second weight factor (h), and calculating said parameter at least on the basis of said new smoothed round trip time value, said new mean deviation value, and a third weight factor, where said calculator is furthermore arranged such that at least one of said first, second and third weight factors is variable over time.
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45. A data unit transmitter arranged for implementing a protocol that provides an acknowledgment feature of sending acknowledgment messages for the correct receipt of data units from the receiver to the sender of a communication, and provides a retransmission time-out feature of retransmitting data units if an acknowledgment does not arrive at the sender within a time-out period, and arranged for determining a parameter associated with said retransmission time-out feature, comprising:
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a round trip time measurer arranged for measuring a round trip time value, the round trip time being indicative of the time that passes between the sending of a given data unit and the receipt of the acknowledgment corresponding to said given data unit, and a calculator arranged for calculating a new smoothed round trip time value at least on the basis of a stored smoothed round trip time value and said measured round trip time value, calculating a new mean deviation value indicative of the mean deviation of said round trip time values over time, at least on the basis of a stored mean deviation value, said measured round trip time value and said stored smoothed round trip time value, and calculating said parameter at least on the basis of said new smoothed round trip time value and said new mean deviation value, where said calculator is furthermore arranged such that said parameter (RTO) is also calculated on the basis of a value V indicative of the number of spurious time-outs that occurred in said communication between said sender and said receiver.
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Specification