Method for measuring delay parameters in a network
AssigneeVocalTec Communications Ltd.
InventorVladimir Pogrebinsky
Life of this patent
Estimating the term…
Abstract
A method for measuring delay parameters in a packet switched network between node A and node B, each having a clock, is disclosed The method includes the steps of: measuring a first relative one way delay (ROWD1) from node A to node B, measuring a second relative one way delay (ROWD2) from nude B to node A and calculating the difference between the first and second relative one way delays for providing a relative one way delay (ROWD) parameter. Methods for improving TCP protocol and detecting congestion in a packet switched network using ROWD measurements are also provided.
Claims14
A method for measuring delay in a packet switched network between node A and node B, each having a clock comprising the steps of:
- measuring a first relative one way delay (ROWD1) from node A to node B by using said clocks at node A and node B which are unsynchronized with respect to each other;
- measuring a second relative one way delay (ROWD2) from node A to node B by using said clocks at node A and node B which are unsynchronized with respect to each other, and
- determining relative one way delay (ROWD) parameter by subtracting said first relative one way delay from said second relative one way delay in accordance with the following equation:
- ROWD=ROWD2−ROWD1.
A method for detecting congestion in a packet switched network by measuring relative one way delay (ROWD), comprising the steps of:
- measuring a first relative one way delay (ROWD1) from node A to node B;
- measuring a second relative one way delay (ROWD2) from node A to node B;
- calculating the difference between said first and second relative one way delays for providing a relative one way delay (ROWD) parameter by using the following equation:
- ROWD=ROWD2−ROWD1;
- estimating a smoothed ROWD average An;
- estimating a smoothed ROWD jitter Jn;
- and
- comparing the last measurement of ROWD with a dynamic threshold, said dynamic threshold being a function of An and Jn for detecting said congestion.
A method for improving bit rate control of Transmission Control Protocols (TCPs) by employing a relative one way delay (ROWD) parameter comprising the steps of:
- providing clocks at node A and node B, said clocks unsynchronized with respect to each other;
- measuring a first relative one way delay (ROWD1) from node A to node B;
- measuring a second relative one way delay (ROWD2) from node A to node B;
- determining the difference between said first and second relative one way delays for providing a relative one way delay (ROWD) parameter by using the following equation:
- ROWD=ROWD2−ROWD1;
- and
- estimating the retransmission timeout value in accordance with a last measured ROWD.
Dependencies are inferred from the claim text.