A method, comprising: when a buffer of a first sublayer of a wireless access link is empty and there is a new data unit in the first sublayer or when the first sublayer buffer is not empty and a data unit leaves the second sublayer buffer, comparing a number of data units currently stored in the second sublayer buffer with a queue length threshold, wherein the queue length threshold defines a total amount of space in the second sublayer buffer; and when the number of data units currently stored in the second sublayer buffer is less than the queue length threshold, transferring a data unit from the first sublayer to the second sublayer; when the data unit is received at the second sublayer, formatting the data unit as a second sublayer data unit; the method being characterized by further comprising: queueing the second sublayer data unit to the second sublayer buffer together with an arrival time stamp equal to a system time when the second sublayer data unit arrived at the second sublayer buffer; periodically computing a delay metric based on at least one delay sample that is obtained, for each second layer data unit, as a difference between a time of departure of the second layer data unit from the second sublayer buffer and the arrival time stamp of the second layer data unit when the second sublayer data unit arrived at the second sublayer buffer; every time the delay metric is computed or after a certain duration of time has elapsed, comparing the delay metric with a delay threshold; and modifying the queue length threshold based on a result of the comparison between the delay metric and the delay threshold. when a buffer of a first sublayer of a wireless access link is empty and there is a new data unit in the first sublayer or when the first sublayer buffer is not empty and a data unit leaves the second sublayer buffer, comparing a number of data units currently stored in the second sublayer buffer with a queue length threshold, wherein the queue length threshold defines a total amount of space in the second sublayer buffer; and when the number of data units currently stored in the second sublayer buffer is less than the queue length threshold, transferring a data unit from the first sublayer to the second sublayer; when the data unit is received at the second sublayer, formatting the data unit as a second sublayer data unit; the method being characterized by further comprising: queueing the second sublayer data unit to the second sublayer buffer together with an arrival time stamp equal to a system time when the second sublayer data unit arrived at the second sublayer buffer; periodically computing a delay metric based on at least one delay sample that is obtained, for each second layer data unit, as a difference between a time of departure of the second layer data unit from the second sublayer buffer and the arrival time stamp of the second layer data unit when the second sublayer data unit arrived at the second sublayer buffer; every time the delay metric is computed or after a certain duration of time has elapsed, comparing the delay metric with a delay threshold; and modifying the queue length threshold based on a result of the comparison between the delay metric and the delay threshold. queueing the second sublayer data unit to the second sublayer buffer together with an arrival time stamp equal to a system time when the second sublayer data unit arrived at the second sublayer buffer; periodically computing a delay metric based on at least one delay sample that is obtained, for each second layer data unit, as a difference between a time of departure of the second layer data unit from the second sublayer buffer and the arrival time stamp of the second layer data unit when the second sublayer data unit arrived at the second sublayer buffer; every time the delay metric is computed or after a certain duration of time has elapsed, comparing the delay metric with a delay threshold; and modifying the queue length threshold based on a result of the comparison between the delay metric and the delay threshold.