Method for flow control in a communication system

1. A method of flow control between communication devices, comprising:

sending flow control messages from a first communication device to a second communication device at a variable rate, the flow control messages indicating the first communication device can accept more data from the second communication device,

the variable rate for sending flow control messages being determined based on a comparison between a measure of data outputted from an output buffer of the first communication device since a previous flow control message was sent and a dynamically adapted threshold level,

the dynamically adapted threshold level being established as a function of data fill in the first communication device output buffer.

2. The method of claim 1 , wherein the threshold amount of data is based on the available data storage capacity such that the greater the available data storage capacity, the higher the threshold amount of data.

3. The method of claim 2 , wherein the amount of data output is the amount of data output since a last flow control message was sent.

4. The method of claim 2 , wherein the threshold is accessed from a look up table using the available storage capacity as an index.

5. The method of claim 1 , further comprising:

determining the available data capacity based on an amount of unused data storage in the first communication device.

6. The method of claim 1 , further comprising:

determining the available data capacity based on the amount of data stored at the first communication device.

7. The method of claim 1 , wherein the amount of data output is the amount of data output since a last flow control message was sent.

8. A method of flow control between communication devices, comprising:

determining a number of data packets stored in a data buffer of a first communication device;

setting a dynamic transmission threshold as a function of data fill in the first communication device data buffer;

counting a number of packets transmitted by the first communication device since a last transmission of a flow control message;

comparing the number of transmitted packets to a present value of the dynamic transmission threshold; and

sending a flow control message from the first communication device to a second communication device at a variable rate, if the number of transmitted packets is equal to or greater than the dynamic threshold value, the flow control message indicating the first communication device can accept more data from the second communication device when a count generated by the counting step equals the transmission threshold.

9. A method of flow control between communication devices comprising:

determining a status of a data storage buffer at a first communication device, the status indicating whether the data storage buffer is approaching underflow or approaching overflow;

establishing a dynamically adapted send threshold value based on the determined status; and

sending a flow control message from the first communication device to a second communication device at a variable rate, if the dynamic threshold value is equal to or greater than an underflow threshold value and less than or equal to an overflow threshold value, indicating the first communication device can accept more data from the second communication device based on the send threshold and an amount of data output by the first communication device since a last flow control message was sent.