Fixed BW measurement. Prevented from measuring between non-monotonic or rexmitted packets.

[ethouris]

The original bandwidth measurement states that 16th and 17th packets in order are sent without delay between one another so that the difference in arrival time between 17th and 16th packet in order can suggest the highest possible potential sender speed, which is the absolute maximum link bandwidth.

This measurement is completely blown, however, in cases when:

• the probe 2 triggered (on the "17th packet"), but there was no 16th packet preceding it received yet
• the 16th packet, which's arrival time has been recorded, is not the direct predecessor of the 17th packet that has triggered the probe 2 - the measurement is then taken between unrelated packets
• the 17th packet has been retransmitted and therefore the distance measured in such a case is completely out of the blue

Even though the bandwidth measurement is prepared to eliminate those values as too much differing to the average, relying on that can be slick, especially if the original state is such that no measurement has been taken yet, or when momentarily the gap between 16th and 17th happens to be occasionally extremely big and therefore an "out of the blue" measurement doesn't seem to be so distant to the valid values.

This fix simply prevents taking any measurements that would not be conducted on exactly two consecutive 16th and 17th packets in order.

[maxsharabayko]

Now the code is perfect except for one condition might not be handled well.
Say packet A is (pkt.m_iSeqNo & PUMASK_SEQNO_PROBE) == 0
Packet B is (pkt.m_iSeqNo & PUMASK_SEQNO_PROBE) == 1

Process the following order of receiving:
Packet A - original
Packet A - re-transmitted
Packet B - original

In this case we can't consider packet B as a probing packet.

[maxsharabayko]

What happened with formatting?

[ethouris]

I wanted to somehow add comments by // to the particular condition being tested.

[rndi]

Please move the comments out of the if() statement. It is not very hard to reword the comment so that it can correlate to relevant parts of the conditions within the if().

[rndi]

Please move the comments out of the if() statement. It is not very hard to reword the comment so that it can correlate to relevant parts of the conditions within the if().