Hi,

In adhoc-wifi-mac.cc, ap-wifi-mac.cc, sta-wifi-mac.cc of wifi moudle and ocb-wifi-mac.cc of wave moudule, there is a method called "Enqueue".
Its implementation has a part about tid:

       // Fill in the QoS control field in the MAC header
      tid = QosUtilsGetTidForPacket (packet);
      // Any value greater than 7 is invalid and likely indicates that
      // the packet had no QoS tag, so we revert to zero, which'll
      // mean that AC_BE is used.
      if (tid >= 7)
        {
          tid = 0;
        }
      hdr.SetQosTid (tid);

Here if tid is greater than 7, then tid will be assigned default valud 0.
However I think we should use "if (tid > 7)" rather than "if (tid >= 7)".
Because if tid from a packet is 7, the correspnding AcIndex is AC_VO.
If tid is chaned to 0 by original code there, the correspnding AcIndex is AC_BE.
So imaging that, there is a packet which is important and wants to use AC_VO MAC queue, but is wrongly inserted into AC_VO MAC queue :(

I found this issue in the old ns-3 version, but seems still there in current devel version.
I still use an old ns-3 version thus I have not created the patch.
Hope the maintainer can review this issue and complete the patch.

Thanks.

Junling