help to keep a fixed rate with broadcast packets
Federico Tramarin <tramarin <at> dei.unipd.it>
2014-12-05 06:31:30 GMT
first of all thank you very much for the support this mailimg list
provides to the users/developers of ath9k drivers.
I am a PostDoc researcher, and I am working on a project related to an
experimental IEEE 802.11n performance analysis. For purposes of
research, in my experimental session I need to be able to purposely set
the tx rate (MCS) of packets sent in broadcast, and keep it fixed (no rc).
More in detail, I need to sent packets between two nodes (say, a client
server UDP application), and to this aim I am using 'scapy' for
transmission at level 2, or even at level 3 of the stack.
I need the packet have a broadcast L2 dest address, since this way the
retransmission/backoff algorithm will be avoided.
The problem is that broadcast L2 packets are sent always at a very low
tx rate (typically 1 MBit/s, strange!) with respect to unicast packets,
even if I indicate the frame is of type data. It seems that being a
broadcast packet it is treated af a typical management/no-ack/control
frame, hence resorting to the using of a rate picked from a basic rate set.
The possible solutions I tried are:
- use of iw -> I (with much difficulties) can control the tx rate
(actually I need to specificy the MCS), but have not control of the rate
used for broadacst packets. Also, I have no way to change the rate in
the basic rates set.
- use of (old) iwconfig -> I have control of the tx rate, honestly more
reliably that with iw. However, iwconfig does not allow to specify the