* Add an intermediate variable, ctsrate, which is currently derived directly
from rate, but may be handled differently later (especially for 11g).
* Assume ACKs are sent at the same rate as the original data packet, as ath
does, shortening the ACK reservation time substantially.
* Add a note that we need to deal with not adding the ACK time for some
packets, though this is not implemented yet.
Questions:
* How do we affect the control rate used to send RTS/CTS packets?
* Is the PLCP header length actually controlled by the preamble length
selection, or should this be based on the transmit rate?
Of course short preamble is not actually implemented/working yet.
e3c9106a08