Nicola wrote:
CwMin should be set to 31 (instead of 15) when using 802.11b.
See IEEE Std. 802.11-2007, section 15.3.3 "DS PHY characteristics". 


Basim wrote:
It seems to me that CwMin parameter is controlled by DcaTxop. Each MAC
handles its own DcaTxop.  Should we add a virtual function SetCwMin may
be added in WifiMac class? For non-QoS MACs, it seems that each mac has
only one DcaTxop and it is straightforward to add one. For QoS  MAC, it
seems that only beacon Dca needs to be set. Does this sound ok?


Gary wrote:
Here is what I see in DcaTxop:
[...] 
The default value of 15 was set at line 105. Why do you think that CwWin has nothing to do with DcaTxop?
 

Mathieu wrote:
1) you can't add a SetCwMin method on WifiMac because there can be more
than one DcaTxop per WifiMac and they should not have the same CwMin.

2) The DcaTxop parameters are initialized in the associated helpers in
src/helper. See QosWifiMacHelper::Default for example.

I don't have any bright idea right now of how this should be dealt with
and what we could do to make this both 'automatic' and flexible to do
something different. Ideas welcome.