Hi All,

 

I have a few questions about ACK/CTS timeout. In a point-to-point or point-to-multipoint setup should all the stations be set to the same ack/cts timeout as set on the AP for the farthest station? Or since collisions are inevitable, therefore, each station should have the timeout set according to their individual distance to the AP? For long distance 5GHz links, should the slottime be adjusted according to the ack timeout or should it be left at the default 9us? I have seen that by increasing the slottime the number of excessive hardware retries almost stops, and stabilizes the throughput.

 

I am using the following equation drawn from the athctrl utility:

               slottime = 9 + distance (m)/300(m/s)  (-+1)

               Acktimeout = 2*slottime + 3

 

I am trying to understand the relationship between ACK timeout and slottime with regards to distance. I have also noticed that sometimes in a congested 5/2.4 GHz omni increasing the ack timeout helps improve the quality of service since the radios are now talking comparatively slower. I made that observation strictly from an ack timeout adjustment perspective. Any input is appreciated, TIA!

 

Hasan R.