Re: How many null-data probes on connection loss?

[Johannes Berg <johannes@sipsolutions.net>]

On Wed, 2018-09-26 at 11:04 -0700, Ben Greear wrote:

> I have been running with mac80211/mlme.c's max_nullfunc_tries set to 5 for many years.
> Long ago it helped with connectivity issues with lots of vdevs and and/orloaded APs
> if I recall correctly.

That's different, that's the number of distinct frames mac80211 will
send.

I thought you were asking about *retries*.

> In fact, I see 62 frames captured on air all with the same sequence number
> in the test I just did, and subsequent frames with the next seq-no are sent
> immediately after the first one.  The frames are all right after each other, so
> I guess this is probably firmware doing lots of HW retransmits and then *also*
> doing software retransmits in the firmware (my reading of mlme.c indicates it should
> only probe every 500ms).

Yes.

> I think I'll start by making sure the firmware does not do software retransmits
> for frames from the driver (self-gen frames are OK to be retransmitted I guess).

You do want it to be doing retries for frames from the driver, since you
want it to recover from temporary collisions with a microwave and
whatnot ... just not *that many*, I guess.

johannes