Bug 2607

Summary:	Minstrel HT manager results in an endless loop when a 802.11ac station is transmitting to a 802.11a access point
Product:	ns-3	Reporter:	sebastien.deronne
Component:	wifi	Assignee:	Matías Richart <matis18>
Status:	RESOLVED FIXED
Severity:	normal	CC:	matis18, ns-bugs, tomh
Priority:	P3
Version:	ns-3.26
Hardware:	All
OS:	All
Bug Depends on:	2605
Bug Blocks:
Attachments:	Correct overflow in channel width loop

Description sebastien.deronne 2017-01-02 17:45:27 UTC

After applying the fix for bug 2605, I noticed minstrel HT manager results in an endless loop when a 802.11ac station is transmitting to a 802.11a access point.
From traces, it seems constantly initializing group 16.
This can be reproduced by using test script and fix attached for bug 2605 and
set AP standard to 802.11ac.

Comment 1 sebastien.deronne 2017-01-02 17:45:52 UTC

Is it also something Tom or Matias could investigate?

Comment 2 Matías Richart 2017-01-11 13:05:36 UTC

(In reply to sebastien.deronne from comment #1)
> Is it also something Tom or Matias could investigate?

The loop problem is because of an overflow. It seems I never test VHT correctly.
I get a throughput of 28.1682 Mbit/s, is that correct?

The test: ./waf --run 'test-backward-compatibility --apVersion=80211a --staVersion=80211ac --apRaa=Minstrel --staRaa=MinstrelHt'

Comment 3 Matías Richart 2017-01-11 13:06:19 UTC

Created attachment 2743 [details]
Correct overflow in channel width loop

Comment 4 sebastien.deronne 2017-01-11 13:07:07 UTC

(In reply to Matías Richart from comment #2)
> (In reply to sebastien.deronne from comment #1)
> > Is it also something Tom or Matias could investigate?
> 
> The loop problem is because of an overflow. It seems I never test VHT
> correctly.
> I get a throughput of 28.1682 Mbit/s, is that correct?
> 
> The test: ./waf --run 'test-backward-compatibility --apVersion=80211a
> --staVersion=80211ac --apRaa=Minstrel --staRaa=MinstrelHt'

Yes it makes sense

Comment 5 sebastien.deronne 2017-01-11 13:08:46 UTC

(In reply to Matías Richart from comment #3)
> Created attachment 2743 [details]
> Correct overflow in channel width loop

Thanks. I will give a try and I'll deliver the patch together with the fix for bug 2605.

Comment 6 sebastien.deronne 2017-01-11 14:40:14 UTC

Fixed in changeset 12526:47ec67af9904