Hi Yeoh,

The authentication daemon is not in the data path:  its role ends once
a new candidate has been authenticated, keys derived and peering
established.  These are the things we investigated, without much
success:

Q1: Are HT data rates used for secured mesh traffic?
A1: Yes, we confirmed that.

Q2: Are there more retries/corrupted frames on secured traffic vs.
open mesh traffic?
A2:  No.  In our environment we observed roughly 10% retransmission rates.

Q3. Is encryption/decryption bound by CPU?
A3: We did observe a 10% higher CPU usage when running mesh in secure
mode.  But our host CPU had ample available cycles to handle that.

Q4: Is software encryption/decryption adding latency to the datapath
and hence decreasing throughput?
A4: We did not observe any additional inter-frame latency.

Q5. Is this HT-related?
A4: No, we have also observed decreased throughput in non-HT modes.

To summarize:  We have also observed the decreased throughput in
secured mode (in our setup, ~50% throughput reduction) and so far we
have not found where the bottleneck is yet.

Cheers,

Javier

On Sun, Nov 13, 2011 at 6:05 PM, Yeoh Chun-Yeow <[email protected]> wrote:
> Hi, Thomas
>
> Managed to get the secured mesh up after applying the linked patch. I have
> managed to test the HT20 mode for secured mesh and non-secured mesh due to
> my embedded platform only supports Fast Ethernet. Here are the results:
>
> Non Secured Mesh (HT20)
> # iperf -s -i 1
> ------------------------------------------------------------
> Server listening on TCP port 5001
> TCP window size: 85.3 KByte (default)
> ------------------------------------------------------------
> [ ID] Interval       Transfer     Bandwidth
> [SUM]  0.0-10.0 sec  72.0 MBytes  60.1 Mbits/sec
>
> Secured Mesh (HT20)
> # iperf -s -i 1
> ------------------------------------------------------------
> Server listening on TCP port 5001
> TCP window size: 85.3 KByte (default)
> ------------------------------------------------------------
> [ ID] Interval       Transfer     Bandwidth
> [SUM]  0.0-10.1 sec  15.6 MBytes  13.0 Mbits/sec
>
> A bit disappointed that the throughput is drop quite significantly. Confirm
> that the aggregation is working:
>
> Rx A-MPDU request on tid 0 result 0
> Open BA session requested for 0a:0b:6b:7d:e3:b9 tid 0
> activated addBA response timer on tid 0
> switched off addBA timer for tid 0
> Aggregation is on for tid 0
>
> Regards,
> Chun-Yeow
>
> On Wed, Nov 9, 2011 at 5:13 AM, Thomas Pedersen <[email protected]> wrote:
>>
>> Hi Chun-Yeow,
>>
>> Have you had any success?
>>
>> I did not have time to properly to properly test throughput in a
>> secure mesh laste time, but now with our ft-ht-mesh + ft-mesh-fixes
>> branches, I'm seeing 55.5Mb/s TCP throughput with a 243Mb/s datarate.
>> Throughput in the non-secure case is more like at least 100Mb/s, so it
>> seems we have quite a bit of overhead.
>>
>> Thomas
>>
>> On Thu, Nov 3, 2011 at 6:28 PM, Yeoh Chun-Yeow <[email protected]>
>> wrote:
>> > Hi, all
>> > Ok. I need to reconfigure authsae in htmode to HT20 and transmission
>> > rate
>> > increased up to 104Mbps with TCP throughput about 7Mbps.
>> > But as Thomas pointed out, aggregation is not working.
>> > Regards,
>> > Chun-Yeow
>> >
>> > On Fri, Nov 4, 2011 at 9:04 AM, Yeoh Chun-Yeow <[email protected]>
>> > wrote:
>> >>
>> >> Hi, all
>> >> I have captured the packet via Wireshark. It shows that the bit rate
>> >> used
>> >> by the two mesh nodes is 6Mbps. That's why the throughput is low.
>> >> Regards,
>> >> Chun-Yeow
>> >> On Fri, Nov 4, 2011 at 1:50 AM, Thomas Pedersen <[email protected]>
>> >> wrote:
>> >>>
>> >>> It seems ADDBA requests are dropped by a peer when security is
>> >>> enabled, thanks for reporting this!
>> >>>
>> >>> Thomas
>> >>>
>> >>> On Thu, Nov 3, 2011 at 9:41 AM, Thomas Pedersen <[email protected]>
>> >>> wrote:
>> >>> > Hi Chun-Yeow,
>> >>> >
>> >>> >> Using authsae, I only managed to get 4Mbps. However, without SAE, I
>> >>> >> managed
>> >>> >> to obtain 60Mbps using iperf 10 parallel TCP streams.
>> >>> >> Others are getting the same results? It seems that performance drop
>> >>> >> is
>> >>> >> too
>> >>> >> significant.
>> >>> >
>> >>> > Did you set the correct channel type with iw before bringing up
>> >>> > authsae?
>> >>> >
>> >>> > Thomas
>> >>> >
>> >>
>> >
>> >
>
>



-- 
Javier Cardona
cozybit Inc.
http://www.cozybit.com
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