VO AC may not use ampdu aggregation so double check that. The reason is that VO are small packet payloads (~200 bytes) and have low relative frequency of transmits. A wireless driver waiting around to fill an AMPDU from a VO queue will cause excessive latency and impact the voice session. Many drivers won't aggregate them. Since VO isn't likely using ampdus and since it has the most preferred wme access settings, a 40 Mb/s iperf flow with VO is going to consume most all the TXOPs. The other access classes won't have many TXOPS at all. (The whole point of WiFi aggregation technologies is to amortize the media access cost which is expensive per collision avoidance. A rough theoretical max estimate for TXOPs is 10,000 per second.) Maybe measure the packets per second of just VO to get an empirical number. It's probably better to reduce this to something more typical of lets say 10 voice calls (or 20 call legs.)
You might also want to consider measuring "network power" which, while a bit of a misnomer, is defined as average throughput over delay. Also, maybe consider changing AIFS too. This can lead to interesting things. Not sure you're exact goals but just some other things to consider. Bob On Tue, Nov 20, 2018 at 9:08 AM Kasper Biegun <kas...@alert.pl> wrote: > Hi Bruce, > > I am making a thesis project and I have to measure influence of a-mpdu > and TXOPlimit on the 802.11ac network efficiency and I have to obtain > plot of BK, BE, VI and VO throughputs, when they are running at the same > time. I have to measure some scenarios with different ampdu sizes and > when TXOPlimit is enabled and disabled. > > Thank you very much for your help, thanks to you I was able to run the > tests, but I am still having some troubles. > > Today I have tried running tests again, but with lower iperf bandwidth > (and window parameter) and it worked better, because I was able to run > all four tests at the same time. But I had troubles with the highest > priority traffic VO - it "takes" whole bandwidth. I mean that when I set > e.g bandwidth (-b) to 40Mbits, VO traffic takes 40Mbits (the rest > 20Mbits is divided to the rest of traffics) and it is undesirable during > my measurements, because it is like manual limitation than network > limitation. > > > Example command: > > #iperf3 -c 10.10.0.1 -p 5025 -b 40M -u -S 0xc0 -i 1 -w 8192B --bind > 10.10.0.2 --cport 5023 > > > Kasper > > > W dniu 2018-11-20 o 00:24, Bruce A. Mah pisze: > > If memory serves me right, Kasper Biegun wrote: > > > >> to connect server and client I am using WiFi 5GHz (802.11ac), band: > >> 20MHz with MCS (7 or 8) so I can get 65 to 78 Mbit/s. When I am testing > >> now, I get around 60Mbit/s for the first test and after that second test > >> starts and reaches around 60Mbit/s. But according to my assumptions it > >> should work at the same time and divide possible bandwidth (I set values > >> of TXOPlimit according to 802.11ac standard). > > Hi Kasper-- > > > > I'm not sure why the tests are serialized. The only thing I can think > > of is that the first test has completely blocked the wireless link so > > that the second test can't even start. > > > > Wait. You're testing over wireless? Yet you're doing 1000Mbps = 1Gbps > > tests. I don't think there's any wireless link that can handle two > > 1Gbps tests, or even one. I think you really are saturating the link. > > Because the tests are using UDP they'll just blast out packets at > > whatever rate you specify regardless of whether the path is actually > > capable of supporting it. You need to turn down the bitrate on both > > tests (especially the first). What scenario are you trying to simulate > > anyway? > > > > Bruce. > > > >> W dniu 2018-11-19 o 21:50, Bruce A. Mah pisze: > >> > >>> If memory serves me right, Kasper Biegun wrote: > >>> > >>>> currently I'm working on project connected with testing UDP throughput > >>>> for different QoS values. To get the needed results I have to use Best > >>>> Effort (0x70), Background (0x28), Voice (0xc0) and Video (0xb8) > traffic > >>>> at the same time. I have troubles with running them, because one > stream > >>>> was waiting for another to finish or if they started - only one was > >>>> working (the rest had 0 bandwidth). Then I updated iperf to newest > >>>> version available on github and installed it. Now, for testing > purposes, > >>>> I am running only Voice and Video at the same time, and I am still > >>>> getting the same issue - one transfer is waiting for the second one to > >>>> finish. > >>>> > >>>> I am using commands: > >>>> > >>>> - on server: #iperf3 -s -p 5015 and #iperf -s -p 5020 > >>>> > >>>> - on transmitter: #iperf3 -c 10.10.0.1 -p 5015 -S 192 --bind > >>>> 10.10.0.2 --cport 5013 -u -b 1000m and > >>>> > >>>> #iperf3 -c 10.10.0.1 -p 5020 -S 184 --bind 10.10.0.2 --cport > >>>> 5018 -u -b 1000m > >>>> > >>>> Server is working on Ubuntu 16.04 and transmitter is on Raspberry Pi > 3. > >>>> > >>>> > >>>> Could you please help me with that? > >>> Hi Kasper-- > >>> > >>> Is it possible that one test is starving the other? What is the > >>> bandwidth on the path between your server and client? > >>> > >>> (For what it's worth you're setting up the tests correctly by using two > >>> independent sets of client and server.) > >>> > >>> Bruce. > >>> > > > > > > _______________________________________________ > Iperf-users mailing list > Iperf-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/iperf-users >
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