I think I should make something a bit more clear regarding this post. In that I am working with a mesh network, I am running these tests over multiple hops. For the previous email I sent, I was transferring over 2 hops:
A->B->C I doubt that I am at the capacity of the network card, because when I cut the number of hops down to 1: A->B I am able to achieve a much high send rate. Here is the same 10Mbps report, only this time for one hop (and yes I am running this many times to make sure this isn't an anomaly) : ------------------------------------------------------------ Client connecting to 5.0.0.9, UDP port 4000 Sending 1470 byte datagrams UDP buffer size: 112 KByte (default) ------------------------------------------------------------ [ 3] local 5.0.0.1 port 59795 connected with 5.0.0.9 port 4000 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.0 sec 12209 KBytes 10000 Kbits/sec [ 3] Sent 8505 datagrams [ 3] Server Report: [ 3] 0.0-10.0 sec 12198 KBytes 9991 Kbits/sec 0.327 ms 7/ 8504 (0.082%) [ 3] 0.0-10.0 sec 1 datagrams received out-of-order It seems as though the longer my chain of nodes are, the lower my max send rate can be. The issue is that I am running UDP, which, unlike TCP, doesn't care about reliability (and therefore doesn't send any ACKs). So, why is iperf (or something else) causing my maximum send rate to suffer? I will be posting the plateau of one hop as soon as the tests are done. Randy On Tue, Apr 27, 2010 at 10:04 AM, Randy Buck <sutekistud...@gmail.com>wrote: > Hi, > > I'm working on a *wireless* mesh network and am trying to use iperf to > benchmark performance. I'm running into an issue that has been very > troublesome to understand. I am using the following setup: > > OS: Ubuntu 9.10 > Wireless chipset: Aetheros > Wireless driver: ath5k (included in 9.10) > Let me know if I've left anything out.... > > > Here is how I am starting the server: > iperf -s -u -p 4000 > > Here is what I am running on the client: > iperf -u -fk -c 5.0.0.9 -b 10000K -p 4000 -t 10 > > Note that I understand that the bandwidth is really 10 Mbps, I'm simply > leaving in terms of Kbps for graphing purposes. > > Here is my output: > > ------------------------------------------------------------ > Client connecting to 5.0.0.9, UDP port 4000 > Sending 1470 byte datagrams > UDP buffer size: 112 KByte (default) > ------------------------------------------------------------ > [ 3] local 5.0.0.5 port 38669 connected with 5.0.0.9 port 4000 > [ ID] Interval Transfer Bandwidth > [ 3] 0.0-10.0 sec 8343 KBytes *6834 Kbits/sec* > [ 3] Sent 5812 datagrams > [ 3] Server Report: > [ 3] 0.0-10.1 sec 8137 KBytes 6631 Kbits/sec 0.698 ms 143/ 5811 > (2.5%) > [ 3] 0.0-10.1 sec 1 datagrams received out-of-order > > My concern is that I am not sending at 10 Mbps, but rather at 6.8 Mbps. I > need to be able to send at 10 Mbp; I don't care what the packet loss is, I > just need to be able to see what it is in terms of what I configured iperf > to send at (10 Mbps). > > When I run over the *wired* network, I get what I expect (namely that I > always send at the correct sending rate). The send rate is much higher for > the wired network: > > Here is how I am starting the server: > iperf -s -u -p 4000 > > Here is what I am running on the client: > iperf -u -fk -c mesh9 -b 200000K -p 4000 -t 10 > ------------------------------------------------------------ > Client connecting to mesh9, UDP port 4000 > Sending 1470 byte datagrams > UDP buffer size: 112 KByte (default) > ------------------------------------------------------------ > [ 3] local 192.168.21.205 port 56030 connected with 192.168.21.209 port > 4000 > [ ID] Interval Transfer Bandwidth > [ 3] 0.0-10.0 sec 247418 KBytes *202684 Kbits/sec* > [ 3] Sent 172351 datagrams > [ 3] Server Report: > [ 3] 0.0-10.3 sec 117083 KBytes 93574 Kbits/sec 13.143 ms 90780/172340 > (53%) > [ 3] 0.0-10.3 sec 1 datagrams received out-of-order > > > Why does iperf (or my wireless card, or my OS, or something else) not send > at the full rate when transferring wirelessly? I'm beginning to believe > that iperf is not the tool to use for wireless measurements. Are there any > better solutions? > Thanks for all your help, > > Randy > >
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