[ippm] Re: iperf2 Android update: Bounceback fixes and IPv 6 support

bob.mcmahon=40umbernetworks.com-Tr9gZwTxerDR74oF6e/[email protected] Thu, 23 Jul 2026 23:38:59 -0700
Newsgroups gmane.ietf.ippm,gmane.ietf.tsvwg,gmane.ietf.irtf.iccrg
Message-ID <[email protected]>
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Hi All,

I've updated the iperf 2 android bounceback test to display the 
histogram with a CDF overlay. UDP L4S bounce back is still beind coded 
up and tested.

On 2026-07-22 11:57, bob.mcmahon-lsms57Fp2aVqO0yjgLDq5wC/[email protected] wrote:

> Hi all,
> 
> An updated iperf2 Android build is available with two Bounceback fixes.
> 
> First, a bug that caused responsiveness and RPS tests under working 
> load to fail after a few seconds has been fixed. The update has been 
> verified with a 50-second Bounceback run under load.
> 
> Second, the selected congestion-control algorithm now applies at both 
> ends of the Bounceback connection. Anyone comparing congestion-control 
> algorithms should repeat those tests with this build.
> 
> The public responde.* servers support Reno, Cubic, and BBR, with Cubic 
> as the default. They do not currently support Prague. Prague testing 
> requires both a server and a device with Prague available.
> 
> The public servers have already been updated. If you use your own 
> iperf2 server, please update it from the 2-2-2 branch.
> 
> The public servers limit tests to 60 seconds, so please select a 
> shorter duration.
> 
> Android client presentation:
> 
> https://www.umbernetworks.com/IPPM_iperf2_Android_Pres.html
> 
> INSTALL THE UPDATED APK
> 
> Download this exact file from the SourceForge file listing:
> 
> iperf2.2.2_21.bb_cca_fix.July2026_android.apk
> 
> https://sourceforge.net/projects/iperf2/files/
> 
> Please select the filename directly rather than using the green 
> Download button, which may retrieve a different file. The APK can be 
> installed over an existing version.
> 
> FEATURES WORTH TESTING
> 
> Bounceback now displays the minimum RTT reported by the kernel's TCP 
> statistics, together with a theoretical RPS ceiling:
> 
> Theoretical RPS ceiling = 1,000 ms / minimum TCP RTT
> 
> For example, a minimum TCP RTT of 20 ms gives a theoretical ceiling of 
> 50 request-and-reply cycles per second.
> 
> Minimum RTT is a TCP statistic, while observed RPS is measured from the 
> application-level Bounceback exchanges. Because each request waits for 
> its reply before the next request is sent, actual RPS will normally be 
> lower because of application processing, scheduling, working load, and 
> other path effects.
> 
> The public responde.* servers in Fremont, Vienna, and Newark also 
> support IPv6. The app can select IPv6 normally through the Host field, 
> or you can enable Force IPv6 (-V) to test the IPv6 path explicitly. 
> Your local network must also support IPv6.
> 
> Thanks again to everyone testing the app and providing feedback. It is 
> very helpful.
> 
> Bob
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=3DUTF-8" /></head><body style=3D'font-size: 10pt; font-family: Verdana,Gen=
eva,sans-serif'>
<p id=3D"reply-intro">Hi All,<br /><br />I've updated the iperf 2 android b=
ounceback test to display the histogram with a CDF overlay. UDP L4S bounce =
back is still beind coded up and tested.<br /><br /><br /><img src=3D"https=
://media.licdn.com/dms/image/v2/D5622AQHzjFPpLxtchQ/feedshare-shrink_160/B5=
6Z.S0MmwIoAk-/0/1784874584804?e=3D1786579200&amp;v=3Dbeta&amp;t=3D3iw9Nhx2O=
AmCDFcwcohx3N8n3k_4dmvWGXZPUcIzV5M" alt=3D"View image" /></p>
<p><br />On 2026-07-22 11:57, bob.mcmahon-lsms57Fp2aVqO0yjgLDq5wC/[email protected] wrote:</p>
<blockquote type=3D"cite" style=3D"padding: 0 0.4em; border-left: #1010ff 2=
px solid; margin: 0">
<div id=3D"replybody1">
<div style=3D"font-size: 10pt; font-family: Verdana,Geneva,sans-serif;">
<p>Hi all,</p>
<p>An updated iperf2 Android build is available with two Bounceback fixes.<=
/p>
<p>First, a bug that caused responsiveness and RPS tests under working load=
 to fail after a few seconds has been fixed. The update has been verified w=
ith a 50-second Bounceback run under load.</p>
<p>Second, the selected congestion-control algorithm now applies at both en=
ds of the Bounceback connection. Anyone comparing congestion-control algori=
thms should repeat those tests with this build.</p>
<p>The public responde.* servers support Reno, Cubic, and BBR, with Cubic a=
s the default. They do not currently support Prague. Prague testing require=
s both a server and a device with Prague available.</p>
<p>The public servers have already been updated. If you use your own iperf2=
 server, please update it from the 2-2-2 branch.</p>
<p>The public servers limit tests to 60 seconds, so please select a shorter=
 duration.</p>
<p>Android client presentation:</p>
<p><a href=3D"https://www.umbernetworks.com/IPPM_iperf2_Android_Pres.html" =
target=3D"_blank" rel=3D"noopener noreferrer">https://www.umbernetworks.com=
/IPPM_iperf2_Android_Pres.html</a></p>
<h2>Install the updated APK</h2>
<p>Download this exact file from the SourceForge file listing:</p>
<p>iperf2.2.2_21.bb_cca_fix.July2026_android.apk</p>
<p><a href=3D"https://sourceforge.net/projects/iperf2/files/" target=3D"_bl=
ank" rel=3D"noopener noreferrer">https://sourceforge.net/projects/iperf2/fi=
les/</a></p>
<p>Please select the filename directly rather than using the green Download=
 button, which may retrieve a different file. The APK can be installed over=
 an existing version.</p>
<h2>Features worth testing</h2>
<p>Bounceback now displays the minimum RTT reported by the kernel's TCP sta=
tistics, together with a theoretical RPS ceiling:</p>
<p>Theoretical RPS ceiling =3D 1,000 ms / minimum TCP RTT</p>
<p>For example, a minimum TCP RTT of 20 ms gives a theoretical ceiling of 5=
0 request-and-reply cycles per second.</p>
<p>Minimum RTT is a TCP statistic, while observed RPS is measured from the =
application-level Bounceback exchanges. Because each request waits for its =
reply before the next request is sent, actual RPS will normally be lower be=
cause of application processing, scheduling, working load, and other path e=
ffects.</p>
<p>The public responde.* servers in Fremont, Vienna, and Newark also suppor=
t IPv6. The app can select IPv6 normally through the Host field, or you can=
 enable Force IPv6 (-V) to test the IPv6 path explicitly. Your local networ=
k must also support IPv6.</p>
<p>Thanks again to everyone testing the app and providing feedback. It is v=
ery helpful.</p>
<p>Bob</p>
</div>
</div>
</blockquote>
<p><br /></p>

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