Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.




1429 posts

Uber Geek
+1 received by user: 189

Trusted

# 251119 9-Jun-2019 21:25
Send private message quote this post

I have been having issues with international speeds recently and at a loss as to why.

 

@NickMack and the team at 2Degrees have been an awesome help with this issue; sending out some test gear to assist with troubleshooting the issue.  (Thanks again guys!)

 

The conclusion of the testing with 2D was that my network, Internet connection and PCs were all fine, the problem was something specific to Windows.  Speeds in Linux were fine.

 

However, nothing I tried made any difference until I discovered this article:
https://argonsys.com/microsoft-cloud/library/windows-network-performance-suffering-from-bad-buffering

 

 

 

As a result I discovered that iPerf3 v3.1.3 for Windows (the latest stable release) comes bundled with a version of Cygwin1.dll (2.5.1) which has a hard-coded TCP window size setting of 278,775.

 

This causes results to be limited to 12.6Mb/s per thread.

 

This is why iPerf speeds in Linux are much better that in Windows.

 

Updating the Cygwin dll to the latest version resolves this issue and I now get the International speeds I am expecting when testing with iPerf.

 

I have informed the iPerf devs of this issue.

 

 

 

As a side-note, speeds with Speedtest.net and nperf to the US are still pretty much rubbish.  I'm not sure why, because they used to be fine.  At then end of the day iPerf (with updated Cygwin1.dll) is the most reliable testing method by far.


Create new topic
187 posts

Master Geek
+1 received by user: 77


  # 2257076 12-Jun-2019 22:04
One person supports this post
Send private message quote this post

You're probably better off with WSL rather than a Cygwin build.

'That VDSL Cat'
10398 posts

Uber Geek
+1 received by user: 2500

Trusted
Spark
Subscriber

  # 2257077 12-Jun-2019 22:13
Send private message quote this post

Yup, window size being fixed will certainly do it. Moment i saw the title i was going to comment on tcp/ip tuning...

 

 

 

 

 

it will prove that your connection is able to consistently perform, but in your day to day you will still be expecting the applications and kernel to do it's thing.

 

Windows has also had a few cases of some REALLY bad drivers...

 

 

 

i'd blame the slow speeds on Nick or Ricky personally... but then i'd do that just to stir them up too.. ;)





#include <std_disclaimer>

 

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.


Create new topic



Twitter and LinkedIn »



Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

Xero announces new smarter tools, push into the North American market
Posted 19-Jun-2019 17:20


New report by Unisys shows New Zealanders want action by social platform companies and police to monitor social media sites
Posted 19-Jun-2019 17:09


ASB adds Google Pay option to contactless payments
Posted 19-Jun-2019 17:05


New Zealand PC Market declines on the back of high channel inventory, IDC reports
Posted 18-Jun-2019 17:35


Air New Zealand uses drones to inspect aircraft
Posted 17-Jun-2019 15:39


TCL Electronics launches its first-ever 8K TV
Posted 17-Jun-2019 15:18


E-scooter share scheme launches in Wellington
Posted 17-Jun-2019 12:34


Anyone can broadcast with Kordia Pop Up TV
Posted 13-Jun-2019 10:51


Volvo and Uber present production vehicle ready for self-driving
Posted 13-Jun-2019 10:47


100,000 customers connected to fibre broadband network through Enable
Posted 13-Jun-2019 10:35


5G uptake even faster than expected
Posted 12-Jun-2019 10:01


Xbox showcases 60 anticipated games
Posted 10-Jun-2019 20:24


Trend Micro Turns Public Hotspots into Secure Networks with WiFi Protection for Mobile Devices
Posted 5-Jun-2019 13:24


Bold UK spinoff for beauty software company Flossie
Posted 2-Jun-2019 14:10


Amazon Introduces Echo Show 5
Posted 1-Jun-2019 15:32



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.


Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.