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In short:

• sFTP throughput is reduced using a high latency connection
  
• Testing has ruled out: encryption processing overhead, traffic shaping and network speed issues
  

I'm using the latest nightly build with the fix for sFTP transfers, but am finding odd issues with sFTP throughput. With some machines (actually overseas from server) the sFTP throughput in FileZilla Client is great, 900 KBps, plenty speed for most needs. However, on these machines, XBMC will only transfer at approx 150 KBps and cause a lot of buffering. Using FTP I get full speeds in XBMC, but not sFTP to the same server.

These are Windows 7 and Windows 8 x64 machines running the Jan 28th nightly. The sFTP scanner bug in Frodo prevents me from testing in that. I've also tried: netsh interface tcp set global autotuninglevel=disabled on the machines with no luck and disabled security software. Thanks

Edit: Found a link between latency and slow sFTP connections discussed below.

I've done additional testing and seen that the slow sFTP throughput is exclusively linked to high latency connections above 100ms ping to the server. However, other sFTP client applications have no issues on the same machine downloading the same media. As well XBMC functions correctly in FTP mode on those machines. In a low latency environment, sFTP functions great in XBMC.

Additional testing has been done to rule out encryption processing overhead, traffic shaping and network speed issues as seen by the testing in the diagram below.

Here is the setup that shows it works perfectly fine in all but one case. These are my actual testing results using 5 different WAN networks. These are clients each using different ISPs.



A bug report has been posted here: http://trac.xbmc.org/ticket/14038

Can anyone replicate the issue or see a problem?

Hi sunnyd71,

I am having similar issues with my installation.

On the internal network I have absolutely no problem to use SFTP for SD and HD content.
Also using a Mac SFTP file transfer on the remote Mac works like a charm and gets me 640KB/s while an XBMC client only gets about 14xx ish KBit/s on the same network which is about 170KB/s and not enough for SD.

I will run some additional tests over the next days but at first sight it seems that we share the same problem.

Regards

I am also getting the same issues with my setup on opnelec. Very slow transfer speeds on ftp and sftp from my remote server. On another computer in the house i can use up the full bandwidth of my connection when connecting to the remote ftp server.

I just tried to stream from my server over sftp and I can confirm the problem/bug in OP. The XBMC fills the buffer and then play the file 10-15 sec and then stops to buffer again. The server is 100/100 and my home connection is 50/5.