Comment 34 for bug 408165

Hi,
I have been battling to get my WUSB600N V2 to work reliably for a few weeks and I think that my experiences are relevant to this thread even though it is not strictly speaking a pure Ubuntu install which I am using.

Before I go too far, and before I violate some rule about acceptable usage of launchpad, I would like to mention that I am actually using Linux Mint 7 32bit, which as I understand is built on Ubuntu 9.04 (Jaunty).

Following the excellent advice from this tread I am able to get a *solid* connection using 5Ghz band and network-manager says that I am connected at 270Mbps.

By *solid* I mean that for regular surfing the net, everything works great and I can leave my Linux box on for hours and it never looses the connection. However, I experience audio glitches when streaming AAC audio to my Linux media center. I am wondering if others who think they have a fully working WUSB600N V2 might also have the same problem but are not aware of it yet. NOTE, if I stream MP3 instead, I do not see these audio glitch problems. I am guessing that it has to do with packet size difference maybe.

I wonder if there are still some issues with the ralink driver that need to be investigated??

I am using the latest ralink rt3572 driver [2.3.0.0] from the ralink website, I ran make and make install to install it as per instructions which I gathered from this thread.

Essentially I get the same results from iwlist/iwpriv as Yohann reported above. The only thing to note is that my makefile is NOT identical, I have one difference - in mine I have 'HAS_KTHREAD_SUPPORT n'

The symptoms:
when streaming AAC audio files from my Windows (samba) share to my Linux box I get frequent 2 second glitches in the audio (about three times in a 4 minute song) . I used Gnome Mplayer, VLC and also Boxee for my testing.

The audio glitches do not happen if I use wired 1Gbps Ethernet connection

Testing/observations:
When I experience the audio glitches, Wireshark reports "TCP: Retransmission" (interestingly, no retransmission events occur when using wired connection)

If I move the WUSB600N V2 to a Windows XP home box and stream the same AAC from the first Windows box (the one which I used for the windows share for my Linux tests) I experience zero audio glitches, this is even though the windows box reports low signal (two bars) and a 40.5Mbps connection! On the windows box I also connect using 5Ghz band.

I have am using the 5Ghz band. I have no microwave oven or other interference source nearby.

network-tools reports zero transmit errors, zero receive errors, zero collisions

I will upload the Wireshark results so you can see the TCP Retransmission events. I will also include the same capture, but for the wired connection, here you will see that there are no TCP retransmissions. The attachment is a zip file containing two CSV files which can be viewed in open office or Excel. One file is for the wireless result, the other is for the wired (1Gbps) result

The other possible issue I am seeing is with the data transfer rate. If I copy a 3+Gb file from my windows box to my Linux box it takes 908 seconds, this works out to be:

  3,171,522,212/908 = 3.49 Mbytes per second

This sounds slow to me, considering that my Linux box says that it is connected at 270Mbps

any help would be very much appreciated.