WZR-AGL300NH and Intel 5100agn - slow 802.11n upstream

[Mandos]

   

Hello,

 

I am using a Fujitsu notebook with Intel WiFi Link 5100agn and the WZR-AGL300NH, firmware 1.50. Downstream at 802.11n 5GHz/40MHz is OK (7 to 8 MBytes/s for a Windows file transfer from a computer connected to the wired LAN to the notebook), but upstream is only 500kBytes/s. An 802.11g connection has a much faster upstream than the 802.11n.

 

The slow upstream speed is there regardless of the router mode; it is the same when I set the WZR-AGL300NH as an access point. The wired network is 1000Mbit Ethernet.

 

I tried the WLAN driver from Fujitsu (12.2.0.11) and the latest from Intel (12.4.0.0); there was no difference.

 

The notebook runs Windows Vista Home Premium x64; I tried the file transfer with two desktop PCs, one with Vista Home Premium x64, the other with XP Professional.

 

Does anyone here know about this effect?

 

Mandos

 

I have done some more tests, and it seems that at least a part of the effect comes from the wired LAN side. It is much better if the WZR-AGL300NH is connected to a 100Mbit switch instead of a gigabit switch. Another strange effect is that it does not appear directly when I start the router; it takes some time, but after that not even a router reboot helps.

 

Mandos

Message Edited by Mandos on 04-16-2009 06:28 PM

[Vaesto]

   

Hi,

 

I own the same WZR-AGL300NH but my clien't device is Linksys WUSB600N. And I have very similar performance problem - I can't achieve Wireless-N speed not even close.

 

At the direct range of 1 m. (3 ft.) Linksys' "Wireless Monitor Utility" shows "theoretical" speed of 270/108 (up/down) for the 5 GHz band and 40 MHz wide channel with no radio neighbours!. BUT - these speeds are on IDLE, when you start downloading or uploading (e.g. ftp) the speeds DROP to 162/54 or even worse. This was tested on 3 PC - results were stable:  I had never seen more than 108 Mbps on "download" speed regardless range and direct visibility, speed constantly droped upon starting downloads/uploads.  

 

In fact actual speed I've got now - 6-8 MBps is slightly better or equal to Wireless-G. This is not the way it should work, my ISP is faster than that!

 

Only hope I have - new firmware which may fix (if possible) this device's problems. But unlike other manufacturers Buffalo doesn't hurry with updates

 

Regards,

Vaesto

[Mandos]

   

Hi Vaesto,

 

I have done another test. This time I connected my notebook by gigabit ethernet. Even then the maximum data rate is less than 13MBytes/s. While I transfer the data, the web interface is so slow that it is all but unusable. The router's CPU seems to be unable to keep up with the demands of a fast data transfer. However, the fact that only the upstream rate through 802.11n@5GHz decreases over time also suggests that there may be some bug in the firmware. The wireless connection speed shown by my notebook is rarely less than 150Mbits/s. Unfortunately the software does not show separate values for upstream and downstream.

 

Regards,

Mandos

[Vaesto]

   

WAN port is only 100 mbps, so if you using it 13 MBps is O.K.

[Mandos]

   

Hi Vaesto,

 

OK, so it says in the manual, but if you set the speed to "Auto" and connect the internet port to a gigabit switch, the diagnostics page shows the wired link as "1000Base-TX". Downstream in this setup is fine, but upstream is slowing down with time. The same happens if I use the WZR-AGL300NH as an AP. If it is connected to a gigabit switch via any of its ethernet ports, upstream slows down.

 

Now for something really weird: I set the WAN port to 100Base-TX full duplex (Internet/LAN advanced settings), and then the downstream was extremely slow!

 

The end result of all these tests is that this router does not work correctly when connected to a gigabit ethernet infrastructure. For now, I leave it connected to my 100base-TX switch, but as its gigabit capability is clearly advertised, I still expect a firmware update that fixes the problem.

 

Thanks for your help!

 

Mandos