Wireless Access

I have a lab with a msm710 and 2 msm422 connected to a 1gbit lan with jumbo frames enabled. (mtu 9000) MSM 422s both show high rates of rx fcs errors. I can consistently reproduce this error: when transferring large files over wlan i get 10 -15 mbyte pr sec until file transfer stalls, after that speed goes down to a matter of kbytes. all other activity on wlan link gets impacted with slow performance. To recover I have to disconnect from wlan and reconnect. Intel wlan card 6250 with driver 14.x. Firmware 5.51 on 710 and 422.
Could this be caused by jumbo frames on the LAN side?

 

 

P.S. This thread has been moved from Communications, Wireless (Legacy ITRC forum) to MSM Series. - Hp forum Moderator

Jumbo frames are Etherent so this will not effect the wireless. FCS typically means cable issue or possible duplex mismatch.

Also, just out of interest, what Wireless Cards are in the machines you are having the issues with.

Trev.

I should have been more clear on this. The fileserver i'm transferring files to and from is on ethernet behind the MSM422s all connected to a switch which is also jumbo frame capable, hence ethernet jumbo frames could come into play. The rx fcs errors is what's leading me towards the jumbo frame issue. I have seen this issue through 3 generations of Thinkpads all with Intel wirreless cards: 3945, 6300 and 6250. I have also seen it through 3 versions of msm422 firmware: 5.36, 5.42 and 5.51.

For a large frame to be transmitted intact from end to end, every component on the path must support that frame size. the Wireless NIC does not support it so it will not be on. if you are trasmitting jumbos then you should see drops on the msm422 lan port possibly.

run a wireshark trace on the msm422 lan port and see what type of frame size you are getting.

if you are running windows7 i would be interested to know if the trace shows "tcp windw full".

trev.

Well, in short it makes sense that the 422 limits mtu on the lan interface if there is no layer 3 packet MTU discovery in the unit capable of fragmenting packets, hence dropping the jumbo frames. But if it is, I would love to see a LAN interface on this unit with MTU packet size selection. In the meantime I'll bite the dust and put the whole MSM family on a different VLAN with a layer 3 device in between the jumbo vlan and non jumbo vlan.

what OS are you running when you run the Test?

Reason I ask is I am having the same issue with the Freez and copy stopping and I was hoping I was not alone.

Trev.

Windows 7 x64 on all tests. intel drivers from 12.x to 14.x. In the process of seperating MSM family into seperate vlan without jumbo frames.

After relocating MSM family to a non jumbo vlan original problem still exists. Copying large files over wlan suddenly stalls and wlan link speed crawls afterwards. There has to be a bug in msm firmware causing this. RX FCS error count are still high.

Hi, i'm just checking to see if there is a solution to this issue. I have the same thing, if i switch off N on radio 1 of the msm422 everything runs fine. Include copying large files. I have updated today to the new firmware 5.5.2.14 and it has made no difference.