Wireless Networking - Linksys WRT350N and Intel 4965AGN

That sounds like a right pain Jamie

I've not had anything similar, but I haven't used that combination.
There are quite a few reports of problems with those two devices, including on the Linksys forums, and Vista is regularly blamed - but other people seem to find it will connect but only at g speeds.

It does seem that there were incompatibility problems between the N versions on the Intel card and the Broadcom silicon on the router - but these should only affect its ability to do N, not to connect at all.

http://forums.linksys.com/linksys/board/message?board.id=Wireless_Routers&thread.id=33874&view=by_date_ascending&page=9

Updated by PeterJudge on Nov 12, 2008 2:47 PM

It is indeed a pain, Peter. I was shocked when I discovered that it was not a Vista problem - I guess there are a few cases where we are all a bit too anxious to blame anything on Vista. I looked at quite a bit of the discussion in the Linksys forums, and I couldn't find a single case where there was a clearly reported "solution", or even a definite identification of what the problem really is, or where it is. That's quite unusual, as there tends to be good solution there, sooner or later.

There are a couple of things I would like to try, changing the settings of the router, but several other people use my wireless connection, so I can't just take it down and change it at will.

In the process of swapping disk drives in my laptop, I noticed that the Intel 4965 module was easily accessible. On a hunch, I looked around to see if I could get a compatible newer Intel module around here, and found both 5100 and 5300 cards available at a reasonable price. So I have ordered a 5300, I'm hoping that I can just swap it in place of the 4965, and see if that makes any difference.

jw 12/11/2008

Posted by J.A. Watson on Nov 12, 2008 2:40 PM

Jamie:
Try turning off the 802.11 configuration or wireless networking PnP services in the offending OS. If the packet coming from the computer is already formatted as 802.11x, it passes straight through the device. XP doesn't have that natively, the packet has to be processed or converted into 802.11n format by the wireless device first. Vista will "talk" straight through the Ethernet radio and has its own WPA encryption. It also is smart enough when UPnP is turned on to enable the pass-through wireless function but the LinkSys might not recognize the Vista formatted 802.11n packets. The other Linux OS's I'm not sure about although Fedora probably will do as Vista does since Enterprise RedHat has a similar capability.

Updated by Xwindowsjunkie on Nov 12, 2008 4:21 PM

Well, I might have stumbled across a solution for this problem. It's still a bit early, but so far it looks good. First, thanks for the sympathy and suggestions from Peter and Xwindowsjunkie. I did follow up on both of those, and it was in the process of looking into them and trying various things that I hit what I have now which appears to work.

What I have done is change a couple of settings in the Linksys router. From the Linksys setup menu go to Wireless, and then Advanced Wireless Settings. There are settings for Fragmentation Threshold and RTS Threshold, both of which default to 2436 bytes. I have lowered them both to 2048.

As soon as I made this change to the router, Ubuntu, Fedora and MEPIS Linux were able to get a wireless connection, and XP was still able to connect. I have not yet tried Vista, as I didn't have that disk at home over the weekend. I did reboot between each of those operating systems multiple times, both last night and this morning, and the wireless connection came up every time.

As I said, it is still too early for me to be certain this has fixed the problem. I have seen it with Vista when I was able to connect, repeatedly, for a day or so before it stopped, so I want to get through a couple of days this way before I will feel confident that this does the trick. This evening I will be trying with Vista, Mandriva and openSuSE as well.

I'm keeping my fingers crossed.

jw 17/11/2008

Updated by J.A. Watson on Nov 17, 2008 10:19 AM

Update: Mostly good, with one (unsurprising) exception. I did quite a bit more testing yesterday evening, and the wireless connection continued to work flawlessly from XP and every version of Linux that I tried (Ubuntu, Mandriva, MEPIS, Fedora and openSuSE). I then swapped in the Vista disk, and it does NOT work. When I looked in the Vista Network Center, it said that the wireless adapter was connected, but it couldn't get an IP address, it couldn't identify the network, and it couldn't get a route to the internet.

So, with the reduction in the packet sizes, the situation has changed from "XP connects and nothing else does" to "Everything connects except Vista", but I still can't explain why, for either of those situations. I will continue watching it this week, and fine-tuning the parameters to see if I can figure out anything else.

jw 18/11/2008

Updated by J.A. Watson on Nov 18, 2008 10:47 AM