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timlang 09-03-2010 03:35 PM

No BB Wifi Connectivity with multiple APs (roaming)
I am having a very strange problem with all our blackberries (about 12 Bold 9700 units) at our main office:

We have a SonicWall NSA240 UTM Router with 4 SonicPoint-N wiress access point radios. These sonicpoint share the same profile (ie: a single SSID/access profile across all of them to facilitate wireless roaming throughout our facility).

All Laptops (PC and MAC), Iphone and Ipads are working great. But I am having a strange problem with all our blackberries:

When I enable only one single sonicpoint (disable all the others), the blackberry works fine with the sonicpoint. As soon as I have more than one sonicpoint enabled, the blackberry will connect to one and get an IP address, work for a few seconds or minutes, but once it notices the other APs, it looses data connectivity (ie: cannot ping back to the gateway or out into the world). As soon as I disable all but one sonicpoint, it works fine again.

I am not using any MAC or RADIUS access control. Just simple WPA-PSK security (I have experimented using WPA, WPA2 and WPA/WPA2 Auto, as well as AES, TKIP and Auto encrpyption - all with similar results).

In looking at the wifi diagnostics in the blackberry, and the sonicpoint station status - the blackberry is not roaming excessively. After I turn on additional stations (beyond the first one), and the blackberry looses connectivity - I can see that it is still associated with the first (closest) station it originally connected to, but no data is flowing.

This problem is not intermittent - it happens 100% of the time that I have more than one sonicpoint turned on. Here is the process to recreate the issue:

1) Disable all but one sonicpoint-N (call it Unit 'A')
2) Blackberry connects properly, and has data connectivity, can ping gateway, etc
3) Enable another sonicpoint in the network (Unit 'B', much further away from where I am doing this testing, but still within range)
4) Within about 60 seconds of the 2nd sonicpoint coming online, the blackberry looses data connectivity and cannot ping the gateway. It remains in this state indefinitely, until I disable all but one sonic point. It still shows that it associated with unit 'A', still has its IP address, and both the berry and the sonicpoint station status for unit 'A' shows my blackberry with strong signal strength.

It does not matter which sonicpoint I use to connect as the first unit, second unit etc (as long as it is in range of course), so the problem isn't specific to a particular sonicpoint.

I have tried changing the sonicpoint radio band to standard - 20Mhz, and have disabled Aggregation in trying to troubleshoot this, but neither seems to help.

I did some packet traces (the Sonicwall devices have a built-in packet trace utility) to see what was going on. With only one sonicpoint turned on, I can do a ping from the BB to and in the packet trace I see the outgoing requests from the BB, and the return ICMP responces from that address (which are successfully received on the BB).

Once I enable more sonicpoints and the blackberry goes into the state of no-connectivity, I do the same ping. I can see in the packet trace, the outgoing requests, AND I can see the same responces being sent back to the BB. In fact, the packet traces from when it was working, and NOT working looked identical. So the problem has to be that that BB is not receiving/accepting the return packets from the AP for some reason.

Again, this problem ONLY exists with blackberries (all other wifi devices work fine).

Do blackberries not support wireless roaming between APs? I put in a support ticket with SonicWall, but they had no idea what the problem was.

Any suggestions would be greatly appreciated.


pepal 09-10-2010 08:17 AM

Glad to see your post. Same setup and issue here.

We just installed 1 SonicWall NSA240 with 3 SonciPoint-N. WP2-PSk. Single SSID across all three. Using BB Bold 9000, connection drops. Laptop works fine. Haven't gotten to try running only 1 SonicPoint however I assume same result as you.

What gives?!?


timlang 09-10-2010 11:14 AM

I have changed the beacon interval on all the sonicpoints to 50 (instead of the default 100), and now my blackberries are being much better behaved. The problem still occurs occassionally, but it is a huge improvement from before.

pepal 09-26-2010 09:23 AM

Thanks. I'll give it a try.

Gayberry 12-13-2010 04:47 AM

Re: No BB Wifi Connectivity with multiple APs (roaming)
timlang, thanks! I had the same problem on my dlink DSL-2640U router. Have my neighbour connecting to my AP as well with his router. So on your site survey it picks up both. Would have connectivity for a day or two even, but then it shows connected to the AP, as well as even an IP, but there would be no traffic, drove me out the walls.

Changed the fragmentation threshold and RTS to 2346 and 2347 (defaults) as I lowered them before and it worked. Then after a day or two my BB started doing the same thing again and I gave up.

Now I lowered the beacon interval and voila it connects again, will check for how long again. What do you guys reckon is the best setting for WiFi for BB's?

I'll put mine in here, have a look and if you have any suggestions, please reply. WPA2-PSK encryption.

Channel: (The channel with the least AP's on it?)
Auto Channel Timer(min): 99999
54gxxx8482; Rate: Auto
Multicast Rate: Auto
Basic Rate: All (1, 2, 5.5,6,11 and 12 mbps and up)
Fragmentation Threshold: 2346
RTS Threshold: 2347
DTIM Interval: 1
Beacon Interval: 50
XPressxxx8482; Technology: Enabled
54gxxx8482; Mode: 54g Auto
54gxxx8482; Protection: Auto
Preamble Type: Long
Transmit Power: 100%

2metres away from the router and my signal strength is -61dBm. 802.11b/g

Gayberry 12-14-2010 08:24 AM

Re: No BB Wifi Connectivity with multiple APs (roaming)
Not working again...anyone any ideas? Please. BB9300 3G.

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