Strange behavior of two paired C25

[Ilya_Semenov]

Hello, everybody!
I have a very strange problem with Extreme Wireless deployment.

There are two C25 paired controllers (9.21) and 65APs (3705 and 3710), spread equally between two buildings: A and B. (Please, take a look at the attached scheme).

There is one open SSID everywhere on all APs and no any authentication or portals. All the clients get their IPs through DHCP server, configured on X670 core switch at Build A. Address space is /22 network.

When I use wifi inside a certain building (A or 😎 its ok - I can move between the floors, watch youtube, browse websites and there are no any interruptions.

Strange things happen when I walk from one building to another. For example, I start to watch a long (~ 1hr) youtube clip in Building B on my laptop at 4th floor. I see that browser starts to cache the content of the clip. Then, I get to floor 2 of Building B and go to Building A through a long glass corridor and there no wifi networks at all. At this short moment I can see that caching process is stopped. So, in about two minutes I get to Building A. I sit down and keep watching the youtube clip. In about a minute browser continue to cache the clip. I check accessibility of other web-sites (including not being visited before) and they are OK. I sure, that at this moment I have connected to APs of Building A. BUT THEN HAPPENS THIS:

About in 5-10 minutes after getting to Building A clip caching stops and all the sites become inaccessible. Windows says: «Limited connection». I try to reconnect to my SSID and get the same result. Turning off/on wifi adapter doesn’t help. I try to restart the notebook – no results. I repeat the operation from B to A with my Nokia Lumia 930 – same things. A guy with Lenovo / Debian repeated it after me. I’ve waited more the 30 minutes and the wifi networks it still inaccessible. I found out, that I didn’t get an IP address and the only way to connect to wifi is to CHANGE MAC-address!!! Simultaneously, for all new clients dhcp and wifi work fine at Building A.

So, my question is: how to made roaming work as it should? Could I use wifi walking from one building to another without interruptions with my deployment?

Gentlemen, please, help! I could provide all the information required/you’ll request.



Many thanks in advance,

Ilya

[Doug]

Yes, I would turn mobility off. You don't need it on if the clients are in the same subnet on both pairs. Time being off will cause the "stuck" issue if you roam the controller pairs. That's why it was the first questions I asked 

1. Have you checked time on the controller pairs, they need to match?

[Ilya_Semenov]

Doug, should I turn the mobility off?

You mean that correcting the time on both controller will solve the issue?

Thanks,

Ilya

[Doug]

You don't need mobility enabled if the same subnets are on both sides of the pair. The time being off should have fixed the original issue.

[Ilya_Semenov]

Hello, Ronald, hello,Doug!

Reporting:

1) I've checked the controllers configuration. There were great difference in time - about 5 hours - I've fixed it.
2) AP availaibility is OK - all the APs are green on both controllers.
3) The mobility were turned off. Now I turned if on on both controllers, one as manager and the second as client.
4) For a while, there are no mobility tunnels up.

Have I configured mobility in a right way?

Please, take a look at screenshots provided.

Many thanks in advance,

Ilya

[Ronald_Dvorak]

What is the topology that you use i.e. routed, bridge@AP, bridge@EWC

Is mobility enabled, GUI > Controller > Services > Mobility Manager
If yes is the Mobility Tunnel up - check on the dashboard (main GUI page) in the lower left corner - green&up or red&down.