Roaming with versus without the same Mobility Groups

[Mitrixsen]

Hello, everyone

I am studying Roaming for my ENCOR exam.

My question is, how exactly does roaming differ if we have an inter-controller roaming scenario where the WLCs are in the same mobility group versus a scenario where they are in different ones? Roaming will still happen, won't it? So how does having them in the same mobility group make it more efficient?

Thank you.
David

[M02@rt37]

David,

with WLC in same mobility group roaming is faster and usually transparent to the user. Session state are preserved and security associations too.

[eglinsky2012]

Without a mobility group, there is no fast roaming, it turns into a full disassociate from the source AP then associate to the destination AP. At least, it does with 802.1x. Not sure about PSK or open networks, but I believe it's the same thing, just less noticeable due to less steps to authenticate.

Just the other day, I received the following complaint from a user: "...Pretty much every time I use it my MacBook will get disconnected from [our 802.1x SSID] multiple times at seemingly random intervals." Turns out the AP in the room they were in was joined to a 9800 but the AP in the room next door was incorrectly joined to an 8540, with no mobility tunnel between the two WLCs. Moving the other AP off the 8540 to the 9800 resolved the issue. This is a reminder that even stationary devices are liable to roam between nearby APs.