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How to design topologies for SSID for 20.000 users?

Userlevel 4
Hello, everybody!

I am going to setup Wireless infrastructure for a big University. I will have Identifi with V2110 controller and 3825i APs. There are 12.000 students and about 8000 employees, who share same internal resouces. They have to use a single SSID.

How many topologies / (networks) should I create to support such amount of users?

I think that creating single /18 net for 8190 host is not a good idea because of broadcasts... Am I right?

I've heard that I can unite several VLANs under one SSID. Is this a solution for me? How will seamless roaming work in this case?

The 2nd question is how can I isolate users from each other but allow them to user internal resources?

Please, share your ideas!

Many thanks for your advices,


12 replies

Userlevel 7
I hope you are aware that the V2110 (large) could only support 4k users per controller.
Userlevel 4
Ron wrote:

I hope you are aware that the V2110 (large) could only support 4k users per controller.

Sure. I will have pair of V2110. The worse thing is it gives 4k only under VMware, which I really hate...( Do know how to get 4k under Hyper-V?
Userlevel 7
You'd use the topology group feature to add more VLANs to a group that is used for a WLAN service.


Block MU 2 MU traffic....
Userlevel 4
Thanks, Ronald!

Is there any recommened amount of host per VLAN for such topology as mine? In other words, how many VLANs should I create? I think about 8 VLANs for /22 net inside each.
Depends on your design. Are you B@AP or B@HWC?
Userlevel 7
Shouldn't a deployment that large be B@AP? B@HWC seems like it would be a huge bottleneck.
Userlevel 4
I am planning at the moment. Almost finished technical design specification. The most difficult things for me now is external authenticaion without NAC and Identifi users limit. Don't you know, whether Extreme is going to increase max. amount of users for Identifi solutions? 16k isn't enought for big universities...
Userlevel 4
I believe it would be B@AP....
Userlevel 5
There are multiple solutions:
- flat network
- topology groups
- solution with ExtremeControl (passive)
All three are currently used by our very dense customers (in terms of number of clients : 20K-50K) .
Can you please contact Kirill Zhukov , so he can forward your mail to me.
Thank you.
Drew, depends on what you are doing. From what I understand, all the NFL stadiums are B@WLC... But I could be wrong. The C5210 has a lot of HP.. not sure about the virtual series. Although, that may have been the case before L7 stuff started popping up on the 3825's...
Userlevel 6
Ilya, please contact local technical team. We do have experience, we do have team for such design. It will be much easier to discuss onsite.
Userlevel 4
Hello, Zdenek! Thanks! Whom could you name from "local technical team"? I've seen you some times in Moscow, so you should know all the members of this team...