Flexconnect client scaling ?

[Thomas Obbekaer Thomsen]

Im have always wondered about Flexconnect scaling.

Not the number of APs in a "group", but the number of clients.

From a "old" Cisco Live session I got these numbers:

"Starting 17.8, the limit is extended to 300 APs and 3000 clients"

But it has always bothered me putting many clients into the same local VLAN.

I mean, historically there has been methods, in local mode, to scale client-count high within the same VLAN.

But what about flexconnect ?

Is a /24 (that we really like for wired lans) ok ?

Or can we go higher ? /23 /22 /21?

All those broadcasts and local multicast packets, needing to go out the wireless interface, at the lowest or highest mandatory datarate, it has some impact Im sure.

So, what's the Cisco recommended max size for a single vlan for clients in Flexconnect ? I just can't seem to find that information in any design document.

What's your "go to" ? or are there any "tricks" to configuration to mitigate those problems ?

Thanks

Thomas

[Flavio Miranda]

@Thomas Obbekaer Thomsen 

 Related to the number of clients , if you are worring about the air interface, I dont see any difference from local mode and flexconnect. 

Is not because you are using a /22 vlan that the AP will get 1024 clients. The number of Clients per AP will be managed by the WLC depending on the number of AP available. 

And the number of multicast/broadcast will be related to number of clients connected on the Access point.  On the backbone, it does not matter. It would be the same as if you had clients connected to the cable. 

I agree with you that broadcast domain size need to be manage accordingly but it will not change because you are using flexconnect or not. 

[Thomas Obbekaer Thomsen]

Usually, when you run local-mode , there are methods within the WLC that can limit broadcast and multicast traffic, but are there similar methods on Flexconnect ? I dont think so.

This is what , "worries" me (perhaps worry is a to harsh word), because a lot of clients will do a lot of broadcast and multicast traffic, even when just "idle", and all the traffic will be forwarded to every AP in a Flex solution, and also needs to be forwarded on the radio , and those packets needs to be transmitted on the lowest datarate (unless you of course use multicast to unicast).

Im just wondering if there are any "best practices", from a configuration perspective, Flexconnect versus Local-mode for high client scale.

[Haydn Andrews]

Your right that flexconnect in 17.9 can support 300 APs per flex group.

As stated already, the number of clients will more affect the airspace. Generally flexconnect is for branch office setup which is why previous versions had max of 100 APs.

[Thomas Obbekaer Thomsen]

I remember "flexconnect" from the REAP / H-REAP days.

So I always tell customers its a solution that should be used for (small) remote offices.

But ever since the 9800-CL was introduced, it seems that more and more customers are running large scale networks in Flexconnect mode.

I was just wondering about best practices about Flexconnect.

[marce1000]

  - Read from : https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-8/FlexConnect_DG.html#pgfId-43339

 M.