What is the optimum size for a WIFI subnet ?

[stuart.reid]

For LAN design fine,  keep the broadcast domain to an optimum size. What about WIFI design though ?  I want to use just 1 SSID and can have multiple vlans if I use AP groups on the controller..But how big is optimum size for a WIFI subnet ? I guess it depends on required speed, number of AP ,vlans and traffic profiles, but are there any recommendations ?

Stu

[George Stefanick · Accepted solution]

Hello,

Great question

First, if you are using a WLC, the WLC will proxy the broadcast for the clien so that it wont be sent over the wireless. With that being said, you will typically see larger subnets on the WLC solution. For exmaple, we have /21 here and they work fine for our voice, data and video SSIDs. Although, some people like smaller subnets and deploy ap groups accordoningly.

Although, I have seen subnets on WiFi voice as a /16 with 5,000 phones in the subnet which to my surprise worked well. Of course, I wouldnt have designed it that large.

If you are autonmous same holds truse, but if you configure the AP to send over the broadcast to the wifi clients you should consider a smaller subnet like a /23 or /24.

As to client mix. Most folks will have a Voice SSID, Data SSID, Guest SSID so you can shape these accordiingly. Again, typically all my designs lead with a /21 or /22.

[stuart.reid]

Thanks George, its good to learn from other real life situations.  Stu,