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WLAN subnets - how to size them, when to sepatate them?

Here's some of the factors and concerns I have had about subnet sizing and WLAN separation guidelines. I'm interested in what others are doing to address this.

1. Right-sizing of subnets: what are folks doing with their wireless subnets in dense deployments? How are you providing scalability to support highly-dense device populations (tags, phones, medical devices)?

Are you using the default WLAN interface and assigning between a /24-/22, or using AP Group WLAN sub-interface mappings?

How are you sizing your AP Groups? Dense vs. Sparse client base, Campus vs. WAN sites, or a set # of APs per group?

2. How are you differentiating your WLANs? By traffic categories (data/voice/video)? Authenticaion methods? Device types (tags, phones, laptops)? Or specific application isolation and policy enforcement?

Thanks for your collective feedback towards a fruitful discussion.

--Bruce Johnson

Hall of Fame Super Silver

Re: WLAN subnets - how to size them, when to sepatate them?

Tough question... I have always sized a wireless vlan at a /24 unless the client wants it sized differently. AP groups are configured per builidng or per sections of the builing (floors) since other buildings will be on a seperate subnet. Rule of thumb is to not have more than 4 SSID's. I have had clients with more than 4 with no issues, but it is dependent on the wifi devices. Voice, Video should have seperate SSID's and the others will have to be combined or spereate depending on encryption (what type of encryption is supported).

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