Is there a limit to how many AE's you can conect ?

In a roaming setup, the network would have a total of about 255 available connections, so you would have to count the number of users and all of their devices that will be connecting and include each AirPort Extreme as a device as well.

In the real world, 15-20 AirPort Extremes would not be too difficult to manage, although you could have many more in theory.

How many were you thinking about for a network?

And....a note of caution regarding the Apple Support document that you are referencing in your post. Most of the "how to" info in the document refers to AirPort Utility 5.x versions that are now almost 4 years out of date, so the setup info bears no resemblance to the actual settings in newer 6.x AirPort Utility versions, which you would be using with El Capitan (10.11.4) mentioned in your profile.

Bob,

I see your name on so many of these posts, and I want to thank you!

I don't know if you're getting paid by Apple, but you SHOULD be!

It's just **** ridiculous that we should be trying to look at 4-year old support documents for the latest versions of OSX and ATC and AE.

GIven this his lack of updated documentation, the impending release of a new mac OS, and the fact that the latest version of ATC is about two years old (USB 2, not 3!), I'm thinking of returning my ATC 3G!

Thanks for the nice words.

We are all users here, just like you, who volunteer our services to try to help other users.

If you want to let Apple know about how you feel, you can use the link below.

Apple - Time Capsule - Feedback