bandwidth requirement between controllers in mobility group

[yubago]

We have a potential project spanning two sites a few miles apart. We are hoping of putting 1 controller at each site in a single mobility group to provide AP failover if one controller is to fail. We are planning on a total of 25-30 APs, roughly half at each site.

Questions:

Whats the minimum bandwidth required between sites?

If bandwidth isn't adequate can this be done with both controllers at one site and H-Reap access points for the other site? Am I correct in thinking that you can have no more than 8 H-Reap access points per WLAN (16 Reap APs per WLAN)?

Thanks!

[irisrios]

It's better to have one controller at each site. Minimum bandwidth requirement would be 128 kbps and not more than 100 ms delay in this WAN link.

[yubago]

Thanks! I think it will be fine. I was more worried about the event of a failed controller which would cause more traffic between the other APs and the backup controller at the other site. However with all the APs in H-Reap local switching mode it should work.