Is it possible to Cluster 2 or more  RFS7000/RFS6000  even if they are on different subnets with firewalls in between?  Do we just need to open TCP/UDP port 51515  for clustering and other ports (wispe, etc)  for AAP with independent wlan to work? Are there anything else that needs to get configured in the network for clustering to work? Any best practices? Your help would be greatly appreciated.