Currently, there is not any NAT in place, SMS has public IP and GW Cluster has two external eths with two public IPs from both ISP. ISP loadbalance is configured on CP Cluster. Cluster has main IP from ISP A, so policy install and SIC communication is realized to ISP A public IPs. The question is what happens if ISP A fail? How to install policy via ISP B public IP?
My assumption which might work when ISP - A fail:
Doing some temporal manual dNAT (x.x.x.x - ISP A to y.y.y.y - ISP B) for connection from SMS to GW
or Change IP of cluster to public IP from ISP B in SmartConsole and try install policy?