Assume its single node installation and Gateway abruptly shut down. What will happen to the requests which are in progress? How can Gateway recover them when it is back?
I don't think there is any way to recover those on the gateway.
Unless you use a technology like message queuing to push and pull messages then the messages traversing through the gateway would be lost. Client applications could also be built with retry functionality if no response is received during any failure that occurs.
Director, CA Support