The total maximum connections per interface = InterfacePortRange(35000) X NumberOfRemoteHosts.
As long as the number of remote hosts is not limited, then the total number of sessions is not limited unless it is based on RAM limit.
We look at all five parts (the quintuple) of a packet (source IP, source port, destination IP, destination port & protocol) to determine what session it belongs to.
A customer would only run into an issue if they had 35,000 concurrent sessions going to the same IP address and port from the same WAN interface using the same protocol.
For example, if they had more than 35,000 HTTP (TCP/80) sessions to a single IP address on WAN1, they would run into our PAT limit.