APM Site Persistence

I have two data centers each running APM with GTM/DNS. GTM has a single WideIP vpn.company.com which is made up of a single pool with two members – one in DC-1 and the other in DC-2. Depending on the load balancing method I use, the response returned for vpn.company.com will be the IP of the virtual in DC-1 or the virtual in DC-2. So far, so good.

When you launch the Edge Client, it will first query for vpn.company.com and GTM will return a single IP address which will be the virtual in one of the Data Centers. I obviously want the connection to stick with the same virtual until the user logs out at the end of the day. I am especially concerned about our iOS and Android clients (running the Edge Client) because they support network roaming and can go from WiFi to Cellular and back to WiFi again.

Does the Edge Client remember the actual IP that it first connected to, or will it periodically execute a new DNS request for vpn.company.com depending on the TTL? If it does another DNS lookup I need to ensure it returns the same IP address it got the first time. Can someone shed some light on how this piece works? Also, if it does do periodic DNS queries, how do I ensure this client always gets the same IP?

Thanks.

APM/GTM 11.5.1