Architecture Design question regarding GTM's
Alright, so here's the deal: Customer is going to VPN data to us, we have apps that are going to work some magic on the insidand then spit what the customer wants back out to them. We're going for georedundancy, so we have GTM's sitting in boxes at 2 datacenters. We're going to utilize LTM's on the inside for the apps, which have 2 components - the servers that run the app itself, and the servers that host the databases this app will be querying in order to work its magic. The GTM's are greek to me, the LTM's only slightly less so. Just need to know if I'm on the right path from a design perspective.
So, the design path I've got in my head here is Customer site (VPN initiation) > cloud > our edge router > our firewall > which then branches off to the GTM that syncs up with our other datacenter > & firewall further branches to our core switch > which contains our active/standby LTM's, which will be handling load balancing the incoming data to our app servers in one pool and also load balancing the queries from the app servers to our database servers in another pool, all of which are also physically connected to the core switch. And then of course, the same setup at our other datacenter, which will sync data so as to provide the necessary redundancy.
Do I have the right vision in my head, or am I misunderstanding where the placement of the GTM needs to be and whether or with regards to the usage of the LTM's? It just "feels" like I'm missing a component here.