One of our customer is planning to have 300 nodes in upcoming years. They are evaluating different solutions but their strict requirement is to remain open for all vendors when it comes to branch routers. At core, they have decided to buy Cisco ASR1000 series router. Now i was thinking of DMVPN solution (as they require encryption in all the branches) but they said open. So it means separate gre tunnel for each branch, separate crypto map (or multiple entries inside) for each branch.
Is there any alternative for that ? (Cant use Getvpn coz other vendors dont support it)