Have many spokes that will connect to a hub site,and won't fit in a router if using one GRE tunnel for each remote. Won't have IPsec. Plan to use DMVPN to allow only one router to handle all the tunnels. Is it possible to use Dynamic Multipoint VPN using only multipoint GRE, without IPsec? In the documents I saw at Cisco's web site, they always tell about GRE and IPsec.
I have this problem too.