Does anyone knows how to run GRE Tunnel over IPSec. The scenario is bit different. Let me try to explain. PE1 and PE2 belongs to ProviderA which is basically public Internet. PE3 and PE4 belongs to ProviderB which runs IPVPN private network.
There is IPSec tunnel between CPE(1) to PE(1) and another IPSec tunnel between PE(1) to PE(3) which is not transparent to customer. Now customer wants to run GRE between CPE1 and CPE2. Does anyone know how it can be done?