I've just got four new C891 routers and have configured them for dual simultaneous GRE-over-IPSec tunnels each, and although the tunnels seem to be up, encrypting and routing data just fine, the VPN LED on the front panel of the unit stays off.
I am using two sub-interfaces on the Gigabit0 WAN port, since my two GRE tunnels from the C891 go to two completely different physical sites (each with a 3845 router), one for a voice VLAN and one for a data VLAN. I am not using the public Internet, but rather a private microwave WAN as my backhaul, and the need for subinterfaces was driven by the fact that there are two completely different numbered IP networks for interfaces which the 3845's each connect to the WWAN, and the C891 would not let me run an IPSec tunnel sourced from a "secondary" ip address.
I'm suspecting that the reason why the LED won't come on is because there's not crypto map on the interface itself, but on the subinterfaces instead, ,and a different crypto map on each subinterface. Is there something I can do to force the LED to light?