I'm new to GRE tunnels and I've some quick questions
1)tunnel at one side stays up, unless the source interface defined under tunnel goes down?
2)if marking(L3) is done at the edge there's no need for qos preclassify
3)in a IPsec over GRE hub and spoke topology: gre multipoint needs only to be configured on the hub? I've seen that for DMVPN needs to be configured on the spokes but I suppose this is because they can dynamically setup tunnels with other spokes?
4) when is cryptomap profile used and when crypto-map?