PIM sparse solution:
In R2 conf you have:
ip mroute 192.168.1.0 255.255.255.0 192.168.12.1
ip mroute 1.1.1.1 255.255.255.255 192.168.12.1
ip route 0.0.0.0 0.0.0.0 192.168.23.3
If you wouldn’t have “ip mroute 192.168.1.0 255.255.255.0 192.168.12.1” your unicast would go by the traditional path instead of the tunnel. Isn’t it? And in that way it wouldn’t work, am I right?
Then in R1 you don’t have any ip mroute. Should we also route the unicast traffic by the tunnel?
If we have a bidir multicast implementation with a GRE tunnel, would it work? But in that case my question about mroute in R1 would make sence, isn’t it?