Lower router's WAN port is connected to upper router's LAN porter.
PC1 is connected to upper router's LAN port.
PC2 is connected to lower router's LAN port.
From PC1 ping PC2, the ping won't go through.
I can see RIPv2 messages sent from lower router broadcasting its WAN side IP
as the next hop. Why my upperside outer not using it to route the ping over
to PC2? Does router accept LAN side dynamic routing updates?