Summary: RON

 A naive overlay network that hides the underlying link structure is only as reliable as its substrate, but overlays that are aware of the base network can actually add a transparent reliability layer: TCP/IP is itself an example.  Like all good ideas, the motivation for RON can be simply and convincingly stated -- and like many systems, the unexpected complexity of the implementation is something of a disappointment. 

The problem is that in implementing a system that can route packets and react more quickly to route outages than core internet routing, you basically need to implement core internet routing in your overlay.  In the process, it becomes clear that the reason BGP reacts slowly to outages is that it damps route topology changes to prevent oscillation: preferring stability to sensitivity was a deliberate design choice.  Detecting an outage is, after all, not straightforward in a distributed system.  

The authors mention early in the paper that another alternative would have been to use a generic overlay in combination with a modified protocol like OSPF.  I don't understand why they couldn't have augmented OSPF with their custom "loss minimizer" in order to prove the basic point that a routing overlay network could provide faster recovery for route loss on the WAN.