Papillon: Greedy Routing in Rings
  We study {\sc greedy} routing over $n$ nodes placed in a ring, with the \emph{distance} between two nodes defined to be the clockwise or the absolute distance between them along the ring. Such graphs arise in the context of modeling social networks and in routing networks for peer-to-peer systems. We construct the first network over $n$ nodes in which {\sc greedy} routing takes $O(\log n / \log d)$ hops in the worst-case, with $d$ out-going links per node. Our result has the first asymptotically optimal greedy routing complexity. Previous constructions required $O(\frac{\log^2 n}{d})$ hops. 
Ittai Abraham and Dahlia Malkhi and Gurmeet Singh Manku