R/Kademlia: No hop-by-hop acknowledgement with backtracking retries
The R/Kademlia paper by Heep et al. proposes that during the recursive lookup, each hop acknowledges the request receival to its immediate predecessor on the path. Missing acknowledgements are supposed to cause the lookup to backtrack and be retried over the next best candidate hop. As of 2359b9c8 this is not implemented. There is no immediate hop-by-hop confirmation, only the lookup reply that arrives if all succeeding lookup hops do not fail. Retries are implemented and happen both for lookup initiators as well as intermediate nodes on the recursive path (although with different timeouts), but as long as #1 is not implemented the same path is retried again and again.