Hi, The RELOAD draft specifies in chapter 12 a modified version of the Chord algorithm. It seems to me that this modified Chord algorithm uses reactive recovery from node failures instead of periodic recovery, which is used by the original Chord algorithm as specified in [1]. In reactive recovery, a node reacts to the loss of a node in its neighborhood set by sending a copy of it neighbor table to all nodes in the neighborhood set. Periodic recovery, in contrast, takes place independently of changes in the neighborhood set. In periodic recovery, a node periodically shares its neighborhood set with each of the members of that set.
It has been shown in [2] that reactive recovery is only efficient at low churn rates. With moderate and high churn rates, periodic recovery uses less bandwidth and the resulting lower contention of the network leads to lower latencies. My concern is that because it uses reactive recovery, the performance of RELOAD's Chord algorithm may degrade under moderate and high churn rates. As an example, the first version of the Bamboo DHT algorithm used reactive recovery. As a consequence, Bamboo suffered a performance degradation under churn. To solve this issue, Bamboo was modified to use periodic recovery from node failures. Any comments? [1] I. Stoica, R. Morris, D. Karger, M. F. Kaashoek, and H. Balakrishnan. Chord: A scalable peer-to-peer lookup service for Internet applications. Technical Report TR-819, MIT, March 2001 [2] S. Rhea, D. Geels, T. Roscoe, and J. Kubiatowicz. Handling churn in a DHT. In Proc. of USENIX Technical Conference, June 2004 Regards, Jouni _______________________________________________ P2PSIP mailing list [email protected] https://www.ietf.org/mailman/listinfo/p2psip
