Generalized Distance Metric for Different DHT Routing Algorithms in Peer-to-Peer Networks

We present a generalized distance metric that can be used to identify routing table entries and implement routing strategies to reach the root node for a given key, in DHT (Distributed Hash Table) networks such as Chord, Kademlia, Tapestry, and Pastry. The generalization shows that all the four DHT algorithms are in fact, the same algorithm but with different parameters in distance representation. This paper also proposes that nodes can have routing tables of varying sizes based on their memory capabilities. But Each node must have at least two entries, one for the node closest from it, and the other for the node from whom it is closest, regardless of memory capacity. With this condition, messages will still reach the correct root nodes. We also further observe that in any network, if the distance metric of the DHT is same at all the nodes, then the root node for a key will also be the same, irrespective of the size of the routing table at different nodes.