Symmetrical Bidirectional Base-k Chord and its Interesting Character

The Chord is a famous peer-to-peer application. There are many variants which change the structure and the routing algorithm of the Chord, and all these variants achieve the higher routing efficiency than those of the original ones. To improve the routing efficiency of base-k Chord, this paper proposes a new finger table for base-k Chord by using symmetrical bidirectional structure, which just like the 2-Chord´s, the difference between them is the hop sequence´s base from 2 to k. Concretely, keeping the odd items in the finger table unchanged, while re-directing the odd items to back direction, does not change the size of the finger table. A new routing algorithm is developed, which always chooses the nearest finger to the destination node. Interesting experimental results show that 1) symmetrical bidirectional base-k Chord has better routing efficiency than its counterparts when the k is even; 2)and the routing efficiency of symmetrical bidirectional base-k Chord is equal(worse more often) to its counterparts almost when the k is odd. We analyze the causation between the structure of symmetrical bidirectional base-k Chord and the routing efficiency.