P2P Network Architectures - Peer-to-Peer Computing: Applications, Architecture, Protocols, and Challenges - page 33

finger table data:
(1) start: 1; interval: [1,2); succ: 1
(2) start: 2; interval: [2,4); succ: 3
(3) start: 4; interval: [4,0); succ: 0
keys stored: 6

finger table data:
(1) start: 2; interval: [2,3); succ: 3
(2) start: 3 interval: [3,5); succ: 3
(3) start: 5 interval: [5,1); succ: 0
keys stored: 1

0

7

1

6 2

finger table data:
(1) start: 4; interval: [4,5); succ: 0
(2) start: 5; interval: [5,7); succ: 0
(3) start: 7; interval: [7,3); succ: 0
keys stored: 2

3

5

4

FIGURE 3.2: Finger tables of the three nodes in the Chord ring [Stoica
et al., 2001a].

1. Construct the finger table of node n.

2. Update the finger tables of existing nodes to incorporate the existence
of n.

3. Notify the higher layer software (e.g., the file sharing application) in
order to properly transfer the data items with the associated identifiers
which are to be handled by node n.

The reverse of the above tasks need to be done when a node leaves the network.
Figures 3.3 and 3.4 illustrate the situations when node 6 joins and then
node 3 leaves.

finger table data:
(1) start: 1; interval: [1,2); succ: 1
(2) start: 2; interval: [2,4); succ: 3
(3) start: 4; interval: [4,0); succ: 6
keys stored: --

finger table data:
(1) start: 2; interval: [2,3); succ: 3
(2) start: 3 interval: [3,5); succ: 3
(3) start: 5 interval: [5,1); succ: 6
keys stored: 1

0

7

1

2

6

finger table data:
(1) start: 7; interval: [7,0); succ: 0
(2) start: 0; interval: [0,2); succ: 0
(3) start: 2; interval: [2,6); succ: 3
keys stored: 6

finger table data:
(1) start: 4; interval: [4,5); succ: 6
(2) start: 5; interval: [5,7); succ: 6
(3) start: 7; interval: [7,3); succ: 0
keys stored: 2

3

5

4

FIGURE 3.3: Updated finger tables of the four nodes in the Chord ring after
node 6 joins [Stoica et al., 2001a].