Question

Explain how chord works. To increasing the fault tolerance in chord, each node maintains a successor list (finger table) instead of a single successor. Explain the lookup algorithm for finding an object in this structure.

Answer 1

A chord is a peer-to-peer lookup service. It Solves problem of locating a data item in
a collection of distributed nodes, considering frequent node arrivals and departures
Most important operation in most peer-to-peer systems is efficient location of data items.
It is capable of supporting just one operation i.e. given a key, it maps the key onto a node.

Algorithm showing working of chord:

// x is a node used to find successor of id
x.find_successor(id)
if (id (x; successor])
return successor;
else
// query is being forwarded around the circle
return successor.find_successor(id);