Chord (peer-to-peer)
In computing, Chord is a protocol and algorithm for a peer-to-peer distributed hash table. A distributed hash table stores key-value pairs by assigning keys to different computers (known as "nodes"); a node will store the values for all the keys for which it is responsible. Chord specifies how keys are assigned to nodes, and how a node can discover the value for a given key by first locating the node responsible for that key. Chord is one of the four original distributed hash table protocols, along with CAN, Tapestry, and Pastry. It was introduced in 2001 by Ion Stoica, Robert Morris, David Karger, Frans Kaashoek, and Hari Balakrishnan, and was developed at MIT. The 2001 Chord paper won an ACM SIGCOMM Test of Time award in 2011. Subsequent research by Pamela Zave has shown that the original Chord algorithm (as specified in the 2001 SIGCOMM paper, the 2001 Technical report, the 2002 PODC paper, and the 2003 TON paper ) can mis-order the ring, produce several rings, and break the ring. Overview Nodes and keys are assigned an -bit identifier using consistent hashing. The SHA-1 algorithm is the base hashing function for consistent hashing. Consistent hashing is integral to the