Chord Protocol Published
MIT researchers publish Chord, introducing Distributed Hash Tables (DHTs) to solve the peer discovery problem efficiently.
In late August 2001, at the SIGCOMM conference in San Diego, researchers from MIT (Ion Stoica, Robert Morris, David Karger, M. Frans Kaashoek, and Hari Balakrishnan) presented Chord, a protocol that introduced the concept of a Distributed Hash Table (DHT). Before Chord, P2P networks largely relied on either a central server (Napster) or inefficient flooding (Gnutella). Chord solved this by arranging nodes in a mathematical ring and assigning data to nodes based on cryptographic hashes (consistent hashing).
Chord allowed a network to grow to millions of nodes while maintaining efficient lookup speeds (O(log N)). This meant that finding a file (or a transaction, or a peer) didn't get slower as the network got bigger. Although Bitcoin uses a gossip protocol for transaction propagation, the concept of using cryptographic hashes to map network topology is fundamental to modern decentralized systems.
DHTs became the standard for all future P2P networks, enabling "trackerless" torrents and resilient data storage. Chord's invention of the Distributed Hash Table provided the mathematical proof that fully decentralized networks could scale efficiently, removing the technical need for central servers in large-scale distributed systems.
Key Sources:
• Original Chord Paper (MIT)
• Wikipedia: Chord Protocol
• SIGCOMM 2001 Proceedings