🌿 Alternef Digital Garden

Distributed Hash Tables

2 min read

Edit on GitHub

Overview

Distributed Hash Tables (DHTs) are a fundamental technology in decentralized and peer-to-peer (P2P) networks, providing a scalable and robust mechanism for distributed data storage and retrieval.

Core Concepts

What is a Distributed Hash Table?

A Distributed Hash Table is a decentralized system that provides a lookup service similar to a hash table. Key characteristics include:

  • Decentralized storage across multiple nodes
  • No central coordination point
  • Ability to store and retrieve key-value pairs
  • Resilience to node failures
  • Scalable architecture

Key Design Principles

  1. Decentralization

    • No single point of failure
    • Nodes are equal participants
    • Self-organizing network topology

  2. Routing Efficiency

    • Logarithmic lookup complexity (O(log N))
    • Efficient key-based routing
    • Minimal network traversal

  3. Fault Tolerance

    • Redundant data storage
    • Automatic node replacement
    • Continuous network operation

Architectural Components

Node Identification

  • Unique node identifiers
  • Consistent hashing for node placement
  • Circular address space

Routing Mechanisms

  • Distributed routing tables
  • Proximity routing
  • Iterative/recursive lookup strategies

  1. Kademlia

    • Used in BitTorrent
    • XOR metric for distance calculation
    • Efficient recursive routing

  2. Chord

    • Consistent hashing ring
    • Finger table for efficient routing
    • O(log N) lookup complexity

  3. CAN (Content Addressable Network)

    • Cartesian coordinate space
    • Dimensional routing
    • Uniform key distribution

Use Cases

  • Peer-to-peer file sharing
  • Blockchain and cryptocurrency networks
  • Decentralized name services
  • Distributed caching systems
  • Peer discovery in decentralized networks

Challenges and Limitations

  • Sybil attacks
  • Churn (frequent node joins/leaves)
  • Performance overhead
  • Complex implementation

Performance Considerations

  • Lookup latency
  • Storage overhead
  • Network bandwidth consumption
  • Computational complexity of routing

Future Directions

  • Integration with blockchain technologies
  • Enhanced security mechanisms
  • More efficient routing algorithms
  • Better handling of network dynamics

References

  • Stoica, I., et al. (2001). Chord: A Scalable Peer-to-peer Lookup Protocol for Internet Applications
  • Ratnasamy, S., et al. (2001). A Scalable Content-Addressable Network

Backlinks

Graph View