BitTorrent Choking Algorithm - Game Theory Perspective

Choking Algorithm

The choking algorithm determines which peers to upload to based on their recent download rates. Key aspects include:

• Unchoking Limit: Peers unchoke 4 other peers at a time (by default).
• Download Rate Measurement: Download rates are measured using a 20-second average.
• Peer Selection: Peers are selected for unchoking based on their upload contributions.

Game Theory Analysis

The repository includes a game-theoretic analysis of peer strategies. The utility function for a peer is defined as:

$u_i(\mu_i) = d_i(\mu_i, \mu_{-i}) - c(\mu_i)$

Where:

• $d_i $: Download rate
• $\mu_i $: Upload bandwidth of peer ( i $
• $c(\mu_i)$: Cost function for uploading

Simulation

This repository includes simulation code to demonstrate the behavior of the choking algorithm under various scenarios:

• Heterogeneous Peer Bandwidths
• Homogeneous Peer Groups

Conclusion

The BitTorrent choking algorithm effectively balances:

• Fairness: Incentivizes users to contribute bandwidth.
• Speed: Optimizes connection efficiency.

This approach ensures a robust and efficient peer-to-peer file-sharing network.