# Designing ISP-friendly Peer-to-Peer Networks Using Game-based Control

## TL;DR

This paper introduces MultiTrack, a game-based P2P overlay system that aligns ISP cost minimization with user quality of service, ensuring stability and fairness through analytical proofs and simulations.

## Contribution

It presents a novel multi-tracker overlay design that balances ISP costs and user quality, with proven stability and utility optimization.

## Key findings

- System is stable and converges to optimal utility.
- Effectively balances ISP costs and user quality of service.
- Validated through Matlab and ns-2 simulations.

## Abstract

The rapid growth of peer-to-peer (P2P) networks in the past few years has brought with it increases in transit cost to Internet Service Providers (ISPs), as peers exchange large amounts of traffic across ISP boundaries. This ISP oblivious behavior has resulted in misalignment of incentives between P2P networks--that seek to maximize user quality--and ISPs--that would seek to minimize costs. Can we design a P2P overlay that accounts for both ISP costs as well as quality of service, and attains a desired tradeoff between the two? We design a system, which we call MultiTrack, that consists of an overlay of multiple \emph{mTrackers} whose purpose is to align these goals. mTrackers split demand from users among different ISP domains while trying to minimize their individual costs (delay plus transit cost) in their ISP domain. We design the signals in this overlay of mTrackers in such a way that potentially competitive individual optimization goals are aligned across the mTrackers. The mTrackers are also capable of doing admission control in order to ensure that users who are from different ISP domains have a fair chance of being admitted into the system, while keeping costs in check. We prove analytically that our system is stable and achieves maximum utility with minimum cost. Our design decisions and control algorithms are validated by Matlab and ns-2 simulations.